The X-ray luminous cluster underlying the bright radio-quiet quasar H1821+643 (2009)
Russell, H. R., Fabian, A. C., Sanders, J. S., Johnstone, R. M., Blundell, K. M., Brandt, W. N., ...
We present a Chandra observation of the only low redshift, z=0.299, galaxy cluster to contain a highly luminous radio-quiet quasar, H1821+643. By simulating the quasar PSF, we subtract the quasar...
Evidence for relativistic disc reflection in the extreme NLS1 IRAS13224-3809 (2009)
Ponti, G., Gallo, L. C., Fabian, A. C., Miniutti, G., Zoghbi, A., Uttley, P., ...
We present a spectral variability study of the XMM-Newton and Suzaku observations of one of the most extreme Narrow Line Seyfert 1 galaxies, IRAS13224-3809. The X-ray spectrum is characterized by two...
Plotkin, Richard M., Anderson, S. F., Brandt, W. N., Diamond-Stanic, A. M., Fan, X., Hall, P. B., ...
We present a sample of 723 optically selected BL Lac candidates from the SDSS DR7 spectroscopic database encompassing 8250 deg^2 of sky; our sample constitutes one of the largest uniform BL Lac...
The LABOCA Survey of the Extended Chandra Deep Field South (2009)
Weiss, A., Kovacs, A., Coppin, K., Greve, T. R., Walter, F., Smail, Ian, ...
We present a sensitive 870 micron survey of the Extended Chandra Deep Field South (ECDFS) using LABOCA on the APEX telescope. The LABOCA ECDFS Submillimetre Survey (LESS) covers the full 30' x 30'...
BLAST: the far-infrared/radio correlation in distant galaxies (2009)
Ivison, R. J., Alexander, David M., Biggs, Andy D., Brandt, W. N., Chapin, Edward L., Coppin, Kristen E. K., ...
We investigate the correlation between far-infrared (FIR) and radio luminosities in distant galaxies, a lynchpin of modern astronomy. We use data from the Balloon-borne Large Aperture Submillimetre...
Chartas, G., Saez, C., Brandt, W. N., Giustini, M., Garmire, G. P.
We present results from multi-epoch spectral analysis of XMM-Newton and Chandra observations of the broad absorption line (BAL) quasar APM 08279+5255. Our analysis shows significant X-ray BALs in all...
Lehmer, B. D., Alexander, D. M., Chapman, S. C., Smail, Ian, Bauer, F. E., Brandt, W. N., ...
We present X-ray point-source catalogs for a deep 400 ks Chandra ACIS-I exposure of the SSA22 field. The observations are centred on a z = 3.09 protocluster, which is populated by Lyman break...
Probing the Origins of the CIV and Fe Kalpha Baldwin Effect (2009)
Wu, Jian, Berk, Daniel E. Vanden, Brandt, W. N., Schneider, Donald, Gibson, Robert, Wu, Jianfeng
We use UV/optical and X-ray observations of 272 radio-quiet Type 1 AGNs and quasars to investigate the CIV Baldwin Effect (BEff). The UV/optical spectra are drawn from the Hubble Space Telescope,...
A Chandra Survey of the X-ray Properties of Broad Absorption Line Radio-Loud Quasars (2009)
Miller, B. P., Brandt, W. N., Gibson, R. R., Garmire, G. P., Shemmer, O.
This work presents the results of a Chandra study of 21 broad absorption line (BAL) radio-loud quasars (RLQs). We conducted a Chandra snapshot survey of 12 bright BAL RLQs selected from SDSS/FIRST...
Fabian, A. C., Zoghbi, A., Ross, R. R., Uttley, P., Gallo, L. C., Brandt, W. N., ...
Since the discovery of the first broad iron-K line in 1995 from the Seyfert Galaxy MCG--6-30-15, broad iron-K lines have been found in several other Seyfert galaxies, from accreting stellar mass...
Coppin, K. E. K., Smail, Ian, Alexander, D. M., Weiss, A., Walter, F., Swinbank, A. M., ...
We report on the identification of the highest redshift submillimetre-selected source currently known LESS J033229.4−275619. This source was detected in the Large Apex Bolometer Camera (LABOCA)...
PHL 1092 as a transient extreme X-ray weak quasar (2009)
Miniutti, G., Fabian, A. C., Brandt, W. N., Gallo, L. C., Boller, Th.
We report a dramatic variability event in the X-ray history of the Narrow-Line quasar PHL 1092 (z=0.396). Our latest 2008 XMM-Newton observation reveals a flux drop of ~200 with respect to the...
Discovery of the Most Distant Double-Peaked Emitter at z = 1.369 (2009)
Luo, B., Brandt, W. N., Silverman, J. D., Strateva, I. V., Bauer, F. E., Capak, P., ...
We report the discovery of the most distant double-peaked emitter, CXOECDFS J033115.0-275518, at z = 1.369. A Keck/DEIMOS spectrum shows a clearly double-peaked broad Mg II λ2799 emission line, with...
Modeling mm- to X-ray flare emission from SgrA* (2009)
Eckart, A., Baganoff, F. K., Morris, M. R., Kunneriath, D., Zamaninasab, M., Witzel, G., ...
We report on new modeling results based on the mm- to X-ray emission of the SgrA* counterpart associated with the massive black hole at the Galactic Center. Our modeling is based on simultaneous...
High-Redshift SDSS Quasars with Weak Emission Lines (2009)
Diamond-Stanic, Aleksandar M., Fan, Xiaohui, Brandt, W. N., Shemmer, Ohad, Strauss, Michael A., Anderson, Scott F., ...
We identify a sample of 74 high-redshift quasars (z>3) with weak emission lines from the Fifth Data Release of the Sloan Digital Sky Survey and present infrared, optical, and radio observations of a...
Eight-dimensional mid-infrared/optical Bayesian quasar selection (2009)
Richards, Gordon T., Deo, Rajesh P., Lacy, Mark, Myers, Adam D., Nichol, Robert C., Zakamska, Nadia L., ...
We explore the multidimensional, multiwavelength selection of quasars from mid-infrared (MIR) plus optical data, specifically from Spitzer-Infrared Array Camera (IRAC) and the Sloan Digital Sky...
Greve, T. R., Weiss, A., Walter, F., Smail, I., Zheng, X. Z., Knudsen, K. K., ...
Using the 330hr ESO-MPG 870-micron survey of the Extended Chandra Deep Field South (ECDF-S) obtained with the Large Apex BOlometer CAmera (LABOCA) on the Atacama Pathfinder EXperiment (APEX), we have...
The 22-Month Swift-BAT All-Sky Hard X-ray Survey (2009)
Tueller, J., Baumgartner, W. H., Markwardt, C. B., Skinner, G. K., Mushotzky, R. F., Ajello, M., ...
We present the catalog of sources detected in the first 22 months of data from the hard X-ray survey (14--195 keV) conducted with the BAT coded mask imager on the \swift satellite. The catalog...
Suzaku Observations of Near-Relativistic Outflows in the BAL Quasar APM 08279+5255 (2009)
Saez, C., Chartas, G., Brandt, W. N.
We present results from three Suzaku observations of the z=3.91 gravitationally lensed broad absorption line quasar APM 08279+5255. We detect strong and broad absorption at rest-frame energies of...
The Growth of Supermassive Black Holes Across Cosmic Time (2009)
Nandra, K., Aird, J. A., Alexander, D. M., Ballantyne, D. R., Barcons, X., Bauer, F. E., ...
One of the main themes in extragalactic astronomy for the next decade will be the evolution of galaxies over cosmic time. Many future observatories, including JWST, ALMA, GMT, TMT and E-ELT will...
Muno, M. P., Bauer, F. E., Baganoff, F. K., Bandyopadhyay, R. M., Bower, G. C., Brandt, W. N., ...
We present a catalog of 9017 X-ray sources identified in Chandra observations of a 2°× 0°.8 field around the Galactic center. This enlarges the number of known X-ray sources in the region by a...
Fundamental Accretion and Ejection Astrophysics (2009)
Miller, J. M., Nowak, M., Nandra, K., Brandt, W. N., Matt, G., Cappi, M., ...
Disk accretion may be the fundamental astrophysical process. Stars and planets form through the accretion of gas in a disk. Black holes and galaxies co-evolve through efficient disk accretion onto...
Tozzi, P., Mainieri, V., Rosati, P., Padovani, P., Kellermann, K. I., Fomalont, E., ...
We discuss the X-ray properties of the radio sources detected in a deep 1.4 and 5 GHz VLA Radio survey of the Extended Chandra Deep Field South (E-CDFS). Among the 266 radio sources detected, we find...
X-ray Insights into the Nature of Weak Emission-Line Quasars at High Redshift (2009)
Shemmer, Ohad, Brandt, W. N., Anderson, Scott F., Diamond-Stanic, Aleksandar M., Fan, Xiaohui, Richards, Gordon T., ...
We present Chandra observations of nine high-redshift quasars (z=2.7-5.9) discovered by the Sloan Digital Sky Survey with weak or undetectable high-ionization emission lines in their UV spectra...
X-Ray Insights Into the Physics of Mini-BAL Quasar Outflows (2009)
Gibson, Robert R., Brandt, W. N., Gallagher, S. C., Schneider, Donald P.
We examine the UV and X-ray properties of 256 radio-quiet SDSS quasars (QSOs) observed in X-rays with Chandra and/or XMM-Newton in order to study the relationship between QSOs with broad CIV...
Discovery of the Most-Distant Double-Peaked Emitter at z=1.369 (2009)
Luo, B., Brandt, W. N., Silverman, J. D., Strateva, I. V., Bauer, F. E., Capak, P., ...
We report the discovery of the most-distant double-peaked emitter, CXOECDFS J033115.0-275518, at z=1.369. A Keck/DEIMOS spectrum shows a clearly double-peaked broad Mg II $\lambda2799$ emission line,...
We present Chandra observations of the hybrid morphology radio sources 3C 433 and 4C 65.15, two members of the rare class of objects possessing an FR I jet on one side of the core and an FR II lobe...
Discovery of the most distant double-peaked emitter at z = 1.369 (2009)
Luo, B., Brandt, W. N., Silverman, J. D., Strateva, I. V., Bauer, F. E., Capak, P., ...
Broad line emission from iron K- and L-shell transitions in the active galaxy 1H 0707-495 (2009)
Fabian, A. C., Zoghbi, A., Ross, R. R., Uttley, P., Gallo, L. C., Brandt, W. N., ...
PHL 1092 as a transient extreme X-ray weak quasar (2009)
Miniutti, G., Fabian, A. C., Brandt, W. N., Gallo, L. C., Boller, Th.
Alexander, D. M., Pope, A., Bauer, F. E., Brandt, W. N., Daddi, E., ...
Many models that seek to explain the origin of the unresolved X-ray background predict that Compton-thick active galactic nuclei (AGNs) are ubiquitous at high redshift. However, few distant...
The Chandra Deep Field-South Survey: 2 Ms Source Catalogs (2008)
Luo, B., Bauer, F. E., Brandt, W. N., Alexander, D. M., Lehmer, B. D., Schneider, D. P., ...
We present point-source catalogs for the ≈2 Ms exposure of the Chandra Deep Field-South (CDF-S); this is one of the two most sensitive X-ray surveys ever performed. The survey covers an area of...
Eight-Dimensional Mid-Infrared/Optical Bayesian Quasar Selection (2008)
Richards, Gordon T., Deo, Rajesh P., Lacy, Mark, Myers, Adam D., Nichol, Robert C., Zakamska, Nadia L., ...
We explore the multidimensional, multiwavelength selection of quasars from mid-IR (MIR) plus optical data, specifically from Spitzer-IRAC and the Sloan Digital Sky Survey (SDSS). We apply modern...
A Catalog of Broad Absorption Line Quasars in Sloan Digital Sky Survey Data Release 5 (2008)
Gibson, Robert R., Jiang, Linhua, Brandt, W. N., Hall, Patrick B., Shen, Yue, Wu, Jianfeng, ...
We present a catalog of 5039 broad absorption line (BAL) quasars (QSOs) in the Sloan Digital Sky Survey (SDSS) Data Release 5 (DR5) QSO catalog that have absorption troughs covering a continuous...
Muno, M. P., Bauer, F. E., Baganoff, F. K., Bandyopadhyay, R. M., Bower, G. C., Brandt, W. N., ...
We present a catalog of 9017 X-ray sources identified in Chandra observations of a 2 by 0.8 degree field around the Galactic center. We increase the number of known X-ray sources in the region by a...
Gibson, Robert R., Brandt, W. N., Schneider, Donald P.
We analyze archived Chandra and XMM-Newton X-ray observations of 536 Sloan Digital Sky Survey (SDSS) Data Release 5 (DR5) quasars (QSOs) at 1.7
A Chandra Look at Five of the Broadest Double-Peaked Balmer-Line Emitters (2008)
Strateva, Iskra V., Brandt, W. N., Eracleous, Michael, Garmire, Gordon
We study the 0.5-10keV emission of a sample of five of the broadest double-peaked Balmer-line emitters with Chandra. The Balmer lines of these objects originate close (within a few hundred...
An X-ray, infrared, and submillimeter flare of Sagittarius A (2008)
Marrone, D. P., Baganoff, F. K., Morris, M. R., Moran, J. M., Ghez, A. M., Hornstein, S. D., ...
Energetic flares are observed in the Galactic supermassive black hole Sagittarius A* from radio to X-ray wavelengths. On a few occasions, simultaneous flares have been detected in IR and X-ray...
The Chandra Deep Field-South Survey: 2 Ms Source Catalogs (2008)
Luo, B., Bauer, F. E., Brandt, W. N., Alexander, D. M., Lehmer, B. D., Schneider, D. P., ...
We present point-source catalogs for the ~2 Ms exposure of the Chandra Deep Field-South (CDF-S); this is one of the two most-sensitive X-ray surveys ever performed. The survey covers an area of ~436...
Alexander, D. M., Brandt, W. N., Smail, I., Swinbank, A. M., Bauer, F. E., Blain, A. W., ...
We place direct observational constraints on the black-hole masses (MBH) of the cosmologically important z ≈ 2 submillimeter-emitting galaxy (SMG; f850μm ≳ 4 mJy) population, and use measured...
Supernova 1996cr: SN 1987A's Wild Cousin? (2008)
Bauer, F. E., Dwarkadas, V. V., Brandt, W. N., Immler, S., Smartt, S., Bartel, N., ...
We report on new VLT optical spectroscopic and multi-wavelength archival observations of SN1996cr, a previously identified ULX known as Circinus Galaxy X-2. Our optical spectrum confirms SN1996cr as...
Shemmer, Ohad, Brandt, W. N., Netzer, Hagai, Maiolino, Roberto, Kaspi, Shai
We study the hard-X-ray spectral properties of ten highly luminous radio-quiet (RQ) active galactic nuclei (AGNs) at z=1.3-3.2, including new XMM-Newton observations of four of these sources. We find...
Lehmer, B. D., Brandt, W. N., Alexander, D. M., Bell, E. F., Hornschemeier, A. E., McIntosh, D. H., ...
We report on the X-ray evolution over the last ~9 Gyr of cosmic history (i.e., since z = 1.4) of late-type galaxy populations in the Chandra Deep Field-North and Extended Chandra Deep Field-South...
Alexander, D. M., Brandt, W. N., Smail, I., Swinbank, A. M., Bauer, F. E., Blain, A. W., ...
We place direct observational constraints on the black-hole masses of the cosmologically important z~2 submillimeter-emitting galaxy (SMG; f850>4mJy) population, and use measured host-galaxy masses...
Alexander, D. M., Chary, R. R., Pope, A., Bauer, F. E., Brandt, W. N., Daddi, E., ...
Many models that seek to explain the origin of the unresolved X-ray background predict that Compton-thick Active Galactic Nuclei (AGNs) are ubiquitious at high redshift. However, few distant...
Saez, C., Chartas, G., Brandt, W. N., Lehmer, B. D., Bauer, F. E., Dai, X., ...
We present results from a statistical analysis of 173 bright radio-quiet AGNs selected from the Chandra Deep Field-North and Chandra Deep Field-South surveys (hereafter, CDFs) in the redshift range...
Muno, M. P., Baganoff, F. K., Brandt, W. N., Morris, M. R.
We present a catalog of 34 diffuse features identified in X-ray images of the Galactic center taken with the Chandra X-Ray Observatory. Several of the features have been discussed in the literature...
New insights into the X-ray properties of the nearby barred spiral galaxy NGC 1672 (2008)
Jenkins, L. P., Brandt, W. N., Colbert, E. J. M., Levan, A. J., Roberts, T. P., Ward, M. J., ...
We present some preliminary results from new Chandra and XMM-Newton X-ray observations of the nearby barred spiral galaxy NGC1672. It shows dramatic nuclear and extra-nuclear star formation activity,...
Lehmer, B. D., Brandt, W. N., Alexander, D. M., Bell, E. F., Hornschemeier, A. E., McIntosh, D. H., ...
A Chandra look at five of the broadest double-peaked Balmer line emitters (2008)
Strateva, Iskra V., Brandt, W. N., Eracleous, Michael, Garmire, Gordon
The Chandra deep field-south survey: 2 Ms source catalogs (2008)
Luo, B., Bauer, F. E., Brandt, W. N., Alexander, D. M., Lehmer, B. D., Schneider, D. P., ...
Lehmer, B. D., Brandt, W. N., Alexander, D. M., Bell, E. F., Hornschemeier, A. E., McIntosh, D. H., ...
We report on the X-ray evolution over the last ~9 Gyr of cosmic history (i.e., since z=1.4) of late-type galaxy populations in the Chandra Deep Field-North and Extended Chandra Deep Field-South...
Polarized NIR and X-ray flares from Sagittarius A* (2008)
Eckart, A., Baganoff, F.K., Zamaninasab, M., Morris, M.R., Schödel, R., Meyer, L., ...
Context. Stellar dynamics indicate the presence of a supermassive 3 - 4 x 10(6) M-circle dot black hole at the Galactic Center. It is associated with the variable radio, near-infrared, and X-ray...
Polarized NIR and X-ray Flares from SgrA* (2007)
Eckart, A., Baganoff, F. K., Zamaninasab, M., Morris, M., Schoedel, R., Meyer, L., ...
Stellar dynamics indicate the presence of a super massive 3-4x10^6 Msun solm black hole at the Galactic Center. It is associated with the variable radio, near-infrared, and X-ray counterpart...
An X-ray, IR, and Submillimeter Flare of Sagittarius A* (2007)
Marrone, D. P., Baganoff, F. K., Morris, M. R., Moran, J. M., Ghez, A. M., Hornstein, S. D., ...
Energetic flares are observed in the Galactic supermassive black hole Sagittarius A* from radio to X-ray wavelengths. On a few occasions, simultaneous flares have been detected in IR and X-ray...
Quasar Broad Absorption Line Variability on Multi-Year Time Scales (2007)
Gibson, Robert R., Brandt, W. N., Schneider, Donald P., Gallagher, S. C.
We use quantitative metrics to characterize the variation of CIV 1549 A broad absorption lines (BALs) over 3--6 (rest-frame) years in a sample of 13 quasars at 1.7
Daddi, E., Alexander, D. M., Dickinson, M., Gilli, R., Renzini, A., Elbaz, D., ...
Approximately 20%-30% of 1.4 ≾ z ≾ 2.5 galaxies with K_(Vega) < 22 detected with Spitzer MIPS at 24 μm show excess mid-IR emission relative to that expected based on the rates of star formation...
Deep-Survey Constraints on X-ray Outbursts from Galactic Nuclei (2007)
Luo, B., Brandt, W. N., Steffen, A. T., Bauer, F. E.
Luminous X-ray outbursts with variability amplitudes as high as ~1000 have been detected from a small number of galactic nuclei. These events are likely associated with transient fueling of nuclear...
The extended Chandra deep field-south survey : Chandra point-source catalogs. (2007)
Lehmer, B. D., Brandt, W. N., Alexander, D. M., Bauer, F. E., Schneider, D. P., Tozzi, P., ...
We present Chandra point‐source catalogs for the Extended Chandra Deep Field–South (E‐CDF‐S) survey. The E‐CDF‐S consists of four contiguous 250 ks Chandra observations covering an...
Lehmer, B. D., Brandt, W. N., Hornschemeier, A. E., Alexander, D. M., Bauer, F. E., Koekemoer, A. M., ...
We analyze a population of intermediate-redshift (z~0.05-0.3) off-nuclear X-ray sources located within optically bright galaxies in the Great Observatories Origins Deep Survey and Galaxy Evolution...
The x-ray evolution of early-type galaxies in the extended Chandra Deep Field-South. (2007)
Lehmer, B. D., Brandt, W. N., Alexander, D. M., Bell, E. F., McIntosh, D. H., Bauer, F. E., ...
We investigate the evolution over the last 6.3 Gyr of cosmic time (i.e., since ) of the average X‐ray properties of early‐type galaxies within the Extended Chandra Deep Field–South...
X-ray properties of Lyman Break galaxies in the Great Observatories Origins Deep Survey. (2007)
Lehmer, B. D., Brandt, W. N., Alexander, D. M., Bauer, F. E., Conselice, C. J., Dickinson, M. E., ...
We constrain the X-ray emission properties of Lyman break galaxies (LBGs) at z 3–6 using the 2 Ms Chandra Deep Field North and 1 Ms Chandra Deep Field South. Large samples of LBGs were discovered...
Silverman, J. D., Mainieri, V., Lehmer, B. D., Alexander, D. M., Bauer, F. E., Bergeron, J., ...
We present an analysis of 109 moderate-luminosity (41.9 < Log L{0.5-8.0 keV} < 43.7) AGN in the Extended Chandra Deep Field-South survey, which is drawn from 5,549 galaxies from the COMBO-17 and GEMS...
The Variable Warm Absorber in Circinus X-1 (2007)
Schulz, N. S., Kallman, T. E., Galloway, D. K., Brandt, W. N.
We observed Circinus X-1 twice during a newly reached low-flux phase near zero orbital phase using the High-Energy Transmission Grating Spectrometer (HETGS) onboard Chandra. In both observations the...
Muno, M. P., Baganoff, F. K., Brandt, W. N., Morris, M. R.
We present a catalog of 34 diffuse features identified in X-ray images of the Galactic center taken with the Chandra X-ray Observatory. Several of the features have been discussed in the literature...
Evidence for a parsec scale X-ray jet from the accreting neutron star Circinus X-1 (2007)
Heinz, S., Schulz, N. S., Brandt, W. N., Galloway, D. K.
We analyzed the zero-order image of a 50 ks Chandra gratings observation of Circinus X-1, taken in 2005 during the source's low-flux state. Circinus X-1 is an accreting neutron star that exhibits...
SN 1996cr: Confirmation of a Luminous Type IIn Supernova in the Circinus Galaxy (2007)
Bauer, F. E., Smartt, S., Immler, S., Brandt, W. N., Weiler, K. W.
We have recently confirmed SN 1996cr as a late-time type IIn supernova (SN) via VLT spectroscopy and isolated its explosion date to ~1 yr using archival optical imaging. We briefly touch upon here...
The X-ray Properties of the Most-Luminous Quasars from the Sloan Digital Sky Survey (2007)
Just, D. W., Brandt, W. N., Shemmer, O., Steffen, A. T., Schneider, D. P., Chartas, G., ...
Utilizing 21 new Chandra observations as well as archival Chandra, ROSAT, and XMM-Newton data, we study the X-ray properties of a representative sample of 59 of the most optically luminous quasars in...
Daddi, E., Alexander, D. M., Dickinson, M., Gilli, R., Renzini, A., Elbaz, D., ...
Approximately 20-30% of 1.4
Steffen, A. T., Brandt, W. N., Alexander, D. M., Gallagher, S. C., Lehmer, B. D.
We employ X-ray stacking techniques to examine the contribution from X-ray undetected, mid-infrared-selected sources to the unresolved, hard (6-8 keV) cosmic X-ray background (CXB). We use the...
Radio Through X-ray Spectral Energy Distributions of 38 Broad Absorption Line Quasars (2007)
Gallagher, S. C., Hines, D. C., Blaylock, M., Priddey, R. S., Brandt, W. N., Egami, E. E.
We have compiled the largest sample of multiwavelength spectral energy distributions (SEDs) of Broad Absorption Line (BAL) quasars to date, from the radio to the X-ray. We present new Spitzer MIPS...
The Realm of the First Quasars in the Universe: the X-ray View (2007)
Vignali, C., Brandt, W. N., Shemmer, O., Steffen, A., Schneider, D. P., Kaspi, S.
We review the X-ray studies of the highest redshift quasars, focusing on the results obtained with Chandra and XMM-Newton. Overall, the X-ray and broad-band properties of z>4 quasars and local...
The Sloan Digital Sky Survey Quasar Catalog IV. Fifth Data Release (2007)
Schneider, Donald P., Hall, Patrick B., Richards, Gordon T., Strauss, Michael A., Berk, Daniel E. Vanden, Anderson, Scott F., ...
We present the fourth edition of the Sloan Digital Sky Survey (SDSS) Quasar Catalog. The catalog contains 77,429 objects; this is an increase of over 30,000 entries since the previous edition. The...
The reversal of the star formation-density relation in the distant universe (2007)
Elbaz, D., Daddi, E., Borgne, D. Le, Dickinson, M., Alexander, D. M., Chary, R-R, ...
We study the relationship between the local environment of galaxies and their star formation rate (SFR) in the Great Observatories Origins Deep Survey, GOODS, at z~1, from ultradeep imaging at 24...
A longer XMM-Newton look at I Zwicky 1: Distinct modes of X-ray spectral variability (2007)
Gallo, L. C., Brandt, W. N., Costantini, E., Fabian, A. C.
The short-term spectral variability of the narrow-line Seyfert 1 galaxy I Zwicky 1 (I Zw 1) as observed in an 85 ks XMM-Newton observation is discussed in detail. I Zw 1 shows distinct modes of...
Costantini, E., Gallo, L. C., Brandt, W. N., Fabian, A. C., Boller, Th.
We present a spectral analysis of the narrow-line Seyfert 1 galaxy I Zwicky 1, focusing on the characteristics of the ionised absorbers as observed with XMM-Newton in 2005. The soft X-ray spectrum...
Discovery of variable iron fluorescence from reflection nebulae in the galactic center (2007)
Muno, M. P., Baganoff, F. K., Brandt, W. N., Park, S., Morris, M. R.
On the basis of 3 years of deep observations of the Galactic center with the Chandra X-Ray Observatory, we report the discovery of changes in the intensities and morphologies of two hard X-ray...
Chartas, G., Brandt, W. N., Gallagher, S. C., Proga, D.
We present results from multi-epoch spectral analysis of XMM-Newton and Chandra observations of the mini broad absorption line (BAL) quasar PG 1115+080. This is one of the few X-ray detected mini-BAL...
The X-ray evolution of early-type galaxies in the extended Chandra deep field-south (2007)
Lehmer, B. D., Brandt, W. N., Alexander, D. M., Bell, E. F., McIntosh, D. H., Bauer, F. E., ...
The reversal of the star formation-density relation in the distant universe (2007)
Elbaz, D., Daddi, E., Le Borgne, D., Dickinson, M., Alexander, D. M., ...
The spectral energy distributions of AGN with double-peaked Balmer lines (2007)
Strateva, I., Brandt, W. N., Eracleous, M., Garmire, G., Komossa, S.
The Sloan Digital Sky Survey Quasar Catalog. IV. Fifth Data Release (2007)
Schneider, Donald P., Hall, Patrick B., Richards, Gordon T., Strauss, Michael A., Vanden Berk, Daniel E., Anderson, Scott F., ...
We present the fourth edition of the Sloan Digital Sky Survey (SDSS) Quasar Catalog. The catalog contains 77,429 objects; this is an increase of over 30,000 entries since the previous edition. The...
The X-ray evolution of early-type galaxies in the Extended Chandra Deep Field-South (2007)
Lehmer, B. D., Brandt, W. N., Alexander, D. M., Bell, E. F., McIntosh, D. H., Bauer, F. E., ...
We investigate the evolution over the last 6.3 Gyr of cosmic time (i.e., since z~0.7) of the average X-ray properties of early-type galaxies within the Extended Chandra Deep Field-South (E-CDF-S)....
Fontanot, F., Cristiani, S., Monaco, P., Nonino, M., Vanzella, E., Brandt, W. N., ...
Aims.In this work the luminosity function of QSOs is measured in the redshift range 3.5
Daddi, E., Alexander, D. M., Dickinson, M., Gilli, R., Renzini, A., Elbaz, D., ...
Approximately 20%-30% of 1.4~1024 cm-2 and an average, unobscured X-ray luminosity L2-8keV~(1-4)×1043 ergs s-1. Their sky density (~3200 deg-2) and space density (~2.6×10-4 Mpc-3) are twice those...
Radio through X-ray spectral energy distributions of 38 broad absorption line quasars. (2007)
Gallagher, S.C., Hines, D.C., Blaylock, M., Priddey, R., Brandt, W.N., Egami, E.
Original article can be found at: http://www.iop.org/EJ/journal/apj Copyright American Astronomical Society. DOI: 10.1086/519438 [Full text of this article is not available in the UHRA]
Reverberation Mapping of High-Luminosity Quasars: First Results (2006)
Kaspi, Shai, Brandt, W. N., Maoz, Dan, Netzer, Hagai, Schneider, Donald P., Shemmer, Ohad
Reverberation mapping of nearby active galactic nuclei has led to estimates of broad-line-region (BLR) sizes and central-object masses for some 37 objects to date. However, successful reverberation...
The Spectral Energy Distributions of AGN with Double-Peaked Balmer Lines (2006)
Strateva, I., Brandt, W. N., Eracleous, M., Garmire, G., Komossa, S.
We summarize the optical, UV, and X-ray properties of double-peaked emitters -- AGN with double-peaked Balmer emission lines believed to originate in the AGN accretion disk. We focus on the X-ray...
The X-ray Properties of Early-Type Galaxies in the Extended Chandra Deep Field-South (2006)
Lehmer, B. D., Brandt, W. N., Alexander, D. M., Bell, E. F., McIntosh, D. H., Bauer, F. E., ...
We investigate the evolution over the last 6.3 Gyr of cosmic time (i.e., since z ~ 0.7) of the average X-ray properties of early-type galaxies within the Extended Chandra Deep Field-South (E-CDF-S)....
Discovery of Variable Iron Fluorescence from Reflection Nebulae in the Galactic Center (2006)
Muno, M. P., Baganoff, F. K., Brandt, W. N., Park, S., Morris, M. R.
Based on three years of deep observations of the Galactic center with the Chandra X-ray Observatory, we report the discovery of changes in the intensities and morphologies of two hard X-ray...
Gallo, L. C., Brandt, W. N., Costantini, E., Fabian, A. C., Iwasawa, K., Papadakis, I. E.
We present the second XMM-Newton observation (85 ks) of the narrow-line Seyfert 1 galaxy (NLS1) I Zw 1 and describe its mean spectral and timing characteristics. On average, I Zw 1 is ~35 per cent...
The Luminosity Function of high-redshift QSOs - A combined analysis of GOODS and SDSS (2006)
Fontanot, F., Cristiani, S., Monaco, P., Nonino, M., Vanzella, E., Brandt, W. N., ...
Aims: In this work the luminosity function of QSOs is measured in the redshift range 3.5
Probing the Evolution of IR Properties of z~6 Quasars: Spitzer Observations (2006)
Jiang, Linhua, Fan, Xiaohui, Hines, Dean C., Shi, Yong, Vestergaard, Marianne, Bertoldi, Frank, ...
We present Spitzer observations of thirteen z~6 quasars using the Infrared Array Camera (IRAC) and Multiband Imaging Photometer for Spitzer (MIPS). All the quasars except SDSS J000552.34-000655.8...
The X-ray Properties of Active Galactic Nuclei with Double-Peaked Balmer Lines (2006)
Strateva, I. V., Brandt, W. N., Eracleous, M., Schneider, D. P., Chartas, G.
Double-peaked Balmer-line profiles originate in the accretion disks of a few percent of optically selected AGN. The reasons behind the strong low-ionization line emission from the accretion disks of...
X-Ray Absorption and an X-Ray Jet in the Radio-Loud Broad Absorption Line Quasar PG 1004+130 (2006)
Miller, B. P., Brandt, W. N., Gallagher, S. C., Laor, A., Wills, Beverley J., Garmire, G. P., ...
We investigate the X-ray properties of PG 1004+130, a low-redshift radio-loud broad absorption line (BAL) quasar with a hybrid FR I/FR II radio morphology. The 22.2 ks XMM-Newton and 41.6 ks Chandra...
Chandra Observations of Red Sloan Digital Sky Survey Quasars (2006)
Hall, Patrick B., Gallagher, S. C., Richards, G. T., Alexander, D. M., Anderson, S. F., Bauer, F., ...
We present short \chandra observations of twelve bright (i
Shemmer, Ohad, Brandt, W. N., Netzer, Hagai, Maiolino, Roberto, Kaspi, Shai
We present new XMM-Newton observations of two luminous and high accretion-rate radio-quiet active galactic nuclei (AGNs) at z~2. Together with archival X-ray and rest-frame optical spectra of three...
Worsley, M. A., Fabian, A. C., Bauer, F. E., Alexander, D. M., Brandt, W. N., Lehmer, B. D.
The emission from individual X-ray sources in the Chandra Deep Fields and XMM-Newton Lockman Hole shows that almost half of the hard X-ray background above 6 keV is unresolved and implies the...
Gallagher, S. C., Brandt, W. N., Chartas, G., Priddey, R., Garmire, G. P., Sambruna, R. M.
We present 4-7 ks Chandra observations of 35 Broad Absorption Line (BAL) quasars from the Large Bright Quasar Survey, the largest sample of sensitive, 0.5-8.0 keV X-ray observations of this class of...
Chandra Observations of the Highest Redshift Quasars from the Sloan Digital Sky Survey (2006)
Shemmer, Ohad, Brandt, W. N., Schneider, Donald P., Fan, Xiaohui, Strauss, Michael A., Diamond-Stanic, Aleksandar M., ...
We present new Chandra observations of 21 z>4 quasars, including 11 sources at z>5. These observations double the number of X-ray detected quasars at z>5, allowing investigation of the X-ray spectral...
Steffen, A. T., Strateva, I., Brandt, W. N., Alexander, D. M., Koekemoer, A. M., Lehmer, B. D., ...
We present partial-correlation analyses that examine the strengths of the relationships between L_UV, L_X, Alpha_OX, and redshift for optically-selected AGNs. We extend the work of Strateva et al....
Lehmer, B. D., Brandt, W. N., Hornschemeier, A. E., Alexander, D. M., Bauer, F. E., Koekemoer, A. M., ...
We analyze a population of intermediate-redshift (z ~ 0.05-0.3), off-nuclear X-ray sources located within optically-bright galaxies in the Great Observatories Origins Deep Survey (GOODS) and Galaxy...
Ota, N., Inada, N., Oguri, M., Mitsuda, K., Richards, G. T., Suto, Y., ...
We present results from Chandra observations of SDSS J1004+4112, a strongly lensed quasar system with a maximum image separation of 15". All four bright images of the quasar, as well as resolved...
Lopez, L. A., Brandt, W. N., Vignali, C., Schneider, D. P., Chartas, G., Garmire, G. P.
We present the results of Chandra ACIS-S snapshot observations of six radio-loud quasars (RLQs) at z=3.5-4.7. These observations sample luminous RLQs with moderate-to-high radio-loudness (R=200-9600)...
Fan, Xiaohui, Strauss, Michael A., Richards, Gordon T., Hennawi, Joseph F., Becker, Robert H., White, Richard L., ...
The flare activity of Sagittarius A*: new coordinated mm to X-ray observations (2006)
Eckart, A., Baganoff, F. K., Schödel, R., Morris, M., Genzel, R., Bower, G. C., ...
The X-ray properties of active galactic nuclei with double-peaked balmer lines (2006)
Strateva, Iskra V., Brandt, W. N., Eracleous, Michael, Schneider, Donald P., Chartas, George
Probing the evolution of infrared properties of z ~ 6 quasars: Spitzer observations (2006)
Jiang, Linhua, Fan, Xiaohui, Hines, Dean C., Shi, Yong, Vestergaard, Marianne, Bertoldi, Frank, ...
We present Spitzer observations of 13 z~6 quasars using the Infrared Array Camera (IRAC) and Multiband Imaging Photometer for Spitzer (MIPS). All the quasars except SDSS J000552.34-000655.8 (SDSS...
The Flare Activity of SgrA*; New Coordinated mm to X-Ray Observations (2005)
Eckart, A., Baganoff, F. K., Schoedel, R., Morris, M., Genzel, R., Bower, G. C., ...
We report new simultaneous near-infrared/sub-millimeter/X-ray observations of the SgrA* counterpart associated with the massive 3-4x10**6 solar mass black hole at the Galactic Center. The main aim is...
Fan, Xiaohui, Strauss, Michael A., Richards, Gordon T., Hennawi, Joseph F., Becker, Robert H., White, Richard L., ...
We present the discovery of seven quasars at z>5.7, selected from ~2000 deg^2 of multicolor imaging data of the Sloan Digital Sky Survey (SDSS). The new quasars have redshifts z from 5.79 to 6.13....
Infrared power-law galaxies in the Chandra Deep Field South: AGN and ULIRGs (2005)
Alonso-Herrero, A., Perez-Gonzalez, P. G., Alexander, D. M., Rieke, G. H., Rigopoulou, D., Floc'h, E. Le, ...
We investigate the nature of a sample of 92 Spitzer/MIPS 24 micron selected galaxies in the CDFS, showing power law-like emission in the Spitzer/IRAC 3.6-8 micron bands. The main goal is to determine...
Spitzer Observations of Massive Red Galaxies at High Redshift (2005)
Papovich, Casey, Moustakas, L. A., Dickinson, M., Floc'h, E. Le, Rieke, G. H., Daddi, E., ...
We investigate the properties of massive galaxies at z=1-3.5 using HST observations, ground-based near-IR imaging, and Spitzer Space Telescope observations at 3-24 micron. We identify 153 distant red...
The X-ray spectral properties of scuba galaxies. (2005)
Alexander, D. M., Bauer, F. E., Chapman, S. C., Smail, I., Blain, A. W., Brandt, W. N., ...
Deep SCUBA surveys have uncovered a large population of massive submillimeter-emitting galaxies (SMGs; f850m 4 mJy) at z 1. Although it is generally believed that these galaxies host intense star...
Isolated, Massive Supergiants near the Galactic Center (2005)
Muno, M. P., Bower, G. C., Burgasser, A. J., Baganoff, F. K., Morris, M. R., Brandt, W. N.
We have carried out a pilot project to assess the feasibility of using radio, infrared, and X-ray emission to identify young, massive stars located between 1 and 25 pc from the Galactic center. We...
Shemmer, O., Brandt, W. N., Gallagher, S. C., Vignali, C., Boller, Th., Chartas, G., ...
We present the results from XMM-Newton observations of the highly optically polarized broad absorption line quasar (BALQSO) CSO 755. By analyzing its X-ray spectrum with a total of ~3000 photons we...
On the X-ray Properties of OH Megamaser Sources: Chandra Snapshot Observations (2005)
Vignali, C., Brandt, W. N., Comastri, A., Darling, J.
We present Chandra snapshot observations for a sample of 7 sources selected from the Arecibo OH megamaser (OHM) survey at z~0.13-0.22 and with far-infrared luminosities in excess of 10^{11} L_sun. In...
The population of BzK selected ULIRGs at z~2 (2005)
Daddi, E., Dickinson, M., Chary, R., Pope, A., Morrison, G., Alexander, D. M., ...
We investigate the multi-wavelength emission of BzK selected star forming galaxies at z~2 in the Great Observatories Origins Deep Survey (GOODS) North region. Most (82%) of the sources are...
The X-ray Spectral Properties of SCUBA Galaxies (2005)
Alexander, D. M., Bauer, F. E., Chapman, S. C., Smail, I., Blain, A. W., Brandt, W. N., ...
Deep SCUBA surveys have uncovered a large population of massive submm galaxies (SMGs) at z>~1. Although it is generally believed that these galaxies host intense star-formation activity, there is...
The Extended Chandra Deep Field-South Survey. Chandra Point-Source Catalogs (2005)
Lehmer, B. D., Brandt, W. N., Alexander, D. M., Bauer, F. E., Schneider, D. P., Tozzi, P., ...
We present Chandra point-source catalogs for the Extended Chandra Deep Field-South (E-CDF-S) survey. The E-CDF-S consists of four contiguous 250 ks Chandra observations covering an approximately...
Variation in the Scattering Shroud Surrounding Markarian 231 (2005)
Gallagher, S. C., Schmidt, Gary D., Smith, Paul S., Brandt, W. N., Chartas, G., Hylton, Shavonne, ...
We present a detailed study of the nuclear structure of the highly polarized broad absorption line quasar, Mrk 231, through a multiwavelength campaign of Chandra observations, optical spectroscopy,...
Gabel, J. R., Kraemer, S. B., Crenshaw, D. M., George, I. M., Brandt, W. N., Hamann, F. W., ...
We present results on the location, physical conditions, and geometry of the outflow in the Seyfert 1 galaxy NGC 3783 from a study of the variable intrinsic UV absorption. Based on 18 observations...
Investigating ionized disc models of the variable narrow-line Seyfert 1 PG 1404+226 (2005)
Crummy, J., Fabian, A. C., Brandt, W. N., Boller, Th.
We investigate the use of relativistically blurred photoionized disc models on an XMM-Newton observation of the Narrow Line Seyfert 1 galaxy PG 1404+226. The model is designed to reproduce the...
Shemmer, O., Brandt, W. N., Vignali, C., Schneider, D. P., Fan, X., Richards, G. T., ...
We perform a detailed investigation of moderate-to-high quality X-ray spectra of ten of the most luminous active galactic nuclei (AGNs) known at z>4 (up to z~6.28). This study includes five new XMM...
Rapid growth of black holes in massive star-forming galaxies. (2005)
Alexander, D. M., Smail, I., Bauer, F. E., Chapman, S. C., Blain, A. W., Brandt, W. N., ...
A Remarkable Low-Mass X-ray Binary within 0.1 pc of the Galactic Center (2005)
Muno, M. P., Lu, J. R., Baganoff, F. K., Brandt, W. N., Garmire, G. P., Ghez, A. M., ...
Recent X-ray and radio observations have identified a transient low-mass X-ray binary (LMXB) located only 0.1 pc in projection from the Galactic center, CXOGC J174540.0-290031. In this paper, we...
Rapid Growth of Black Holes in Massive Star-Forming Galaxies (2005)
Alexander, D. M., Smail, I., Bauer, F. E., Chapman, S. C., Blain, A. W., Brandt, W. N., ...
The tight relationship between the masses of black holes and galaxy spheroids in nearby galaxies implies a causal connection between the growth of these two components. Optically luminous quasars...
Vignali, C., Brandt, W. N., Schneider, D. P., Kaspi, S.
We report on Chandra observations of a sample of 11 optically luminous (Mb4 quasars known and hence represent ideal witnesses of the end of the "dark age ''. Nine quasars are detected by Chandra,...
Deep Extragalactic X-ray Surveys (2005)
Deep surveys of the cosmic X-ray background are reviewed in the context of observational progress enabled by the Chandra X-ray Observatory and the X-ray Multi-Mirror Mission-Newton. The sources found...
EXO'S : a population of dusty, high-redshift AGN (2005)
Kroekemoer, Anton M., Alexander, D. M., Bauer, F. E., Brandt, W. N., Christiani, S., ...
Early spitzer detections of Extreme X-ray / Optical sources (EXOs) (2005)
Koekemoer, A. M., Alexander, D. M., Bauer, F. E., Bergeron, J., Brandt, W. N., Cristiani, S., ...
First simultaneous NIR/X-ray flare detection from SgrA (2005)
Eckart, A., Baganoff, F. K., Morris, M., Bautz, M. W., Brandt, W. N., Garmire, G. P., ...
The sloan digital sky survey quasar catalog - III. Third data release (2005)
Schneider, Donald P., Hall, Patrick B., Richards, Gordon T., Vanden Berk, Daniel E., Anderson, Scott F., Fan, Xiaohui, ...
EXOs: a population of dusty AGN in the early universe (2005)
Koekemoer, A. M., Alexander, D. M., Bauer, F. E., Bergeron, J., Brandt, W. N., Cristiani, S., ...
The extended Chandra deep field-south survey: Chandra point-source catalogs (2005)
Lehmer, B. D., Brandt, W. N., Alexander, D. M., Bauer, F. E., Bouwens, D. P., Tozzi, P., ...
Resolving the X-ray background (2005)
Worsley, M. A., Fabian, A. C., Alexander, D. M., Bauer, F. E., Brandt, W. N., Hasinger, G., ...
An Overabundance of Transient X-ray Binaries within 1 pc of the Galactic Center (2004)
Muno, M. P., Pfahl, E., Baganoff, F. K., Brandt, W. N., Ghez, A., Lu, J., ...
During five years of Chandra observations, we have identified seven X-ray transients located within 23 pc of Sgr A*. These sources each vary in luminosity by more than a factor of 10, and have peak...
Worsley, M. A., Fabian, A. C., Bauer, F. E., Alexander, D. M., Hasinger, G., Mateos, S., ...
We extend our earlier work on X-ray source stacking in the deep XMM-Newton observation of the Lockman Hole, to the 2 Ms Chandra Deep Field North and the 1 Ms Chandra Deep Field South. The XMM-Newton...
X-rays from the First Massive Black Holes (2004)
Brandt, W. N., Vignali, C., Lehmer, B. D., Lopez, L. A., Schneider, D. P., Strateva, I. V.
We briefly review some recent results from Chandra and XMM-Newton studies of the highest redshift (z > 4) active galactic nuclei (AGNs). Specific topics covered include radio-quiet quasars,...
Alexander, D. M., Chartas, G., Bauer, F. E., Brandt, W. N., Simpson, C., Vignali, C.
We present a ~20 ks Chandra ACIS-S observation of the strongly lensed z=2.285 ultra-luminous infrared galaxy FSC10214+4724. Although this observation achieves the equivalent sensitivity of an up-to...
X-ray Insights Into Interpreting CIV Blueshifts and Optical/UV Continua (2004)
Gallagher, S. C., Richards, G. T., Hall, P. B., Brandt, W. N., Schneider, D. P., Berk, D. E. Vanden
We present 0.5-8.0 keV Chandra observations of six bright quasars that represent extrema in quasar emission-line properties -- three quasars each with small and large blueshifts of the CIV emission...
X-ray Properties of Lyman Break Galaxies in the Great Observatories Origins Deep Survey (2004)
Lehmer, B. D., Brandt, W. N., Alexander, D. M., Bauer, F. E., Conselice, C. J., Dickinson, M. E., ...
We constrain the X-ray emission properties of Lyman break galaxies (LBGs) at z ~ 3-6 using the 2 Ms Chandra Deep Field-North and 1 Ms Chandra Deep Field-South. Large samples of LBGs were discovered...
The narrow-line quasar NAB 0205+024 observed with XMM-Newton (2004)
Gallo, L. C., Boller, Th., Brandt, W. N., Fabian, A. C., Vaughan, S.
The XMM-Newton observation of the narrow-line quasar NAB 0205+024 reveals three striking differences since it was last observed in the X-rays with ASCA. Firstly, the 2-10 keV power-law is notably...
Obscured AGN and the X-ray, Optical and Far-Infrared Number Counts of AGN in the GOODS Fields (2004)
Treister, E., Urry, C. M., Chatzichristou, E., Bauer, F., Alexander, D. M., Koekemoer, A., ...
The deep X-ray, optical, and far-infrared fields that constitute GOODS are sensitive to obscured AGN (N_H>10^{22} cm^{-2}) at the quasar epoch (z~2-3), as well as to unobscured AGN as distant as z~7....
Bauer, F. E., Alexander, D. M., Brandt, W. N., Schneider, D. P., Treister, E., Hornschemeier, A. E., ...
We investigate the X-ray number counts in the 1-2 Ms Chandra Deep Fields (CDFs) to determine the contributions of faint X-ray source populations to the extragalactic X-ray background (XRB). X-ray...
X-ray Surveys and Wide-Field Optical/Near-Infrared Imaging with the Joint Dark Energy Mission (2004)
I briefly describe a few important scientific issues that could be addressed effectively via the combination of data from JDEM and X-ray missions. The topics covered are largely focused on active...
The z>4 Quasar Population Observed by Chandra and XMM-Newton (2004)
Vignali, C., Brandt, W. N., Schneider, D. P.
The current status of our Chandra and XMM-Newton project on high-redshift (z>4) quasars is briefly reviewed. We report the main results obtained in the last few years for the detected quasars, along...
Long-term spectral changes in the partial-covering candidate NLS1 1H 0707-495 (2004)
Gallo, L. C., Tanaka, Y., Boller, Th., Fabian, A. C., Vaughan, S., Brandt, W. N.
We compare two XMM-Newton observations of the Narrow-Line Seyfert 1 galaxy 1H 0707-495 separated by two years, and discuss the results in terms of the partial-covering phenomenon. The second longer...
Fan, Xiaohui, Hennawi, Joseph F., Richards, Gordon T., Strauss, Michael A., Schneider, Donald P., Donley, Jennifer L., ...
We present the discovery of five new quasars at z>5.7, selected from the multicolor imaging data of the Sloan Digital Sky Survey (SDSS). Three of them, at redshifts 5.93, 6.07, and 6.22, were...
Gallo, L. C., Boller, Th., Brandt, W. N., Fabian, A. C., Grupe, D.
The narrow-line quasar PHL 1092 was observed by XMM-Newton at two epochs separated by nearly thirty months. Timing analyses confirm the extreme variability observed during previous X-ray missions. A...
Feigelson, E. D., Hornschemeier, A. E., Micela, G., Bauer, F. E., Alexander, D. M., Brandt, W. N., ...
The extremely sensitive Chandra Deep Field-North (CDF-N) pencil-beam X-ray survey is used to identify and characterize the X-ray emission from old high-latitude main sequence Galactic stars. Our...
Bassett, L. C., Brandt, W. N., Schneider, D. P., Vignali, C., Chartas, G., Garmire, G. P.
We present the results of Chandra observations of six radio-loud quasars (RLQs) and one optically bright radio-quiet quasar (RQQ) at z = 4.1-4.4. These observations cover a representative sample of...
X-ray Survey Results on Active Galaxy Physics and Evolution (2004)
Brandt, W. N., Alexander, D. M., Bauer, F. E., Vignali, C.
This "pedagogical" review describes the key Chandra and XMM-Newton extragalactic surveys to date and details some of their implications for AGN physics and evolution. We additionally highlight two...
First Simultaneous NIR/X-ray Detection of a Flare from SgrA* (2004)
Eckart, A., Baganoff, F. K., Morris, M., Bautz, M. W., Brandt, W. N., Garmire, G. P., ...
We report on the first simultaneous near-infrared/X-ray detection of the Sgr A* counterpart which is associated with the massive black hole at the center of the Milky Way. The observations have been...
High-redshift QSOs in the GOODS (2004)
Cristiani, S., Alexander, D. M., Bauer, F., Brandt, W. N., Chatzichristou, E. T., Fontanot, F., ...
The Great Observatories Origins Deep Survey provides significant constraints on the space density of less luminous QSOs at high redshift, which is particularly important to understand the interplay...
Muno, M. P., Arabadjis, J. S., Baganoff, F. K., Bautz, M. W., Brandt, W. N., Broos, P. S., ...
We examine the X-ray spectra and variability of the sample of X-ray sources with L_X = 10^{31}-10^{33} erg s^{-1} identified within the inner 9' of the Galaxy. Very few of the sources exhibit...
The Power of Exploratory Chandra Observations (2004)
Gallagher, S. C., Richards, G. T., Brandt, W. N., Chartas, G.
With its excellent spatial resolution, low background, and hard-band response, the Chandra X-ray Observatory is ideal for performing exploratory surveys. These efficient, sensitive observations can...
Kaspi, Shai, Brandt, W. N., Collinge, M. J., Elvis, Martin, Reynolds, Christopher S.
We present three Far Ultraviolet Spectroscopic Explorer (FUSE) observations of the Narrow-Line Seyfert 1 galaxy NGC4051. The most prominent features in the far-ultraviolet (FUV) spectrum are the OVI...
Fact: Many SCUBA galaxies harbour AGNs (2004)
Alexander, D. M., Bauer, F. E., Chapman, S. C., Smail, I., Blain, A. W., Brandt, W. N., ...
Deep SCUBA surveys have uncovered a large population of ultra-luminous galaxies at z>1. These sources are often assumed to be starburst galaxies, but there is growing evidence that a substantial...
Fan, Xiaohui, Hennawi, Joseph F., Richards, Gordon T., Strauss, Michael A., Schneider, Donald P., Donley, Jennifer L., ...
I Zw 1 observed with XMM-Newton (2004)
Gallo, L. C., Boller, Th., Brandt, W. N., Fabian, A. C., Vaughan, S.
First simultaneous NIR/X-ray detection of a flare from Sgr A (2004)
Eckart, A., Baganoff, F. K., Morris, M., Bautz, M. W., Brandt, W. N., Garmire, G. P., ...
The narrow-line quasar NAB 0205+024 observed with XMM-Newton (2004)
Gallo, L. C., Boller, T., Brandt, W. N., Fabian, A. C., Vaughan, S.
Arakelian 564: an XMM-Newton view (2004)
Vignali, Cristian, Brandt, W. N., Boller, Th., Fabian, A. C., Vaughan, Simon
Exploring the nature of weak Chandra sources near the Galactic centre (2004)
E. Pfahl, K. M. Blundell, Ph. Podsiadlowski, Q. D. Wang, R. M. Bandyopadhyay, ...
Exploring the Nature of Weak Chandra Sources near the Galactic Centre (2003)
Bandyopadhyay, R. M., Blundell, K. M., Podsiadlowski, Ph., Wang, Q. D., Brandt, W. N., ...
We present early results from the first IR imaging of the weak X-ray sources discovered in a recent Chandra survey towards the Galactic Centre. From our VLT observations we will identify likely...
Gallo, L. C., Boller, Th., Brandt, W. N., Fabian, A. C., Vaughan, S.
We present a 20 ks XMM-Newton observation of the prototypical Narrow-Line Seyfert 1 galaxy IZw1. The best-fit model to the data is a double blackbody plus a dominant power-law, on which complex soft...
Dramatic X-ray Spectral Variability of the Broad Absorption Line Quasar PG2112+059 (2003)
Gallagher, S. C., Brandt, W. N., Wills, Beverley J., Charlton, J. C., Chartas, G., Laor, A.
With a 1999 ASCA observation, PG2112+059 became notable as the first Broad Absorption Line (BAL) quasar found to exhibit a typical radio-quiet quasar X-ray continuum underlying a large amount of...
Vignali, C., Brandt, W. N., Schneider, D. P.
Quasars at z>4 provide direct information on the first massive structures to form in the Universe. Recent ground-based optical surveys (e.g., the Sloan Digital Sky Survey) have discovered large...
X-raying Active Galaxies Found and Missed by the Sloan Digital Sky Survey (2003)
Brandt, W. N., Schneider, D. P., Vignali, C.
Current X-ray observatories, archival X-ray data, and the Sloan Digital Sky Survey (SDSS) represent a powerful combination for addressing key questions about active galactic nuclei (AGN). We describe...
Arakelian 564: An XMM-Newton view (2003)
Vignali, C., Brandt, W. N., Boller, Th., Fabian, A. C., Vaughan, S.
We report on two XMM-Newton observations of the bright narrow-line Seyfert 1 galaxy Ark 564 taken one year apart (2000 June and 2001 June). The 0.6-10 keV continuum is well described by a soft...
We present a Chandra and HST study of IC 10 X-1, the most luminous X-ray binary in the closest starburst galaxy to the Milky Way. Our new hard X-ray observation of X-1 confirms that it has an average...
The XMM-Newton view of NGC 6251 (2003)
Gliozzi, M., Sambruna, R. M., Brandt, W. N., Mushotzky, R., Eracleous, M.
We report on the nuclear X-ray properties of the radio galaxy NGC 6251 observed with XMM-Newton. NGC 6251 is a well-known radio galaxy with intermediate FRI/II radio properties. It is optically...
Restless Quasar Activity: From BeppoSAX to Chandra and XMM-Newton (2003)
Vignali, C., Comastri, A., Brandt, W. N.
We briefly review some of the progress made in the last decade in the study of the X-ray properties of the quasar population from the luminous, local objects observed by BeppoSAX to the large,...
Gallo, L. C., Boller, Th., Tanaka, Y., Fabian, A. C., Brandt, W. N., Welsh, W. F., ...
We report on the XMM-Newton timing properties of the most X-ray variable, radio-quiet, NLS1 IRAS 13224-3809. IRAS 13224-3809 continues to display the extremely variable behavior that was previously...
Netzer, H., Kaspi, S., Behar, E., Brandt, W. N., Chelouche, D., George, I. M., ...
We present a detailed spectral analysis of the data obtained from NGC 3783 during the period 2000-2001 using Chandra. This analysis leads us to the following results. 1) NGC 3783 fluctuated in...
The Space Density of High-Redshift QSOs in the GOODS Survey (2003)
Cristiani, S., Alexander, D. M., Bauer, F., Brandt, W. N., Chatzichristou, E. T., Fontanot, F., ...
We present a sample of 17 high-redshift (3.5
The Sloan Digital Sky Survey Quasar Catalog II. First Data Release (2003)
Schneider, Donald P., Fan, Xiaohui, Hall, Patrick B., Jester, Sebastian, Richards, Gordon T., Stoughton, Chris, ...
We present the second edition of the Sloan Digital Sky Survey (SDSS) Quasar Catalog. The catalog consists of 16713 objects in the SDSS First Data Release (DR1) that have luminosities larger than...
Lower Mass Black Holes in the GOODS? Off-nuclear X-ray Sources (2003)
Hornschemeier, A. E., Alexander, D. M., Bauer, F. E., Brandt, W. N., Chary, R., Conselice, C., ...
We have identified a sample of 10 highly reliable off-nuclear (> 2 kpc) X-ray sources at z=0.03-0.25 in late-type host galaxies within the two GOODS fields (i.e., the two Chandra Deep Fields). The...
X-ray Sources with Periodic Variability in a Deep Chandra Image of the Galactic Center (2003)
Muno, M. P., Baganoff, F. K., Bautz, M. W., Brandt, W. N., Garmire, G. P., Ricker, G. R., ...
We report the discovery of eight X-ray sources with periodic variability in 487 ks of observations of the Galactic center with Chandra. The sources are identified from a sample of 285 objects...
The X-ray Properties of the Nearby Star-Forming Galaxy IC 342: The XMM-Newton View (2003)
Bauer, F. E., Brandt, W. N., Lehmer, B.
We present the X-ray properties of IC342 using XMM-Newton. Thirty-five sources are detected coincident with the disk of IC342 (more than tripling the number known), of which ~31 are likely to be...
The 2 Ms Chandra Deep Field-North: Moderate-luminosity AGNs and dusty starburst galaxies (2003)
Alexander, D. M., Bauer, F. E., Brandt, W. N., Hornschemeier, A. E.
The 2 Ms Chandra Deep Field-North survey provides the deepest view of the Universe in the 0.5--8.0 keV X-ray band. In this brief review we investigate the diversity of X-ray selected sources and...
The Chandra Deep Field North Survey. XIII. 2 Ms point-source catalogs. (2003)
Alexander, D. M., Bauer, F. E., Brandt, W. N., Schneider, D. P., Hornschemeier, A. E., Vignali, C., ...
We present point-source catalogs for the 2 Ms exposure of the Chandra Deep Field North, currently the deepest X-ray observation of the universe in the 0.58.0 keV band. Five hundred and three (503)...
On the origin of the X-rays and the nature of accretion in NGC 4261 (2003)
Gliozzi, M., Sambruna, R. M., Brandt, W. N.
We report on the X-ray properties of the radio galaxy NGC 4261, combining information from the XMM, Chandra, and SAX satellites. Goals of this study are to investigate the origin of the X-rays from...
A Possible New Population of Sources with Extreme X-Ray / Optical Ratios (2003)
Koekemoer, Anton M., Alexander, D. M., Bauer, F. E., Bergeron, J., Brandt, W. N., Chatzichristou, E., ...
We describe a possible new class of X-ray sources that have robust detections in ultra-deep Chandra data, yet have no detections at all in our deep multi-band GOODS Hubble Space Telescope (HST) ACS...
Gabel, J. R., Crenshaw, D. M., Kraemer, S. B., Brandt, W. N., George, I. M., Hamann, F. W., ...
We report an intrinsic absorber with decreasing outflow velocity in the Seyfert 1 galaxy NGC 3783. This is the first detection of a change in radial velocity in an outflow associated with a Seyfert...
Optical and Infrared Properties of the 2 Ms Chandra Deep Field-North X-ray Sources (2003)
Barger, A. J., Cowie, L. L., Capak, P., Alexander, D. M., Bauer, F. E., Fernandez, E., ...
We present an optical and NIR catalog for the X-ray sources in the 2 Ms Chandra observation of the Hubble Deep Field-North region. We have high-quality multicolor images of all 503 X-ray point...
XMM-NEWTON Reveals the Quasar Outflow in PG 1115+080 (2003)
Chartas, G., Brandt, W. N., Gallagher, S. C.
We report on an observation of the Broad Absorption Line (BAL) quasar PG 1115+080 performed with the XMM-Newton observatory. Spectral analysis reveals the second case of a relativistic X-ray...
XMM-Newton spectral properties of the Narrow-Line Seyfert 1 galaxy IRAS 13224--3809 (2003)
Boller, Th., Tanaka, Y., Fabian, A., Brandt, W. N., Gallo, L., Anabuki, N., ...
We report on the first XMM-Newton observation of the highly X-ray variable, radio-quiet, Narrow-Line Seyfert 1 galaxy IRAS 13224-3809 obtained during the guaranteed time programme with a 64 ks...
The Chandra Deep Field-North Survey. XV. Optically Bright, X-ray Faint Sources (2003)
Hornschemeier, A. E., Bauer, F. E., Alexander, D. M., Brandt, W. N., Sargent, W. L. W., Bautz, M. W., ...
We have analyzed optically bright, X-ray faint [OBXF; i.e., log(fX/fR) < -2] sources identified in an 178.9 square arcminute area within the Chandra Deep Field-North (CDF-N) 2 Ms survey. We find 43...
The Chandra Deep Field-North Survey. XIII. 2 Ms Point-Source Catalogs (2003)
Alexander, D. M., Bauer, F. E., Brandt, W. N., Schneider, D. P., Hornschemeier, A. E., Vignali, C., ...
We present catalogs for the ~2 Ms Chandra Deep Field-North, currently the deepest X-ray observation of the Universe in the 0.5-8.0 keV band. Five hundred and three (503) X-ray sources are detected...
Probing the Complex and Variable X-ray Absorption of Markarian 6 with XMM-Newton (2003)
Immler, S., Brandt, W. N., Vignali, C., Bauer, F., Crenshaw, D. M., Feldmeier, J. J., ...
We report on an X-ray observation of the Seyfert 1.5 galaxy Mrk 6 obtained with the EPIC instruments onboard XMM-Newton. Archival BeppoSAX PDS data from 18-120 keV were also used to constrain the...
Vignali, C., Brandt, W. N., Schneider, D. P., Anderson, S. F., Fan, X., Gunn, J. E., ...
We report on Chandra and XMM-Newton observations of a sample of 13 quasars at z~4.7-5.4 mostly taken from the Sloan Digital Sky Survey (SDSS). The present sample complements previous X-ray studies of...
Chandra and XMM-Newton observations of Tololo 0109-383 (2003)
Matt, G., Bianchi, S., Guainazzi, M., Brandt, W. N., Fabian, A. C., Iwasawa, K., ...
We present and discuss Chandra and XMM-Newton observations of the Seyfert 2 galaxy and Compton-thick absorbed source, Tololo~0109-383. The hard X-ray emission (i.e. above $\sim$2 keV), is dominated...
The XMM-Newton View of the Nucleus of NGC 4261 (2003)
Sambruna, R. M., Gliozzi, M., Eracleous, M., Brandt, W. N., Mushotzky, R.
We present the first results from an XMM-Newton observation of the FRI galaxy NGC 4261, which harbors a supermassive black hole and a low-ionization nuclear emission-line region (LINER). Here we...
A Deep Chandra Catalog of X-ray Point Sources toward the Galactic Center (2003)
Muno, M. P., Baganoff, F. K., Bautz, M. W., Brandt, W. N., Broos, P. S., Feigelson, E. D., ...
(abridged) We present a catalog of 2357 point sources detected during 590 ks of Chandra observations of the 17-by-17 arcminute field around Sgr A*. This field encompasses a physical area of 40 by 40...
The Redshift Evolution of the 2-8 keV X-ray Luminosity Function (2003)
Cowie, L. L., Barger, A. J., Bautz, M. W., Brandt, W. N., Garmire, G. P.
The high angular resolution and sensitivity of the Chandra X-ray Observatory has yielded large numbers of faint X-ray sources with measured redshifts in the soft (0.5-2 keV) and hard (2-8 keV) energy...
Very High Redshift X-ray Selected AGN in the Chandra Deep Field-North (2003)
Barger, A. J., Cowie, L. L., Capak, P., Alexander, D. M., Bauer, F. E., Brandt, W. N., ...
Deep Chandra X-ray exposures provide an efficient route for locating optically faint active galactic nuclei (AGN) at high redshifts. We use deep multicolor optical data to search for z>5 AGN in the 2...
Fan, Xiaohui, Strauss, Michael A., Schneider, Donald P., Becker, Robert H., White, Richard L., Haiman, Zoltan, ...
We present the discovery of three new quasars at z>6 in 1300 deg^2 of SDSS imaging data, J114816.64+525150.3 (z=6.43), J104845.05+463718.3 (z=6.23) and J163033.90+401209.6 (z=6.05). The first two...
Chandra X-ray spectroscopic imaging of Sagittarius A* and the central parsec of the Galaxy (2003)
Baganoff, F. K., Maeda, Y., Morris, M., Bautz, M. W., Brandt, W. N., Cui, W., ...
We report the results of the first-epoch observation with the ACIS-I instrument on the Chandra X-Ray Observatory of Sagittarius A* (Sgr A*), the compact radio source associated with the supermassive...
XMM-Newton spectral properties of the narrow-line Seyfert 1 galaxy IRAS 13224-3809. (2003)
Boller, Th., Tanaka, Y., Fabian, A., Brandt, W. N., Gallo, L., Anabuki, N., ...
Bauer, F. E., Vignali, C., Alexander, D. M., Brandt, W. N., Garmire, G. P., Hornschemeier, A. E., ...
We investigate the nature of the faint X-ray source population through X-ray spectroscopy and variability analyses of 136 AGN detected in the 2 Ms Chandra Deep Field-North survey with > 200...
Probing Broad Absorption Line Quasar Outflows: X-ray Insights (2002)
Gallagher, S. C., Brandt, W. N., Chartas, G., Garmire, G. P., Sambruna, R. M.
Energetic outflows appear to occur in conjunction with active mass accretion onto supermassive black holes. These outflows are most readily observed in the approximately 10% of quasars with broad...
X-rays from the First Massive Black Holes (2002)
Brandt, W. N., Vignali, C., Schneider, D. P., Alexander, D. M., Anderson, S. F., Bauer, F. E., ...
X-ray studies of high-redshift (z > 4) active galaxies have advanced substantially over the past few years, largely due to results from the new generation of X-ray observatories. As of this writing...
The Weak Outnumbering the Mighty: Normal Galaxies in Deep Chandra Surveys (2002)
Hornschemeier, A. E., Bauer, F. E., Alexander, D. M., Brandt, W. N., Sargent, W. L. W., Vignali, C., ...
Chandra is detecting a significant population of normal and starburst galaxies in extremely deep X-ray exposures. For example, approximately 15% of the sources arising in the 2 Ms Chandra Deep...
Alexander, D. M., Bauer, F. E., Brandt, W. N., Hornschemeier, A. E., Vignali, C., Garmire, G. P., ...
We provide X-ray constraints and perform the first X-ray spectral analyses for bright (f_850>=5mJy; S/N>=4) SCUBA sources in an 8.4'x8.4' area of the 2 Ms Chandra Deep Field-North survey containing...
Vignali, C., Brandt, W. N., Schneider, D. P.
We investigate the X-ray properties of the color-selected radio-quiet quasars (RQQs) in the Sloan Digital Sky Survey (SDSS) Early Data Release using ROSAT, Chandra, and XMM-Newton data. In the...
Reverberation Mapping of High-Redshift, High-Luminosity Quasars (2002)
Kaspi, Shai, Netzer, Hagai, Maoz, Dan, Shemmer, Ohad, Brandt, W. N., Schneider, Donald P.
We present preliminary results from a reverberation mapping program to measure the Broad Line Region size in high-redshift, high-luminosity quasars. The observations are carried out at the...
Vignali, C., Bauer, F. E., Alexander, D. M., Brandt, W. N., Hornschemeier, A. E., Schneider, D. P., ...
We present X-ray spectral analyses of the three z>4 Active Galactic Nuclei (AGNs) thus far spectroscopically identified in the Chandra Deep Field-North Survey, at redshifts of 5.186, 4.424, and...
Vignali, C., Brandt, W. N., Schneider, D. P., Garmire, G. P., Kaspi, S.
We present the results from exploratory Chandra observations of nine high-z (z=4.1-4.5) optically selected quasars. These quasars, taken from the DPOSS, are among the optically most luminous z>4...
Alexander, D. M., Bauer, F. E., Brandt, W. N., Garmire, G. P., Hornschemeier, A. E., Schneider, D. P., ...
With ~2 Ms of Chandra exposure, the Chandra Deep Field-North (CDF-N) survey provides the deepest view of the Universe in the 0.5-8.0 keV band. Five hundred and three (503) X-ray sources are detected...
X-rays from the High-Redshift Universe: The Chandra view (2002)
Vignali, C., Brandt, W. N., Schneider, D. P., Garmire, G. P., Kaspi, S., Bauer, F. E., ...
The study of the X-ray properties of z>4 quasars has grown substantially over the last few years, mostly thanks to Chandra. Here we focus on (1) the average X-ray properties of an optically selected,...
Bauer, F. E., Vignali, C., Alexander, D. M., Brandt, W. N., Garmire, G. P., Hornschemeier, A. E., ...
We briefly report here on our ongoing X-ray spectroscopy and variability analyses of 136 faint X-ray sources discovered in the 2 Ms Chandra Deep Field North observations spanning 1.4x10-15 to 2x10-13...
Vignali, C., Brandt, W. N., Schneider, D. P., Garmire, G. P., Kaspi, S.
We present the results obtained from exploratory Chandra observations of nine high-redshift (z=4.09-4.51) quasars, selected from among the optically brightest Palomar Digital Sky Survey quasars...
The Ionized Gas and Nuclear Environment in NGC 3783 II. Averaged HST/STIS and FUSE Spectra (2002)
Gabel, Jack R., Crenshaw, D. Michael, Kraemer, Steven B., Brandt, W. N., George, Ian M., Hamann, Frederick W., ...
We present observations of the intrinsic absorption in the Seyfert 1 galaxy NGC 3783 obtained with the STIS/HST and FUSE. We have coadded multiple STIS and FUSE observations to obtain a high S/N...
On the nature of Extremely Red Objects: the 2 Ms Chandra Deep Field-North Survey results (2002)
Vignali, C., Alexander, D. M., Bauer, F. E., Brandt, W. N., Hornschemeier, A. E., Garmire, G. P., ...
Understanding the nature of Extremely Red Objects [EROs; (I-K)>=4] is one of the most challenging issues in observational cosmology. Here we report on the X-ray constraints provided by the 2 Ms...
Grating X-ray Spectroscopy of High-Velocity Outflows from Active Galaxies (2002)
X-ray absorption and emission lines now serve as powerful diagnostics of the outflows from active galaxies. Detailed X-ray line studies of outflows have recently been enabled for a significant number...
Vaughan, S., Boller, Th., Fabian, A. C., Ballantyne, D. R., Brandt, W. N., Trumper, J.
We present an XMM-Newton observation of the bright, narrow-line, ultrasoft Seyfert 1 galaxy Ton S180. The 0.3-10 keV X-ray spectrum is steep and curved, showing a steep slope above 2.5 keV (Gamma ~...
Bauer, F. E., Alexander, D. M., Brandt, W. N., Hornschemeier, A. E., Vignali, C., Garmire, G. P., ...
We investigate the relationship between faint X-ray and 1.4 GHz radio source populations detected within 3' of the Hubble Deep Field North using the 1 Ms Chandra and 40 uJy VLA surveys. Within this...
Chandra Detects Relativistic Broad Absorption Lines from APM 08279+5255 (2002)
Chartas, G., Brandt, W. N., Gallagher, S. C., Garmire, G. P.
We report the discovery of X-ray broad absorption lines (BALs) from the BALQSO APM 08279+5255 originating from material moving at relativistic velocities with respect to the central source. The large...
Barger, A. J., Cowie, L. L., Brandt, W. N., Capak, P., Garmire, G. P., Hornschemier, A. E., ...
We present the optical, near-infrared, submillimeter, and radio follow-up catalog of the X-ray selected sources from the 1 Ms Chandra observation of the Hubble Deep Field North region. We have B, V,...
Donley, J. L., Brandt, W. N., Eracleous, M. C., Boller, Th.
In recent years, luminous X-ray outbursts with variability amplitudes as high as ~ 400 have been serendipitously detected from a small number of active and inactive galaxies. These outbursts may...
An Exploratory Chandra survey of Large Bright Quasar Survey broad absorption line QSOs (2002)
Gallagher, S. C., Brandt, W. N., Chartas, G., Sambruna, R. M.
We are in the process of obtaining a complete sample of exploratory X-ray observations of broad absorption line (BAL) QSOs from the Large Bright Quasar Survey (LBQS). This survey is composed of short...
Brandt, W. N., Vignali, C., Fan, X., Kaspi, S., Schneider, D. P.
We review X-ray studies of the highest redshift (z > 4) quasars, focusing on recent advances enabled largely by the capabilities of Chandra and XMM-Newton. Included are discussions of basic X-ray...
Kaspi, S., Brandt, W. N., George, I. M., Netzer, H., Crenshaw, D. M., Gabel, J. R., ...
We present results from a 900 ks exposure of NGC 3783 with the High-Energy Transmission Grating Spectrometer on board the Chandra X-ray Observatory. The resulting X-ray spectrum has the best...
Alexander, D. M., Aussel, H., Bauer, F. E., Brandt, W. N., Hornschemeier, A. E., Vignali, C., ...
Using the 1 Ms Chandra Deep Field North and 15 micron ISOCAM HDF-N surveys we find a tight correlation between the population of strongly evolving starbursts discovered in faint 15 micron ISOCAM...
The Chandra Deep Field-North Survey and the Cosmic X-ray Background (2002)
Brandt, W. N., Alexander, D. M., Bauer, F. E., Hornschemeier, A. E.
Chandra has performed a 1.4 Ms survey centred on the Hubble Deep Field-North (HDF-N), probing the X-ray Universe 55-550 times deeper than was possible with pre-Chandra missions. We describe the...
Exploratory Chandra Observations of the Three Highest Redshift Quasars Known (2002)
Brandt, W. N., Schneider, D. P., Fan, X., Strauss, M. A., Gunn, J. E., Richards, G. T., ...
We report on exploratory Chandra observations of the three highest redshift quasars known (z = 5.82, 5.99, and 6.28), all found in the Sloan Digital Sky Survey. These data, combined with a previous...
Exotic sources detected in the 1 Ms Chandra Deep Field North Survey (2002)
Alexander, D. M., Bauer, F. E., Brandt, W. N., Hornschemeier, A. E., Vignali, C., Garmire, G. P., ...
We provide constraints on optically faint (I>=24) X-ray sources, z>6 AGN, Very Red Objects (VROs; I-K>=4), and optically faint radio sources using the 1 Ms Chandra Deep Field North survey. We argue...
2-8 keV X-ray number counts determined from Chandra blank field observations (2002)
Cowie, L. L., Garmire, G. P., Bautz, M. W., Barger, A. J., Brandt, W. N., Hornschemeier, A. E.
We present the 2-8 keV number counts from the 1Ms Chandra observation of the Chandra Deep Field North (CDF-N). We combine these with the number counts from a 78ks exposure of the Hawaii Survey Field...
The Luminosity Dependence of UV Absorption in AGN (2002)
We describe the results of a survey of the UV absorption properties of the Boroson & Green sample of AGN, which extends from the Seyfert (M_V ~ -21) to the luminous quasar (M_V ~ -27) level. The...
Vaughan, S., Boller, T., Fabian, A. C., Ballantyne, D. R., Brandt, W. N., Trümper, J.
We present an XMM-Newton observation of the bright, narrow- line, ultrasoft type 1 Seyfert galaxy Ton S180. The 0.3-10 keV X-ray spectrum is steep and curved, showing a steep slope above 2.5 keV...
Donley, J. L., Brandt, W. N., Eracleous, Michael, Boller, Th.
In recent years, luminous X-ray outbursts with variability amplitudes as high as 400 have been serendipitously detected from a small number of active and inactive galaxies. These outbursts may result...
Boller, Th., Fabian, A. C., Sunyaev, R., Trümper, J., Vaughan, S., Ballantyne, D. R., ...
We report the first detection of a sharp spectral feature in a narrow-line Seyfert 1 galaxy. Using XMM-Newton we have observed 1H 0707 - 495 and find a drop in flux by a factor of more than 2 at a...
Boller, T., Fabian, A. C., Sunyaev, R., Trümper, J., Vaughan, S., Ballantyne, D. R., ...
We report the first detection of a sharp spectral feature in a narrow-line Seyfert 1 galaxy. Using XMM-Newton we have observed 1H 0707 - 495 and find a drop in flux by a factor of more than 2 at a...
Variability of the X-ray P Cygni Line Profiles from Circinus X-1 Near Zero Phase (2001)
The luminous X-ray binary Circinus X-1 has been observed twice near zero orbital phase using the High-Energy Transmission Grating Spectrometer (HETGS) onboard Chandra. The source was in a high-flux...
Gallagher, S. C., Brandt, W. N., Chartas, G., Garmire, G. P., Sambruna, R.
With 40 ks of Chandra ACIS-S3 exposure, new information on both the starburst and QSO components of the X-ray emission of Markarian 231, an ultraluminous infrared galaxy and Broad Absorption Line...
The Chandra Deep Field North Survey. IX. Extended X-ray Sources (2001)
Bauer, F. E., Alexander, D. M., Brandt, W. N., Hornschemeier, A. E., Miyaji, T., Garmire, G. P., ...
The ~1 Ms Chandra Deep Field North observation is used to study the extended X-ray sources in the region surrounding the Hubble Deep Field North (HDF-N), yielding the most sensitive probe of extended...
The Chandra Deep Field North Survey. X. X-ray Emission from Very Red Objects (2001)
Alexander, D. M., Vignali, C., Bauer, F. E., Brandt, W. N., Hornschemeier, A. E., Garmire, G. P., ...
The multi-wavelength properties of Very Red Objects (VROs; I-K>=4) are largely unknown as many of these sources are optically faint (I>=24) and undetected at most wavelengths. Here we provide...
Alexander, D. M., Brandt, W. N., Hornschemeier, A. E., Garmire, G. P., Schneider, D. P., Bauer, F. E., ...
We provide constraints on the nature of the optically faint (I 24) X-ray source population from a 1 Ms Chandra exposure of a 84 × 84 region within the Hawaii flanking-field area containing the...
X-ray Spectroscopy of QSOs with Broad Ultraviolet Absorption Lines (2001)
Gallagher, S. C., Brandt, W. N., Chartas, G., Garmire, G.
For the population of QSOs with broad ultraviolet absorption lines, we are just beginning to accumulate X-ray observations with enough counts for spectral analysis at CCD resolution. From a sample of...
Boller, Th., Fabian, A. C., Sunyaev, R., Truemper, J., Vaughan, S., Ballantyne, D. R., ...
We report the first detection of a sharp spectral feature in a Narrow-Line Seyfert 1 galaxy. Using XMM-Newton we have observed 1H0707-495 and find a drop in flux by a factor of more than 2 at a...
Crenshaw, D. M., Kraemer, S. B., Turner, T. J., Collier, S., Peterson, B. M., Brandt, W. N., ...
We use Hubble Space Telescope UV and optical spectra of the narrow-line Seyfert 1 (NLS1) galaxy Akn 564 to investigate its internal reddening and properties of its emission-line and intrinsic UV...
Hornschemeier, A. E., Brandt, W. N., Alexander, D. M., Bauer, F. E., Garmire, G. P., Schneider, D. P., ...
We present a statistical X-ray study of spiral galaxies in the Hubble Deep Field-North and its Flanking Fields using the Chandra Deep Field North 1 Ms dataset. We find that approximately L_star...
J-Band Spectroscopy of the z = 5.74 BAL QSO SDSSp J104433.04-012502.2 (2001)
Goodrich, R. W., Campbell, R., Chaffee, F., Hill, G. M., Sprayberry, D., Brandt, W. N., ...
We use the NIRSPEC near-IR spectrometer on Keck II to obtain moderate resolution (R = 1540) spectroscopy that shows conclusively that the C IV emission line in the z = 5.74 quasar SDSSp...
Rapid X-ray flaring from the direction of the supermassive black hole at the Galactic Centre (2001)
Baganoff, F. K., Bautz, M. W., Brandt, W. N., Chartas, G., Feigelson, E. D., Garmire, G. P., ...
Most galactic nuclei are now believed to harbour supermassive black holes. Studies of stellar motions in the central few light-years of our Milky Way Galaxy indicate the presence of a dark object...
The Chandra Deep Field North Survey. V. 1 Ms Source Catalogs (2001)
Brandt, W. N., Alexander, D. M., Hornschemeier, A. E., Garmire, G. P., Schneider, D. P., Barger, A. J., ...
An extremely deep X-ray survey (about 1 Ms) of the Hubble Deep Field North and its environs (about 450 arcmin^2) has been performed with the Advanced CCD Imaging Spectrometer on board the Chandra...
Vignali, C., Brandt, W. N., Fan, X., Gunn, J. E., Kaspi, S., Schneider, D. P., ...
We report exploratory Chandra observations of 14 high-redshift (z=4.06-5.27), optically selected quasars. Ten of these quasars are detected, increasing the number of z>4 X-ray detected quasars by...
Alexander, D. M., Brandt, W. N., Hornschemeier, A. E., Garmire, G. P., Schneider, D. P., Bauer, F. E., ...
We provide constraints on the nature of the optically faint (I>=24) X-ray source population from a 1 Ms Chandra exposure of a 8.4x8.4 arcmin region containing the Hubble Deep Field North. We detect...
HST STIS Observations of PG 0946+301: the Highest Quality UV Spectrum of a BALQSO (2001)
Arav, Nahum, De Kool, Martijn, Korista, Kirk T., Crenshaw, D. Michael, Van Breugel, Wil, Brotherton, Michael, ...
We describe deep (40 orbits) HST/STIS observations of the BALQSO PG 0946+301 and make them available to the community. These observations are the major part of a multi-wavelength campaign on this...
The Chandra Deep Field North Survey. VII. X-ray Emission from Lyman Break Galaxies (2001)
Brandt, W. N., Hornschemeier, A. E., Schneider, D. P., Alexander, D. M., Bauer, F. E., Garmire, G. P., ...
We present results from stacking analyses, using the 1 Ms Chandra Deep Field North data, that constrain the X-ray emission of Lyman break galaxies at z = 2-4. Stacking the counts from 24 individually...
The Submillimeter Properties of the 1 Ms Chandra Deep Field North X-ray Sample (2001)
Barger, A. J., Cowie, L. L., Steffen, A. T., Hornschemeier, A. E., Brandt, W. N., Garmire, G. P.
We present submillimeter observations for 136 of the 370 X-ray sources detected in the 1 Ms exposure of the Chandra Deep Field North. Ten of the X-ray sources are significantly detected in the...
Collier, S., Crenshaw, D. M., Peterson, B. M., Brandt, W. N., Clavel, J., Edelson, R., ...
We present results of an intensive two-month campaign of approximately daily spectrophotometric monitoring of the narrow-line Seyfert 1 galaxy Akn 564 with HST. The fractional variability amplitude...
Barger, A. J., Cowie, L. L., Bautz, M. W., Brandt, W. N., Garmire, G. P., Hornschemeier, A. E., ...
We describe the optical, near-infrared, and radio properties of a sample of hard (2-7 keV) X-ray sources detected in a deep Chandra observation of the field surrounding the Abell 370 cluster. We...
X-ray Spectroscopy of BAL and Mini-BAL QSOs (2001)
Gallagher, S. C., Brandt, W. N., Chartas, G., Garmire, G. P.
BAL QSOs are notoriously faint X-ray sources, presumably due to extreme intrinsic absorption. However, several objects have begun to appear through the obscuration with recent X-ray observations by...
Brandt, W. N., Gallagher, S. C., Kaspi, S.
We briefly review X-ray studies of ionized AGN outflows and high-redshift AGN. We discuss recent progress with Chandra and XMM-Newton as well as prospects and requirements for future X-ray missions.
Nuclear obscuration in the high-ionization Seyfert 2 galaxy Tol 0109-383 (2001)
Iwasawa, K., Matt, G., Fabian, A. C., Bianchi, S., Brandt, W. N., Guainazzi, M., ...
We report the BeppoSAX detection of a hard X-ray excess in the X-ray spectrum of the classical high-ionization Seyfert 2 galaxy Tol0109-383. The X-ray emission of this source observed below 7 keV is...
Collinge, M. J., Brandt, W. N., Kaspi, Shai, Crenshaw, D. Michael, Elvis, Martin, Kraemer, Steven B., ...
We present the results from simultaneous observations of the Narrow-Line Seyfert 1 galaxy NGC 4051 with the Chandra High Energy Transmission Grating Spectrometer and the HST Space Telescope Imaging...
A Chandra Study of the Circinus Galaxy Point-Source Population (2001)
Bauer, F. E., Brandt, W. N., Sambruna, R. M., Chartas, G., Garmire, G. P., Kaspi, S., ...
We have used the Chandra X-ray Observatory to resolve spatially and spectrally the X-ray emission from the Circinus Galaxy. We report here on the nature of the X-ray emission from the off-nuclear...
Detection of Nuclear X-ray Sources in Nearby Galaxies with Chandra (2001)
Ho, Luis C., Feigelson, Eric D., Townsley, Leisa K., Sambruna, Rita M., Garmire, Gordon P., Brandt, W. N., ...
We report preliminary results from an arcsecond-resolution X-ray survey of nearby galaxies using ACIS on board Chandra. The total sample consists of 41 low-luminosity AGNs, including Seyferts,...
Brandt, W. N., Hornschemeier, A. E., Alexander, D. M., Garmire, G. P., Schneider, D. P., Broos, P. S., ...
We present results from a 479.7 ks Chandra exposure of the Hubble Deep Field North (HDF-N) and its immediate vicinity. In our X-ray image, the deepest ever reported with a 0.5-2.0 keV flux limit of...
Maeda, Y., Baganoff, F. K., Feigelson, E. D., Morris, M., Bautz, M. W., Brandt, W. N., ...
We report on the X-ray emission from the shell-like, non-thermal radio source Sgr A East located in the inner few parsecs of the Galaxy based on observations made with the ACIS detector on board...
Chandra X-ray Spectroscopic Imaging of Sgr A* and the Central Parsec of the Galaxy (2001)
Baganoff, F. K., Maeda, Y., Morris, M., Bautz, M. W., Brandt, W. N., Cui, W., ...
We present results of our Chandra observation with the ACIS-I instrument centered on the position of Sagittarius A* (Sgr A*), the compact nonthermal radio source associated with the massive black...
Kaspi, Shai, Brandt, W. N., Netzer, Hagai, George, Ian M., Chartas, George, Behar, Ehud, ...
(abridged) The high-resolution X-ray spectrum of NGC 3783 shows several dozen absorption lines and a few emission lines from the H-like and He-like ions of O, Ne, Mg, Si, and S as well as from Fe...
Hornschemeier, A. E., Brandt, W. N., Garmire, G. P., Schneider, D. P., Barger, A. J., Broos, P. S., ...
We present results from a 221.9 ks Chandra exposure of the HDF-N and its vicinity, concentrating on the 8.6' X 8.7' area covered by the Caltech Faint Field Galaxy Redshift Survey (the `Caltech...
Broad P Cygni X-ray Lines from Circinus X-1 (2000)
Chandra High Energy Transmission Grating Spectrometer (HETGS) observations of the extremely luminous and violent X-ray binary Cir X-1 reveal many X-ray emission lines showing broad P Cygni profiles....
PMN J0525-3343: soft X-ray spectral flattening in a blazar at z=4.4 (2000)
Fabian, A. C., Celotti, A., Iwasawa, K., McMahon, R. G., Carilli, C. L., Brandt, W. N., ...
We report optical, radio and X-ray observations of a new distant blazar, PMN J0525-3343, at a redshift of 4.4. The X-ray spectrum measured from ASCA and BeppoSAX flattens below a few keV, in a manner...
Comastri, A., Stirpe, G. M., Vignali, C., Brandt, W. N., Leighly, K. M., Fiore, F., ...
The BeppoSAX observations of the bright Narrow-Line Seyfert 1 galaxy Ark 564 are presented along with a high quality optical spectrum taken at the 1.5m telescope at La Silla. The 0.1-10 keV X-ray...
X-ray imaging of the Seyfert 2 galaxy Circinus with Chandra (2000)
Sambruna, R. M., Brandt, W. N., Chartas, G., Netzer, H., Kaspi, S., Garmire, G. P., ...
We present results from the zeroth-order imaging of a Chandra HETGS observation of the nearby Seyfert 2 galaxy Circinus. Twelve X-ray sources were detected in the ACIS-S image of the galaxy, embedded...
High-resolution X-ray spectroscopy of the Seyfert 2 galaxy Circinus with Chandra (2000)
Sambruna, R. M., Netzer, H., Kaspi, S., Brandt, W. N., Chartas, G., Garmire, G. P., ...
Results from a 60 ks Chandra HETGS observation of the nearby Seyfert 2 Circinus are presented. The spectrum shows a wealth of emission lines at both soft and hard X-rays, including lines of Ne, Mg,...
An XMM-Newton detection of the z=5.80 X-ray weak quasar SDSSp J104433.04-012502.2 (2000)
Brandt, W. N., Guainazzi, M., Kaspi, S., Fan, X., Schneider, D. P., Strauss, Michael A., ...
We report on an XMM-Newton observation of the most distant known quasar, SDSSp J104433.04-012502.2, at z=5.80. We have detected this quasar with high significance in the rest-frame 3.4-13.6 keV band,...
On the Origin of Intrinsic Narrow Absorption Lines in z (2000)
Ganguly, Rajib, Bond, Nicholas A., Charlton, Jane C., Eracleous, Michael, Brandt, W. N., Churchill, Christopher W.
We present a statistical analysis of the associated, high ionization narrow absorption line (NAL) systems in a sample of 59 QSOs defined from the HST QSO Absorption Line Key Project. We have compiled...
Bautz, M. W., Malm, M. R., Baganoff, F. K., Ricker, G. R., Canizares, C. R., Brandt, W. N., ...
We report the detection by Chandra of SMM J02399-0134 and SMM J02399-0136, two distant (z=1.06 and z=2.81, respectively) submillimeter sources gravitationally magnified by the galaxy cluster Abell...
We present the first grating-resolution X-ray spectra of the X-ray binary Cir X-1, obtained with the High Energy Transmission Grating Spectrometer on Chandra. These reveal a rich set of lines from...
Heavy X-ray Absorption in Soft X-ray Weak Active Galactic Nuclei (2000)
Gallagher, S. C., Brandt, W. N., Laor, A., Elvis, M., Mathur, S., Wills, Beverley J., ...
Recent ROSAT studies have identified a significant population of Active Galactic Nuclei (AGN) that are notably faint in soft X-rays relative to their optical fluxes. Are these AGN intrinsically X-ray...
Compton-Thick X-ray Absorption in the Seyfert Galaxies Tololo 0109-383 and ESO 138-G1 (2000)
Collinge, M. J., Brandt, W. N.
We present analyses of the ASCA X-ray spectra of two Seyfert galaxies, Tololo 0109-383 and ESO 138-G1. In both cases, spectral fitting reveals two statistically acceptable continuum models: Compton...
Mineo, T., Fiore, F., Laor, A., Costantini, E., Brandt, W. N., Comastri, A., ...
We present results from BeppoSAX observations of 10 low redshift quasars. The quasars are part of the Laor et al. (1997) sample of 23 optically selected PG quasars with redshift 400 eV) is however...
[OII] Emission, Eigenvector 1 and Orientation in Radio-quiet Quasars (2000)
Kuraszkiewicz, J., Wilkes, B. J., Brandt, W. N., Vestergaard, M.
We present supportive evidence that the Boroson and Green eigenvector 1 is not driven by source orientation. Until recently it was generally accepted that eigenvector 1 does not depend on orientation...
Brandt, W. N., Gallagher, S. C.
Luminous ultrasoft NLS1s and low-ionization BALQSOs share many properties, and they both represent important extremes of the active galaxy phenomenon. We briefly discuss their observational...
The UV spectra of NLS1s - Implications for their broad line regions (2000)
Kuraszkiewicz, J. K., Wilkes, B. J., Czerny, B., Mathur, S., Brandt, W. N., Vestergaard, M.
We study the UV spectra of NLS1 galaxies and compare them with typical Seyfert 1 galaxies and quasars. The NLS1 spectra show narrower UV lines as well as weaker CIV lambda 1549 and CIII] lambda 1909...
Boller, Th., Fabian, A. C., Brandt, W. N., Freyberg, M. J.
We report on a ROSAT PSPC observation of the highly-luminous z = 4.72 radio-loud quasar GB 1428+4217 obtained between 1998 December 11 and 17, the final days of the ROSAT satellite. The low-energy...
X-ray Sources in the Hubble Deep Field Detected by Chandra (2000)
Hornschemeier, A. E., Brandt, W. N., Garmire, G. P., Schneider, D. P., Broos, P. S., Townsley, L. K., ...
We present first results from an X-ray study of the Hubble Deep Field North (HDF-N) and its environs obtained using 166 ks of data collected by the Advanced CCD Imaging Spectrometer (ACIS) on board...
Discovery of Narrow X-ray Absorption Lines from NGC 3783 with the Chandra HETGS (2000)
Kaspi, Shai, Brandt, W. N., Netzer, Hagai, Sambruna, Rita, Chartas, George, Garmire, Gordon P., ...
We present the first grating-resolution X-ray spectra of the Seyfert 1 galaxy NGC 3783, obtained with the High Energy Transmission Grating Spectrometer on the Chandra X-ray Observatory. These spectra...
ROSAT HRI monitoring of X-ray variability in the NLS1 galaxy PKS 0558-504 (2000)
Gliozzi, M., Boller, Th., Brinkmann, W., Brandt, W. N.
We present the results of ROSAT High Resolution Imager (HRI) observations and the survey data of the radio-loud Narrow-Line Seyfert 1 galaxy (NLS1) PKS 0558--504. We find strong and persistent X-ray...
Brandt, W. N., Hornschemeier, A. E., Schneider, D. P., Garmire, G. P., Chartas, G., Hill, Gary J., ...
We present results from a study of 2-8 keV X-ray sources detected by the Advanced CCD Imaging Spectrometer (ACIS) instrument on the Chandra X-ray Observatory in the field of the z=0.516 cluster CRSS...
A broadband X-ray view of NGC4945 (2000)
Guainazzi, M., Matt, G., Brandt, W. N., Antonelli, L. A., Barr, P., Bassani, L.
We present the results of a BeppoSAX observation of the nearby spiral galaxy NGC4945 in the 0.1-200 keV energy band. The nuclear X-ray emission emerges above ~7 keV, through an absorber with column...
The X-ray Properties of z>4 Quasars (2000)
Kaspi, Shai, Brandt, W. N., Schneider, Donald P.
We report on a search for X-ray emission from quasars with redshifts greater than four using the ROSAT public database. Our search has doubled the number of z>4 quasars detected in X-rays from 6 to...
New X-ray Constraints on Starburst and Seyfert Activity in the Barred Spiral Galaxy NGC 1672 (1999)
De Naray, P. J., Brandt, W. N., Halpern, J. P., Iwasawa, K.
The nearby barred spiral galaxy NGC 1672 shows dramatic starburst activity and may also host a Seyfert 2 nucleus. We present new X-ray observations that set constraints on starburst and Seyfert...
X-ray Absorption in Radio-Quiet QSOs (1999)
Brandt, W. N., Gallagher, S. C., Laor, A., Wills, Beverley J.
Major flows of ionized gas are thought to be present in the nuclei of most luminous QSOs, and absorption by these flows often has a significant effect upon the observed X-ray continuum from the black...
BeppoSAX unveils the nuclear component in NGC 6240 (1999)
Vignati, P., Molendi, S., Matt, G., Guainazzi, M., Antonelli, L. A., Bassani, L., ...
The direct nuclear X-ray emission of the ultraluminous IRAS galaxy NGC 6240 has been observed for the first time by BeppoSAX. It is seen through an absorber with N_H=2*10^{24} cm^{-2}. The 2-10 keV...
On the Nature of Soft X-ray Weak Quasi-Stellar Objects (1999)
Brandt, W. N., Laor, A., Wills, Beverley J.
Recent studies of QSOs with ROSAT suggest the existence of a significant population of Soft X-ray Weak QSOs (SXW QSOs) where the soft X-ray flux is ~ 10-30 times smaller than in typical QSOs. As a...
Lee, J. C., Fabian, A. C., Brandt, W. N., Reynolds, C. S., Iwasawa, K.
We report on a joint ASCA and RXTE observation spanning an $\sim$ 400~ks time interval of the bright Seyfert~1 galaxy MCG--6-30-15. The data clearly confirm the presence of a broad skewed iron line...
Variability of the extreme z=4.72 blazar, GB 1428+4217 (1999)
Fabian, A. C., Celotti, A., Pooley, G., Iwasawa, K., Brandt, W. N., McMahon, R. G., ...
We report X-ray and radio variability of GB 1428+4217 which confirm its blazar nature. IR observations reveal a powerful optical-UV component, not obscured by dust, which is suggestive of the...
Wills, Beverley J., Brandt, W. N., Laor, A.
The existence of BAL outflows in only radio-quiet QSOs was thought to be an important clue to mass ejection and the radio-loud - radio-quiet dichotomy. Recently a few radio-loud BAL QSOs have been...
The optical variability of the narrow line Seyfert 1 galaxy IRAS 13224-3809 (1999)
Young, A. J., Crawford, C. S., Fabian, A. C., Brandt, W. N., O'Brien, P. T.
We report on a short optical monitoring programme of the narrow-line Seyfert 1 Galaxy IRAS 13224-3809. Previous X-ray observations of this object have shown persistent giant variability. The degree...
Exploratory ASCA Observations of Broad Absorption Line Quasi-Stellar Objects (1999)
Gallagher, S. C., Brandt, W. N., Sambruna, R. M., Mathur, S., Yamasaki, N.
We present the analysis and interpretation of a sample of eight ASCA observations of Broad Absorption Line Quasi-Stellar Objects (BALQSOs). This is the first moderate-sized sample of sensitive BALQSO...
ROSAT HRI Monitoring of Extreme X-ray Variability in the Narrow-Line Quasar PHL 1092 (1999)
Brandt, W. N., Boller, Th., Fabian, A. C., Ruszkowski, M.
We report results from an 18-day ROSAT HRI monitoring campaign on the ultrasoft Narrow-Line Seyfert 1 (NLS1) class quasar PHL 1092. This luminous, radio-quiet quasar showed strong X-ray variability...
A Simultaneous ASCA and RXTE Long Look at the Seyfert 1 Galaxy MCG--6-30-15 (1998)
Lee, J. C., Fabian, A. C., Iwasawa, K., Brandt, W. N., Reynolds, C. S.
We report on a joint RXTE and ASCA observation spanning $\sim$ 400~ks of the Seyfert 1 galaxy MCG--6-30-15. The low energy coverage of ASCA coupled with the high energy coverage of RXTE have allowed...
Matt, G., Guainazzi, M., Maiolino, R., Molendi, S., Perola, G. C., Antonelli, L. A., ...
The Circinus Galaxy has been observed, for the first time above 10 keV, by BeppoSAX. An excess emission above the extrapolation of the best fit 0.1--10 keV spectrum is apparent in the PDS data. The...
Limits on the X-ray emission from several hyperluminous IRAS galaxies (1998)
Wilman, R. J., Fabian, A. C., Cutri, R. M., Crawford, C. S., Brandt, W. N.
We report long, pointed ROSAT HRI observations of the hyperluminous galaxies IRAS F00235+1024, F12514+1027, F14481+4454 and F14537+1950. Two of them are optically classified as Seyfert-like. No X-ray...
Recent X-ray observations have advanced the study of ultrasoft Narrow-Line Seyfert 1 galaxies and have revealed strikingly clear correlations between optical emission line properties and the shape of...
1H0419-577: A "two-state" soft X-ray Seyfert galaxy (1998)
Guainazzi, M., Comastri, A., Stripe, G. M., Brandt, W. N., Fiore, F., Leighly, K. M., ...
In this paper we report on the first simultaneous optical and X-ray (Beppo-SAX) observations of the radio-quiet AGN 1H0419-577. The optical spectrum clearly leads us to classify this source as a...
Heavy and Complex X-ray Absorption Towards the Nucleus of Markarian 6 (1998)
Feldmeier, John, Brandt, W. N., Elvis, M., Fabian, A. C., Iwasawa, K., Mathur, S.
We have used the ASCA satellite to make the first X-ray spectra of Markarian 6, a bright Seyfert 1.5 galaxy with complex and variable permitted lines, an ionization cone, and remarkable radio...
Conference on Structure and Kinematics of Quasar Broad Line Regions (1998)
Gaskell, C M, Brandt, W N, Dietrich, M, Dulzin-Hacyan, D, Eracleous, M
Lee, J. C., Fabian, A. C., Reynolds, C. S., Iwasawa, K., Brandt, W. N.
We report on a 50 ks observation of the bright Seyfert 1 galaxy MCG--6-30-15 with the Rossi X-ray Timing Explorer. The data clearly show the broad fluorescent iron line (equivalent width ~ 250 eV),...
The changing X-ray period of the Seyfert galaxy IRAS18325-5926 (1998)
Fabian, A. C., Lee, J. C., Brandt, W. N., Iwasawa, K., Jahoda, K., Reynolds, C. S.
We report on two observations of the Seyfert galaxy IRAS18325-5926 made in 1997 December and 1998 February with the Rossi X-ray Timing Explorer (RXTE). We find evidence for periodicities in the...
The ASCA spectrum of the z=4.72 blazar, GB 1428+4217 (1998)
Fabian, A. C., Iwasawa, K., Celotti, A., Brandt, W. N., McMahon, R. G., Hook, I. M.
The X-ray luminous quasar GB 1428+4217 at redshift 4.72 has been observed with ASCA. The observed 0.5-10 keV flux is 3.2E-12 erg/s/cm2. We report here on the intrinsic 4-57 keV X-ray spectrum, which...
Detection of an X-ray periodicity in the Seyfert galaxy IRAS18325-5926 (1998)
Iwasawa, K., Fabian, A. C., Brandt, W. N., Kunieda, H., Misaki, K., Reynolds, C. S., ...
We report the detection of a 58 ks (16 hr) periodicity in the 0.5-10 keV X-ray light curve of the Seyfert galaxy IRAS18325-5926 (Fairall49), obtained from a 5-day ASCA observation. Nearly 9 cycles of...
Comastri, A., Brandt, W. N., Leighly, K. M., Fiore, F., Guainazzi, M., Matt, G., ...
Results are presented for the first year of observations of a selected sample of Narrow-Line Seyfert 1 galaxies (Ton S 180, RE J1034+396, Ark 564) obtained with the imaging instruments onboard...
1H0419-577: a two-state Seyfert Galaxy? (1997)
Guainazzi, M., Comastri, A., Stirpe, G., Brandt, W. N., Parmar, A., Puchnarewicz, E. M.
The preliminary results of the BeppoSAX observation of the radio-quiet AGN 1H0419-577 are presented. Despite its broad line optical spectrum, the intermediate X-ray spectrum (i.e. 2--10 keV) is...
BeppoSAX observations of Narrow-Line Seyfert 1 galaxies:I. Ton S 180 (1997)
Comastri, A., Fiore, F., Guainazzi, M., Matt, G., Stirpe, G. M., Zamorani, G., ...
We report on the first spectrum up to 10 keV of the bright narrow-line Seyfert 1 galaxy Ton S 180, obtained with the imaging instruments onboard BeppoSAX. This is the first observed source in a...
Ultrasoft Narrow-Line Seyfert 1 Galaxies and X-ray Surveys (1997)
We describe how recent X-ray surveys have led to advances in the understanding of ultrasoft narrow-line Seyfert 1 galaxies. The number of known ultrasoft narrow-line Seyfert 1s has increased greatly...
ROSAT HRI observations of the Local Group galaxies IC 10, NGC 147 and NGC 185 (1997)
Brandt, W. N., Ward, M. J., Fabian, A. C., Hodge, P. W.
We report on pointed X-ray observations of IC 10, NGC 147 and NGC 185 made with the ROSAT High Resolution Imager (HRI). These are three Local Group galaxies that have never been previously studied in...
Optical and X-ray properties of the RIXOS AGN: II - Emission lines (1997)
Puchnarewicz, E. M., Mason, K. O., Carrera, F. J., Brandt, W. N., Cabrera-Guera, F., Carballo, R., ...
We present the optical and UV emission line properties of 160 X-ray selected AGN taken from the RIXOS survey (including Halpha, Hbeta, [OIII]5007, MgII2798 and CIII]1909). This sample is believed to...
AXJ1749+684: a narrow emission-line galaxy with a flat X-ray spectrum (1997)
Iwasawa, K., Fabian, A. C., Brandt, W. N., Crawford, C. S., Almaini, O.
We report the serendipitous detection of an X-ray source, AXJ1749+684, with the ASCA Gas Imaging Spectrometer. AXJ1749+684 is identified with a LINER/starburst-type spiral galaxy KUG 1750+683A at a...
X-ray absorption in the strong FeII narrow-line Seyfert 1 galaxy Mrk 507 (1997)
Iwasawa, K., Brandt, W. N., Fabian, A. C.
We present results from spectral analysis of ASCA data on the NLS1 Mrk 507. This galaxy was found to have an exceptionally flat ROSAT spectrum among the NLS1s. The ASCA spectrum however shows a clear...
X-ray absorption by ionized oxygen in ASCA spectra of the infrared quasar IRAS 13349+2438 (1997)
Brandt, W. N., Mathur, S., Reynolds, C. S., Elvis, M.
We present evidence for X-ray absorption by ionized oxygen in ASCA spectra of the prototype infrared quasar IRAS 13349+2438. This powerful (2E46 erg/s) quasar was studied in detail with ROSAT, and...
Hard X--ray detection of NGC 1068 with BeppoSAX (1997)
Matt, G., Guainazzi, M., Frontera, F., Bassani, L., Brandt, W. N., Fabian, A. C., ...
We report on the first detection above ~10 keV of the archetypal Compton-thick Seyfert 2 galaxy NGC 1068. This detection, obtained with the PDS instrument onboard BeppoSAX in the 20-100 keV range,...
Boller, Th., Brandt, W. N., Fabian, A. C., Fink, H. H.
We report evidence for persistent giant and rapid X-ray variability in the radio-quiet, ultrasoft, strong Fe II, narrow-line Seyfert 1 galaxy IRAS 13224-3809. Within a 30 day ROSAT High Resolution...
A comparison of the hard ASCA spectral slopes of broad and narrow-line Seyfert 1 galaxies (1997)
Brandt, W. N., Mathur, S., Elvis, M.
The soft (\approx 0.1--2.0 keV) X-ray spectra of narrow-line Seyfert 1 galaxies are known to be generally steeper than those of Seyfert 1 galaxies with broader optical permitted lines. This has been...
ASCA observations of the nearby galaxies Dwingeloo 1 and Maffei 1 (1996)
Reynolds, C. S., Loan, A. J., Fabian, A. C., Makishima, K., Brandt, W. N., Mizuno, T.
We present ASCA observations of the nearby galaxies Dwingeloo 1 (Dw1) and Maffei 1 (Mf1). X-ray sources are clearly detected within 3 arcminutes of the optical nuclei of both galaxies. Despite the...
Brandt, W. N., Fabian, A. C., Dotani, T., Nagase, F., Inoue, H., Kotani, T., ...
We report on ASCA energy spectra of Cir X-1 taken near its zero phase on 1994 August 4-5. The ASCA SIS detectors allow a more detailed study of the iron K complex than has been possible before. We...
Brandt, W. N., Iwasawa, K., Reynolds, C. S.
We report on a powerful and variable off-nuclear X-ray source in the nearby spiral galaxy NGC 4945. Two ROSAT PSPC observations show the source to brighten in 0.5--2.0 keV flux by a factor of about 9...
Steep Spectrum Seyfert Galaxies (1996)
Seyfert-type AGN that exhibit unusually strong and steep soft X-ray spectra are reviewed, building on observations made during the ROSAT all-sky survey. Two individual cases are described in brief...
The variable iron K emission line in MCG-6-30-15 (1996)
Iwasawa, K., Fabian, A. C., Reynolds, C. S., Nandra, K., Otani, C., Inoue, H., ...
We report on the variability of the iron K emission line in the Seyfert 1 galaxy MCG--6-30-15 during a four-day ASCA observation. The line consists of a narrow core at an energy of about 6.4 keV, and...
ROSAT PSPC and Hri Observations of the Composite Starburst/Seyfert 2 Galaxy NGC 1672 (1996)
Brandt, W. N., Halpern, J. P., Iwasawa, K.
The nearby barred spiral galaxy NGC 1672 is thought to have a weak Seyfert nucleus in addition to its strong starburst activity. Observations with the PSPC and HRI instruments on board the ROSAT...
Ross, R. R., Fabian, A. C., Brandt, W. N.
We consider the spectra of Thomson-thick, geometrically-thin accretion discs around Galactic black hole candidates in the reflection model and compute their iron K edges and iron K$\alpha$ lines. We...
Brandt, W. N., Fabian, A. C., Pounds, K. A.
We present spatial, temporal and spectral analyses of ROSAT Position Sensitive Proportional Counter (PSPC) observations of the infrared loud quasar IRAS 13349+2438. IRAS 13349+2438 is the archetypal...
On broad iron K-alpha lines in Seyfert 1 galaxies (1995)
Fabian, A. C., Nandra, K., Reynolds, C. S., Brandt, W. N., Otani, C., Tanaka, Y., ...
The X-ray spectrum obtained by Tanaka et al from a long observation of the active galaxy MCG$-6-30-15$ shows a broad iron K$\alpha$ line skewed to low energies. The simplest interpretation of the...
Soft X-ray properties of "narrow-line" Seyfert 1 galaxies (1995)
Boller, Th., Brandt, W. N., Fink, H.
We report on AGN with extremely soft X-ray spectra observed with ROSAT. From their optical emission lines these objects are classified as narrow-line Seyfert 1 galaxies (NLS1), almost all with...
THE UNUSUAL X-RAY AND OPTICAL PROPERTIES OF THE ULTRASOFT AGN ZWICKY 159.034 (RE J 1237+264) (1995)
Brandt, W. N., Pounds, K. A., Fink, H.
Zwicky 159.034, one of the Seyfert galaxies identified with EUV sources detected during the ROSAT Wide Field Camera (WFC) all-sky survey, has unusual properties. The ROSAT Position Sensitive...
Brandt, W. N., Podsiadlowski, Ph.
We systematically investigate the effects of high supernova kick velocities on the orbital parameters of post-supernova neutron-star binaries. Using Monte- Carlo simulations, we determine the...
Brandt, W. N., Fabian, A. C., Nandra, K., Reynolds, C. S., Brinkmann, W.
We present spatial, temporal and spectral analyses of ROSAT Position Sensitive Proportional Counter (PSPC) observations of the Seyfert 1 galaxies Ark 564, NGC 985, Kaz 163, Mrk 79 and RX...