A Vigorous Explorer Program (2009)
Elvis, Martin, Beasley, Matthew, Brissenden, Roger, Chakrabarti, Supriya, Cherry, Michael, Devlin, Mark, ...
Explorers have made breakthroughs in many fields of astrophysics. The science from both these missions contributed to three Nobel Prizes - Giacconi (2002), Mather, and Smoot (2006). Explorers have:...
The Quasar Mass-Luminosity Plane II: High Mass Turnoff Evolution and a Synchronization Puzzle (2009)
Steinhardt, Charles L., Elvis, Martin
We use 62,185 quasars from the Sloan Digital Sky Survey DR5 sample and standard virial mass scaling laws based on the widths of H beta, Mg II, and C IV lines and adjacent continuum luminosities to...
The Quasar Mass-Luminosity Plane I: A Sub-Eddington Limit for Quasars (2009)
Steinhardt, Charles L., Elvis, Martin
We use 62,185 quasars from the Sloan Digital Sky Survey DR5 sample to explore the relationship between black hole mass and luminosity. Black hole masses were estimated based on the widths of their...
AGN Feedback: Does it work? (2009)
Mathur, Smita, Stoll, Rebecca, Krongold, Yair, Nicastro, Fabrizio, Brickhouse, Nancy, Elvis, Martin
While feedback is important in theoretical models, we do not really know if it works in reality. Feedback from jets appears to be sufficient to keep the cooling flows in clusters from cooling too...
The Nature of Optically Dull Active Galactic Nuclei in COSMOS (2009)
Trump, Jonathan R., Impey, Chris D., Taniguchi, Yoshi, Brusa, Marcella, Civano, Francesca, Elvis, Martin, ...
We present infrared, optical, and X-ray data of 48 X-ray bright, optically dull AGNs in the COSMOS field. These objects exhibit the X-ray luminosity of an active galactic nucleus (AGN) but lack broad...
The zCOSMOS 10k-Bright Spectroscopic Sample (2009)
Lilly, Simon J., Le Brun, Vincent, Maier, Christian, Mainieri, Vincenzo, Mignoli, Marco, Scodeggio, Marco, ...
We present spectroscopic redshifts of a large sample of galaxies with I_(AB) < 22.5 in the COSMOS field, measured from spectra of 10,644 objects that have been obtained in the first two years of...
The Chandra COSMOS Survey. I. Overview and Point Source Catalog (2009)
Elvis, Martin, Civano, Francesca, Vignali, Cristian, Puccetti, Simonetta, Fiore, Fabrizio, Cappelluti, Nico, ...
The Chandra COSMOS Survey (C-COSMOS) is a large, 1.8 Ms, Chandra program that has imaged the central 0.5 deg^2 of the COSMOS field (centered at 10 ^h , +02 ^o ) with an effective exposure of ~160 ks,...
Jahnke, Knud, Bongiorno, Angela, Brusa, Marcella, Capak, Peter, Cappelluti, Nico, Cisternas, Mauricio, ...
We constrain the ratio of black hole (BH) mass to total stellar mass of type-1 AGN in the COSMOS survey at 1
Observational limits on type 1 active galactic nucleus rate in COSMOS (2009)
Trump, Jonathan R., Impey, Chris D., Kelly, Brandon C., Elvis, Martin, Merloni, A., Bongiorno, Angela, ...
We present black hole masses and accretion rates for 182 Type 1 active galactic nuclei (AGNs) in COSMOS. We estimate masses using the scaling relations for the broad H β, Mg ii, and C iv emission...
The COSMOS Active Galactic Nucleus Spectroscopic Survey. I. XMM-Newton Counterparts (2009)
Trump, Jonathan R., Impey, Chris D., Elvis, Martin, McCarthy, Patrick J., Huchra, John P., Brusa, Marcella, ...
We present optical spectroscopy for an X-ray and optical flux-limited sample of 677 XMM-Newton selected targets covering the 2 deg^2 Cosmic Evolution Survey field, with a yield of 485 high-confidence...
Observational Limits on Type 1 AGN Accretion Rate in COSMOS (2009)
Trump, Jonathan R., Impey, Chris D., Kelly, Brandon C., Elvis, Martin, Merloni, Andrea, Bongiorno, Angela, ...
We present black hole masses and accretion rates for 182 Type 1 AGN in COSMOS. We estimate masses using the scaling relations for the broad Hb, MgII, and CIV emission lines in the redshift ranges 0.16
Active Galactic Nuclei and their role in Galaxy Formation and Evolution (2009)
Kraemer, Steve, Windhorst, Rogier, Carpenter, Kenneth G., Crenshaw, Mike, Elvis, Martin, Karovska, Margarita
There are several key open questions as to the nature and origin of AGN including: 1) what initiates the active phase, 2) the duration of the active phase, and 3) the effect of the AGN on the host...
Quasar Feedback: More Bang for Your Buck (2009)
Hopkins, Philip F., Elvis, Martin
We propose a two-stage model for the effects of feedback from a bright quasar on the cold gas in a galaxy. It is difficult for feedback from near the accretion disk to directly impact dense molecular...
Bell, Eric, Davis, Marc, Dey, Arjun, Van Dokkum, Pieter, Ellis, Richard, Eisenstein, Daniel, ...
Over the last decade optical spectroscopic surveys have characterized the low redshift galaxy population and uncovered populations of star-forming galaxies back to z ~ 7. This work has shown that the...
The Chandra COSMOS Survey, I: Overview and Point Source Catalog (2009)
Elvis, Martin, Civano, Francesca, Vignali, Cristian, Puccetti, Simonetta, Fiore, Fabrizio, Cappelluti, Nico, ...
The Chandra COSMOS Survey (C-COSMOS) is a large, 1.8 Ms, Chandra} program that has imaged the central 0.5 sq.deg of the COSMOS field (centered at 10h, +02deg) with an effective exposure of ~160ksec,...
Probing Quiescent Massive Black Holes: Insights from Tidal Disruption Events (2009)
Gezari, Suvi, Strubbe, Linda, Bloom, Joshua S., Grindlay, J. E., Soderberg, Alicia, Elvis, Martin, ...
Tidal disruption events provide a unique probe of quiescent black holes in the nuclei of distant galaxies. The next generation of synoptic surveys will yield a large sample of flares from the tidal...
Soria, Roberto, Risaliti, Guido, Elvis, Martin, Fabbiano, Giuseppina, Bianchi, Stefano, Kuncic, Zdenka
Based on our long (~ 300 ks) 2007 XMM-Newton observation of the Seyfert galaxy NGC 1365, we report here on the spectral and timing behaviour of two ultraluminous X-ray sources, which had previously...
The COSMOS active galactic nucleus spectroscopic survey - I. XMM-Newton counterparts (2009)
Trump, Jonathan R., Impey, Chris D., Elvis, Martin, McCarthy, Patrick J., Huchra, John P., Brusa, Marcella, ...
Observational limits on type 1 active galactic nucleus accretion rate in COSMOS (2009)
Trump, Jonathan R., Impey, Chris D., Kelly, Brandon C., Elvis, Martin, Merloni, Andrea, Bongiorno, Angela, ...
The Chandra COSMOS survey - I. Overview and point source catalog (2009)
Elvis, Martin, Civano, Francesca, Vignali, Christian, Puccetti, Simonetta, Fiore, Fabrizio, Cappelluti, Nico, ...
The COSMOS AGN Spectroscopic Survey I: XMM Counterparts (2008)
Trump, Jonathan R., Impey, Chris D., Elvis, Martin, McCarthy, Patrick J., Huchra, John P., Brusa, Marcella, ...
We present optical spectroscopy for an X-ray and optical flux-limited sample of 677 XMM-Newton selected targets covering the 2 deg^2 COSMOS field, with a yield of 485 high-confidence redshifts. The...
Properties of warm absorbers in active galaxies: a systematic stability curve analysis (2008)
Chakravorty, Susmita, Kembhavi, Ajit K., Elvis, Martin, Ferland, Gary
Signatures of warm absorbers are seen in soft X-ray spectra of about half of all Seyfert1 galaxies observed and in some quasars and blazars. We use the thermal equilibrium curve to study the...
XMM-Newton View of the Multi-Phase Warm Absorber in Seyfert 1 Galaxy NGC985 (2008)
Krongold, Yair, Jimenez-Bailon, Elena, Santos-Lleo, Maria, Nicastro, Fabrizio, Elvis, Martin, Brickhouse, Nancy, ...
We present an analysis of an XMM-Newton observation of the Seyfert 1 Galaxy NGC 985. The EPIC spectra present strong residuals to a single power-law model, indicating the presence of ionized...
The Reddest DR3 SDSS/XMM Quasars (2008)
Young, Monica, Elvis, Martin, Risaliti, Guido
We have cross-correlated the SDSS DR3 Schneider et al. (2005) quasar catalog with the XMM-Newton archive. Color and redshift selections (g - r > 0.5 and 0.9 z < 2.1) result in a sample of 17 red,...
Unveiling the nature of Seyfert nuclei with 1 - 100 micron spectral energy distributions (2008)
Buchanan, Catherine, Gallimore, Jack, Dea, Christopher, Baum, Stefi, Axon, David, Robinson, Andrew, ...
Talk given at "The Central Kiloparsec: Active Galactic Nuclei and Their Hosts", Ierapetra, Crete, 4-6 June, 2008. To appear in Volume 79 of the Memorie della Societa Astronomica Italiana. 4 pages, 5...
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...
Dielectronic recombination and stability of warm gas in active galactic nuclei (2008)
Chakravorty, Susmita, Kembhavi, Ajit K., Elvis, Martin, Ferland, Gary, Badnell, N.R.*
Understanding the thermal equilibrium (stability) curve may offer insights into the nature of the warm absorbers often found in active galactic nuclei. Its shape is determined by factors such as the...
Dielectronic recombination and stability of warm gas in active galactic nuclei (2008)
Chakravorty, Susmita, Kembhavi, Ajit K., Elvis, Martin, Ferland, Gary, Badnell, N.R.
Understanding the thermal equilibrium (stability) curve may offer insights into the nature of the warm absorbers often found in active galactic nuclei. Its shape is determined by factors such as the...
Dielectronic recombination and stability of warm gas in active galactic nuclei (2008)
Chakravorty, Susmita, Kembhavi, Ajit K., Elvis, Martin, Ferland, Gary, Badnell, N.R.
Understanding the thermal equilibrium (stability) curve may offer insights into the nature of the warm absorbers often found in active galactic nuclei. Its shape is determined by factors such as the...
Can Ionized Outflows in AGN Produce Important Feedback Effects? The Case of NGC 4051 (2008)
Elena Jiménez Bailón, Fabrizio Nicastro, Luc Binette, Martin Elvis, Nancy Brickhouse, Smita Mathur, ...
Using a 100 ks XMM-Newton exposure of the Narrow Line Seyfert 1 NGC 4051, we show that the time evolution of the ionization state of the X-ray absorbers in response to the rapid and highly variable...
Missing Baryons and the Warm-Hot Intergalactic Medium (2007)
Nicastro, F., Mathur, Smita, Elvis, Martin
Stars and gas in galaxies, hot intracluster medium, and intergalactic photo-ionized gas make up at most half of the baryons that are expected to be present in the universe. The majority of baryons...
Richard Schilizzi, Stuart Vogel, Francesco Paresce, Martin Elvis, Heino Falcke, Peter L. Biermann, ...
Sgr A*: observations, models, and imaging of the event horizon with VLBI
Aneta Siemiginowska, Martin Elvis, Alanna Connors, Peter Freeman, Vinay Kashyap, Eric Feigelson
The high quality of the AXAF X-ray data provides new challenges for the X-ray data analysis. It is clear that an "old " approach is not enough to fully exploit the capabilities of...
Deriving the Quasar Luminosity Function from Accretion Disk Instabilities (2007)
Aneta Siemiginowska Martin, Martin Elvis
We have derived the quasar luminosity function assuming that the quasar activity is driven by a thermal-viscous unstable accretion disk around a supermassive black hole. The instabilities produce...
Dielectronic recombination and stability of warm gas in AGN (2007)
Chakravorty, Susmita, Kembhavi, Ajit K., Elvis, Martin, Ferland, Gary, Badnell, N. R.
Understanding the thermal equilibrium (stability) curve may offer insights into the nature of the warm absorbers often found in active galactic nuclei. Its shape is determined by factors like the...
Resolving the BLR in NGC 3783 (2007)
Lira, P., Kishimoto, M., Robinson, Andrew, Young, Stuart, Axon, David, Elvis, Martin, ...
Also archived in: arXiv:astro-ph/0612647 v1 Dec 2006
The Near-Infrared Broad Emission Line Region of Active Galactic Nuclei -- I. The Observations (2007)
Landt, Hermine, Bentz, Misty C., Ward, Martin J., Elvis, Martin, Peterson, Bradley M., Korista, Kirk T., ...
We present high quality (high signal-to-noise ratio and moderate spectral resolution) near-infrared (near-IR) spectroscopic observations of 23 well-known broad-emission line active galactic nuclei...
Krongold, Yair, Nicastro, Fabrizio, Elvis, Martin, Brickhouse, Nancy, Binette, Luc, Mathur, Smita, ...
(Abridged) Using a 100 ks XMM-Newton exposure of NGC 4051, we show that the time evolution of the ionization state of the X-ray absorbers in response to the rapid and highly variable X-ray continuum...
Time-Evolving Photoionization: the Thin and Compact X-Ray Wind of NGC 4051 (2007)
Nicastro, Fabrizio, Krongold, Yair, Elvis, Martin, Brickhouse, Nancy, Mathur, Smita, Binette, Luc
We discuss the power of time-evolving photoionization as a diagnostic tool to measure the electron density of photoionized gas. We apply this technique to a XMM-Newton observation of the ionized...
A survey of AGN and supermassive black holes in the COSMOS survey (2007)
Impey, Chris D., Trump, Jon R., McCarthy, Pat J., Elvis, Martin, Huchra, John P., Scoville, Nick Z., ...
Magellan spectroscopy of AGN candidates in the COSMOS field (2007)
Trump, Jonathan R., Impey, Chris D., McCarthy, Patrick J., Elvis, Martin, Huchra, John P., Brusa, Marcella, ...
A multiwavelength study of AGN with COSMOS: Do low-Eddington ratio type 1 AGN exist? (2007)
Trump, Jonathan R., Impey, Chris D., Gabor, Jared M., McCarthy, Patrick J., Elvis, Martin, Huchra, John, ...
Magellan spectroscopy of AGN candidates in the COSMOS field (2007)
Trump, Jonathan R., Impey, Chris D., McCarthy, Patrick J., Elvis, Martin, Huchra, John P., Brusa, Marcella, ...
We present spectroscopic redshifts for the first 466 X-ray- and radio-selected AGN targets in the 2 deg2 COSMOS field. Spectra were obtained with the IMACS instrument on the Magellan (Baade)...
A survey of AGN and supermassive black holes in the COSMOS survey (2007)
Impey, Chris D., Trump, Jon R., McCarthy, Pat J., Elvis, Martin, Huchra, John P., Scoville, Nick Z., ...
Not Available
Williams, Rik J., Mathur, Smita, Nicastro, Fabrizio, Elvis, Martin
The X-ray bright z=0.116 quasar PKS 2155-304 is frequently observed as a Chandra calibration source, with a total of 483 ksec of Low Energy Transmission Grating (LETG) exposure time accumulated...
The Extreme Physics Explorer (2006)
Some tests of fundamental physics - the equation of state at supra-nuclear densities, the metric in strong gravity, the effect of magnetic fields above the quantum critical value - can only be...
Active X-ray Optics for Generation-X, the Next High Resolution X-ray Observatory (2006)
Elvis, Martin, Brissenden, R. J., Fabbiano, G., Schwartz, D. A., Reid, P., Podgorski, W., ...
X-rays provide one of the few bands through which we can study the epoch of reionization, when the first galaxies, black holes and stars were born. To reach the sensitivity required to image these...
Quasar Structure and Cosmological Feedback (2006)
Feedback from quasars and AGNs is being invoked frequently in several cosmological settings. Currently, order of magnitude, or more, uncertainties in the structure of both the wind and the 'obscuring...
Magellan Spectroscopy of AGN Candidates in the COSMOS Field (2006)
Trump, Jonathan R., Impey, Chris D., McCarthy, Patrick J., Elvis, Martin, Huchra, John P., Brusa, Marcella, ...
We present spectroscopic redshifts for the first 466 X-ray and radio-selected AGN targets in the 2 deg^2 COSMOS field. Spectra were obtained with the IMACS instrument on the Magellan (Baade)...
Buchanan, Catherine, Gallimore, Jack, O’Dea, Christopher, Baum, Stefi, Axon, David, Robinson, Andrew, ...
Accepted to the Astronomical Journal (July issue). Also archived in: arXiv: astro-ph/0604222 v1 10 Apr 2006
Buchanan, Catherine L., Gallimore, Jack F., O'Dea, Christopher P., Baum, Stefi A., Axon, David J., Robinson, Andrew, ...
We are conducting a large observing program with the Spitzer Space Telescope to determine the mid-to-far infrared spectral energy distributions of a well-defined sample of 87 nearby, 12...
Infrared SEDs of Seyfert Galaxies: Starbursts and the Nature of the Obscuring Medium (2006)
Buchanan, Catherine L., Gallimore, Jack F., O'Dea, Christopher P., Baum, Stefi A., Axon, David J., Robinson, Andrew, ...
We present the results of IRS low-resolution spectroscopy of 51 Seyfert galaxies, part of a large Spitzer observing program to determine the mid-to-far infrared spectral energy distributions of a...
Infrared SEDs of Seyfert galaxies: Starbursts and the nature of the obscuring medium (2006)
Buchanan, Catherine, Gallimore, Jack, O’Dea, Christopher, Baum, Stefi, Axon, David, Robinson, Andrew, ...
"Infrared Diagnostics of Galaxy Evolution," Proceedings of the Spitzer Science Center 2005 Conference. Astronomical Society of the Pacific Conference Series. Held at the Pasadena Hilton, Pasadena,...
Infrared SEDs of Seyfert galaxies: Starbursts and the nature of the obscuring medium (2006)
Buchanan, Catherine, Gallimore, Jack, O’Dea, Christopher, Baum, Stefi, Axon, David, Robinson, Andrew, ...
"Infrared Diagnostics of Galaxy Evolution," Proceedings of the Spitzer Science Center 2005 Conference. Astronomical Society of the Pacific Conference Series. Held at the Pasadena Hilton, Pasadena,...
XMM-Newton View of the z>0 Warm-Hot Intergalactic Medium Toward Markarian 421 (2006)
Williams, Rik J., Mathur, Smita, Nicastro, Fabrizio, Elvis, Martin
The recent detection with Chandra of two warm-hot intergalactic medium (WHIM) filaments toward Mrk 421 by Nicastro et al. provides a measurement of the bulk of the "missing baryons" in the nearby...
Soria, Roberto, Graham, Alister W., Fabbiano, Giuseppina, Baldi, Alessandro, Elvis, Martin, Jerjen, Helmut, ...
Our X-ray study of the nuclear activity in a new sample of six quiescent early-type galaxies, and in a larger sample from the literature, confirmed (Soria et al., Paper I) that the Bondi accretion...
Accretion and nuclear activity of quiescent supermassive black holes. I: X-ray study (2005)
Soria, Roberto, Fabbiano, Giuseppina, Graham, Alister W., Baldi, Alessandro, Elvis, Martin, Jerjen, Helmut, ...
We have studied the nuclear activity in a sample of six quiescent early-type galaxies, with new Chandra data and archival HST optical images. Their nuclear sources have X-ray luminosities ~ 10^{38} -...
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...
Probing the Local Group Medium Toward Mkn 421 with Chandra and FUSE (2005)
Williams, Rik J., Mathur, Smita, Nicastro, Fabrizio, Elvis, Martin, Drake, Jeremy J., Fang, Taotao, ...
We report the detection of highly-ionized gas at z~0 seen in resonant UV and X-ray absorption lines toward the z=0.03 blazar Mkn 421. A total of 13 X-ray and 3 UV lines were measured (or upper limits...
Chandra Detection of the First X-ray Forest along the Line of Sight To Mkn 421 (2005)
Nicastro, Fabrizio, Mathur, Smita, Elvis, Martin, Drake, Jeremy, Fiore, Fabrizio, Fang, Taotao, ...
We present the first >=3.5 sigma (conservative) or >=5.8 sigma (sum of lines significance) detection of two Warm-Hot Intergalactic Medium (WHIM) filaments at z>0, which we find along the line of...
Measured Cosmological Mass Density in the WHIM: the Solution to the 'Missing Baryons' Problem (2005)
Nicastro, Fabrizio, Elvis, Martin, Fiore, Fabrizio, Mathur, Smita
We review the current high-significance X-ray detections of Warm-Hot Intergalactic Medium (WHIM) filaments at z>0 along the lines of sight to the two blazars Mrk 421 (z=0.03) and 1ES 1028+511...
An Unveiling Event in the Type 2 AGN NGC4388: A Challenge for a Parsec Scale Absorber (2004)
Elvis, Martin, Risaliti, G., Nicastro, F., Miller, J. M., Fiore, F ., Puccetti, S.
We present two Rossi Xray Timing Explorer (RXTE) PCA observations of the type~2 Seyfert galaxy NGC 4388 caught in an unusual low X-ray absorption state. The observations were triggered by a detection...
Extreme Physics via X-rays from Black Holes and `Neutron' Stars (2004)
A combination of microchannel plate optics and a 32x32 pixel microcalorimeter would allow the successor to the Rossi XTE to explore new domains of spectroscopic timing in a MIDEX class mission. With...
The faint X-ray Source Population near 3C 295 (2004)
D'Elia, Valerio, Fiore, Fabrizio, Elvis, Martin, Cappi, Massimo, Mathur, Smita, Mazzotta, Pasquale, ...
We present a statistical analysis of the Chandra observation of the source field around the 3C 295 galaxy cluster (z=0.46) aimed at the search for clustering of X-ray sources. We applied three...
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...
Quasar Winds as Dust Factories at High Redshift (2003)
Elvis, Martin, Marengo, Massimo, Karovska, Margarita
Winds from AGN and quasars will form large amounts of dust, as the cool gas in these winds passes through the (pressure, temperature) region where dust is formed in AGB stars. Conditions in the gas...
Quasar Atmospheres: Toward a "Low" Theory for Quasars (2003)
After 40 years we have no "low" theory of quasars to predict the atomic absorption and emission features so abundant in quasar spectra. Here I take the first step, using results selected for their...
Spatially Resolved Circumnuclear Dust in Centaurus A (2003)
Karovska, Margarita, Marengo, Massimo, Elvis, Martin, Fazio, Giovanni, Hora, Joseph, Hinz, Philip, ...
In this paper we present results from our exploratory mid-IR study of Centaurus A circumnuclear environment using high-angular resolution imaging at the Magellan 6.5m telescope with the MIRAC/BLINC...
The X-ray absorber of PKS2126-158 (2003)
Fiore, Fabrizio, Elvis, Martin, Maiolino, Roberto, Nicastro, Fabrizio, Siemiginowska, Aneta, Stratta, Giulia, ...
BeppoSAX observed the z=3.27 quasar PKS2126-158 on 1999 May 24-28 when its 2-10keV and 0.1-2.5keV fluxes were 1.1E-11 and 4.4E-12 cgs respectively, a factor of 2 higher than in all previous ROSAT and...
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...
A High Resolution Intergalactic Explorer for the Soft X-ray/FUV (2003)
Elvis, Martin, Fiore, Fabrizio, Team, The CWE
We present a mission concept for high resolution X-ray spectroscopy with a resolving power, R~6000, (c.f. R=
Distances on Cosmological Scales with VLTI (2003)
Karovska, Margarita, Elvis, Martin, Marengo, Massimo
We present here a new method using interferometric measurements of quasars, that allows the determination of direct geometrical distances on cosmic scales. Quasar Broad Emission Line Regions sizes...
Quasar Parallax: a Method for Determining Direct Geometrical Distances to Quasars (2002)
Elvis, Martin, Karovska, Margarita
We describe a novel method to determine direct geometrical distances to quasars that can measure the cosmological constant, Lambda, with minimal assumptions. This method is equivalent to geometric...
ROSAT Blank Field Sources I: Sample Selection and Archival Data (2002)
Cagnoni, Ilaria, Elvis, Martin, Kim, Dong-Woo, Nicastro, Fabrizio, Celotti, Annalisa
We have identified a population of blank field sources (or `blanks') among the ROSAT bright unidentified X-ray sources with faint optical counterparts. The extreme X-ray over optical flux ratio of...
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...
Smoking Quasars: a New Source for Cosmic Dust (2002)
Elvis, Martin, Marengo, Massimo, Karovska, Margarita
Although dust is widely found in astrophysics, forming dust is surprisingly difficult. The proper combination of low temperature (
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...
The model I recently proposed for the structure of quasars offers to unify the many aspects of Type 1 AGN: emission lines, absorption lines and reflection features. This makes the model heavily...
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...
Tests of a Structure for Quasars (2001)
The model I recently proposed for the structure of quasars (astro-ph/0008064) claims to unify all the emission, absorption and reflection phenomenology of quasars and AGN, and so is heavily...
Thermal Limit Spectroscopy as a Goal for X-ray Astronomy (2001)
The R~300-1000 grating spectra from XMM-Newton and Chandra are a radical advance, allowing spectroscopic physics techniques to be applied to X-ray astronomy, revolutionizing a wide range of research....
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...
A Chandra Survey of Broad Absorption Line Quasars (2001)
Green, Paul J., Aldcroft, Thomas L., Mathur, Smita, Wilkes, Belinda J., Elvis, Martin
We have carried out a survey with the Chandra X-ray Observatory of a sample of 10 optically bright broad absorption line (BAL) QSOs. Eight out of ten sources are detected. The 6 brightest X-ray...
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...
Blank field X-ray sources (2001)
Cagnoni, Ilaria, Celotti, Annalisa, Elvis, Martin, Dong-Woo Kim, Nicastro, Fabrizio
The X-ray sky is not as well known as is sometimes thought. We report on our search of minority populations (Kim & Elvis 1999). One of the most intriguing is that of `blank field sources', i.e....
A Structure for Quasars (2000)
This paper proposes a simple, empirically derived, unifying structure for the inner regions of quasars. This structure is constructed to explain the broad absorption line (BAL) regions, the narrow...
Blank Field X-Ray Sources (2000)
Cagnoni, Ilaria, Celotti, Annalisa, Elvis, Martin, Kim, Dong-Woo, Nicastro, Fabrizio
The X-ray sky is not as well known as is sometimes thought. We report on our search of minority populations (Kim & Elvis 1999). One of the most intriguing is that of `blank field sources', i.e....
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...
A Structure for Quasars (2000)
We propose a simple unifying structure for the inner regions of quasars and AGN. This empirically derived model links together the BALs, the narrow UV/X-ray ionized absorbers, the BELR, and the...
Multiple Velocity Components in the CIV Absorption Line of NGC5548 (1999)
Mathur, Smita, Elvis, Martin, Wilkes, Belinda
We have observed the much studied Seyfert 1 galaxy NGC5548 with the GHRS spectrometer on HST. Our 14ksec observation covers the CIV emission line at a resolution of >20,000. Our purpose was to study...
Radio-Quite Red Quasars (1998)
We have performed a successful targetted search for a population of red radio-quiet, and probably absorbed, quasars. Radio-quiet, optically-red ROSAT PSPC X-ray sources brighter than 10^{-13} erg...
The U.S. ISO Key Project on Quasars (1998)
Hooper, Eric, Wilkes, Belinda, McLeod, Kim, McDowell, Jonathan, Elvis, Martin, Malkan, Matthew, ...
Observations for the U.S. key project on quasars using ISO were completed in April when the satellite's cryogen supply expired. This proceeding presents an update of the project, including...
NGC 7582: The Prototype Narrow-Line X-ray Galaxy (1998)
Schachter, Jonathan F., Fiore, Fabrizio, Elvis, Martin, Mathur, Smita, Wilson, Andrew S., Morse, Jon A., ...
NGC 7582 is a candidate prototype of the Narrow Line X-ray Galaxies (NLXGs) found in deep X-ray surveys. An ASCA observation shows the hard (> 3 keV) X-ray continuum of NGC 7582 drops 40% in ~6 ks,...
Mathur, Smita, Wilkes, Belinda, Elvis, Martin
The unified picture of X-ray/UV absorbers offers an unique opportunity to probe the nuclear environment of AGNs. To test the unified absorber scenario and to understand the physical properties of the...
The variability properties of X-ray steep and X-ray flat quasars (1998)
Fiore, Fabrizio, Laor, Ari, Elvis, Martin, Nicastro, Fabrizio, Giallongo, Emanuele
We have studied the variability of 6 low redshift, radio quiet `PG' quasars on three timescales (days, weeks, and months) using the ROSAT HRI. The quasars were chosen to lie at the two extreme ends...
AXAF in Context: A Revolution (1997)
The unique power of AXAF (NASA's Advanced X-ray Astrophysics Facility) - due for launch in late 1988 - make it both the culmination of 20 years of X-ray astronomy, and a new starting point for X-ray...
X-ray Spectral Survey of WGACAT Quasars, I: Spectral Evolution & Low Energy Cut-offs (1997)
Fiore, Fabrizio, Elvis, Martin, Giommi, Paolo, Padovani, Paolo
We have used the WGA catalog of ROSAT PSPC X-ray sources to study the X-ray spectrum of about 500 quasars in the redshift interval 0.1--4.1, detected with a signal to noise better than 7. We have...
Elvis, Martin, Fiore, Fabrizio, Giommi, Paolo, Padovani, Paolo
We have selected quasars with X-ray colors suggestive of a low energy cut-off, from the ROSAT PSPC pointed archive. We examine the radio and optical properties of these 13 quasars. Five out of the...
Obscuration in the Host Galaxies of Soft X-ray Selected Seyferts (1997)
Simcoe, Robert, McLeod, K. K., Schachter, Jonathan, Elvis, Martin
We define a new sample of 96 low-redshift (z
Deriving the Quasar Luminosity Function from Accretion Disk Instabilities (1997)
Siemiginowska, Aneta, Elvis, Martin
We have derived the quasar luminosity function assuming that the quasar activity is driven by a thermal-viscous unstable accretion disk around a supermassive black hole. The instabilities produce...
Science Driven arguments for a 10 sq.meter, 1 arcsecond X-ray Telescope (1996)
Elvis, Martin, Fabbiano, Giuseppina
X-ray astronomy needs to set bold, science driven goals for the next decade. Only with defined science goals can we know what to work on, and a funding agency appreciate the need for significant...
Associated Absorption at Low and High Redshift (1996)
Elvis, Martin, Mathur, Smita, Wilkes, Belinda J., Fiore, Fabrizio, Giommi, Paolo, Padovani, Paolo, ...
Combining information on absorbing material in AGN from X-ray and the UV creates a powerful investigative tool. Here we give examples from both low and high redshift.
Laor, Ari, Fiore, Fabrizio, Elvis, Martin, Wilkes, Belinda J., McDowell, Jonathan C.
We present the final results of a ROSAT PSPC program to study the soft X-ray emission properties of a complete sample of low $z$ quasars. The main results are: 1. There is no evidence for significant...
Strong X-ray Absorption in a BALQSO: PHL5200 (1995)
Mathur, Smita, Elvis, Martin, Singh, K. P.
We present $\it {ASCA}$ observations of the z=1.98 prototype BALQSO: PHL5200. The source was detected in both SIS and GIS. A power-law spectrum ($\alpha_E = 0.6^{+0.9}_{-0.6}$) with large intrinsic...