- ID:
- ivo://CDS.VizieR/J/A+A/525/A127
- Title:
- Properties of X-ray selected AGNs
- Short Name:
- J/A+A/525/A127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- There is mounting evidence that active galactic nuclei (AGN) selected through optical emission lines or radio luminosities comprise two distinct AGN populations, whose activity is triggered by different processes. In two previous papers, we studied the host galaxies and environment of radio-loud AGN. In this third paper we study the properties of a sample of Type-2 AGN that were selected on the basis of their [2-10]keV X-ray luminosity. We find that the X-ray luminosity function is in good agreement with previous studies and that the fraction of galaxies hosting an X-ray AGN is a strong function of the stellar mass of the host galaxy. The shape of this fraction-mass relation is similar to the fraction of galaxies that are emission-line AGN, while it differs significantly from the relation observed for radio-selected AGN. The AGN in our sample tend to be located in underdense environments where galaxy mergers and interactions are likely to occur. For all host galaxy masses, the Type-2 AGN display a strong infrared excess at short (~3.5um) wavelengths, suggesting the presence of hot dust possibly associated with a hot dusty torus. These results add weight to the belief that the X-ray selection criteria identifies a population of AGN similar to the emission-line selected population but distinct from the radio population at high masses.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/893/L20
- Title:
- Proton synchrotron gamma-rays in blazars
- Short Name:
- J/ApJ/893/L20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The origin of high-energy emission in blazars jets (i.e., leptonic versus hadronic) has been a longstanding matter of debate. Here, we focus on one variant of hadronic models where proton synchrotron radiation accounts for the observed steady {gamma}-ray blazar emission. Using analytical methods, we derive the minimum jet power (P_j,min_) for the largest blazar sample analyzed to date (145 sources), taking into account uncertainties of observables and jet's physical parameters. We compare P_j,min_ against three characteristic energy estimators for accreting systems, i.e., the Eddington luminosity, the accretion disk luminosity, and the power of the Blandford-Znajek process, and find that P_j,min_ is about 2 orders of magnitude higher than all energetic estimators for the majority of our sample. The derived magnetic field strengths in the emission region require either large amplification of the jet's magnetic field (factor of 30) or place the {gamma}-ray production site at sub-pc scales. The expected neutrino emission peaks at ~0.1-10EeV, with typical peak neutrino fluxes ~10^-4^ times lower than the peak {gamma}-ray fluxes. We conclude that if relativistic hadrons are present in blazar jets, they can only produce a radiatively subdominant component of the overall spectral energy distribution of the blazar's steady emission.
- ID:
- ivo://CDS.VizieR/J/ApJ/747/107
- Title:
- QSO Candidates in the MACHO LMC database
- Short Name:
- J/ApJ/747/107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog the 2566 QSO candidates in the MACHO LMC database. In these catalogs, we complied number of properties of the objects including RA, Dec, crossmatched IDs with several catalogs, magnitudes, photometric redshifts, etc. See Kim et al. (2011ApJ...735...68K) for the SVM (a.k.a. Support Vector Machine, a supervised machine learning algorithm) QSO classification model based on the time variability of lightcurves. We used the model to select the 2566 QSO candidates. In this work, we employed multiple diagnostics such as X-ray flux, mid-IR color and AGN SED fitting in order to select 663 promising QSO candidates among the 2,566 candidates. These candidates are flagged in the catalog. We calibrated the MACHO RA and Dec of the candidates using the UCAC3 catalog and improved the average astrometric accuracy from ~3" to ~0.5".
- ID:
- ivo://CDS.VizieR/J/A+A/635/A157
- Title:
- QSO J1538+0855 MUSE datacube
- Short Name:
- J/A+A/635/A157
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In recent years, Ly{alpha} nebulae have been routinely detected around high redshift, radio-quiet quasars thanks to the advent of the highly sensitive integral field spectrographs. Constraining the physical properties of the Ly{alpha} nebulae is crucial for a full understanding of the circum-galactic medium (CGM). The CGM acts both as a repository for intergalactic and galactic baryons as well as a venue of feeding and feedback processes. The most luminous quasars are privileged test-beds to study these processes, given their large ionising fluxes and dense CGM environments in which they are expected to be embedded.We aim to characterise the rest-frame ultraviolet (UV) emission lines in the CGM around a hyper-luminous, broad emission line, radio-quiet quasar at z~3.6, which exhibits powerful outflows at both nuclear and host galaxy scales.We analyse VLT/MUSE observations of the quasar J1538+08 (Lbol=6*10^47^erg/s), and we performed a search for extended UV emission lines to characterise its morphology, emissivity, kinematics, and metal content.We report the discovery of a very luminous (2*10^44^erg/s), giant (150kpc) Ly{alpha} nebula and a likely associated extended (75kpc) CIV nebula. The Ly{alpha} nebula emission exhibits moderate blueshift (440km/s) compared to the quasar systemic redshift and a large average velocity dispersion (700km/s) across the nebula, while the CIV nebula shows average velocity dispersion of 350km/s. The Ly{alpha} line profile exhibits a significant asymmetry towards negative velocity values at 20-30kpc south of the quasar and is well parametrised by the following two Gaussian components: a narrow (470km/s) systemic one plus a broad (1200km/s), blueshifted (1500km/s) one. Our analysis of the MUSE observation of J1538+08 reveals metal-enriched CGM around this hyper-luminous quasar. Furthermore, our detection of blueshifted emission in the emission profile of the Ly{alpha} nebula suggests that powerful nuclear outflows can propagate through the CGM over tens of kiloparsecs.
- ID:
- ivo://CDS.VizieR/J/ApJS/194/45
- Title:
- QSO properties from SDSS-DR7
- Short Name:
- J/ApJS/194/45
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a compilation of properties of the 105783 quasars in the Sloan Digital Sky Survey Data Release 7 (DR7) quasar catalog (Cat. VII/260). In this product, we compile continuum and emission line measurements around the H{alpha}, H{beta}, MgII, and CIV regions, as well as other quantities such as radio properties, and flags indicating broad absorption line quasars, disk emitters, etc. We also compile virial black hole mass estimates based on various calibrations. For the fiducial virial mass estimates we use the Vestergaard & Peterson (VP06; 2006ApJ...641..689V) calibrations for H{beta} and CIV, and our own calibration for MgII which matches the VP06 H{beta} masses on average. We describe the construction of this catalog and discuss its limitations.
646. QSOs in the M3 field
- ID:
- ivo://CDS.VizieR/J/A+A/392/851
- Title:
- QSOs in the M3 field
- Short Name:
- J/A+A/392/851
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a variability and proper motion (VPM) search for QSOs in the field around M3. The VPM search is demonstrated to be powerful technique for efficiently finding QSOs without major selection effects with regard to the spectral energy distribution. Remarkably, the properties of the VPM QSOs do not significantly differ from those of samples from more conventional optical search techniques. The lightcurves of the QSOs from the resulting sample provide an interesting data set for the statistical investigation of QSO long-term variability.
647. QSOs properties
- ID:
- ivo://CDS.VizieR/J/ApJ/625/78
- Title:
- QSOs properties
- Short Name:
- J/ApJ/625/78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the properties of infrared-selected QSOs (IR QSOs), optically selected Palomar-Green QSOs (PG QSOs), and narrow-line Seyfert 1 galaxies (NLS1s). We compare their properties from the IR to the optical and examine various correlations among the black hole mass, accretion rate, star formation rate, and optical and IR luminosities.
- ID:
- ivo://CDS.VizieR/J/ApJ/669/791
- Title:
- Quasar black hole masses
- Short Name:
- J/ApJ/669/791
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the time-dependent variations of ultraviolet (UV) black hole mass estimates of quasars in the Sloan Digital Sky Survey (SDSS). From SDSS spectra of 615 high-redshift (1.69<z<4.75) quasars with spectra from two epochs, we estimate black hole masses using a single-epoch technique, which employs an additional, automated night-sky line removal and relies on UV continuum luminosity and CIV {lambda}1549 emission-line dispersion. Mass estimates show variations between epochs at about the 30% level for the sample as a whole. We determine that for our full sample, measurement error in the line dispersion likely plays a larger role than the inherent variability in terms of contributing to variations in mass estimates between epochs. However, we use the variations in quasars with r-band spectral signal-to-noise ratio greater than 15 to estimate that the contribution to these variations from inherent variability is roughly 20%. We conclude that these differences in black hole mass estimates between epochs indicate that variability does not make a large contribution to the current factor of 2 scatter between mass estimates derived from low- and high-ionization emission lines.
- ID:
- ivo://CDS.VizieR/J/AZh/78/675
- Title:
- Quasar-galaxy associations
- Short Name:
- J/AZh/78/675
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A new catalog of 8382 close quasar-galaxy pairs is presented. The catalog was composed using published catalogued quasars and active galactic nuclei containing 11358 objects, as well as the LEDA catalog of galaxies, which contains on the order of 100000 objects.
- ID:
- ivo://CDS.VizieR/VII/235
- Title:
- Quasars and Active Galactic Nuclei (11th Ed.)
- Short Name:
- VII/235
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue is an update of the previous versions. The recent release of the final release of the 2dF quasar catalogue and of the first part of the SLOAN catalogue, almost doubling the number of known QSOs, led us to prepare an updated version of our Catalogue of quasars and active nuclei, which now contains 48921 quasars, 876 BL Lac objects and 15069 active galaxies (including 11777 Seyfert 1). Like the tenth edition, it includes position and redshift as well as photometry (U, B, V) and 6 and 11 cm flux densities when available. The present edition this catalogue contains the quasars with measured redshift known prior to August 1st, 2003.
