Browsing by Author "Treister, Ezequiel "

Now showing 1 - 20 of 173
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    A comparative analysis of virial black hole mass estimates of moderate-luminosity active galactic nuclei using Subaru/FMOS.
    (2013) Matsuoka, K.; Treister, Ezequiel; Silverman, J. D.; Schramm, M.; Steinhardt C. L.; Nagao, T.; Kartaltepe, J.; Sanders, David B.; Hasinger, G.; Akiyama, M.
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    A forward modeling approach to AGN variability-method description and early applications
    (2019) Sartori, L.F.; Trakhtenbrot, B.; Schawinski, K.; Caplar, N.; Treister, Ezequiel; Zhang, C.
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    A Hard X-Ray Test of HCN Enhancements As a Tracer of Embedded Black Hole Growth
    (2020) Privon, George C.; Ricci, Claudio; Aalto, S.; Viti, Serena; Armus, Lee; Diaz-Santos, Tanio; González-Alfonso, E.; Treister, Ezequiel; Bauer, Franz Erik; Garg, P.
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    A massive, distant proto-cluster at z = 2.47 caught in a phase of rapid formation?
    (2015) Casey, C. M.; Treister, Ezequiel; Cooray, A.; Capak, P.; Fu, H.; Kovac, K.; Lilly, S.; Sanders, David B.; Scoville, Nick Z.
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    A model for AGN variability on multiple time-scales.
    (2018) Sartori, Lia F.; Treister, Ezequiel; Schawinski, Kevin; Trakhtenbrot, Benny; Caplar, Neven; Koss, M.; Urry, Claudia Megan; Zhang, Ce
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    A multiwavelength-motivated X-ray model for the Circinus Galaxy
    (2022) Andonie, Carolina; Ricci, Claudio; Paltani, Stéphane; Arévalo, Patricia; Treister, Ezequiel; Bauer, Franz; Stalevski, Marko
    Reprocessed X-ray emission in active galactic nuclei can provide fundamental information about the circumnuclear environments of supermassive black holes. Recent mid-infrared studies have shown evidence of an extended dusty structure perpendicular to the torus plane. In this work, we build a self-consistent X-ray model for the Circinus Galaxy including the different physical components observed at different wavelengths and needed to reproduce both the morphological and spectral properties of this object in the mid-infrared. The model consists of four components: the accretion disc, the broad-line region (BLR), a flared disc in the equatorial plane, and a hollow cone in the polar direction. Our final model reproduces well the 3-70 keV Chandra and NuSTAR spectra of Circinus, including the complex Fe K alpha zone and the spectral curvature, although several additional Gaussian lines, associated with either ionized iron or broadened Fe K alpha/K beta lines, are needed. We find that the flared disc is Compton-thick (N-H,N-d = 1.01(-0.24)(+0.03) x 10(25) cm(-2)) and geometrically thick (CF = 0.55(-0.05)(+0.01)), and that the hollow cone has a Compton-thin column density (N-H,N-c = 2.18(-0.43)(+0.47) x 10(23) cm(-2)), which is consistent with the values inferred by mid-infrared studies. Including also the BLR, the effective line-of-sight column density is NH = 1.47(-0.24)(+0.03) x 10(25) cm(-2). This approach to X-ray modelling, i.e. including all the different reprocessing structures, will be very important to fully exploit data from future X-ray missions.
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    A new population of compton-thick AGNs identified using the spectral curvature above 10 keV.
    (2016) Koss, M.; Bauer, Franz Erik; Ricci, Claudio; Treister, Ezequiel; Assef T., Roberto; Balokovic, M.; Stern, Daniel.; Gandhi, P.; Lamperti, I.; Alexander, D. M.
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    A new, faint population of X-ray transients.
    (2017) Bauer, Franz Erik; Treister, Ezequiel; Schulze, Steve.; Schawinski, Kevin; Luo, B.; Alexander, D. M.; Brandt, W N.; Comastri, A.; Forster, Francisco; Gilli, Roberto
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    A NuSTAR survey of nearby ultraluminous infrared galaxies.
    (2015) Teng, Stacy H.; Bauer, Franz Erik; Treister, Ezequiel; Rigby, Jane R.; Stern, Daniel.; Ptak, Andrew.; Alexander, D. M.; Boggs, Stephen E.; Brandt, W N.; Christensen, Finn E.
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    A population of luminous accreting black holes with hidden mergers
    (2018) Koss, Michael J.; Blecha, Laura; Bernhard, Phillip; Hung, Chao-Ling; Lu, Jessica R.; Trakhtenbrot, Benny; Treister, Ezequiel; Weigel, Anna; Sartori, Lia F.; Mushotzky, Richard; Schawinski, Kevin; Ricci, Claudio; Veilleux, Sylvain; Sanders, David B.
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    A statistical relation between the X-ray spectral index and Eddington ratio of active galactic nuclei in deep surveys.
    (2013) Brightman, M.; Treister, Ezequiel; Silverman, J. D.; Mainieri, V.; Ueda, Y.; Schramm, M.; Matsuoka, K.; Nagao, T.; Steinhardt C. L.; Kartaltepe, J.
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    Accretion history of AGN: Estimating the host galaxy properties in X-ray luminous AGN from z=0-3
    (2022) Coleman, Brandon; Kirkpatrick, Allison; Cooke, Kevin C.; Glikman, Eilat; La Massa, Stephanie; Marchesi, Stefano; Peca, Alessandro; Treister, Ezequiel; Auge, Connor; Urry, C. Megan; Sanders, Dave; Turner, Tracey Jane; Ananna, Tonima Tasnim
    We aim to determine the intrinsic far-Infrared (far-IR) emission of X-ray-luminous quasars over cosmic time. Using a 16 deg(2) region of the Stripe 82 field surveyed by XMM-Newton and Herschel Space Observatory, we identify 2905 X-ray luminous (L-X > 10(42) erg/s) active galactic nuclei (AGN) in the range z approximate to 0-3. The IR is necessary to constrain host galaxy properties such as star formation rate (SFR) and gas mass. However, only 10 per cent of our AGN are detected both in the X-ray and IR. Because 90 per cent of the sample is undetected in the far-IR by Herschel, we explore the mean IR emission of these undetected sources by stacking their Herschel/SPIRE images in bins of X-ray luminosity and redshift. We create stacked spectral energy distributions from the optical to the far-IR, and estimate the median SFR, dust mass, stellar mass, and infrared luminosity using a fitting routine. We find that the stacked sources on average have similar SFR/L-bol ratios as IR detected sources. The majority of our sources fall on or above the main sequence line suggesting that X-ray selection alone does not predict the location of a galaxy on the main sequence. We also find that the gas depletion time scales of our AGN are similar to those of dusty star forming galaxies. This suggests that X-ray selected AGN host high star formation and that there are no signs of declining star formation.
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    Accretion History of AGNs. II. Constraints on AGN Spectral Parameters Using the Cosmic X-Ray Background
    (2020) Ananna, Tonima; Treister, Ezequiel; Urry, C. Megan; Ricci, Claudio; Hickox, R. C.; Padmanabhan, Nikhil; Marchesi, Stefano; Kirkpatrick, Allison
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    Accretion history of AGNs. III. Radiative efficiency and AGN contribution to reionization
    (2020) Ananna, T. T.; Urry, C. M.; Treister, Ezequiel; Hickox, R. C.; Shankar, F.; Ricci, Claudio; Cappelluti, N.; Marchesi, S.; Turner, T. J.
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    Active galactic nuclei unification and the X-ray background.
    (2005) Treister, Ezequiel ; Urry, Claudia Megan
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    AGN Feedback and Star Formation of Quasar Host Galaxies: Insights from the Molecular Gas
    (2020) Shangguan, Jinyi ; Ho, Luis C. ; Bauer, Franz Erik; Wang, Ran ; Treister, Ezequiel
    Molecular gas serves as a key probe of the complex interplay between black hole accretion and star formation in the host galaxies of active galactic nuclei (AGNs). We use CO(2-1) observations from a new Atacama Large Millimeter/submillimeter Array survey, in conjunction with literature measurements, to investigate the molecular gas properties of a representative sample of 40z < 0.3 Palomar-Green quasars, the largest and most sensitive study of molecular gas emission to date for nearby quasars. We find that the AGN luminosity correlates with both the CO luminosity and black hole mass, suggesting that AGN activity is loosely coupled to the cold gas reservoir of the host. The observed strong correlation between host galaxy total infrared luminosity and AGN luminosity arises from their common dependence on the molecular gas. We argue that the total infrared luminosity, at least for low-redshift quasars, can be used to derive reliable star formation rates for the host galaxy. The host galaxies of low-redshift quasars have a molecular gas content similar to that of star-forming galaxies of comparable stellar mass. Moreover, they share similar gas kinematics, as evidenced by their CO Tully-Fisher relation and the absence of detectable molecular outflows down to sensitive limits. There is no sign that AGN feedback quenches star formation for the quasars in our sample. On the contrary, the abundant gas supply forms stars prodigiously, at a rate that places most of them above the star-forming main sequence and with an efficiency that rivals that of starburst systems.
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    An ALMA CO(2–1) Survey of Nearby Palomar–Green Quasars
    (2020) Shangguan, Jinyi; Ho, Luis C.; Bauer, Franz Erik; Wang, Ran; Treister, Ezequiel
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    An X-Ray-selected Active Galactic Nucleus at z=4.6 Discovered by the CYDER Survey.
    (2004) Treister, Ezequiel; Castander, Francisco J.; Maccarone, Thomas J.; Herrera, David; Gawiser, Eric; Maza, José; Coppi, Paolo S.
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    BASS. XLII. The Relation between the Covering Factor of Dusty Gas and the Eddington Ratio in Nearby Active Galactic Nuclei
    Ricci, C.; Ichikawa, K.; Stalevski, M.; Kawamuro, T.; Yamada, S.; Ueda, Y.; Mushotzky, R.; Privon, G. C.; Koss, M. J.; Trakhtenbrot, B.; Fabian, A. C.; Ho, L. C.; Asmus, D.; Bauer, Franz Erik; Chang, C. S.; Gupta, K. K.; Oh, K.; Powell, M.; Pfeifle, R. W.; Rojas, A.; Ricci, F.; Temple, M. J.; Toba, Y.; Tortosa, A.; Treister, Ezequiel; Harrison, F.; Stern, D.; Urry, C. M.
    Accreting supermassive black holes (SMBHs) located at the centers of galaxies are typically surrounded by large quantities of gas and dust. The structure and evolution of this circumnuclear material can be studied at different wavelengths, from the submillimeter to the X-ray. Recent X-ray studies have shown that the covering factor of the obscuring material tends to decrease with increasing Eddington ratio, likely due to radiative feedback on dusty gas. Here we study a sample of 549 nearby (z less than or similar to 0.1) hard X-ray (14-195 keV) selected nonblazar active galactic nuclei (AGN) and use the ratio between the AGN infrared and bolometric luminosity as a proxy of the covering factor. We find that, in agreement with what has been found by X-ray studies of the same sample, the covering factor decreases with increasing Eddington ratio. We also confirm previous findings that showed that obscured AGN typically have larger covering factors than unobscured sources. Finally, we find that the median covering factors of AGN located in different regions of the column density-Eddington ratio diagram are in good agreement with what would be expected from a radiation-regulated growth of SMBHs.
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    BASS. XXIII. A New Mid-infrared Diagnostic for Absorption in Active Galactic Nuclei
    (2022) Pfeifle, Ryan W.; Ricci, Claudio; Boorman, Peter G.; Stalevski, Marko; Asmus, Daniel; Trakhtenbrot, Benny; Koss, Michael J.; Stern, Daniel; Ricci, Federica; Satyapal, Shobita; Ichikawa, Kohei; Rosario, David J.; Caglar, Turgay; Treister, Ezequiel; Powell, Meredith; Oh, Kyuseok; Urry, C. Megan; Harrison, Fiona
    In this study, we use the Swift/BAT AGN sample, which has received extensive multiwavelength follow-up analysis as a result of the BAT AGN Spectroscopic Survey, to develop a diagnostic for nuclear obscuration by examining the relationship between the line-of-sight column densities (N-H), the 2-10 keV to 12 mu m luminosity ratio, and WISE mid-infrared colors. We demonstrate that heavily obscured AGNs tend to exhibit both preferentially "redder" mid-infrared colors and lower values of L-X,L-Obs./L-12 mu m than less obscured AGNs, and we derive expressions relating N-H to the L-X,L-Obs./L-12 mu m and L-22 mu m/L-4.6 mu m luminosity ratios, as well as develop diagnostic criteria using these ratios. Our diagnostic regions yield samples that are greater than or similar to 80% complete and greater than or similar to 60% pure for AGNs with log(N-H/cm(-2)) >= 24, as well as greater than or similar to 85% pure for AGNs with log(N-H/cm(-2)) greater than or similar to 23.5. We find that these diagnostics cannot be used to differentiate between optically star-forming galaxies and active galaxies. Further, mid-IR contributions from host galaxies that dominate the observed 12 mu m emission can lead to larger apparent X-ray deficits and redder mid-IR colors than the AGNs would intrinsically exhibit, though this effect helps to better separate less and more obscured AGNs. Finally, we test our diagnostics on two catalogs of AGNs and infrared galaxies, including the XMM-Newton XXL-N field, and we identify several known Compton-thick AGNs, as well as a handful of candidate heavily obscured AGNs based upon our proposed obscuration diagnostics.