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 AGN with 956 independent measurements of the Ca H+K and Mg b region (3880-5550A) and the Ca triplet region (8350-8730A) from 642 spectra mainly from VLT/Xshooter or Palomar/DoubleSpec. Our sample spans velocity dispersions of 40-360 km/s, corresponding to 4-5 orders of magnitude in black holes mass (MBH=10^5.5-9.6 Msun), bolometric luminosity (LBol~10^{42-46 ergs/s), and Eddington ratio (L/Ledd~10^{-5}-2). For 281 AGN, our data provide the first published central velocity dispersions, including 6 AGN with low mass black holes (MBH=10^5.5-6.5 Msun), discovered thanks to our high spectral resolution observations (sigma~25 km/s). The survey represents a significant advance with a nearly complete census of hard-X-ray selected obscured AGN with measurements for 99% of nearby AGN (z<0.1) outside the Galactic plane. The BASS AGN have higher velocity dispersions than the more numerous optically selected narrow line AGN (i.e., ~150 vs. ~100 km/s), but are not biased towards the highest velocity dispersions of massive ellipticals (i.e., >250 km/s). Despite sufficient spectral resolution to resolve the velocity dispersions associated with the bulges of small black holes (~10^4-5 Msun), we do not find a significant population of super-Eddington AGN. Using estimates of the black hole sphere of influence, direct stellar and gas black hole mass measurements could be obtained with existing facilities for more than ~100 BASS AGN.
We present the BAT AGN Spectroscopic Survey (BASS) Near-infrared Data Release 2 (DR2), a study of 168 nearby (\(\bar z\) = 0.04, \(z\) < 0.6) active galactic nuclei (AGN) from the all-sky Swift Burst ...Array Telescope X-ray survey observed with Very Large Telescope (VLT)/X-shooter in the near-infrared (NIR; 0.8 - 2.4 \(\mu\)m). We find that 49/109 (45%) Seyfert 2 and 35/58 (60%) Seyfert 1 galaxies observed with VLT/X-shooter show at least one NIR high-ionization coronal line (CL, ionization potential \(\chi\) > 100 eV). Comparing the emission of the Si vi \(\lambda\)1.9640 CL with the X-ray emission for the DR2 AGN, we find a significantly tighter correlation, with a lower scatter (0.37 dex) than for the optical O iii \(\lambda\)5007 line (0.71 dex). We do not find any correlation between CL emission and the X-ray photon index \(\Gamma\). We find a clear trend of line blueshifts with increasing ionization potential in several CLs, such as Si vi \(\lambda\)1.9640, Si x \(\lambda\)1.4300, S viii \(\lambda\)0.9915, and S ix \(\lambda\)1.2520, indicating the radial structure of the CL region. Finally, we find a strong underestimation bias in black hole mass measurements of Sy 1.9 using broad H\(\alpha\) due to the presence of significant dust obscuration. In contrast, the broad Pa\(\alpha\) and Pa\(\beta\) emission lines are in agreement with the \(M\)-\(\sigma\) relation. Based on the combined DR1 and DR2 X-shooter sample, the NIR BASS sample now comprises 266 AGN with rest-frame NIR spectroscopic observations, the largest set assembled to date.
We constrain the intrinsic Eddington ratio (\lamEdd ) distribution function for local AGN in bins of low and high obscuration (log NH <= 22 and 22 < log NH < 25), using the Swift-BAT 70-month/BASS ...DR2 survey. We interpret the fraction of obscured AGN in terms of circum-nuclear geometry and temporal evolution. Specifically, at low Eddington ratios (log lamEdd < -2), obscured AGN outnumber unobscured ones by a factor of ~4, reflecting the covering factor of the circum-nuclear material (0.8, or a torus opening angle of ~ 34 degrees). At high Eddington ratios (\log lamEdd > -1), the trend is reversed, with < 30% of AGN having log NH > 22, which we suggest is mainly due to the small fraction of time spent in a highly obscured state. Considering the Eddington ratio distribution function of narrow-line and broad-line AGN from our prior work, we see a qualitatively similar picture. To disentangle temporal and geometric effects at high lamEdd, we explore plausible clearing scenarios such that the time-weighted covering factors agree with the observed population ratio. We find that the low fraction of obscured AGN at high lamEdd is primarily due to the fact that the covering factor drops very rapidly, with more than half the time is spent with < 10% covering factor. We also find that nearly all obscured AGN at high-lamEdd exhibit some broad-lines. We suggest that this is because the height of the depleted torus falls below the height of the broad-line region, making the latter visible from all lines of sight.
The BAT AGN Spectroscopic Survey (BASS) is designed to provide a highly complete census of the key physical parameters of supermassive black holes (SMBHs) that power local active galactic nuclei ...(AGN) (z<0.3), including their bolometric luminosity, black hole mass, accretion rates, and line-of-sight gas obscuration, and the distinctive properties of their host galaxies (e.g., star formation rates, masses, and gas fractions). We present an overview of the BASS data release 2 (DR2), an unprecedented spectroscopic survey in spectral range, resolution, and sensitivity, including 1449 optical (3200-10000 A) and 233 NIR (1-2.5 um) spectra for the brightest 858 ultra-hard X-ray (14-195 keV) selected AGN across the entire sky and essentially all levels of obscuration. This release provides a highly complete set of key measurements (emission line measurements and central velocity dispersions), with 99.9% measured redshifts and 98% black hole masses estimated (for unbeamed AGN outside the Galactic plane). The BASS DR2 AGN sample represents a unique census of nearby powerful AGN, spanning over 5 orders of magnitude in AGN bolometric luminosity, black hole mass, Eddington ratio, and obscuration. The public BASS DR2 sample and measurements can thus be used to answer fundamental questions about SMBH growth and its links to host galaxy evolution and feedback in the local universe, as well as open questions concerning SMBH physics. Here we provide a brief overview of the survey strategy, the key BASS DR2 measurements, data sets and catalogs, and scientific highlights from a series of DR2-based works.
In this paper we study the impact of cosmic variance and observational
uncertainties in constraining the mass and occupation fraction, $f_{\rm occ}$,
of dark matter halos hosting Ly-$\alpha$ Emitting ...Galaxies (LAEs) at high
redshift. To this end, we construct mock catalogs from an N-body simulation to
match the typical size of observed fields at $z=3.1$ ($\sim 1 {\rm deg^2}$). In
our model a dark matter halo with mass in the range $M_{\rm min}<M_{\mathrm
h}<M_{\rm max}$ can only host one detectable LAE at most. We proceed to explore
the parameter space determined by $M_{\rm min}$,$M_{\rm max}$ and $f_{\rm occ}$
with a Markov Chain Monte-Carlo algorithm using the angular correlation
function (ACF) and the LAEs number density as observational constraints. We
find that the preferred minimum and maximum masses in our model span a wide
range $10^{10.0}h^{-1}{\rm{M_{\odot}}}\leq M_{\rm min} \leq
10^{11.1}h^{-1}{\rm{M_{\odot}}}$ , $10^{11.0}h^{-1}{\rm{M_{\odot}}}\leq M_{\rm
max} \leq 10^{13.0}h^{-1}{\rm{M_{\odot}}}$; followed by a wide range in the
occupation fraction $0.02\leq f_{\rm occ} \leq 0.30$. As a consequence the
median mass, $M_{50}$, of all the consistent models has a large uncertainty
$M_{50} = 3.16^{+9.34}_{-2.37}\times 10^{10}$$h^{-1}{\rm{M_{\odot}}}$. However,
we find that the same individual models have a relatively tight $1\sigma$
scatter around the median mass $\Delta M_{1\sigma} = 0.55^{+0.11}_{-0.31}$ dex.
We are also able to show that \focc\ is uniquely determined by $M_{\rm min}$,
regardless of $M_{\rm max}$. We argue that upcoming large surveys covering at
least $25$ deg$^{2}$ should be able to put tighter constraints on $M_{\rm min}$
and $f_{\rm occ}$ through the LAE number density distribution width constructed
over several fields of $\sim 1$ deg$^{2}$.
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).
We determine the low-redshift X-ray luminosity function (XLF), active black hole mass function (BHMF), and Eddington-ratio distribution function (ERDF) for both unobscured (Type 1) and obscured (Type ...2) active galactic nuclei (AGN) using the unprecedented spectroscopic completeness of the BAT AGN Spectroscopic Survey (BASS) data release 2. In addition to a straightforward 1/Vmax 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 is the first directly observationally constrained BHMF and ERDF of Type 2 AGN. We find that after accounting for all observational biases, the intrinsic ERDF of Type 2 AGN is significantly skewed towards lower Eddington ratios than the intrinsic ERDF of Type 1 AGN. 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 SMBH. We also present the log N-log S of Swift-BAT 70-month sources.
We present two independent measurements of stellar velocity dispersions ( \(\sigma_\rm{\star}\) ) from the Ca\,H+K \& Mg\,\textsc{i} region (3880--5550~\AA) and the Calcium Triplet region (CaT, ...8350--8750~\AA) for 173 hard X-ray-selected Type 1 AGNs (\(z \leq\) 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 (SE) 'virial' black hole mass (\(M_\rm{BH}\)) estimates and \(\sigma_\rm{\star}\) measurements obtained from high spectral resolution data, allowing us to test the usage of such methods for SMBH studies. We find that the two independent \(\sigma_\rm{\star}\) measurements are highly consistent with each other, with an average offset of only \(0.002\pm0.001\) dex. Comparing \(M_\rm{BH}\) estimates based on broad emission lines and stellar velocity dispersion measurements, we find that the former is systematically lower by \(\approx\)0.12 dex. Consequently, Eddington ratios estimated through broad-line \(M_\rm{BH}\) determinations are similarly biased (but in the opposite way). We argue that the discrepancy is driven by extinction in the broad-line region (BLR). We also find an anti-correlation between the offset from the \(M_\rm{BH}\) - \(\sigma_\rm{\star}\) relation and the Eddington ratio. Our sample of Type 1 AGNs shows a shallower \(M_\rm{BH}\) - \(\sigma_\rm{\star}\) relation (with a power law exponent of \(\approx\)3.5) compared with that of inactive galaxies (with a power-law exponent of \(\approx\)4.5), confirming earlier results obtained from smaller samples.
La hipertrigliceridemia (HTG) es una causa potencial de pancreatitis aguda (PA), especialmente cuando los valores son mayores de 1.000 mg/dL. Se han propuesto diferentes medidas para el tratamiento ...de pacientes con PA secundaria a HTG, entre ellas la que parece ser más efectiva: la plasmaféresis. Se reporta el caso de un paciente con HTG grave (triglicéridos de 6.480 mg/dL) que presentó una PA y cuya evolución fue favorable con la plasmaféresis.
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