Browsing by Author "Treister, Ezequiel "

Now showing 1 - 20 of 183
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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 XLIV. Morphological preferences of local hard X-ray selected AGNs
    (EDP Sciences, 2025) Parra Tello, Miguel Agustín; Bauer, Franz E.; Cicco, Demetra de; Doll, Goran; Koss, Michael; Treister, Ezequiel; Finlez, Carolina; Troncoso Balbiano, Marco Javier; Auge, Connor; Moral Castro, Ignacio del; Chung, Aeree; Gupta, Kriti K.; Kim, Jeein; Oh, Kyuseok; Ricci, Claudio; Ricci, Federica; Rojas, Alejandra; Caglar, Turgay; Harrison, Fiona; Powell, Meredith C.; Stern, Daniel; Trakhtenbrot, Benny; Urry, C. Megan
    We present detailed morphological classifications for the hosts of 1189 hard X-ray selected (14–195 keV) active galactic nuclei (AGNs) from the Swift-BAT 105-month catalog as part of the BAT AGN Spectroscopic Survey (BASS). BASS provides a powerful all-sky census of nearby AGNs, minimizing obscuration biases and providing a robust dataset for studying AGN-host galaxy connections. Classifications are based on a volunteer-based visual inspection workflow on the Zooniverse platform, adapted from the Galaxy Zoo DECaLS (GZD) project. Dual-contrast grz color composite images, generated from public surveys (e.g., NOAO Legacy Survey, Pan-STARRS, SDSS) and dedicated observations enabled key morphological features to be identified. Our analysis reveals that, with respect to a control sample of inactive galaxies, BASS AGN hosts show a deficiency of smooth elliptical galaxies (∼70%) and spiral galaxies with prominent arms (∼80%), while displaying an excess of mergers or disturbed systems (∼400%), and disk galaxies without a spiral structure (∼300%). These trends are found after controlling for redshift and i-band magnitude, which suggests a preference for AGN activity in gas-rich, dynamically disturbed environments or transitional disk systems. We also find a higher bar fraction among AGN hosts than in a control sample (∼50% vs. ∼30%). We further explore the relationships between AGN properties (e.g., X-ray luminosity, black hole mass, and Eddington ratio) and host morphology, and find that high-luminosity and high-accretion AGNs preferentially reside in smooth or point-like hosts. At the same time, lower-luminosity AGNs are more common in disk galaxies. These results underscore the importance of morphological studies in understanding the fueling and feedback mechanisms that drive AGN activity and their role in galaxy evolution. Our dataset provides a valuable benchmark for future multiwavelength surveys (e.g. LSST, Roman, and Euclid) and automated morphological classification efforts.
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    BASS. LIII. The Eddington Ratio as the Primary Regulator of the Fraction of X-Ray Emission in Active Galactic Nuclei
    (2025) Gupta, Kriti Kamal; Ricci, Claudio; Tortosa, Alessia; Temple, Matthew J.; Koss, Michael J.; Trakhtenbrot, Benny; Bauer, Franz E.; Treister, Ezequiel; Mushotzky, Richard; Kammoun, Elias; Papadakis, Iossif; Oh, Kyuseok; Rojas, Alejandra; Chang, Chin-Shin; Diaz, Yaherlyn; Jana, Arghajit; Kakkad, Darshan; Moral Castro, Ignacio del; Peca, Alessandro; Powell, Meredith C.; Stern, Daniel; Urry, C. Megan; Harrison, Fiona
    Active galactic nuclei (AGN) emit radiation via accretion across the entire energy spectrum. While the standard disk and corona model can somewhat describe this emission, it fails to predict specific features such as the soft X-ray excess, the short-term optical/UV variability, and the observed UV/X-ray correlation in AGN. In this context, the fraction of AGN emission in different bands (i.e., bolometric corrections) can be useful to better understand the accretion physics of AGN. Past studies have shown that the X-ray bolometric corrections are strongly dependent on the physical properties of AGN, such as their luminosities and Eddington ratios. However, since these two parameters depend on each other, it has been unclear which is the main driver of the X-ray bolometric corrections. We present here results from a large study of hard-X-ray-selected (14–195 keV) nearby (z < 0.1) AGN. Based on our systematic analysis of the simultaneous optical-to-X-ray spectral energy distributions of 236 unobscured AGN, we found that the primary parameter controlling the X-ray bolometric corrections is the Eddington ratio. Our results show that, while the X-ray bolometric correction increases with the bolometric luminosity for sources with intermediate Eddington ratios (0.01–1), this dependence vanishes for sources with lower Eddington ratios (<0.01). This could be used as evidence for a change in the accretion physics of AGN at low Eddington ratios.