Browsing by Author "Koss, Michael J."
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- ItemA 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.
- ItemBASS. 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, SylvainWe 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.
- ItemBASS. XXXIV. A Catalog of the Nuclear Millimeter-wave Continuum Emission Properties of AGNs Constrained on Scales ≤ 100-200 pc(IOP Publishing Ltd, 2023) Kawamuro, Taiki; Ricci, Claudio; Mushotzky, Richard F.; Imanishi, Masatoshi; Bauer, Franz Erik; Ricci, Federica; Koss, Michael J.; Privon, George C.; Trakhtenbrot, Benny; Izumi, Takuma; Ichikawa, Kohei; Rojas, Alejandra F.; Smith, Krista Lynne; Shimizu, Taro; Oh, Kyuseok; den Brok, Jakob S.; Baba, Shunsuke; Balokovic, Mislav; Chang, Chin-Shin; Kakkad, Darshan; Pfeifle, Ryan W.; Temple, Matthew J.; Ueda, Yoshihiro; Harrison, Fiona; Powell, Meredith C.; Stern, Daniel; Urry, Meg; Sanders, David B.We present a catalog of the millimeter-wave (mm-wave) continuum properties of 98 nearby (z < 0.05) active galactic nuclei (AGNs) selected from the 70 month Swift/BAT hard-X-ray catalog that have precisely determined X-ray spectral properties and subarcsecond-resolution Atacama Large Millimeter/submillimeter Array Band 6 (211-275 GHz) observations as of 2021 April. Due to the hard-X-ray (>10 keV) selection, the sample is nearly unbiased for obscured systems at least up to Compton-thick-level obscuration, and provides the largest number of AGNs with high-physical-resolution mm-wave data (less than or similar to 100-200 pc). Our catalog reports emission peak coordinates, spectral indices, and peak fluxes and luminosities at 1.3 mm (230 GHz). Additionally, high-resolution mm-wave images are provided. Using the images and creating radial surface brightness profiles of mm-wave emission, we identify emission extending from the central sources and isolated blob-like emission. Flags indicating the presence of these emission features are tabulated. Among 90 AGNs with significant detections of nuclear emission, 37 AGNs (approximate to 41%) appear to have both or one of extended or blob-like components. We, in particular, investigate AGNs that show well-resolved mm-wave components and find that these seem to have a variety of origins (i.e., a jet, radio lobes, a secondary AGN, stellar clusters, a narrow-line region, galaxy disk, active star formation regions, or AGN-driven outflows), and some components have currently unclear origins.
- ItemBASS. XXXV. The MBH-σ* Relation of 105 Month Swift-BAT Type 1 AGNs(IOP Publishing Ltd, 2023) Caglar, Turgay; Koss, Michael J.; Burtscher, Leonard; Trakhtenbrot, Benny; Erdim, M. Kiyami; Mejia-Restrepo, Julian E.; Ricci, Federica; Powell, Meredith C.; Ricci, Claudio; Mushotzky, Richard; Bauer, Franz Erik; Ananna, Tonima T.; Baer, Rudolf E.; Brandl, Bernhard; Brinchmann, Jarle; Harrison, Fiona; Ichikawa, Kohei; Kakkad, Darshan; Oh, Kyuseok; Riffel, Rogerio; Sartori, Lia F.; Smith, Krista L.; Stern, Daniel; Urry, C. MeganWe present two independent measurements of stellar velocity dispersions (sigma(star)) from the Ca II H+K lambda 3969, 3934 and Mg I b lambda 5183, 5172, 5167 region (3880-5550 angstrom) and the calcium triplet region (8350-8750 angstrom) for 173 hard X-ray-selected Type 1 active galactic nuclei (AGNs; z <= 0.08) from the 105 month Swift-BAT catalog. We construct one of the largest samples of local Type 1 AGNs that have both single-epoch virial black hole mass (M-BH) estimates and sigma(star) measurements obtained from high spectral resolution data, allowing us to test the usage of such methods for supermassive black hole studies. We find that the two independent sigma(star) measurements are highly consistent with each other, with an average offset of only 0.002 +/- 0.001 dex. Comparing M-BH estimates based on broad emission lines and stellar velocity dispersion measurements, we find that the former is systematically lower by approximate to 0.12 dex. Consequently, Eddington ratios estimated through broad-line MBH determinations are similarly biased (but in the opposite way). We argue that the discrepancy is driven by extinction in the broad-line region. We also find an anticorrelation between the offset from the M-BH-sigma(star) relation and the Eddington ratio. Our sample of Type 1 AGNs shows a shallower M-BH-sigma(star) relation (with a power-law exponent of approximate to 3.5) compared with that of inactive galaxies (with a power-law exponent of approximate to 4.5), confirming earlier results obtained from smaller samples.
- ItemJoint NuSTAR and Chandra analysis of the obscured quasar in IC 2497-Hanny's Voorwerp system(2018) Sartori, Lia F.; Schawinski, Kevin; Koss, Michael J.; Ricci, Claudio; Treister, Ezequiel; Stern, Daniel; Lansbury, George; Maksym, W. Peter; Baloković, Mislav; Gandhi, Poshak
- ItemNuSTAR RESOLVES THE FIRST DUAL AGN ABOVE 10 keV IN SWIFT J2028.5+2543(2016) Koss, Michael J.; Glidden, Ana; Baloković, Mislav; Stern, Daniel; Lamperti, Isabella; Assef, Roberto; Bauer, Franz Erik; Ballantyne, David; Boggs, Steven E.; Craig, William W.; Farrah, Duncan; Fürst, Felix; Gandhi, Poshak; Gehrels, Neil; Hailey, Charles J.; Harrison, Fiona A.; Markwardt, Craig; Masini, Alberto; Ricci, Claudio; Treister, Ezequiel; Koss, Michael J.; Glidden, Ana; Baloković, Mislav; Stern, Daniel; Lamperti, Isabella; Assef, Roberto; Bauer, Franz Erik; Ballantyne, David; Boggs, Steven E.; Craig, William W.; Farrah, Duncan; Fürst, Felix; Gandhi, Poshak; Gehrels, Neil; Hailey, Charles J.; Harrison, Fiona A.; Markwardt, Craig; Masini, Alberto; Ricci, Claudio; Treister, Ezequiel
- ItemThe complete infrared view of active galactic nuclei from the 70 month Swift/BAT catalog(2017) Ichikawa, Kohei; Ricci, Claudio; Ueda, Yoshihiro; Matsuoka, Kenta; Toba, Yoshiki; Kawamuro, Taiki; Trakhtenbrot, Benny; Koss, Michael J.