Abstract 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 λ 3969, 3934 and Mg I λ 5175 region (3880–5550 Å) and the calcium triplet region (8350–8730 Å) 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 ⊙ ), bolometric luminosity ( L bol ∼ 10 42–46 erg s −1 ), and Eddington ratio ( L / L Edd ∼ 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 ⊙ ), discovered thanks to high spectral resolution observations ( σ inst ∼ 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 (∣ b ∣ > 10°). The BASS AGN have much higher velocity dispersions than the more numerous optically selected narrow-line AGN (i.e., ∼150 versus ∼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 (∼10 4–5 M ⊙ ), 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 ∼100 BASS AGN.
Abstract 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 λ 5007/H β versus N ii λ 6584/H α , despite the high signal-to-noise ratio of their spectra. This value increases to 35% in the O iii λ 5007/O ii λ 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 α /H β > 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).
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.
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
Recenzirano
Odprti dostop
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
To understand the origin of nuclear (≲100 pc) millimeter-wave (mm-wave) continuum emission in active galactic nuclei (AGNs), we systematically analyzed subarcsecond resolution Band-6 ...(211–275 GHz) Atacama Large Millimeter/submillimeter Array data of 98 nearby AGNs (
z
< 0.05) from the 70 month Swift/BAT catalog. The sample, almost unbiased for obscured systems, provides the largest number of AGNs to date with high mm-wave spatial resolution sampling (∼1–200 pc), and spans broad ranges of 14–150 keV luminosity {
40
<
log
L
14
−
150
/
(
erg
s
−
1
)
<
45
}, black hole mass
5
<
log
(
M
BH
/
M
⊙
)
<
10
, and Eddington ratio (
−
4
<
log
λ
Edd
<
2
). We find a significant correlation between 1.3 mm (230 GHz) and 14–150 keV luminosities. Its scatter is ≈0.36 dex, and the mm-wave emission may serve as a good proxy of the AGN luminosity, free of dust extinction up to
N
H
∼ 10
26
cm
−2
. While the mm-wave emission could be self-absorbed synchrotron radiation around the X-ray corona according to past works, we also discuss different possible origins of the mm-wave emission: AGN-related dust emission, outflow-driven shocks, and a small-scale (<200 pc) jet. The dust emission is unlikely to be dominant, as the mm-wave slope is generally flatter than expected. Also, due to no increase in the mm-wave luminosity with the Eddington ratio, a radiation-driven outflow model is possibly not the common mechanism. Furthermore, we find independence of the mm-wave luminosity on indicators of the inclination angle from the polar axis of the nuclear structure, which is inconsistent with a jet model whose luminosity depends only on the angle.
ABSTRACT
Changing-look (CL) AGN are unique probes of accretion onto supermassive black holes (SMBHs), especially when simultaneous observations in complementary wavebands allow investigations into ...the properties of their accretion flows. We present the results of a search for CL behaviour in 412 Swift-BAT detected AGN with multiple epochs of optical spectroscopy from the BAT AGN Spectroscopic Survey (BASS). 125 of these AGN also have 14–195 keV ultra-hard X-ray light curves from Swift-BAT which are contemporaneous with the epochs of optical spectroscopy. Eight CL events are presented for the first time, where the appearance or disappearance of broad Balmer line emission leads to a change in the observed Seyfert type classification. Combining with known events from the literature, 21 AGN from BASS are now known to display CL behaviour. Nine CL events have 14–195 keV data available, and five of these CL events can be associated with significant changes in their 14–195 keV flux from BAT. The ultra-hard X-ray flux is less affected by obscuration and so these changes in the 14–195 keV band suggest that the majority of our CL events are not due to changes in line-of-sight obscuration. We derive a CL rate of 0.7–6.2 per cent on 10–25 yr time-scales, and show that many transitions happen within at most a few years. Our results motivate further multiwavelength observations with higher cadence to better understand the variability physics of accretion onto SMBHs.
We present the discovery of PSO J083.8371+11.8482, a weak emission line quasar with extreme star formation rate at z = 6.3401. This quasar was selected from Pan-STARRS1, UHS, and unWISE photometric ...data. Gemini/GNIRS spectroscopy follow-up indicates a Mg ii-based black hole mass of M and an Eddington ratio of , in line with an actively accreting supermassive black hole (SMBH) at z 6. Hubble Space Telescope imaging sets strong constraint on lens boosting, showing no relevant effect on the apparent emission. The quasar is also observed as a pure point source with no additional emission component. The broad-line region (BLR) emission is intrinsically weak and not likely caused by an intervening absorber. We found rest-frame equivalent widths of EW , EW (3 upper limit), and EW . A small proximity zone size ( pMpc) indicates a lifetime of only years from the last quasar phase ignition. ALMA shows extended C ii emission with a mild velocity gradient. The inferred far-infrared luminosity ( ) is one of the highest among all known quasar hosts at z 6. Dust and C ii emissions put a constraint on the star formation rate of SFR = 900- , similar to that of a hyperluminous infrared galaxy. Considering the observed quasar lifetime and BLR formation timescale, the weak-line profile in the quasar spectrum is most likely caused by a BLR that is not yet fully formed rather than by continuum boosting by gravitational lensing or a soft continuum due to super-Eddington accretion.
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.
Students' perception of the Chilean National Nursing Exam Rojas-Rivera, Alejandra F; Drago-Machado, Verónica Del Carmen; Vergara-Beltrán, Irella Alejandra ...
Revista medíca de Chile,
12/2022, Letnik:
150, Številka:
12
Journal Article
Recenzirano
Odprti dostop
BACKGROUNDIn 2008, the Chilean National Nursing Examination Commission, COENENF, developed a national nursing exam (ENENF). Since 2013, COENENF has implemented a validated opinion survey at the time ...of the national examination to strengthen the quality of the exam and facilitate its continuous improvement.AIMTo determine the perception of nursing students about general aspects, specific areas, representativeness, mastery and usefulness of the 2018 ENENF.MATERIAL AND METHODSA descriptive, cross-sectional study, using a self-administered Likert-type survey, was administered in 2018 to 2949 last-year nursing students from 29 nursing schools who took the ENENF. The survey comprised three areas: representativeness of the questions, student mastery of each area, and the usefulness of the exam.RESULTSStudents had a positive perception of the Chilean ENENF and its application. Theoretical knowledge is effectively assessed and close to half of the sample agreed that the ENENF is useful. The results also suggest areas that should be improved.CONCLUSIONSNursing students had a positive perception of the ENENF.
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