Abstract 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 H α , H β , Mg ii λ 2798, and/or C iv λ 1549 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 H α 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 H α but no broad H β ) 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 H α component ( L bH α and FWHMbH α ) 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.
BASS. XXII. The BASS DR2 AGN Catalog and Data Koss, Michael J.; Ricci, Claudio; Trakhtenbrot, Benny ...
The Astrophysical journal. Supplement series,
07/2022, Letnik:
261, Številka:
1
Journal Article
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Abstract We present the active galactic nucleus (AGN) catalog and optical spectroscopy for the second data release of the Swift BAT AGN Spectroscopic Survey (BASS DR2). With this DR2 release we ...provide 1449 optical spectra, of which 1182 are released for the first time, for the 858 hard-X-ray-selected AGNs in the Swift BAT 70-month sample. The majority of the spectra (801/1449, 55%) are newly obtained from Very Large Telescope (VLT)/X-shooter or Palomar/Doublespec. Many of the spectra have both higher resolution ( R > 2500, N ∼ 450) and/or very wide wavelength coverage (3200–10000 Å, N ∼ 600) that are important for a variety of AGN and host galaxy studies. We include newly revised AGN counterparts for the full sample and review important issues for population studies, with 47 AGN redshifts determined for the first time and 790 black hole mass and accretion rate estimates. This release is spectroscopically complete for all AGNs (100%, 858/858), with 99.8% having redshift measurements (857/858) and 96% completion in black hole mass estimates of unbeamed AGNs (722/752). This AGN sample represents a unique census of the brightest hard-X-ray-selected AGNs in the sky, spanning many orders of magnitude in Eddington ratio ( L / L Edd = 10 −5 –100), black hole mass ( M BH = 10 5 –10 10 M ⊙ ), and AGN bolometric luminosity ( L bol = 10 40 –10 47 erg s −1 ).
Abstract Virial black hole (BH) mass ( M BH ) determination directly involves knowing the broad-line region (BLR) clouds’ velocity distribution, their distance from the central supermassive BH ( R ...BLR ), and the virial factor ( f ). Understanding whether biases arise in M BH estimation with increasing obscuration is possible only by studying a large ( N > 100) statistical sample of obscuration-unbiased (hard) X-ray-selected active galactic nuclei (AGNs) in the rest-frame near-infrared (0.8–2.5 μ m) since it penetrates deeper into the BLR than the optical. We present a detailed analysis of 65 local Burst Alert Telescope (BAT) selected Seyfert galaxies observed with Magellan/FIRE. Adding these to the near-infrared BAT AGN spectroscopic survey database, we study a total of 314 unique near-infrared spectra. While the FWHMs of H α and near-infrared broad lines (He i , Pa β , Pa α ) remain unbiased to either BLR extinction or X-ray obscuration, the H α broad-line luminosity is suppressed when N H ≳ 10 21 cm −2 , systematically underestimating M BH by 0.23–0.46 dex. Near-infrared line luminosities should be preferred to H α until N H < 10 22 cm −2 , while at higher obscuration a less-biased R BLR proxy should be adopted. We estimate f for Seyfert 1 and 2 using two obscuration-unbiased M BH measurements, i.e., the stellar velocity dispersion and a BH mass prescription based on near-infrared and X-ray, and find that the virial factors do not depend on the redshift or obscuration, but some broad lines show a mild anticorrelation with M BH . Our results show the critical impact obscuration can have on BLR characterization and the importance of the near-infrared and X-rays for a less-biased view of the BLR.
We present the results of our spatially resolved investigation into the interplay between the ages of the stellar populations and the kinematics of the warm ionised outflows in the well-studied type ...II quasar Markarian 34. Utilising IFS data, we determine the spatial distribution of the young stellar population (YSP; \(t_{ysp} < 100 \mbox{ Myr}\)) using spectral synthesis modelling. We also employ the \(\mbox{OIII}\lambda 5007\) emission line as a tracer of the warm ionised gas kinematics. We demonstrate a spatial correlation between the outer edges of the blue-side of the outflow and an enhancement in the proportion of the YSP flux, suggesting that the outflow is responsible for triggering star formation in this region. In regions with more highly disrupted gas kinematics, we find that the proportion of YSP flux is consistent with that found outside the outflow region, suggesting that the increased disruption is preventing a similar enhancement in star formation from occurring. Our analysis suggests that Mrk 34 is an example of quasar driven outflows simultaneously producing both `positive' and `preventive' feedback, further demonstrating the complex nature of the relationship between quasars and their host galaxies.
AGN are thought to play an essential role in the evolution of galaxies. Despite this, the means by which the nuclear activity is triggered remains a matter of much debate. In this thesis, the ...triggering issue is addressed by investigating the properties of a sample of 20 (0.3 < z < 0.41) type II quasar host galaxies, using high-quality optical imaging and spectroscopic data obtained using Gemini GMOS-S Evidence for galaxy interactions in the form of tidal features (tails, fans, shells), double nuclei and close pairs is presented in Chapter 3. It is found the 75 % of the sample show clear evidence of recent mergers, consistent with the rate found for a matched control sample of early-type galaxies. However, the surface brightnesses of the tidal features in the type II quasars are up to two magnitudes brighter than those of the control sample. Major mergers also lead to intense bursts of star formation. Therefore, an analysis of the stellar populations of the type II quasar host galaxies is presented in Chapters 4 and 5. It is shown that, in 79 % of the type II quasars, spectral synthesis models require the inclusion of a young stellar component with an age < 100 Myr. The stellar masses derived from the spectral synthesis modelling are presented in Chapter 6. It is shown that type II quasars are exclusively hosted by galaxies with stellar mass > 10^10 solar masses, and, in a minimum of 26 % of cases, major gas-rich mergers are required to form the young stellar populations. The results presented in the thesis clearly demonstrate that the host galaxies of type II quasars are dynamic, evolving systems, with compelling evidence that the luminous AGN activity has been triggered by recent mergers in the majority of cases. They also suggest that quasar activity is triggered at around the same time as the merger-induced starbursts.
AGN are thought to play an essential role in the evolution of galaxies. Despite this, the means by which the nuclear activity is triggered remains a matter of much debate. In this thesis, the ...triggering issue is addressed by investigating the properties of a sample of 20 (0.3 < z < 0.41) type II quasar host galaxies, using high-quality optical imaging and spectroscopic data obtained using Gemini GMOS-S Evidence for galaxy interactions in the form of tidal features (tails, fans, shells), double nuclei and close pairs is presented in Chapter 3. It is found the 75 % of the sample show clear evidence of recent mergers, consistent with the rate found for a matched control sample of early-type galaxies. However, the surface brightnesses of the tidal features in the type II quasars are up to two magnitudes brighter than those of the control sample. Major mergers also lead to intense bursts of star formation. Therefore, an analysis of the stellar populations of the type II quasar host galaxies is presented in Chapters 4 and 5. It is shown that, in 79 % of the type II quasars, spectral synthesis models require the inclusion of a young stellar component with an age < 100 Myr. The stellar masses derived from the spectral synthesis modelling are presented in Chapter 6. It is shown that type II quasars are exclusively hosted by galaxies with stellar mass > 1010 solar masses, and, in a minimum of 26 % of cases, major gas-rich mergers are required to form the young stellar populations. The results presented in the thesis clearly demonstrate that the host galaxies of type II quasars are dynamic, evolving systems, with compelling evidence that the luminous AGN activity has been triggered by recent mergers in the majority of cases. They also suggest that quasar activity is triggered at around the same time as the merger-induced starbursts.
Large-scale cosmological simulations suggest that feedback from active galactic nuclei (AGN) plays a crucial role in galaxy evolution. In this study, we directly test this hypothesis utilising SDSS ...spectra of a sample of 48 low redshift (z<0.14) type 2 quasars (QSO2s). We characterised the kinematics of the warm ionised gas by performing a non-parametric analysis of the OIII\(\lambda 5007\) emission line, as well as constrain the properties of the young stellar populations (YSP) of their host galaxies through spectral synthesis modelling. These analyses revealed that 85% of the QSO2s display gas velocity dispersions larger than that of the stellar component of their host galaxies, indicating the presence of AGN-driven outflows. Comparing the gas kinematics to the AGN properties, we found a positive correlation between gas velocity dispersion and 1.4 GHz radio luminosity but not with AGN bolometric luminosity or Eddington ratio, suggesting that, either the radio luminosity is the key factor in driving outflows or that the outflows themselves are shocking the ISM and producing synchrotron emission. We found that 98% of the sample host YSPs to varying degrees, with star formation rates (SFR) \(0 \le SFR \le 92 \mbox{ M}_{\odot} \mbox{yr}^{-1}\), averaged over 100 Myr. We compared the gas kinematics and outflow properties to the SFRs to establish possible correlations which may suggest that the presence of the outflowing gas is impacting SF and find that none exists, leading to the conclusion that, on the scales probed by the SDSS fibre, AGN-driven outflows do not impact SF on the timescales probed in this study. However, we found a positive correlation between the light-weighted stellar ages of the QSO2s and the black hole mass, which may indicate that successive AGN episodes lead to the suppression of SF over the course of galaxy evolution.
We present measurements of broad emission lines and virial estimates of supermassive black hole masses (\(M_{BH}\)) for a large sample of ultra-hard 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 689 AGNs, determined from the H\(\alpha\), H\(\beta\), \(MgII\lambda2798\), and/or \(CIV\lambda1549\) 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 H\(\alpha\) emission lines in obscured AGNs (\(\log (N_{\rm H}/{\rm cm}^{-2})> 22.0\)) are on average a factor of \(8.0_{-2.4}^{+4.1}\) weaker, relative to ultra-hard X-ray emission, and about \(35_{-12}^{~+7}\)\% narrower than in unobscured sources (i.e., \(\log (N_{\rm H}/{\rm cm}^{-2}) < 21.5\)). 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 H\(\alpha\) but no broad H\(\beta\)) and/or sources with \(\log (N_{\rm H}/{\rm cm}^{-2}) > 22.0\). We provide simple multiplicative corrections for the observed luminosity and width of the broad H\(\alpha\) component (\(L{\rm b}{\rm H}\alpha\) and FWHMbH\(\alpha\)) in such sources to account for this effect, and to (partially) remedy \(M_{BH}\) estimates for Type 1.9 objects. As key ingredient of BASS/DR2, our work provides the community with the data needed to further study powerful AGNs in the low-redshift Universe.
We present the AGN catalog and optical spectroscopy for the second data release of the Swift BAT AGN Spectroscopic Survey (BASS DR2). With this DR2 release we provide 1425 optical spectra, of which ...1181 are released for the first time, for the 858 hard X-ray selected AGN in the Swift BAT 70-month sample. The majority of the spectra (813/1425, 57%) are newly obtained from VLT/Xshooter or Palomar/Doublespec. Many of the spectra have both higher resolution (R>2500, N~450) and/or very wide wavelength coverage (3200-10000 A, N~600) that are important for a variety of AGN and host galaxy studies. We include newly revised AGN counterparts for the full sample and review important issues for population studies, with 44 AGN redshifts determined for the first time and 780 black hole mass and accretion rate estimates. This release is spectroscopically complete for all AGN (100%, 858/858) with 99.8% having redshift measurements (857/858) and 96% completion in black hole mass estimates of unbeamed AGN (outside the Galactic plane). This AGN sample represents a unique census of the brightest hard X-ray selected AGN in the sky, spanning many orders of magnitude in Eddington ratio (Ledd=10^-5-100), black hole mass (MBH=10^5-10^10 Msun), and AGN bolometric luminosity (Lbol=10^40-10^47 ergs/s).
