Browsing by Author "Schawinski, Kevin"

Now showing 1 - 20 of 47
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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 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 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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    AGNs and their host galaxies in the local universe : two mass-independent Eddington ratio distribution functions characterize black hole growth.
    (2017) Weigel, Anna; Ezequiel Treister.; Schawinski, Kevin; Caplar, Neven; Wong, O. Ivy; Trakhtenbrot, Benny
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    BASS. XXI. The Data Release 2 Overview
    (2022) Koss, Michael J.; Trakhtenbrot, Benny ; Ricci, Claudio ; Bauer, Franz Erik; Treister, Ezequiel ; Mushotzky, Richard ; Urry, C. Megan ; Ananna, Tonima T. ; Baloković, Mislav ; den Brok, Jakob S. ; Cenko, S. Bradley ; Harrison, Fiona ; Ichikawa, Kohei ; Lamperti, Isabella; Lein, Amy ; Mejía-Restrepo, Julian E. ; Oh, Kyuseok ; Pacucci, Fabio ; Pfeifle, Ryan W. ; Powell, Meredith C. ; Privon, George C. ; Ricci, Federica; Salvato, Mara ; Schawinski, Kevin ; Shimizu, Taro ; Krista L. Smith; Stern, Daniel
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    BASS. XXII. The BASS DR2 AGN Catalog and Data
    (2022) Koss, Michael J. ; Ricci, Claudio ; Trakhtenbrot, Benny ; Oh, Kyuseok ; den Brok, Jakob S. ; Mejía-Restrepo, Julian E. ; Stern, Daniel ; Privon, George C. ; Treister, Ezequiel ; Powell, Meredith C.; Mushotzky, Richard ; Bauer, Franz Erik; Ananna, Tonima T. ; Baloković, Mislav ; Bär, Rudolf ; Becker, George ; Bessiere, Patricia ; Burtscher, Leonard ; Caglar, Turgay ; Congiu, Enrico ; Evans, Phil ; Harrison, Fiona ; Heida, Marianne ; Ichikawa, Kohei ; Kamraj, Nikita; Lamperti, Isabella; Pacucci, Fabio ; Ricci, Federica ; Riffel, Rogério; Rojas, Alejandra F. ; Schawinski, Kevin ; Temple, Matthew J. ; Urry, C. Megan ; Veilleux, Sylvain ; Williams, Jonathan
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    BASS. XXIV. The BASS DR2 Spectroscopic Line Measurements and AGN Demographics
    (2022) Oh, Kyuseok; Koss, Michael J.; Ueda, Yoshihiro; Stern, Daniel; Ricci, Claudio; Trakhtenbrot, Benny; Powell, Meredith C.; den Brok, Jakob S.; Lamperti, Isabella; Mushotzky, Richard; Ricci, Federica; Bar, Rudolf E.; Rojas, Alejandra F.; Ichikawa, Kohei; Riffel, Rogerio; Treister, Ezequiel; Harrison, Fiona; Urry, C. Megan; Bauer, Franz E.; Schawinski, Kevin
    We present the second catalog and data release of optical spectral line measurements and active galactic nucleus (AGN) demographics of the BAT AGN Spectroscopic Survey, which focuses on the Swift-BAT hard X-ray detected AGNs. We use spectra from dedicated campaigns and publicly available archives to investigate spectral properties of most of the AGNs listed in the 70 month Swift-BAT all-sky catalog; specifically, 743 of the 746 unbeamed and unlensed AGNs (99.6%). We find a good correspondence between the optical emission line widths and the hydrogen column density distributions using the X-ray spectra, with a clear dichotomy of AGN types for N (H) = 10(22) cm(-2). Based on optical emission-line diagnostics, we show that 48%-75% of BAT AGNs are classified as Seyfert, depending on the choice of emission lines used in the diagnostics. The fraction of objects with upper limits on line emission varies from 6% to 20%. Roughly 4% of the BAT AGNs have lines too weak to be placed on the most commonly used diagnostic diagram, [O iii]lambda 5007/H beta versus [N ii]lambda 6584/H alpha, despite the high signal-to-noise ratio of their spectra. This value increases to 35% in the [O iii]lambda 5007/[O ii]lambda 3727 diagram, owing to difficulties in line detection. Compared to optically selected narrow-line AGNs in the Sloan Digital Sky Survey, the BAT narrow-line AGNs have a higher rate of reddening/extinction, with H alpha/H beta > 5 (similar to 36%), indicating that hard X-ray selection more effectively detects obscured AGNs from the underlying AGN population. Finally, we present a subpopulation of AGNs that feature complex broad lines (34%, 250/743) or double-peaked narrow emission lines (2%, 17/743).
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    BASS. XXV. DR2 Broad-line-based Black Hole Mass Estimates and Biases from Obscuration
    (2022) Mejía-Restrepo, Julian E.; Trakhtenbrot, Benny; Koss, Michael J.; Oh, Kyuseok; den Brok, Jakob; Stern, Daniel; Powell, Meredith C.; Ricci, Federica; Caglar, Turgay; Ricci, Claudio; Bauer, Franz Erik; Treister , Ezequiel; Harrison, Fiona A.; Urry, C. M.; Ananna, Tonima Tasnim; Asmus, Daniel; Assef, Roberto J.; Bär, Rudolf E.; Bessiere, Patricia S.; Burtscher, Leonard; Ichikawa, Kohei; Kakkad, Darshan; Kamraj, Nikita; Mushotzky, Richard; Privon, George C.; Rojas, Alejandra F.; Sani, Eleonora; Schawinski, Kevin; Veilleux, Sylvain
    We present measurements of broad emission lines and virial estimates of supermassive black hole masses (M _{BH} ) for a large sample of ultrahard X-ray-selected active galactic nuclei (AGNs) as part of the second data release of the BAT AGN Spectroscopic Survey (BASS/DR2). Our catalog includes M _{BH} estimates for a total of 689 AGNs, determined from the Hα, Hβ, Mg II λ2798, and/or C_{IV} λ1549 broad emission lines. The core sample includes a total of 512 AGNs drawn from the 70 month Swift/BAT all-sky catalog. We also provide measurements for 177 additional AGNs that are drawn from deeper Swift/BAT survey data. We study the links between M _{BH} estimates and line-of-sight obscuration measured from X-ray spectral analysis. We find that broad Hα emission lines in obscured AGNs (Log(N_{H} / cm^{-2} > 22.0) are on average a factor of 8.0_{-2.4}^{+4.1} weaker relative to ultrahard X-ray emission and about 35_{-12}^{,+7} % narrower than those in unobscured sources (i.e.(Log(N_{H} / cm^{-2} > 21.5). This indicates that the innermost part of the broad-line region is preferentially absorbed. Consequently, current single-epoch M _{BH} prescriptions result in severely underestimated (>1 dex) masses for Type 1.9 sources (AGNs with broad Hα but no broad Hβ) and/or sources with Log(N_{H} / cm^{-2} >= 22.0 . We provide simple multiplicative corrections for the observed luminosity and width of the broad Hα component (LbHα and FWHMbHα) in such sources to account for this effect and to (partially) remedy M _{BH} estimates for Type 1.9 objects. As a key ingredient of BASS/DR2, our work provides the community with the data needed to further study powerful AGNs in the low-redshift universe.
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    BASS. XXVI. DR2 Host Galaxy Stellar Velocity Dispersions
    (2022) Koss, Michael J.; Trakhtenbrot, Benny; Ricci, Claudio; Oh, Kyuseok; Bauer, Franz E.; Stern, Daniel; Caglar, Turgay; den Brok, Jakob S.; Mushotzky, Richard; Ricci, Federica; Mejia-Restrepo, Julian E.; Lamperti, Isabella; Treister, Ezequiel; Baer, Rudolf E.; Harrison, Fiona; Powell, Meredith C.; Privon, George C.; Riffel, Rogerio; Rojas, Alejandra F.; Schawinski, Kevin; Urry, C. Megan
    We present new central stellar velocity dispersions for 484 Sy 1.9 and Sy 2 from the second data release of the Swift/BAT AGN Spectroscopic Survey (BASS DR2). This constitutes the largest study of velocity dispersion measurements in X-ray-selected obscured active galactic nuclei (AGN) with 956 independent measurements of the Ca ii H and K lambda 3969, 3934 and Mg I lambda 5175 region (3880-5550 angstrom) and the calcium triplet region (8350-8730 angstrom) from 642 spectra mainly from VLT/X-Shooter or Palomar/DoubleSpec. Our sample spans velocity dispersions of 40-360 km s(1), corresponding to 4-5 orders of magnitude in black hole mass (M (BH) = 10(5.5-9.6) M (circle dot)), bolometric luminosity (L (bol) similar to 10(42-46) erg s(-1)), and Eddington ratio (L/L (Edd) similar to 10(-5) to 2). For 281 AGN, our data and analysis provide the first published central velocity dispersions, including six AGN with low-mass black holes (M (BH) = 10(5.5-6.5) M (circle dot)), discovered thanks to high spectral resolution observations (sigma (inst) similar to 25 km s(-1)). The survey represents a significant advance with a nearly complete census of velocity dispersions of hard X-ray-selected obscured AGN with measurements for 99% of nearby AGN (z < 0.1) outside the Galactic plane ( divide b divide > 10 degrees). The BASS AGN have much higher velocity dispersions than the more numerous optically selected narrow-line AGN (i.e., similar to 150 versus similar to 100 km s(-1)) but are not biased toward the highest velocity dispersions of massive ellipticals (i.e., >250 km s(-1)). Despite sufficient spectral resolution to resolve the velocity dispersions associated with the bulges of small black holes (similar to 10(4-5) M (circle dot)), we do not find a significant population of super-Eddington AGN. Using estimates of the black hole sphere of influence from velocity dispersion, direct stellar and gas black hole mass measurements could be obtained with existing facilities for more than similar to 100 BASS AGN.
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    BAT AGN Spectroscopic Survey (BASS) – VI. The ΓX–L/LEdd relation.
    (2017) Trakhtenbrot, Benny; Ricci, Claudio; Treister, Ezequiel; Koss, M.; Schawinski, Kevin; Mushotzky, Richard; Ueda, Yoshihiro; Veilleux, Sylvain; Lamperti, Isabella; Oh, Kyuseok; Stern, Daniel; Harrison, F.; Baloković, Mislav; Gehrels, Neil
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    BAT AGN Spectroscopic Survey - III : an observed link between AGN Eddington ratio and narrow-emission-line ratios.
    (2017) Oh, Kyuseok; Ricci, Claudio; Treister, Ezequiel; Schawinski, Kevin; Koss, M.; Trakhtenbrot, Benny; Lamperti, Isabella; Mushotzky, Richard; Veilleux, Sylvain; Berney, Simon; Crenshaw, D. Michael
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    BAT AGN Spectroscopic Survey - IV : near-Infrared Coronal Lines, Hidden Broad Lines, and Correlation with Hard X-ray emission.
    (2017) Lamperti, Isabella; Ricci, Claudio; Treister, Ezequiel; Koss, M.; Trakhtenbrot, Benny; Schawinski, Kevin; Oh, Kyuseok; Landt, Hermine; Riffel, Rogério; Rodríguez-Ardila, Alberto; Gehrels, Neil
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    BAT AGN Spectroscopic Survey - XIII. The nature of the most luminous obscured AGN in the low-redshift universe
    (2019) Bar, Rudolf E.; Trakhtenbrot, Benny; Oh, Kyuseok; Koss, Michael J.; Wong, Ivy; Ricci, Claudio; Schawinski, Kevin; Weigel, Anna K.; Sartori, Lia F.; Ichikawa, Kohei; Secrest, Nathan J.; Stern, Daniel; Pacucci, Fabio; Mushotzky, Richard; Powell, Meredith C.; Ricci, Federica; Sani, Eleonora; Smith, Krista L.; Harrison, Fiona A.; Lamperti, Isabella; Urry, C. Megan
    We present a multiwavelength analysis of 28 of the most luminous low-redshift narrow-line, ultra-hard X-ray-selected active galactic nuclei (AGN) drawn from the 70-month Swift/BAT all-sky survey, with bolometric luminosities of log(L-bol/erg s(-1)) greater than or similar to 45.25. The broad goal of our study is to determine whether these objects have any distinctive properties, potentially setting them aside from lower luminosity obscured AGN in the local Universe. Our analysis relies on the first data release of the BAT AGN Spectroscopic Survey (BASS/DR1) and on dedicated observations with the VLT, Palomar, and Keck observatories. We find that the vast majority of our sources agree with commonly used AGN selection criteria which are based on emission line ratios and on mid-infrared colours. Our AGN are pre-dominantly hosted in massive galaxies (9.8 less than or similar to log (M-*/M-circle dot) less than or similar to 11.7); based on visual inspection of archival optical images, they appear to be mostly ellipticals. Otherwise, they do not have distinctive properties. Their radio luminosities, determined from publicly available survey data, show a large spread of almost four orders of magnitude- much broader than what is found for lower X-ray luminosity obscured AGN in BASS. Moreover, our sample shows no preferred combination of black hole masses (M-BH) and/or Eddington ratio (lambda(Edd)), covering 7.5 less than or similar to log (M-BH/M-circle dot) less than or similar to 10.3 and 0.01 less than or similar to lambda(Edd) less than or similar to 1. Based on the distribution of our sources in the lambda(Edd)-N-H plane, we conclude that our sample is consistent with a scenario where the amount of obscuring material along the line of sight is determined by radiation pressure exerted by the AGN on the dusty circumnuclear gas.
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    BAT AGN Spectroscopic Survey - XVII. The parsec-scale jet properties of the ultrahard X-ray-selected local AGNs
    (2019) Baek, Junhyun; Chung, Aeree; Schawinski, Kevin; Oh, Kyuseok; Wong, O. Ivy; Koss, Michael; Ricci, Claudio; Trakhtenbrot, Benny; Smith, Krista Lynne; Ueda, Yoshihiro
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    BAT AGN spectroscopic survey-II. X-ray emission and high-ionization optical emission lines.
    (2015) Berney, Simon; Ricci, Claudio; Treister, Ezequiel; Koss, M.; Trakhtenbrot, Benny; Lamperti, Isabella; Schawinski, Kevin; Crenshaw, D. Michael; Fischer, Travis; Gehrels, Neil
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    BAT AGN Spectroscopic Survey. I. Spectral Measurements, Derived Quantities, and AGN Demographics.
    (2017) Koss, M.; Ricci, Claudio; Treister, Ezequiel; Trakhtenbrot, Benny; Lamperti, Isabella; Oh, Kyuseok; Berney, Simon; Schawinski, Kevin; Baloković, Mislav; Baronchelli, Linda; Crenshaw, D. Michael
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    BAT AGN Spectroscopic Survey. VIII. Type 1 AGN with Massive Absorbing Columns
    (2018) Shimizu, T. Taro; Davies, Richard I.; Koss, Michael; Ricci, Claudio; Lamperti, Isabella; Oh, Kyuseok; Schawinski, Kevin; Trakhtenbrot, Benny; Burtscher, Leonard; Genzel, Reinhard; Lin, Ming-yi; Lutz, Dieter; Rosario, David; Sturm, Eckhard; T
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    BAT AGN Spectroscopic Survey. XX. Molecular Gas in Nearby Hard-X-Ray-selected AGN Galaxies
    (2021) Koss, Michael J. ; Strittmatter, Benjamin ; Lamperti, Isabella; Shimizu, Taro ; Trakhtenbrot, Benny ; Saintonge, Amelie ; Treister, Ezequiel ; Cicone, Claudia; Mushotzky, Richard ; Oh, Kyuseok; Ricci, Claudio ; Stern, Daniel ; Tasnim Ananna, Tonima ; Bauer, Franz Erik; Privon, George C. ; Bär, Rudolf ; De Breuck, Carlos; Harrison, Fiona ; Ichikawa, Kohei ; Powell, Meredith C. ; Rosario, David ; Sanders, David B. ; Schawinski, Kevin ; Shao, Li ; Urry, C. Megan ; Veilleux, Sylvain
    We present the host-galaxy molecular gas properties of a sample of 213 nearby (0.01.<.z.<.0.05) hard-X-rayselected active galactic nucleus (AGN) galaxies, drawn from the 70-month catalog of Swift's Burst Alert Telescope (BAT), with 200 new CO(2-1) line measurements obtained with the James Clerk Maxwell Telescope and the Atacama Pathfinder Experiment telescope. We find that AGN in massive galaxies (log(M*/M-circle dot) > 10.5) tend to have more molecular gas and higher gas fractions than inactive galaxies matched in stellar mass. When matched in star formation, we find AGN galaxies show no difference from inactive galaxies, with no evidence that AGN feedback affects the molecular gas. The higher molecular gas content is related to AGN galaxies hosting a population of gas-rich early types with an order of magnitude more molecular gas and a smaller fraction of quenched, passive galaxies (similar to 5% versus 49%) compared to inactive galaxies. The likelihood of a given galaxy hosting an AGN (L-bol > 10(44) erg s(-1)) increases by similar to 10-100 between a molecular gas mass of 10(8.7)M(circle dot) and 10(10.2)M(circle dot). AGN galaxies with a higher Eddington ratio (log(L/L-Edd) > -1.3) tend to have higher molecular gas masses and gas fractions. The log(N-H/cm(-2)) > 23.4) of AGN galaxies with higher column densities are associated with lower depletion timescales and may prefer hosts with more gas centrally concentrated in the bulge that may be more prone to quenching than galaxy-wide molecular gas. The significant average link of host-galaxy molecular gas supply to supermassive black hole (SMBH) growth may naturally lead to the general correlations found between SMBHs and their host galaxies, such as the correlations between SMBH mass and bulge properties, and the redshift evolution of star formation and SMBH growth.
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    Black hole growth in the early Universe is self-regulated and largely hidden from view.
    (2011) Treister, Ezequiel; Schawinski, Kevin; Volonteri, Marta; Natarajan, Priyamvada; Gawiser, Eric.
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    Chandra Observations of Galaxy Zoo Mergers : Frequency of Binary Active Nuclei in Massive Mergers.
    (2012) Teng, Stacy H.; Treister, Ezequiel; Schawinski, Kevin; Urry, C. Meg; Darg, Dan W.; Kaviraj, Sugata; Oh, Kyuseok; Bonning, Erin W.; Cardamone, Carolin N.; Keel, William C.; Lintott, Chris J.; Simmons, Brooke D.