In the manuscript, we discuss properties of the SDSS J1042-0018 which is a broad line AGN but mis-classified as a HII galaxy in the BPT diagram (SDSS J1042-0018 called as a mis-classified broad line AGN). The emission lines around H$α$ and around H$β$ are well described by different model functions, considering broad Balmer lines to be described by Gaussian or Lorentz functions. Different model functions lead to different determined narrow emission line fluxes, but the different narrow emission line flux ratios lead the SDSS J1042-0018 as a HII galaxy in the BPT diagram. In order to explain the unique properties of the mis-classified broad line AGN SDSS J1042-0018, two methods are proposed, the starforming contributions and the compressed NLRs with high electron densities near to critical densities of forbidden emission lines. Fortunately, the strong starforming contributions can be preferred in the SDSS J1042-0018. The mis-classified broad line AGN SDSS J1042-0018, well explained by starforming contributions, could provide further clues on the applications of BPT diagrams to the normal broad line AGN.
Narrow emission-line galaxies can be distinguished in the well-known BPT diagrams through narrow emission line properties. However, there are no boundaries visible to the naked eye between type-2 AGN and HII galaxies in BPT diagrams, besides the extreme dividing lines expected by theoretical photoionization models. Here, based on powerful t-SNE technique applied to the local narrow emission-line galaxies in SDSS DR15, type-2 AGN and HII galaxies can be clearly separated in the t-SNE determined two-dimensional projected map, and then the dividing lines can be mathematically determined in BPT di…
In the manuscript, we discuss properties of SDSS J1451+2709, a normal blue quasar but mis-classified as a HII galaxy in the BPT diagram (called as a mis-classified quasar). The emission lines around H$α$ and H$β$ are well measured by different model functions with broad Balmer lines being described by Gaussian or Lorentz functions, in the SDSS spectrum in 2007 and in the KPNO spectrum in 1990. After considering variations of broad emission lines, different model functions lead to different fluxes of narrow emission lines, but the different narrow emission line flux ratios lead the SDSS J1451+2…
We consider the circumnuclear regions of MaNGA galaxies. The spectra are classified as AGN-like, HII-region-like (or SF-like), and intermediate (INT) spectra according to their positions on the BPT diagram. There are the following four configurations of the radiation distributions in the circumnuclear regions: 1) AGN+INT, the innermost region of the AGN-like radiation is surrounded by a ring of radiation of the intermediate type; 2) INT, the central area of radiation of the intermediate type; 3) SF+INT, the inner region of the HII-region-like radiation is surrounded by a ring of radiation of t…
In this work, we investigate the reliability of the BPT diagram for excluding galaxies that host an AGN. We determine the prevalence of X-ray AGN in the star-forming region of the BPT diagram and discuss the reasons behind this apparent misclassification, focusing primarily on relatively massive ($\log(M_{*})\gtrsim10$) galaxies. X-ray AGN are selected from deep XMM observations using a new method that results in greater samples with a wider range of X-ray luminosities, complete to $\log(L_{X})>41$ for $z<0.3$. Taking X-ray detectability into account, we find the average fraction of X-ray AGN …
This is the first paper of a series dedicated to nebular physics and the chemical evolution of nearby galaxies by investigating large samples of HII regions with the CFHT imaging spectrograph SITELLE. We present a technique adapted to imaging spectroscopy to identify and extract parameters from 4285 HII region candidates found in the disc of NGC628. Using both the spatial and spectral capabilities of SITELLE, our technique enables the extraction of the position, dust extinction, velocity, Halpha profile, diffuse ionised gas (DIG) background, luminosity, size, morphological type, and the emissi…
We fit theoretical models to the emission-line spectra of 2766 Seyfert galaxies from the Sloan Digital Sky Survey (SDSS). The model line fluxes are derived by `mixing' photoionization model predictions of active galactic nucleus (AGN) narrow line region (NLR) emission and HII region emission. The observed line fluxes in each spectrum were directly compared to the grid of mixed models using the Bayesian parameter estimation code NebulaBayes, thereby measuring the degree of mixing in each spectrum for the first time. We find that the majority of the Balmer line emission in the majority of Seyfer…
JWST spectra are consistent with the edge-on star-forming galaxy scenario for the "runaway supermassive black hole"
Instituto de Astrofísica de Canarias（加那利群岛天体物理研究所）；Universidad de La Laguna（拉古纳大学）；Universidad Nacional Autónoma de México（墨西哥国立自治大学）；Institute of Space Sciences (ICE, CSIC)（空间科学研究所）
The Baldwin, Philips, & Terlevich diagram of [O III]/H$β$ vs. [N II]/H$α$ (hereafter N2-BPT) has long been used as a tool for classifying galaxies based on the dominant source of ionizing radiation. Recent observations have demonstrated that galaxies at $z\sim2$ reside offset from local galaxies in the N2-BPT space. In this paper, we conduct a series of controlled numerical experiments to understand the potential physical processes driving this offset. We model nebular line emission in a large sample of galaxies, taken from the SIMBA cosmological hydrodynamic galaxy formation simulation, using…
DIGging into HII regions: the role of ionizing photon leakage and spectral hardening in coupling HII regions and diffuse ionized gas
Kavli Institute for Particle Astrophysics & Cosmology, Stanford University（斯坦福大学卡弗里粒子天体物理与宇宙学研究所）；Center for Decoding the Universe, Stanford University（斯坦福大学解码宇宙中心）；Racah Institute of Physics, The Hebrew University of Jerusalem（耶路撒冷希伯来大学拉卡物理学研究所）；Universität Heidelberg, Zentrum für Astronomie, Astronomisches Rechen-Institut（海德堡大学天文中心计算天文研究所）；Observatories of the Carnegie Institution for Science（卡内基科学学会天文台）；Department of Astronomy & Astrophysics, University of California, San Diego（加州大学圣地亚哥分校天文学与天体物理学系）；Department of Astronomy and Joint Space-Science Institute, University of Maryland, College Park（马里兰大学学院公园分校天文学系与联合空间科学研究所）；Departamento de Astronomía, Universidad de Chile（智利大学天文学系）；Max-Planck-Instit（马克斯·普朗克研究所）
Ionization sources other than HII regions give rise to the right-hand branch in the standard ([NII]) BPT diagram, populated by Seyfert 2s and LINERs. However, because the majority of Seyfert/LINER hosts are star forming (SF), HII regions contaminate the observed lines to some extent, making it unclear if the position along the branch is merely due to various degrees of mixing between pure Seyfert/LINER and SF, or whether it reflects the intrinsic diversity of Seyfert/LINER ionizing sources. In this study, we empirically remove SF contributions in ~100,000 Seyfert/LINERs from SDSS using the dop…
We use integral field spectroscopy from the PHANGS-MUSE survey, which resolves the ionised interstellar medium at ${\sim}50$ pc resolution in 19 nearby spiral galaxies, to study the origin of the diffuse ionised gas (DIG). We examine the physical conditions of the diffuse gas by first removing morphologically-defined HII regions and then binning the low-surface-brightness areas to achieve significant detections of the key nebular lines. A simple model for the leakage and propagation of ionising radiation from HII regions is able to reproduce the observed distribution of H$α$ in the DIG. Leakin…
We present results on the emission-line properties of 1.3<=z<=2.7 galaxies drawn from the complete MOSFIRE Deep Evolution Field (MOSDEF) survey. Specifically, we use observations of the emission-line diagnostic diagram of [OIII]5007/Hb vs. [SII]6717,6731/Ha, i.e., the "[SII] BPT diagram," to gain insight into the physical properties of high-redshift star-forming regions. High-redshift MOSDEF galaxies are offset towards lower [SII]6717,6731/Ha at fixed [OIII]5007/Hb, relative to local galaxies from the Sloan Digital Sky Survey (SDSS). Furthermore, at fixed [OIII]5007/Hb, local SDSS galaxies fol…
Nebular HeII$λ$4686Å~line emission is useful to unveil active galactic nuclei (AGN) residing in actively star-forming (SF) galaxies, typically missed by the standard BPT classification. Here we adopt the HeII diagnostic to identify hidden AGN in the Local Universe using for the first time spatially-resolved data from the Data Release 15 of the Mapping Nearby Galaxies at APO survey (MaNGA DR15). By combining results from HeII and BPT diagnostics, we overall select 459 AGN host candidates ($\sim$10% in MaNGA DR15), out of which 27 are identified as AGN by the HeII diagram only. The HeII-only AGN…
Beyond diagnostic-diagrams: A critical exploration on the classification of ionization processes
Instituto de Astronomía, Universidad Nacional Autonóma de México（墨西哥国立自治大学天文研究所）；Instituto de Astrofísica de Canarias（加那利群岛天体物理研究所）；Departamento de Astrofísica, Universidad de La Laguna（拉帕尔马大学天体物理学系）；Instituto de Radioastronomía and Astrofísica (IRyA-UNAM)（无线电天文学与天体物理研究所）；Instituto de Astrofísica de Andalucía (IAA-CSIC)（安达卢西亚天体物理研究所）
HII-CHI-mistry for active galactic nuclei: optical sulphur abundances without empirical ionisation correction factors
Universidade do Vale do Paraíba（帕拉伊巴山谷大学）；Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg（海德堡大学天文学计算中心）；Main Astronomical Observatory, National Academy of Sciences of Ukraine（乌克兰国家科学院主天文台）；INAF - Osservatorio Astronomico di Roma（意大利国家天体物理研究所罗马天文台）
Future and on-going infrared and radio observatories such as JWST, METIS or ALMA will increase the amount of rest-frame IR spectroscopic data for galaxies by several orders of magnitude. While studies of the chemical composition of the ISM based on optical observations have been widely spread over decades for SFG and, more recently, for AGN, similar studies need to be performed using IR data. This regime can be especially useful in the case of AGN given that it is less affected by temperature and dust extinction, traces higher ionic species and can also provide robust estimations of the chemic…
We provide a new method to derive heavy element abundances based on the unique suite of nebular lines in the mid- to far-infrared (IR) range. Using grids of photo-ionisation models that cover a wide range in O/H and N/O abundances, and ionisation parameter, our code HII-Chi-mistry-IR (HCm-IR) provides model-based abundances based on extinction free and temperature insensitive tracers, two significant advantages over optical diagnostics. The code is probed using a sample of 56 galaxies observed with $Spitzer$ and $Herschel$ covering a wide range in metallicity, $7.2 \lesssim 12+\log(O/H) \lesss…
Origins of Extreme Emission-Line Ratios in z > 3 Galaxies: Insights from the Lumen Model
École Polytechnique Fédérale de Lausanne (EPFL)（洛桑联邦理工学院）；INAF-Osservatorio Astronomico di Trieste（意大利国家天体物理研究所的里雅斯特天文台）；Sorbonne Université, CNRS, UMR 7095, Institut d’Astrophysique de Paris（索邦大学、法国国家科学研究中心、巴黎天体物理研究所）；Center for Computational Astrophysics, Flatiron Institute（平顿研究所计算天体物理学中心）；University of Hertfordshire（赫特福德大学）；INAF – Osservatorio Astrofisico di Arcetri（意大利国家天体物理研究所阿尔切特里天文台）；Département d’Astronomie, Université de Genève（日内瓦大学天文学系）
Within the SECCO survey we identified a candidate stellar counterpart to the Ultra Compact High Velocity Cloud (UCHVC) HVC274.68+74.70-123, that was suggested by Adams et al. (2013) as a possible mini-halo within the Local Group of galaxies. The spectroscopic follow-up of the brightest sources within the candidate reveals the presence of two HII regions whose radial velocity is compatible with physical association with the UVHVC. The available data does not allow us to give a definite answer on the nature of the newly identified system. A few alternative hypotheses are discussed. However, the …
Metal poor dwarf galaxies in the local universe, such as those found in the RESOLVE galaxy survey, often produce high [O III]/H\b{eta} ratios close to the star forming demarcation lines of the diagnostic BPT diagram. Modeling the emission from these galaxies at lower metallicities generally underpredicts this line ratio, which is typically attributed to a deficit of photons >35 eV. We show that applying a model that includes empirical abundances scaled with metallicity strongly influences the thermal balance in HII regions and preserves the [O III]/H\b{eta} offset even in the presence of a har…
We present the first optical identification and confirmation of a sample of supernova remnants (SNRs) in the nearby galaxy NGC3344. Using high spectral and spatial resolution data, obtained with the CFHT imaging Fourier transform spectrograph SITELLE, we identified about 2200 emission line regions, many of which are HII regions, diffuse ionized gas regions, and also SNRs. Considering the stellar population and diffuse ionized gas background, that are quite important in NGC3344, we have selected 129 SNR candidates based on four criteria for regions where the emission lines flux ratio [S II]/H$α…
Linear polarization of diffuse Galactic emission is a signature of magnetic fields in the interstellar medium of our Galaxy. Observations at high frequencies are less affected by Faraday depolarization than those at lower frequencies and are able to detect polarized emission from more distant Galactic regions. We attempt to perform a sensitive survey of the polarized emission from the Galactic disk at 6 cm wavelength. We made polarization observations of the Galactic plane using the Urumqi 25-m telescope at 6 cm covering the area of 60deg< l <129deg and |b|<5deg. Missing large-scale structures…
We present an updated, optimized version of GAME (GAlaxy Machine learning for Emission lines), a code designed to infer key interstellar medium physical properties from emission line intensities of UV/optical/far infrared galaxy spectra. The improvements concern: (a) an enlarged spectral library including Pop III stars; (b) the inclusion of spectral noise in the training procedure, and (c) an accurate evaluation of uncertainties. We extensively validate the optimized code and compare its performance against empirical methods and other available emission line codes (PYQZ and HII-CHI-MISTRY) on …
H ii regions in galaxies are the sites of star formation and thus particular places to understand the build-up of stellar mass in the universe. The line ratios of this ionized gas are frequently used to characterize the ionization conditions. We use the Hii regions catalogue from the CALIFA survey (~5000 H ii regions), to explore their distribution across the classical [OIII]/Hbeta vs. [NII]/Halpha diagnostic diagram, and how it depends on the oxygen abundance, ionization parameter, electron density, and dust attenuation. We compared the line ratios with predictions from photoionization models…
Using the CoDa II simulation, we study the Ly$α$ transmissivity of the intergalactic medium (IGM) during reionization. At $z>6$, a typical galaxy without an active galactic nucleus fails to form a proximity zone around itself due to the overdensity of the surrounding IGM. The gravitational infall motion in the IGM makes the resonance absorption extend to the red side of Ly$α$, suppressing the transmission up to roughly the circular velocity of the galaxy. In some sight lines, an optically thin blob generated by a supernova in a neighboring galaxy results in a peak feature, which can be mistake…
Using new VLT/XShooter spectral observations we analyse the physical properties of five z~0.3-0.4 confirmed LyC leakers. Strong resonant MgII 2796,2803 emission lines (I(2796,2803)/I(Hbeta)=10-38 per cent) and non-resonant FeII* 2612,2626 emission lines are observed in spectra of five and three galaxies, respectively. We find high electron densities Ne~400cm-3, significantly higher than in typical low-z, but comparable to those measured in z~2-3 star-forming galaxies. The galaxies have a mean value of logN/O=-1.16, close to the maximum values found for star-forming (SF) galaxies in the metalli…
We present detailed studies of a $z=2.12$ submillimeter galaxy, ALESS67.1, using sub-arcsecond resolution ALMA, AO-aided VLT/SINFONI, and HST/CANDELS data to investigate the kinematics and spatial distributions of dust emission (870 $μ$m continuum), $^{12}$CO($J$=3-2), strong optical emission lines, and visible stars. Dynamical modelling of the optical emission lines suggests that ALESS67.1 is not a pure rotating disk but a merger, consistent with the apparent tidal features revealed in the HST imaging. Our sub-arcsecond resolution dataset allow us to measure half-light radii for all the trace…
SITELLE is a novel integral field unit spectroscopy instrument that has an impressive spatial (11 by 11 arcmin), spectral coverage, and spectral resolution (R=1-20000). SIGNALS is anticipated to obtain deep observations (down to 3.6x10-17ergs s-1cm-2) of 40 galaxies, each needing complex and substantial time to extract spectral information. We present a method that uses Convolution Neural Networks (CNN) for estimating emission line parameters in optical spectra obtained with SITELLE as part of the SIGNALS large program. Our algorithm is trained and tested on synthetic data representing typical…
Although studying outflows in the host galaxies of AGN have become the forefront of extra-galactic astronomy in recent years, estimating the energy associated with these outflows have been a major challenge. Determination of the energy associated with an outflow often involves an assumption of uniform density in the NLR, which span a wide range in literature leading to large systematic uncertainties in energy estimation. In this paper, we present electron density maps for a sample of outflowing and non-outflowing Seyfert galaxies at z<0.02 drawn from the S7 survey and understand the origin and…
We perform SED fitting analysis on a COSMOS sample covering UV-to-FIR wavelengths with emission lines from the FMOS survey. The sample of 182 objects with H$α$ and [OIII]$\lambda5007$ emission spans over a range of $1.40<\rm{z}<1.68$. We obtain robust estimates of stellar mass ($10^{9.5}-10^{11.5}~\rm{M_\odot}$) and SFR ($10^1-10^3~\rm{M_\odot}~\rm{yr}^{-1}$) from the Bayesian analysis with CIGALE fitting continuum photometry and H$α$. We obtain a median attenuation of A$_\rm{Hα}=1.16\pm0.19$ mag and A$_\rm{[OIII]}=1.41\pm0.22$ mag. H$α$ and [OIII]$\lambda5007$ attenuations are found to increa…
Integral field spectroscopy studies based on CALIFA data have recently revealed the presence of ongoing low-level star formation (SF) in the periphery of ~10% of local early-type galaxies (ETGs), witnessing a still ongoing inside-out galaxy growth process. A distinctive property of the nebular component in these ETGs, classified i+, is a two-radial-zone structure, with the inner zone displaying LINER emission with a Hαequivalent width EW~1Å, and the outer one (3Å<EW<~20Å) showing HII-region characteristics. Using CALIFA IFS data, we empirically demonstrate that the confinement of nebular emiss…
The derivation of abundances in gaseous nebulae ionised by massive stars using optical collisionally excited emission lines is studied in this work comparing the direct or $T_e$ method with updated grids of photoionisation models covering a wide range of input conditions of O/H and N/O abundances and ionisation parameter. The abundances in a large sample of compiled objects with at least one auroral line are re-derived and later compared with the $χ^2$ weighted-mean abundances from the models. The agreement between the abundances using the two methods both for O/H and N/O is excellent with no …
Based on SITELLE spectroscopy, we studied the ionised gas emission for the 175 H$α$ emission regions in the Stephan's Quintet (SQ). A detailed analysis is performed of the star formation rate (SFR), oxygen abundance (O/H), and nitrogen-to-oxygen abundance ratio (N/O) of the SQ regions, to explore the provenance and evolution of this complex structure. According to the BPT diagram, we found 91 HII, 17 composite, and 7 active galactic nucleus-like regions in SQ. Several regions are compatible with fast shocks models without a precursor for solar metallicity and low density (n=0.1 cm$^{-3}$), wit…
We present deep H$α$ imaging of three nearby dwarf galaxies, carefully selected to optimize observations with the Maryland-Magellan Tunable Filter (MMTF) on the Magellan 6.5m telescope. An effective bandpass of $\sim$13Å is used, and the images reach 3$σ$ flux limits of $\sim$8$\times10^{-18}$ ergs s$^{-1}$ cm$^{-2}$, which is about an order of magnitude lower than standard narrowband observations obtained by the most recent generation of local H$α$ galaxy surveys. The observations were originally motivated by the finding that the H$α$/FUV flux ratio of galaxies systematically declines as glob…
The origin of double-peaked narrow emission-line galaxies in MaNGA Survey
Nanjing University（南京大学）；Shanghai Astronomical Observatory, Chinese Academy of Sciences（中国科学院上海天文台）；Max Planck Institute for Astrophysics（马克斯·普朗克天体物理研究所）
We consider AGN photoionization of gas in companion galaxies (cross-ionization) as a way to sample the intensity of AGN radiation in both direction and time, independent of the gas properties of the AGN host galaxies. From an initial set of 212 AGN+companion systems, identified with the help of Galaxy Zoo participants, we obtained long-slit optical spectra of 32 pairs which were a priori likely to show cross-ionization based on projected separation or angular extent of the companion. From emission-line ratios, 10 of these systems are candidates for cross-ionization, roughly the fraction expect…
Existing star-forming vs. active galactic nucleus (AGN) classification schemes using optical emission-line diagnostics mostly fail for low-metallicity and/or highly star-forming galaxies, missing AGN in typical $z\sim0$ dwarfs. To recover AGN in dwarfs with strong emission lines (SELs), we present a classification scheme optimizing the use of existing optical diagnostics. We use SDSS emission-line catalogs overlapping the volume- and mass-limited RESOLVE and ECO surveys to determine the AGN percentage in SEL dwarfs. Our photoionization grids show that the [O III]/H$β$ versus [S II]/H$α$ diagra…
We compare the oxygen abundance (O/H) of the Narrow Line Regions (NLRs) of Seyfert 2 AGNs obtained through strong-line methods and from direct measurements of the electron temperature (Te-method). The aim of this study is to explore the effects of the use of distinct methods on the range of metallicity and on the mass-metallicity relation of AGNs at low redshifts (z < 0.4). We used the Sloan Digital Sky Survey (SDSS) and NASA/IPAC Extragalactic Database (NED) to selected optical (3000 < A < 7000) emission line intensities of 463 confirmed Seyfert 2 AGNs. The oxygen abundance of the NLRs were e…
We present an adapted version of the code HII-CHI-Mistry-UV (Pérez-Montero & Amorín 2017) to derive chemical abundances from emission lines in the ultraviolet, for use in narrow line regions (NLR) of Active Galactic Nuclei (AGN). We evaluate different ultraviolet emission line ratios and how different assumptions about the models, including the presence of dust grains, the shape of the incident spectral energy distribution, or the thickness of the gas envelope around the central source, may affect the final estimates as a function of the set of emission lines used. We compare our results with …
Machine learning technique for morphological classification of galaxies from SDSS. IV. Visual inspection vs CNN for merging, irregular, edge-on, barred, ringed, and with dust lanes galaxies at 0.02<z<0.1
Main Astronomical Observatory of the NAS of Ukraine（乌克兰国家科学院主天文台）
The joint catalogue of Active Galactic Nuclei selected from optical identifications of X-ray sources was created as a combination of two samples: Hamburg-ROSAT Catalogue (HRC) and Byurakan-Hamburg-ROSAT Catalogue (BHRC). Both are based on optical identifications of X-ray sources from ROSAT catalogues using low-dispersion spectra of Hamburg Quasar Survey (HQS). However, HRC and BHRC contain a number of misidentifications and using the recent optical and multiwavelength (MW) catalogues we have revised both samples excluding false AGN and adding new genuine ones. Thus a new large homogeneous comp…
Local star-forming galaxies show properties that are thought to differ from galaxies in the early Universe. Among them, the ionizing stellar populations and the gas geometry make the recipes designed to derive chemical abundances from nebular emission lines to differ from those calibrated in the Local Universe. A sample of 1969 Extreme Emission Line Galaxies (EELGs) at a redshift 0 < z < 0.49, selected from the Sloan Digital Sky Survey (SDSS) to be local analogues of high-redshift galaxies, was used to analyze their most prominent emission lines and to derive total oxygen abundances and nitrog…
Using ~1,700,000 target- and sky-fiber spectra from the SDSS, we have carried out a systematic search for Galactic planetary nebulae (PNe) via detections of the [OIII] 4959, 5007 lines. Thanks to the excellent sensitivity of the SDSS spectroscopic surveys, this is by far the deepest search for PNe ever taken, reaching a surface brightness of the [OIII] 5007 line down to about 29.0 mag./arcsec^2. The search recovers 13 previously known PNe in the Galactic Caps. In total, 44 new PN candidates are identified, including 7 candidates of multiple detections and 37 candidates of single detection. The…
Sulphur abundances in star-forming regions from optical emission lines: A new approach based on photoionization models consistent with the direct method
A detailed understanding of how the activity of a galactic nucleus regulates the growth of its host is still missing. To understand the activity and the types of accretion of supermassive black holes in different hosts, it is essential to study radio-optical properties of a large sample of extragalactic sources. In particular, we aim at studying the radio spectral index trends across the optical emission line diagnostic diagrams to search for potential (anti)correlations. To this goal, we combine flux densities from the radio FIRST survey at $1.4\,{\rm GHz}$ (with the flux density range $10\,{…
We report the results of a Sloan Digital Sky Survey-IV eBOSS program to target X-ray sources and mid-infrared-selected WISE AGN candidates in a 36.8 deg$^2$ region of Stripe 82. About half this survey (15.6 deg$^2$) covers the largest contiguous portion of the Stripe 82 X-ray survey. This program represents the largest spectroscopic survey of AGN candidates selected solely by their WISE colors. We combine this sample with X-ray and WISE AGN in the field identified via other sources of spectroscopy, producing a catalog of 4847 sources that is 82% complete to $r\sim22$. Based on X-ray luminositi…
We present the first catalog and data release of the Swift-BAT AGN Spectroscopic Survey (BASS). We analyze optical spectra of the majority of AGN (77%, 641/836) detected based on their 14-195 keV emission in the 70-month Swift BAT all-sky catalog. This includes redshift determination, absorption and emission line measurements, and black hole mass and accretion rate estimates for the majority of obscured and un-obscured AGN (74%, 473/641) with 340 measured for the first time. With ~90% of sources at z<0.2, the survey represents a significant census of hard-X-ray selected AGN in the local univer…
