Search Publications
Three-year Swift-BAT Survey of Active Galactic Nuclei: Reconciling Theory and Observations?
Greiner, J.; Merloni, A.; Comastri, A. +3 more
It is well accepted that unabsorbed as well as absorbed active galactic nuclei (AGNs) are needed to explain the nature and shape of the Cosmic X-ray background (CXB), even if the fraction of highly absorbed objects (dubbed Compton-thick sources) still substantially escapes detection. We derive and analyze the absorption distribution using a comple…
Dissecting Photometric Redshift for Active Galactic Nucleus Using XMM- and Chandra-COSMOS Samples
Kneib, J. -P.; Aussel, H.; Le Floc'h, E. +62 more
In this paper, we release accurate photometric redshifts for 1692 counterparts to Chandra sources in the central square degree of the Cosmic Evolution Survey (COSMOS) field. The availability of a large training set of spectroscopic redshifts that extends to faint magnitudes enabled photometric redshifts comparable to the highest quality results pr…
Evidence for Ultra-fast Outflows in Radio-quiet Active Galactic Nuclei. II. Detailed Photoionization Modeling of Fe K-shell Absorption Lines
Cappi, M.; Dadina, M.; Tombesi, F. +3 more
X-ray absorption line spectroscopy has recently shown evidence for previously unknown Ultra-fast Outflows (UFOs) in radio-quiet active galactic nuclei (AGNs). These have been detected essentially through blueshifted Fe XXV/XXVI K-shell transitions. In the previous paper of this series we defined UFOs as those highly ionized absorbers with an outfl…
A Complete Sample of Ultraluminous X-ray Source Host Galaxies
Soria, Roberto; Tennant, Allyn F.; Swartz, Douglas A. +1 more
One hundred seven ultraluminous X-ray sources (ULXs) with 0.3-10.0 keV luminosities in excess of 1039 erg s-1 are identified in a complete sample of 127 nearby galaxies. The sample includes all galaxies within 14.5 Mpc above the completeness limits of both the Uppsala Galaxy Catalogue and the Infrared Astronomical Satellite s…
Shocks and Cavities from Multiple Outbursts in the Galaxy Group NGC 5813: A Window to Active Galactic Nucleus Feedback
Simionescu, A.; Churazov, E.; Giacintucci, S. +10 more
We present results from new Chandra, GMRT, and SOAR observations of NGC 5813, the dominant central galaxy in a nearby galaxy group. The system shows three pairs of collinear cavities at 1 kpc, 8 kpc, and 20 kpc from the central source, from three distinct outbursts of the central active galactic nucleus (AGN), which occurred 3 × 106, 2 …
X-Ray Properties of the First Sunyaev-Zel'dovich Effect Selected Galaxy Cluster Sample from the South Pole Telescope
Gladders, M. D.; Ade, P. A. R.; Rest, A. +60 more
We present results of X-ray observations of a sample of 15 clusters selected via their imprint on the cosmic microwave background from the thermal Sunyaev-Zel'dovich (SZ) effect. These clusters are a subset of the first SZ-selected cluster catalog, obtained from observations of 178 deg2 of sky surveyed by the South Pole Telescope (SPT).…
Three Millisecond Pulsars in Fermi LAT Unassociated Bright Sources
Abdo, A. A.; Camilo, F.; Çelik, Ö. +33 more
We searched for radio pulsars in 25 of the non-variable, unassociated sources in the Fermi LAT Bright Source List with the Green Bank Telescope at 820 MHz. We report the discovery of three radio and γ-ray millisecond pulsars (MSPs) from a high Galactic latitude subset of these sources. All of the pulsars are in binary systems, which would have mad…
Galaxies in X-Ray Groups. I. Robust Membership Assignment and the Impact of Group Environments on Quenching
Koekemoer, Anton M.; Coccato, Lodovico; Leauthaud, Alexie +19 more
Understanding the mechanisms that lead dense environments to host galaxies with redder colors, more spheroidal morphologies, and lower star formation rates than field populations remains an important problem. As most candidate processes ultimately depend on host halo mass, accurate characterizations of the local environment, ideally tied to halo m…
Accretion Rate and the Physical Nature of Unobscured Active Galaxies
Koekemoer, Anton M.; Trump, Jonathan R.; Urry, C. Megan +15 more
We show how accretion rate governs the physical properties of a sample of unobscured broad-line, narrow-line, and lineless active galactic nuclei (AGNs). We avoid the systematic errors plaguing previous studies of AGN accretion rates by using accurate intrinsic accretion luminosities (L int) from well-sampled multiwavelength spectral en…
The XMM-Newton Wide Field Survey in the COSMOS Field: Redshift Evolution of AGN Bias and Subdominant Role of Mergers in Triggering Moderate-luminosity AGNs at Redshifts up to 2.2
Finoguenov, A.; Salvato, M.; Merloni, A. +14 more
We present a study of the redshift evolution of the projected correlation function of 593 X-ray selected active galactic nuclei (AGNs) with I AB < 23 and spectroscopic redshifts z < 4, extracted from the 0.5-2 keV X-ray mosaic of the 2.13 deg2 XMM- Cosmic Evolution Survey (COSMOS). We introduce a method to estimate the …