Taylor, Edward N, Franx, Marijn, Van Dokkum, Pieter G, Quadri, Ryan F, Gawiser, Eric, Bell, Eric F, ...
We present a new K-selected, optical-to-near-infrared photometric catalog of the Extended Chandra Deep Field South (ECDFS), making it publicly available to the astronomical community. The dataset is...
The Space Density of Compton Thick AGN and the X-ray Background (2009)
Treister, E., Urry, C. Megan, Virani, Shanil
We constrain the number density and evolution of Compton-thick Active Galactic Nuclei (AGN). In the local Universe we use the wide area surveys from the Swift and INTEGRAL satellites, while for high...
Do Moderate-Luminosity Active Galactic Nuclei Suppress Star Formation? (2009)
Schawinski, Kevin, Virani, Shanil, Simmons, Brooke, Urry, C. Megan, Treister, Ezequiel, Kaviraj, Sugata, ...
The growth of supermassive black holes and their host galaxies are thought to be linked, but the precise nature of this symbiotic relationship is still poorly understood. Both observations and...
Taylor, Edward N, Franx, Marijn, Van Dokkum, Pieter G, Bell, Eric F, Brammer, Gabriel B, Rudnick, Gregory, ...
We present the color-magnitude and color-stellar mass diagrams for galaxies with z_phot < ~2, based on a K < 22 (AB) catalog of the Extended Chandra Deep Field South (ECDFS) from the MUltiwavelength...
Carilli, C. L., Lee, Nicholas, Capak, P., Schinnerer, E., McCraken, H., ...
We present an analysis of the radio properties of large samples of Lyman Break Galaxies (LBGs) at $z \sim 3$, 4, and 5 from the COSMOS field. The median stacking analysis yields a statistical...
Mid-infrared Properties and Color Selection for X-ray Detected AGN in the MUSYC ECDF-S field (2008)
Cardamone, Carolin N., Urry, C. Megan, Damen, Maaike, Van Dokkum, Pieter, Treister, Ezequiel, Labbé, Ivo, ...
We present the mid-infrared colors of X-ray-detected AGN and explore mid-infrared selection criteria. Using a statistical matching technique, the likelihood ratio, over 900 IRAC counterparts were...
Carilli, C. L., Lee, Nicholas, Capak, P., Schinnerer, E., Lee, K. S., McCraken, H., ...
We present an analysis of the radio properties of large samples of Lyman break galaxies (LBGs) at z~3, 4, and 5 from the COSMOS field. The median stacking analysis yields a statistical detection of...
Supermassive Black Holes in Deep Multiwavelength Surveys (2007)
In recent years deep X-ray and infrared surveys have provided an efficient way to find accreting supermassive black holes, otherwise known as active galactic nuclei (AGN), in the young universe. Such...
On the Relation between Radio and Non-Radio Elliptical Galaxies (2007)
Riccardo Scarpa, C. Megan Urry
Empirical evidence suggests that elliptical galaxies hosting a radio source may not be di#erent from normal non-radio ellipticals. To test this possibility, we use Monte Carlo simulations to...
HST snapshot imaging of BL Lac objects (2007)
Falomo Osservatorio Astronomico, R. Falomo, C. Megan Urry, Riccardo Scarpa, Joseph E. Pesce, Aldo Treves
. Snapshot images of 100 BL Lac objects were obtained with WFPC2 on HST. Sources from various samples, in the redshift range 0.05 to 1.2, were observed and 61 resolved (51 with known z). The high...
Four Gravitational Lens Candidates in the HST Snapshot Survey of BL Lac Objects. (2007)
Riccardo Scarpa, C. Megan Urry, Space Telescope
this conference) we have found 4 gravitational lens
C. Megan Urry, Riccardo Scarpa, Tom Broadhurst, Renato Falomo, Jochen Heidt, Aldo Treves, ...
We have carried out an HST snapshot survey of 108 BL Lac objects, at redshifts from z = 0.051 to z 1
On the Physical Conditions in AGN Optical Jets (2007)
Riccardo Scarpa, C. Megan Urry
The energy budget of all known optical jets is discussed. It is found that to power the extended radio lobes of radio galaxies, the jet bulk motion on kpc scales must be relativistic, on average....
C. Megan Urry, Riccardo Scarpa, Mauro Giavalisco, Renato Falomo, Joseph E. Pesce, Aldo Treves
AGN are known to lie in galaxies, and both galaxies and AGN evolve similarly over cosmic time (e.g., Silk and Rees 1998). This suggests a close connection between the nuclear phenomena associated...
Hubble Space Telescope Observations of BL Lacertae Environments. I. The GO Targets (2007)
Joseph E. Pesce, C. Megan Urry, Riccardo Scarpa, Renato Falomo, Aldo Treves
We analyze images of BL Lacertae objects obtained with the Hubble Space Telescope WFPC2 and the F814W filter. The nine objects cover a redshift range of 0.19 to 0.997. The relatively deep images are...
Ly Alpha-Emitting Galaxies at z=3.1: L* Progenitors Experiencing Rapid Star Formation (2007)
Gawiser, Eric, Francke, Harold, Lai, Kamson, Schawinski, Kevin, Gronwall, Caryl, Ciardullo, Robin, ...
We studied the clustering properties and multiwavelength spectral energy distributions of a complete sample of 162 Ly Alpha-Emitting (LAE) galaxies at z=3.1 discovered in deep narrow-band MUSYC...
McHardy, Ian, Lawson, Anthony, Newsam, Andrew, Marscher, Alan P., Sokolov, Andrei S., Urry, C. Megan, ...
The X-ray emission from quasars, such as 3C273, is generally agreed to arise from Compton scattering of low-energy seed photons by relativistic electrons in a relativistic jet oriented close to the...
Kriek, Mariska, Van Dokkum, Pieter G., Franx, Marijn, Illingworth, Garth D., Coppi, Paolo, Förster Schreiber, Natascha M., ...
Quadri, Ryan, Marchesini, Danilo, Van Dokkum, Pieter, Gawiser, Eric, Franx, Marijn, Lira, Paulina, ...
Publicación ISI
Quadri, Ryan, Marchesini, Danilo, Van Dokkum, Pieter, Gawiser, Eric, Franx, Marijn, Lira, Paulina, ...
Publicación ISI
Quadri, Ryan, Marchesini, Danilo, Van Dokkum, Pieter, Gawiser, Eric, Franx, Marijn, Lira, Paulina, ...
We present deep near-infrared JHK imaging of four 10'x10' fields. The observations were carried out as part of the Multiwavelength Survey by Yale-Chile (MUSYC) with ISPI on the CTIO 4m telescope. The...
The evolution of obscuration in active galactic nuclei (2006)
Treister, Ezequiel, Urry, C. Megan
In order to study the evolution of the relative fraction of obscured active galactic nuclei (AGNs), we constructed the largest sample to date of AGNs selected in hard X-rays. The full sample contains...
Kriek, Mariska, Van Dokkum, Pieter G., Franx, Marijn, Illingworth, Garth D., Coppi, Paolo, Schreiber, Natascha M. Forster, ...
Using the Gemini Near-InfraRed Spectrograph (GNIRS), we have assembled a complete sample of 20 K-selected galaxies at 2.0
The Evolution of Obscuration in AGN (2006)
Treister, Ezequiel, Urry, C. Megan
In order to study the evolution of the relative fraction of obscured Active Galactic Nuclei (AGN) we constructed the largest sample to date of AGN selected in hard X-rays. The full sample contains...
Kriek, Mariska, Dokkum, Pieter G. Van, Franx, Marijn, Quadri, Ryan, Gawiser, Eric, Herrera, David, ...
We present first results of a spectroscopic survey targeting K-selected galaxies at using the Gemini z = 2.0 - 2.7 near-infrared spectrograph (GNIRS). We obtained near-infrared spectra with a...
The physical nature of Ly alpha-emitting galaxies at z=3.1 (2006)
Gawiser, Eric, Dokkum, Pieter G. Van, Gronwall, Caryl, Ciardullo, Robin, Blanc, Guillermo A., Castander, Francisco J., ...
We selected 40 candidate Ly alpha-emitting galaxies ( LAEs) at z similar or equal to 3.1 with observed-frame equivalent widths greater than 150 and inferred emission-line fluxes above 2.5 x 10(-17)...
The Physical Nature of Lyman Alpha Emitting Galaxies at z=3.1 (2006)
Gawiser, Eric, Van Dokkum, Pieter G., Gronwall, Caryl, Ciardullo, Robin, Blanc, Guillermo A., Castander, Francisco J., ...
We selected 40 candidate Lyman Alpha Emitting galaxies (LAEs) at z ~=3.1 with observed frame equivalent widths >150A and inferred emission line fluxes >2.5x10^-17 ergs/cm^2/s from deep narrow-band...
Gawiser, Eric, Dokkum, Pieter G. Van, Herrera, David, Maza, José, Castander, Francisco J., Infante, Leopoldo, ...
We present UBVRIz' optical images taken with MOSAIC on the CTIO 4 m telescope of the 0.32 deg(2) Extended Hubble Deep Field-South. This is one of four fields comprising the MUSYC survey, which is...
Shedding new light on the 3C 273 jet with the Spitzer Space Telescope (2006)
Uchiyama, Yasunobu, Urry, C. Megan, Cheung, C. C., Jester, Sebastian, Van Duyne, Jeffrey, Coppi, Paolo, ...
We have performed infrared imaging of the jet of the quasar 3C 273 at wavelengths of 3.6 and 5.8 mum with the Infrared Array Camera (IRAC) on the Spitzer Space Telescope. When combined with the...
Kriek, Mariska, Van Dokkum, Pieter G., Franx, Marijn, Quadri, Ryan, Gawiser, Eric, Herrera, David, ...
We present first results of a spectroscopic survey targeting K-selected galaxies at z=2.0-2.7 using the Gemini near-infrared spectrograph (GNIRS). We obtained near-infrared spectra with a wavelength...
Spitzer Number Counts of AGN in the GOODS fields (2005)
Treister, Ezequiel, Urry, C. Megan, Van Duyne, Jeffrey, Dickinson, Mark, Chary, Ranga-Ram, Alexander, David M., ...
We present mid-infrared observations of AGN in the GOODS fields, performed with the Spitzer Space Telescope. These are the deepest infrared and X-ray fields to date and cover a total area of ~0.1...
Obscured and Unobscured AGN Evolution and the X-ray background (2005)
Treister, Ezequiel, Urry, C. Megan, Lira, Paulina
The Great Observatories Origins Deep Survey (GOODS) combines deep HST and Spitzer imaging with the deepest Chandra/XMM observations to probe obscured AGN at higher redshifts than previous...
The Extended Chandra Deep Field-South Survey: Optical Properties of X-ray Detected Sources (2005)
Virani, Shanil, Treister, Ezequiel, Urry, C. Megan, Gawiser, Eric, Collaboration, The MUSYC
The Extended Chandra Deep Field-South (E-CDF-S) survey consists of 4 Chandra ACIS-I pointings and covers ~1100 square arcminutes (~0.3 deg^2) centered on the original CDF-S field to a depth of...
The Extended Chandra Deep Field-South Survey: X-ray Point-Source Catalog (2005)
Virani, Shanil, Treister, Ezequiel, Urry, C. Megan, Gawiser, Eric
The Extended Chandra Deep Field-South (ECDFS) survey consists of 4 Chandra ACIS-I pointings and covers $\approx$ 1100 square arcminutes ($\approx$ 0.3 deg$^2$) centered on the original CDF-S field to...
Infrared Number Counts of AGN in the GOODS Fields (2005)
Treister, E., Urry, C. Megan, Team, The GOODS AGN
Using the known numbers and evolution of unobscured AGN, and assuming that there is a large number of corresponding obscured AGN -- as expected if AGN unification is correct -- we predict the...
Treister, Ezequiel, Castander, Francisco, Maccarone, Thomas, Gawiser, Eric, Coppi, Paolo, Urry, C. Megan, ...
We present the first results from the Cal\'an-Yale Deep Extragalactic Research (CYDER) survey. The main goal of this survey is to study serendipitous X-ray sources detected by Chandra in an...
Host Galaxy Evolution in Radio-Loud AGN (2004)
O'Dowd, Matthew, Urry, C. Megan
We investigate the luminosity evolution of the host galaxies of radio-loud AGN through Hubble Space Telescope imaging of 72 BL Lac objects, including new STIS imaging of nine z > 0.6 BL Lacs. With...
H1517+656: the Birth of a BL Lac Object? (2004)
O'Dowd, Matthew, Urry, C. Megan, Scarpa, Riccardo, Wayth, Randall B., Webster, Rachel L.
H1517+656 is an unusual source, even for a BL Lac object. It is one of the most luminous BL Lacs known, with extreme emission properties at radio, optical, and X-ray frequencies. Furthermore, in our...
AGN Unification: An Update (2003)
The paradigm for AGN unification is reviewed, in terms of its optical manifestation as obscuration in the equatorial plane and its radio manifestation as relativistic beaming of the jet emission....
Near-Infrared Observations of BL Lacertae Host Galaxies (2003)
Cheung, C. C., Urry, C. Megan, Scarpa, Riccardo, Giavalisco, Mauro
Multi-band near-infrared images of twelve BL Lacertae objects were obtained with the 2.5m telescope at the Las Campanas Observatory in order to determine the properties of their underlying host...
The Speed and Orientation of the Parsec-Scale Jet in 3C 279 (2003)
Piner, B. Glenn, Unwin, Stephen C., Wehrle, Ann E., Zook, Alma C., Urry, C. Megan, Gilmore, Diane M.
We have calculated inverse-Compton Doppler factors for 3C 279 using the collection of VLBI data recently published by us, and the collection of multiwavelength spectra recently published by Hartman...
The Independence of AGN Black Hole Mass and Radio-Loudness (2002)
We revisit the issue of whether radio loudness in AGN is associated with central black hole mass, as has been suggested in the literature. We present new estimates of black hole mass for 295 AGN...
The Host Galaxies of Radio-Loud AGN: The Black Hole--Galaxy Connection (2002)
O'Dowd, Matthew, Urry, C. Megan, Scarpa, Riccardo
We have studied the host galaxies of a sample of radio-loud AGN spanning more than four decades in the energy output of the nucleus. The core sample includes 40 low-power sources (BL Lac objects) and...
AGN Black Hole Masses and Bolometric Luminosities (2002)
Black hole mass, along with mass accretion rate, is a fundamental property of active galactic nuclei. Black hole mass sets an approximate upper limit to AGN energetics via the Eddington limit. We...
A survey of extended radio jets in AGN with Chandra and HST: First Results (2002)
Sambruna, Rita M., Maraschi, L., Tavecchio, F., Urry, C. Megan, Cheung, C. C., Chartas, G., ...
We present the first results from an X-ray and optical survey of a sample of AGN radio jets with Chandra and HST. We focus here on the first six sources observed at X-rays, in four of which a bright...
Workshop on the Status of Women in Astronomy (2001)
Urry, C Megan, Danly, Laura, Sherbert, Lisa E, Gonzaga, Shireen
Tanihata, Chiharu, Urry, C. Megan, Takahashi, Tadayuki, Kataoka, Jun, Wagner, Stefan J., Madejski, Greg M., ...
Three uninterrupted, long (lasting respectively 7, 10, and 10 days) ASCA observations of the well-studied TeV-bright blazars Mrk 421, Mrk 501 and PKS 2155-304 all show continuous strong X-ray...
Detection of an X-ray jet in 3C 371 with Chandra (2001)
Pesce, Joseph E., Sambruna, Rita M., Tavecchio, F., Maraschi, L., Cheung, C. C., Urry, C. Megan, ...
We report the detection at X-rays of the radio/optical jet of 3C 371, from a short (10 ks) Chandra exposure in March 2000. We also present a new MERLIN observation at 1.4 GHz together with a...
On The Parent Population of Radio Galaxies and the FRI - FRII Dichotomy (2001)
Scarpa, Riccardo, Urry, C. Megan
We test the hypothesis that radio galaxies are a random subset of otherwise normal elliptical galaxies. Starting with the observed optical luminosity functions for elliptical galaxies, we show that...
On The Parent Population of Radio Galaxies and the FR I--II Dichotomy (2001)
Scarpa, Riccardo, Urry, C. Megan
The possibility of radio galaxies being random sample of otherwise normal elliptical galaxies is tested. Starting with the observed optical luminosity functions for elliptical galaxies, it is shown...
Chandra Observations of the X-Ray Jet of 3C273 (2001)
Sambruna, Rita M., Urry, C. Megan, Tavecchio, F., Maraschi, L., Scarpa, R., Chartas, G., ...
We report results from Chandra observations of the X-ray jet of 3C~273 during the calibration phase in 2000 January. The zeroeth-order images and spectra from two 40-ks exposures with the HETG and...
Issues in Blazar Research (2001)
Padovani, Paolo, Urry, C. Megan
As an overview of blazar research, we briefly discuss some of the themes of this conference, including the various types of blazars, blazar samples and selection effects, unified schemes, evolution,...
On the Relation Between Radio and Non-Radio Elliptical Galaxies (2000)
Scarpa, Riccardo, Urry, C. Megan
Empirical evidence suggests that elliptical galaxies hosting a radio source may not be different from normal non-radio ellipticals. To test this possibility, we use Monte Carlo simulations to...
The HST Survey of BL~Lacertae Objects. IV. Infrared Imaging of Host Galaxies (2000)
Scarpa, Riccardo, Urry, C. Megan, Padovani, Paolo, Calzetti, Daniela, O'Dowd, Matthew
The HST NICMOS Camera 2 was used for H-band imaging of 12 BL Lacertae objects taken from the larger sample observed with the WFPC2 in the R band (Urry et al. 2000; Scarpa et al. 2000). Ten of the 12...
Testing the Blazar Paradigm: ASCA Observations of FSRQs with Steep Soft X-ray Spectra (1999)
Sambruna, Rita M., Chou, Lester L., Urry, C. Megan
We present the first observations at medium-hard X-rays with ASCA in 1998 August--November of four Flat Spectrum Radio Quasars (FSRQs), characterized by unusually steep soft X-ray spectra (photon...
Scarpa, Riccardo, Urry, C. Megan, Falomo, Renato, Pesce, Joseph E., Treves, Aldo
We report on a large HST imaging survey of BL Lac objects, at spatial resolution ~10 times better than previous ground-based surveys. We focus on data reduction and analysis, describing the...
The HST Survey of BL Lacertae Objects. II. Host Galaxies (1999)
Urry, C. Megan, Scarpa, Riccardo, O'Dowd, Matthew, Falomo, Renato, Pesce, Joseph E., Treves, Aldo
We have used the HST WFPC2 camera to survey 132 BL Lac objects comprising seven complete radio-, X-ray-, and optically-selected samples. We obtained useful images for 110 targets spanning the...
On the Physical Conditions in AGN Optical Jets (1999)
Scarpa, Riccardo, Urry, C. Megan
The energy budget of all known optical jets is discussed. It is found that to power the extended radio lobes of radio galaxies, the jet bulk motion on kpc scales must be relativistic, on average....
Multiwavelength Properties of Blazars (1999)
Blazar spectral energy distributions (SEDs) are double peaked and follow a self-similar sequence in luminosity. The so-called "blue" blazars, whose first SED component peaks at X-ray energies, are...
BL Lac Objects and Blazars: Past, Present, and Future (1998)
The past 20 years have seen phenomenal progress in our understanding of BL Lac objects. They form part of the blazar class, which are radio-loud AGN whose relativistic jets are aligned along our line...
HST snapshot imaging of BL Lac objects (1998)
Falomo, R., Urry, C. Megan, Scarpa, Riccardo, Pesce, Joseph E., Treves, Aldo
Snapshot images of about 100 BL Lac objects were obtained with WFPC2 on HST. Sources from various samples, in the redshift range 0.05 to 1.2, were observed and 61 resolved (51 with known z). The high...
HST Observations of the Host Galaxies of BL Lacertae Objects (1998)
Urry, C. Megan, Falomo, Renato, Scarpa, Riccardo, Pesce, Joseph E., Treves, Aldo, Giavalisco, Mauro
Six BL Lac objects from the complete 1 Jy radio-selected sample of 34 objects were observed in Cycle 5 with the HST WFPC2 camera to an equivalent limiting flux of mu_I~26 mag/arcsec^2. Here we report...
BeppoSAX Observations of Unprecedented Synchrotron Activity in the BL Lac Object Mkn 501 (1997)
Pian, Elena, Vacanti, Giuseppe, Tagliaferri, Gianpiero, Ghisellini, Gabriele, Maraschi, Laura, Treves, Aldo, ...
The BL Lac object Mkn 501, one of the only three extragalactic sources (with Mkn 421 and 1ES 2344+514) so far detected at TeV energies, was observed with the BeppoSAX satellite on 7, 11, and 16 April...
Monitoring Ly alpha Emission from the Blazar 3C 279 (1997)
Koratkar, Anuradha, Pian, Elena, Urry, C. Megan, Pesce, Joseph E.
The blazar 3C 279 is well studied and shows frequent large continuum flares from radio to gamma-ray wavelengths. There have been a number of multi-wavelength observations of 3C 279, and hence there...
Pian, Elena, Urry, C. Megan, Treves, Aldo, Maraschi, Laura, Penton, Steve, Shull, J. Michael, ...
PKS 2155-304, the brightest BL Lac object in the ultraviolet sky, was monitored with the IUE satellite at ~1 hour time-resolution for ten nearly uninterrupted days in May 1994. The campaign, which...
Urry, C. Megan, Treves, A., Maraschi, L., Marshall, H., Kii, T., Madejski, G., ...
In May 1994 the BL Lac object PKS 2155-304 was observed continuously for ~10 d with IUE and EUVE and for 2 d with ASCA, as well as with ROSAT and with ground- based radio, IR, and optical telescopes....
Multiwavelength Properties of Blazars (1997)
The multiwavelength spectra of blazars appear to be dominated by nonthermal emission from a relativistic jet oriented close to the line of sight. The recent detection of many blazars at gamma-ray...
An Overview of Blazar Variability (1996)
Blazars are characterized by rapid variability at virtually all wavelengths from radio through TeV gamma-rays. The challenge since their discovery has been to understand the origin of their luminous,...
Unified Schemes for Radio-Loud Active Galactic Nuclei (1995)
Urry, C. Megan, Padovani, Paolo
The appearance of active galactic nuclei (AGN) depends so strongly on orientation that our current classification schemes are dominated by random pointing directions instead of more interesting...