Galaxies at Redshift ~0.5 Around Three Closely Spaced Quasar Sightlines (2009)
Crighton, Neil H. M., Morris, Simon L., Bechtold, Jill, Crain, Robert A., Jannuzi, Buell T., Shone, Allen, ...
We examine the relationship between galaxies and the intergalactic medium at z < 1 using a group of three closely spaced background QSOs with z_em ~1 observed with the Hubble Space Telescope. Using a...
Host Galaxies of z=4 Quasars (2009)
We have undertaken a project to investigate the host galaxies and environments of a sample of quasars at z~4. In this paper, we describe deep near-infrared imaging of 34 targets using the Magellan I...
An Observational Determination of the Proton to Electron Mass Ratio in the Early Universe (2009)
Thompson, Rodger I., Bechtold, Jill, Black, John H., Eisenstein, Daniel, Fan, Xiaohui, Kennicutt, Robert C., ...
In an effort to resolve the discrepancy between two measurements of the fundamental constant mu, the proton to electron mass ratio, at early times in the universe we reanalyze the same data used in...
Are the Variations in Quasar Optical Flux Driven by Thermal Fluctuations? (2009)
Kelly, Brandon C., Bechtold, Jill, Siemiginowska, Aneta
We analyze a sample of optical light curves for 100 quasars, 70 of which have black hole mass estimates. Our sample is the largest and broadest used yet for modeling quasar variability. The sources...
Galaxies at redshift ~0.5 around three closely spaced quasar sightlines (2009)
Crighton, Neil H. M., Morris, Simon L., Bechtold, Jill, Crain, Robert A., Jannuzi, Buell T., Shone, Allen, ...
We examine the relationship between galaxies and the intergalactic medium at z > 1 using a group of three closely spaced background QSOs with z_em ~1 observed with the Hubble Space Telescope. Using a...
Alternative Data Reduction Procedures for UVES: Wavelength Calibration and Spectrum Addition (2008)
Thompson, Rodger I., Bechtold, Jill, Black, John H.
This paper addresses alternative procedures to the ESO supplied pipeline procedures for the reduction of UVES spectra of two quasar spectra to determine the value of the fundamental constant mu =...
X-ray Properties of the GigaHertz-Peaked and Compact Steep Spectrum Sources (2008)
Siemiginowska, Aneta, LaMassa, Stephanie, Aldcroft, Thomas L., Bechtold, Jill, Elvis, Martin
We present {\it Chandra} X-ray Observatory observations of Giga-Hertz Peaked Spectrum (GPS) and Compact Steep Spectrum (CSS) radio sources. The {\it Chandra} sample contains 13 quasars and 3 galaxies...
Kelly, Brandon C., Bechtold, Jill, Trump, Jonathan R., Vestergaard, Marianne, Siemiginowska, Aneta
In this work we use a sample of 318 radio-quiet quasars (RQQ) to investigate the dependence of the ratio of optical/UV flux to X-ray flux, alpha_ox, and the X-ray photon index, Gamma_X, on black hole...
A deep large binocular telescope view of the Canes Venatici I dwarf galaxy (2008)
Martin, Nicolas F., Coleman, Matthew G., Rix, Hans-Walter, Bell, Eric F., Sand, David J., ...
Discovery of the dust-enshrouded progenitor of SN 2008S with Spitzer (2008)
Prieto, José L., Kistler, Matthew D., Thompson, Todd A., Yüksel, Hasan, Kochanek, Christopher S., Stanek, Krzysztof Z., ...
We report the discovery of the progenitor of the recent Type IIn SN 2008S in the nearby galaxy NGC 6946. Surprisingly, it was not found in deep, preexplosion optical images of its host galaxy taken...
A deep Large Binocular Telescope view of the Canes Venatici I dwarf galaxy (2008)
Martin, Nicolas F., Coleman, Matthew G., Rix, Hans-Walter, Bell, Eric F., Sand, David J., ...
We present the first deep color-magnitude diagram of the Canes Venatici I (CVn I) dwarf galaxy from observations with the wide-field Large Binocular Camera on the Large Binocular Telescope. Reaching...
Jennifer Scott, Jill Bechtold, Adam Dobrzycki, Varsha P. Kulkarni
Moderate-resolution data for 40 quasi-stellar objects (QSOs) at z B 2 were combined with spectra of comparable resolution of 59 QSOs with redshifts greater than 1.7 found in the literature to form a...
Jennifer Scott, Jill Bechtold, Miwa Morita, Adam Dobrzycki, Varsha P. Kulkarni
extragalactic ionizing background at low redshift
Jennifer Scott, Jill Bechtold, Adam Dobrzycki
We present moderate-resolution data for 39 quasi-stellar objects (QSOs) at z B 2 obtained at the Multiple Mirror Telescope. These data are combined with spectra of comparable resolution of 60 QSOs...
Jill Bechtold, Adam Dobrzycki, Brenda Wilden, Miwa Morita, Jennifer Scott, Danuta Dobrzycka, ...
2 We analyzed the absorption line spectra of all quasars observed with the high resolution gratings of the Faint Object Spectrograph on board the Hubble Space Telescope. We examined 788 spectra for...
Adam Dobrzycki, Jill Bechtold, Jennifer Scott, Miwa Morita
A uniform analysis of the Ly- forest at z = 0 5:
Michael A. Pahre, S. G. Djorgovski, Jill Bechtold, Richard Elston
We report the detection, both in line and continuum emission, of a galaxy responsible for a damped Lyff absorption (DLA) system at z = 3:15 projected 2:3
A deep Large Binocular Telescope view of the Canes Venatici I dwarf galaxy (2007)
Martin, Nicolas F., Coleman, Matthew G., Rix, Hans-Walter, Bell, Eric F., Sand, David J., ...
We present the first deep color-magnitude diagram of the Canes Venatici I (CVnI) dwarf galaxy from observations with the wide field Large Binocular Camera on the Large Binocular Telescope. Reaching...
Siemiginowska, Aneta, Aldcroft, Thomas L., Burke, Doug, Bechtold, Jill, Cheung, C. C., LaMassa, Stephanie, ...
X-ray cluster emission has been observed mainly in clusters with "inactive" cD galaxies (L_bol ~1E40-1E43erg/sec), which do not show signs of accretion onto a SMBH. Our recent Chandra discovery of...
The Case of the 300 kpc Long X-ray Jet in PKS 1127-145 at z=1.18 (2007)
Siemiginowska, Aneta, Harris, D. E., Aldcroft, Thomas L., Stawarz, Lukasz, Cheung, C. C., Sikora, Marek, ...
The complex X-ray morphology of the 300 kpc long X-ray jet in PKS1127-145 (z=1.18 quasar) is clearly discerned in a ~100 ksec Chandra observation. The jet X-ray surface brightness gradually decreases...
The Elongated Structure of the Hercules dSph from Deep LBT Imaging (2007)
Coleman, Matthew G., Martin, Nicolas F., Rix, Hans-Walter, Sand, David J., Bell, Eric F., ...
We present a deep, wide-field photometric survey of the newly-discovered Hercules dwarf spheroidal galaxy, based on data from the Large Binocular Telescope. Images in B, V and r were obtained with...
Coleman, Matthew G., Martin, Nicolas F., Rix, Hans-Walter, Sand, David J., Bell, Eric F., ...
We present a deep, wide-field photometric survey of the newly discovered Hercules dwarf spheroidal galaxy (dSph), based on data from the Large Binocular Telescope. Images in B, V, and r were obtained...
The 300 kpc Long X-ray Jet in PKS 1127-145, z=1.18 Quasar: Constraining X-ray Emission Models (2006)
Siemiginowska, Aneta, Stawarz, Lukasz, Cheung, C. C., Harris, D. E., Sikora, Marek, Aldcroft, Thomas L., ...
We present a ~100 ksec Chandra X-ray observation and new VLA radio data of the large scale, 300 kpc long X-ray jet in PKS1127-145, a radio loud quasar at redshift z=1.18. With this deep X-ray...
Evolution of the X-ray Emission of Radio-Quiet Quasars (2006)
Kelly, Brandon C., Bechtold, Jill, Siemiginowska, Aneta, Aldcroft, Tom, Sobolewska, Malgorzata
We report new Chandra observations of seven optically faint, z \sim 4 radio-quiet quasars. We have combined these new observations with previous Chandra observations of radio-quiet quasars to create...
Virial Masses of Black Holes from Single Epoch Spectra of AGN (2006)
Kelly, Brandon C., Bechtold, Jill
We describe the general problem of estimating black hole masses of AGN by calculating the conditional probability distribution of M_BH given some set of observables. Special attention is given to the...
Elemental Abundance Measurements in Low-redshift Damped Lyman Alpha Absorbers (2006)
Meiring, Joseph D., Kulkarni, Varsha P., Khare, Pushpa, Bechtold, Jill, York, Donald G., Cui, Jun, ...
We present elemental abundance measurements for 9 damped Ly-alpha systems (DLAs) and 1 sub-DLA at 0.1 < z < 1.5 from recent observations with the Multiple Mirror Telescope. Most of these absorbers...
Molecular Hydrogen in the Damped Ly alpha Absorber of Q1331+170 (2005)
Cui, Jun, Bechtold, Jill, Ge, Jian, Meyer, David M.
We used HST/STIS to obtain the spectrum of molecular hydrogen associated with the damped Ly$\alpha$ system at $z_{\rm abs}=1.7765$ toward the quasar Q1331+170 at $z_{\rm em}=2.084$. Strong ${\rm...
X-ray Cluster Associated with the z=1.063 CSS Quasar 3C 186: The Jet is NOT Frustrated (2005)
Siemiginowska, Aneta, Cheung, C. C., LaMassa, Stephanie, Burke, D. J., Aldcroft, Thomas L., Bechtold, Jill, ...
We report the Chandra discovery of an X-ray cluster at redshift z = 1.063 associated with the Compact Steep Spectrum radio loud quasar 3C 186 (Q0740+380). Diffuse X-ray emission is detected out to...
X-Ray Emission from the Quasar PKS 1127-145: Comptonized IR Photons on Parsec Scales (2003)
Blazejowski, Michal, Siemiginowska, Aneta, Sikora, Marek, Moderski, Rafal, Bechtold, Jill
We model the broad-band spectral energy distribution of the innermost "core-jet" region of the redshift z=1.187 quasar PKS 1127-145. We propose a scenario where the high energy photons are produced...
X-ray emission from GPS/CSS sources (2003)
Siemiginowska, Aneta, Aldcroft, Thomas L., Bechtold, Jill, Brunetti, Gianfranco, Elvis, Martin, Stanghellini, Carlo
The high spatial resolution of the Chandra X-ray Observatory allows us to study the environment of GPS/CSS sources to within an arcsec of the strong compact core. We present the discovery of X-ray...
Chandra Discovery of an X-ray jet and Extended X-ray Structure in z=0.63 quasar, B2 0738+313 (2003)
Siemiginowska, Aneta, Stanghellini, Carlo, Brunetti, Gianfranco, Fiore, Fabrizio, Aldcroft, Thomas L., Bechtold, Jill, ...
We have made a 30 ksec Chandra observation of the redshift z=0.63 GPS quasar B2 0738+313. We detected X-ray emission from the core and have discovered a 200 kpc (projected on the sky) X-ray jet. The...
Chandra Survey of Radio-quiet, High-redshift Quasars (2002)
Bechtold, Jill, Siemiginowska, Aneta, Shields, Joseph, Czerny, Bozena, Janiuk, Agnieszka, Hamann, Fred, ...
We observed 17 optically-selected, radio-quiet high-redshift quasars with the Chandra Observatory ACIS, and detected 16 of them. The quasars have redshift between 3.70 and 6.28 and include the...
Chandra Discovery of a 300 kpc X-ray Jet in the GPS Quasar PKS1127-145 (2002)
Siemiginowska, Aneta, Bechtold, Jill, Aldcroft, Thomas L., Elvis, Martin, Harris, D. E., Dobrzycki, Adam
We have discovered an X-ray jet with Chandra imaging of the z=1.187 radio-loud quasar PKS1127-145. In this paper we present the Chandra X-ray data, follow-up VLA observations, and optical imaging...
Quasar Absorption Lines (2001)
The absorption lines observed in quasar spectra have given us a detailed picture of the intergalactic medium and the metal abundance and kinematics of high redshift galaxies. In this review, we...
Scott, Jennifer, Bechtold, Jill, Morita, Miwa, Dobrzycki, Adam, Kulkarni, Varsha
In Paper III of our series "A Uniform Analysis of the Ly-alpha forest at z=0 - 5", we presented a set of 270 quasar spectra from the archives of the Faint Object Spectrograph on the Hubble Space...
A uniform analysis of the Lyman alpha forest at z = 0-5: III. HST FOS Spectral Atlas (2001)
Bechtold, Jill, Dobrzycki, Adam, Wilden, Brenda, Morita, Miwa, Scott, Jennifer, Dobrzycka, Danuta, ...
We analyzed the absorption line spectra of all quasars observed with the high resolution gratings of the Faint Object Spectrograph on board the Hubble Space Telescope. We examined 788 spectra for 334...
Dobrzycki, Adam, Bechtold, Jill, Scott, Jennifer, Morita, Miwa
We present results on the evolution and clustering of Ly-alpha lines at low z. The sample contains 1298 Ly-alpha lines from 165 quasar spectra mined from the archives of the HST/FOS. Our sample...
Chandra Detection of X-ray Absorption Associated with a Damped Lyman Alpha System (2001)
Bechtold, Jill, Siemiginowska, Aneta, Aldcroft, Thomas L., Elvis, Martin, Dobrzycki, Adam
We have observed three quasars, PKS 1127-145, Q 1331+171 and Q0054+144, with the ACIS-S aboard the Chandra X-ray Observatory, in order to measure soft X-ray absorption associated with intervening...
Kuhn, Olga, Elvis, Martin, Bechtold, Jill, Elston, Richard
For 15 bright (V3) quasars, we have obtained IR spectra and photometry, and optical spectrophotometry and photometry, which we use to construct their rest-frame 1285-5100 AA spectral energy...
150 keV Emission from PKS2149-306 with BeppoSAX (2000)
Elvis, Martin, Fiore, Fabrizio, Siemiginowska, Aneta, Bechtold, Jill, Mathur, Smita, McDowell, Jonathan
A BeppoSAX observation of the z=2.34 quasar PKS2149-306 produced a strong signal in the high energy PDS instrument up to a maximum observed energy of nearly 50 keV, 150 keV in the quasar frame. The...
Q1208+1011: Search for the lensing galaxy (1998)
Siemiginowska, Aneta, Bechtold, Jill, Aldcroft, Thomas L., McLeod, K. K., Keeton, Charles R.
We present a high-resolution spectrum of the high redshift, lensed quasar Q1208+1101, obtained with the echellette spectrograph on the Multiple Mirror Telescope. We examine the new and published...
Star Formation in High Redshift Galaxies (1998)
Bechtold, Jill, Elston, Richard, Yee, Howard K. C., Ellingson, Erica, Cutri, Roc M.
Observations of the high redshift Universe, interpreted in the context of a new generation of computer simulated model Universes, are providing new insights into the processes by which galaxies and...
Distribution of the Lyman-alpha Forest at z = 0.0-1.7 (1997)
Dobrzycki, Adam, Bechtold, Jill
We present the analysis of a sample of the Ly-$\alpha$ forest spectra of 152 quasars taken with the HST FOS. The Ly-$\alpha$ lines show little evolution at $0
Spectroscopy of PKS 0528-260: New Limits on CO Absorption and Emission (1997)
Ge, Jian, Bechtold, Jill, Walker, Constance, Black, H.
We have obtained a moderate resolution spectrum of the quasar PKS 0528-250 with the Red Channel Spectrograph on the Multiple Mirror Telescope (MMT) in order to study a damped Lyman alpha absorption...
We present a new ultra-violet spectrum of the QSO 0013-004 with 0.9 \AA resolution obtained with the MMT Blue spectrograph. The \upsilon = 0 - 0, 1 - 0, 2 - 0 and 3 - 0 Lyman bands of H_2 associated...
A New Measurements of the Cosmic Microwave Background Radiation Temperature at z = 1.97 (1996)
Ge, Jian, Bechtold, Jill, Black, John H.
We present detections of absorption from the ground state and excited states of C I in the z = 1.9731 damped Ly\al\ system of the QSO 0013$-$004. The excitation temperature between the J = 0 and J =...
The Size and Nature of Lyman alpha Forest Clouds Probed by QSO Pairs and Groups (1995)
Fang, Yihu, Duncan, Robert C., Crotts, Arlin P. S., Bechtold, Jill
We describe a robust Bayesian statistical method for determining Lyman alpha forest cloud sizes in spherical and in thin disk geometries, using absorption in adjacent sightlines toward closely...
Bechtold, Jill, Crotts, Arlin P. S., Duncan, Robert C., Fang, Yihu
We have obtained spectroscopy of Q 1343+266 AB, a pair of quasars at redshift z = 2.03 with a projected separation of 9.5 arcseconds. This system is well-suited for probing the Ly-alpha forest, since...
Crotts, Arlin P. S., Bechtold, Jill, Fang, Yihu, Duncan, Robert C.
We present spectra of QSOs 1343+266 A B, covering Ly-beta to C~IV emission at 2\AA~resolution, and find further evidence that this system is not gravitationally lensed. We see, however, a large...