BASS. XXII. The BASS DR2 AGN Catalog and Data

Koss, Michael; Ricci, Cláudio; Trakhtenbrot, Benny; Oh, Kyuseok; Brok, Jakob S. den; Mejía-Restrepo, Julián E.; Stern, Daniel; Privon, George C.; Treister, Ezequiel; Powell, Meredith C.; Mushotzky, R. F.; Bauer, F. E.; Ananna, Tonima Tasnim; Baloković, Mislav; Bär, Rudolf E.; Becker, George D.; Bessiere, P. S.; Burtscher, L.; Çağlar, Turgay; Congiu, Enrico; Evans, P. A.; Harrison, Fiona A.; Heida, Marianne; Ichikawa, Kohei; Lamperti, Isabella; Pacucci, Fabio; Ricci, F.; Riffel, Rogério; Rojas, Alejandra F.; Schawinski, Kevin; Temple, Matthew J.; Urry, C. M.; Veilleux, Sylvain; Williams, Jonathan

doi:10.3847/1538-4365/ac6c05

Cited by 66 publications

(124 citation statements)

References 111 publications

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“…These basic measurements are described in Section 2.2 below, while the chosen ranges are listed in . Throughout our analysis, we further classify sources as being either broad-line ("Type 1," hereafter) or narrow-line ("Type 2," hereafter) AGNs, based on the presence of any broad Balmer lines (as described in Koss et al 2022aKoss et al , 2022b, and on how their most reliable measures of M BH and λ E were derived (see Section 2.2 below), which in turn has consequences for uncertainty and incompleteness estimations. Thus, our sample of Type 1 AGNs (366 sources)-sources that have at least one broad Balmer emission line-also includes socalled "Seyfert 1.9" AGNs, with broad Hα but no broad Hβ.…”

Section: Final Redshift-restricted Agn Samplementioning

confidence: 99%

BASS. XXX. Distribution Functions of DR2 Eddington Ratios, Black Hole Masses, and X-Ray Luminosities

Ananna

Weigel

Trakhtenbrot

et al. 2022

ApJS

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We determine the low-redshift X-ray luminosity function, active black hole mass function (BHMF), and Eddington ratio distribution function (ERDF) for both unobscured (Type 1) and obscured (Type 2) active galactic nuclei (AGNs), using the unprecedented spectroscopic completeness of the BAT AGN Spectroscopic Survey (BASS) data release 2. In addition to a straightforward 1/V max approach, we also compute the intrinsic distributions, accounting for sample truncation by employing a forward-modeling approach to recover the observed BHMF and ERDF. As previous BHMFs and ERDFs have been robustly determined only for samples of bright, broad-line (Type 1) AGNs and/or quasars, ours are the first directly observationally constrained BHMF and ERDF of Type 2 AGNs. We find that after accounting for all observational biases, the intrinsic ERDF of Type 2 AGNs is significantly more skewed toward lower Eddington ratios than the intrinsic ERDF of Type 1 AGNs. This result supports the radiation-regulated unification scenario, in which radiation pressure dictates the geometry of the dusty obscuring structure around an AGN. Calculating the ERDFs in two separate mass bins, we verify that the derived shape is consistent, validating the assumption that the ERDF (shape) is mass-independent. We report the local AGN duty cycle as a function of mass and Eddington ratio, by comparing the BASS active BHMF with the local mass function for all supermassive black holes. We also present the log N − log S of the Swift/BAT 70 month sources.

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Section: Final Redshift-restricted Agn Samplementioning

confidence: 99%

BASS. XXX. Distribution Functions of DR2 Eddington Ratios, Black Hole Masses, and X-Ray Luminosities

Ananna

Weigel

Trakhtenbrot

et al. 2022

ApJS

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“…The aim of the BASS DR2 is to provide comprehensive spectroscopic data and measurements of the AGNs identified in the 70 month Swift-BAT all-sky ultra-hard X-ray (14-195 keV) survey catalog 30 (Baumgartner et al 2013). This catalog presents 1210 objects, of which 858 sources have been identified to date as extragalactic AGNs in follow-up work (BASS DR2; Koss et al 2022aKoss et al , 2022b. This catalog is complete across the full sky except for seven sources deep within the Galactic plane (0 < b < 3°) with very high optical extinction values (5-43 A V mag) making optical spectroscopy impossible.…”

Section: The 70 Month Swift-bat Catalogmentioning

confidence: 99%

“…Here we provide a brief description of the instrumental setups for the DR2 data used in this project and subsequent data reduction procedures. Full details on the spectroscopic observations and reductions are provided in Koss et al (2022b).…”

Section: Targeted Spectroscopic Observationsmentioning

confidence: 99%

“…We masked the spectral regions that were potentially affected by Notes. A more detailed list of instrumental setups for the full BASS DR2 is provided in Koss et al (2022b); here we provide a list for the spectra and telescopes used in this project. The instrumental setups of the optical spectra released in the DR1 are summarized in Table 1 of Koss et al (2017).…”

Section: Spectroscopic Measurementsmentioning

confidence: 99%

“…For the objects with unknown redshift, we estimated the redshift using either the peak of O III or narrow Hα emission lines considering the presence of O III outflows. A full list of redshifts estimated from single emission-line fits to O III, and errors is provided in Koss et al (2022b), and this should be used for NLR emission offset studies.…”

Section: Redshift Distributionmentioning

confidence: 99%

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BASS. XXIV. The BASS DR2 Spectroscopic Line Measurements and AGN Demographics

Oh¹,

Koss²,

Ueda³

et al. 2022

ApJS

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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 = 1022 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]λ5007/Hβ versus [N ii]λ6584/Hα, despite the high signal-to-noise ratio of their spectra. This value increases to 35% in the [O iii]λ5007/[O ii]λ3727 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 Hα/Hβ > 5 (∼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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The X-ray variability of active galactic nuclei: Power spectrum and variance analysis of the Swift/BAT light curves

Papadakis,

Binas-Valavanis

2024

A&A

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We study the X-ray power spectrum of active galactic nuclei (AGN) in order to investigate whether Seyfert I and II power spectra are similar or not and whether AGN variability depends on the mass and accretion rate of black holes as well as to compare the power spectra of AGN with the power spectra of Galactic X-ray black hole binaries. We used 14-195 keV band light curves from the 157-month hard X-ray survey, and we computed the mean power spectrum and excess variance of AGN in narrow black hole mass and AGN luminosity bins. We fitted a power-law model to the AGN power spectra, and we investigated whether the power spectrum parameters and the excess variance depend on the black hole mass, luminosity, and accretion rate of AGN. We found the Seyfert I and Seyfert II power spectra to be identical, in agreement with AGN unification models. The mean AGN X-ray power spectrum has the same power-law like shape, with a slope of $-1$ in all AGN irrespective of their luminosity and black hole mass. We did not detect any flattening to a slope of zero at frequencies as low as $10^ $ Hz. We detected an anti-correlation between the power spectral density function (PSD) amplitude and the accretion rate, similar to what has been seen in the past in the 2-10 keV band. This implies that the variability amplitude in AGN decreases with an increasing accretion rate. The universal AGN power spectrum is consistent with the mean 2-9 keV band Cyg X-1 power spectrum in its soft state. We detected a small difference in amplitude, but this is probably due to the difference in energy. The mean low-frequency AGN X-ray power spectrum is consistent with the extension of the mean 0.01-25 Hz Cyg X-1 power spectrum in its soft state to lower frequencies. We cannot prove that the mean AGN PSD is analogous to the mean Cyg X-1 PSD in its soft state, as we do not know the location of the high-frequency break in the hard X-ray AGN PSDs. However, if this is the case, then the accretion disc in AGN probably extends to the radius of the innermost circular stable orbit (as is probably the case with the black hole binaries in their soft sate). The X-ray corona will then be located on top, illuminating the disc and producing the X-ray reflection and disc reverberation phenomena commonly observed in these objects. Furthermore, the agreement between the PSD amplitude in AGN and the Cyg X-1 (either in the soft or the hard state) over many decades in frequency indicates that the X-ray variability process is probably the same in all accreting objects, irrespective of the mass of the compact object. We plan to investigate this issue further in the near future.

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BASS. XXII. The BASS DR2 AGN Catalog and Data

Cited by 66 publications

References 111 publications

BASS. XXX. Distribution Functions of DR2 Eddington Ratios, Black Hole Masses, and X-Ray Luminosities

BASS. XXX. Distribution Functions of DR2 Eddington Ratios, Black Hole Masses, and X-Ray Luminosities

BASS. XXIV. The BASS DR2 Spectroscopic Line Measurements and AGN Demographics

The X-ray variability of active galactic nuclei: Power spectrum and variance analysis of the Swift/BAT light curves

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