- ID:
- ivo://CDS.VizieR/II/203A
- Title:
- Second Extreme Ultra-Violet Explorer Catalog
- Short Name:
- II/203A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Extreme Ultraviolet Explorer satellite was launched on June 7, 1992 from Cape Canaveral, Florida on a Delta II rocket. The payload contains three EUV scanning telescopes equipped with imaging detectors as well as a Deep Survey Spectrometer instrument which divides the light from a fourth telescope between an imaging detector and three EUV spectrometers. There are three source tables in this catalogue: - table1 lists count rates and positions of 514 objects detected during the all-sky survey. - table2 lists 35 sources detected by the deep survey of half the ecliptic plane; three deep survey objects are also detected in the all sky survey. - table3 lists 188 sources that have been detected in other ways, principally by deep exposures with the scanner telescopes as part of the Right Angle Program or by long exposures with the deep survey instrument; table3 includes right angle detections through December 24, 1994. Because the objects listed in table3 have been derived with a variety of instruments and exposure strategies, the flux limits and detection thresholds vary over a wide range; interested readers should consult the reference listed. Each table has an associated list of identified sources, id1, id2 and id3 (one EUVE source may by associated to 0, one or more counterparts); in nearly all cases they lie within 1 arcmin of the actual source position. The 534 objects in the "faint" part were detected jointly in the EUVE and in the ROSAT X-Ray Telescope 0.25keV band (50{AA}). This joint selection criterion permits use of a low count rate threshold in each survey, roughly 60% of the threshold used in the EUVE all-sky surveys, and 166 of the objects listed in the "faint" part are new EUV sources, appearing in neither the Second EUVE Source Catalog (tables 1 to 3) nor the ROSAT Wide Field Camera Second Catalog (J/MNRAS/274/1165)
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- ID:
- ivo://CDS.VizieR/J/A+A/505/417
- Title:
- Second INTEGRAL AGN catalogue
- Short Name:
- J/A+A/505/417
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The INTEGRAL mission provides a large data set for studying the hard X-ray properties of AGN and allows testing the unified scheme for AGN. We present analysis of INTEGRAL IBIS/ISGRI, JEM-X, and OMC data for 199 AGN that have been reported to be detected by INTEGRAL above 20keV. The data analysed here allow a significant spectral extraction on 148 objects and optical variability study of 57 AGN. The slopes of the hard X-ray spectra of Seyfert 1 and Seyfert 2 galaxies are found to be consistent within the uncertainties, whereas lower luminosities are measured for the more absorbed/type 2 AGN. The intermediate Seyfert 1.5 objects exhibit hard X-ray spectra consistent with those of Seyfert 1. When applying a Compton reflection model, the underlying continua appear still the same in Seyfert 1 and 2 with photon index 2, and the reflection strength is about R=1, when assuming different inclination angles. A significant correlation is found between the hard X-ray and optical luminosity and the mass of the central black hole in the sense that the more luminous objects appear to be more massive. There is also a general trend for the absorbed sources and type 2 AGN to have lower Eddington ratios. The black hole mass appears to form a fundamental plane together with the optical and X-ray luminosity of the form LV being proportional to LX^0.6^.M^0.2^, similar to that found between radio luminosity LR, LX, and M. The unified model for Seyfert galaxies seems to hold, showing in hard X-rays that the central engine is the same in Seyfert 1 and 2 but seen under different inclination angles and absorption.
- ID:
- ivo://CDS.VizieR/J/A+A/588/A103
- Title:
- Second ROSAT all-sky survey (2RXS) source catalog
- Short Name:
- J/A+A/588/A103
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the second ROSAT all-sky survey source catalogue, hereafter referred to as the 2RXS catalogue. This is the second publicly released ROSAT catalogue of point-like sources obtained from the ROSAT all-sky survey (RASS) observations performed with the position-sensitive proportional counter (PSPC) between June 1990 and August 1991, and is an extended and revised version of the bright and faint source catalogues. We used the latest version of the RASS processing to produce overlapping X-ray images of 6.4 by 6.4 degrees sky regions. To create a source catalogue, a likelihood-based detection algorithm was applied to these, which accounts for the variable point-spread function (PSF) across the PSPC field of view. Improvements in the background determination compared to 1RXS were also implemented. X-ray control images showing the source and background extraction regions were generated, which were visually inspected. Simulations were performed to assess the spurious source content of the 2RXS catalogue. X-ray spectra and light curves were extracted for the 2RXS sources, with spectral and variability parameters derived from these products. We obtained about 135,000 X-ray detections in the 0.1-2.4keV energy band down to a likelihood threshold of 6.5, as adopted in the 1RXS faint source catalogue. Our simulations show that the expected spurious content of the catalogue is a strong function of detection likelihood, and the full catalogue is expected to contain about 30 per cent spurious detections. A more conservative likelihood threshold of 9, on the other hand, yields about 71,000 detections with a 5 per cent spurious fraction. We recommend thresholds appropriate to the scientific application. X-ray images and overlaid X-ray contour lines provide an additional user product to evaluate the detections visually, and we performed our own visual inspections to flag uncertain detections. Intra-day variability in the X-ray light curves was quantified based on the normalised excess variance and a maximum amplitude variability analysis. X-ray spectral fits were performed using three basic models, a power law, a thermal plasma emission model, and black-body emission. Thirty-two large extended regions with diffuse emission and embedded point sources were identified and excluded from the present analysis. The 2RXS catalogue provides the deepest and cleanest X-ray all-sky survey catalogue in advance of eROSITA.
- ID:
- ivo://CDS.VizieR/IX/30
- Title:
- Second ROSAT PSPC Catalog
- Short Name:
- IX/30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue contains sources from PSPC-ROSAT (Position-Sensitive Proportional Counter aboard the Roentgen Satellite), as provided by Max-Planck Institut fuer extraterrestrische Physik (MPE). It supersedes the 1994 version (Cat. <IX/11>) The current release of the catalog is comprised of results from 4093 sequences (sky coverage of 14.5%). The complete version contains entries for 95,331 detections whereas the short version has 43,156 detections. 2189 obvious sources were not detected by the automated Standard Analysis Software System (SASS), and are not yet contained in this catalogue. These data have been screened by ROSAT data centers in the US, Germany, and the UK as a step in the production of the ROSAT RESULTS ARCHIVE. The RRA contains extracted source and associated products with an indication of reliability for the primary parameters.
- ID:
- ivo://CDS.VizieR/J/ApJS/206/4
- Title:
- SED and bolometric corrections for luminous QSOs
- Short Name:
- J/ApJS/206/4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We explore the mid-infrared (mid-IR) through ultraviolet (UV) spectral energy distributions (SEDs) of 119652 luminous broad-lined quasars with 0.064<z<5.46 using mid-IR data from Spitzer and WISE, near-infrared data from the Two Micron All Sky Survey and UKIDSS, optical data from the Sloan Digital Sky Survey, and UV data from the Galaxy Evolution Explorer. The mean SED requires a bolometric correction (relative to 2500{AA}) of BC_2500{AA}_=2.75+/-0.40 using the integrated light from 1um-2keV, and we further explore the range of bolometric corrections exhibited by individual objects. In addition, we investigate the dependence of the mean SED on various parameters, particularly the UV luminosity for quasars with 0.5<~z<~3 and the properties of the UV emission lines for quasars with z>~1.6; the latter is a possible indicator of the strength of the accretion disk wind, which is expected to be SED-dependent.
- ID:
- ivo://CDS.VizieR/J/ApJ/716/30
- Title:
- SED of Fermi bright blazars
- Short Name:
- J/ApJ/716/30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted a detailed investigation of the broadband spectral properties of the {gamma}-ray selected blazars of the Fermi LAT Bright AGN Sample (LBAS, Cat. J/ApJ/700/597). By combining our accurately estimated Fermi {gamma}-ray spectra with Swift, radio, infra-red, optical, and other hard X-ray/{gamma}-ray data, collected within 3 months of the LBAS data taking period, we were able to assemble high-quality and quasi-simultaneous spectral energy distributions (SED) for 48 LBAS blazars. We have used these SED to characterize the peak intensity of both the low- and the high-energy components. The results have been used to derive empirical relationships that estimate the position of the two peaks from the broadband colors (i.e., the radio to optical, {alpha}_ro_, and optical to X-ray, {alpha}_ox_, spectral slopes) and from the {gamma}-ray spectral index. While more than 50% of known radio bright high energy peaked (HBL) BL Lacs are detected in the LBAS sample, only less than 13% of known bright broad-lined flat spectrum radio quasars (FSRQs) and LBL BL Lacs are included. This suggests that the latter sources, as a class, may be much fainter {gamma}-ray emitters than LBAS blazars, and could in fact radiate close to the expectations of simple synchrotron self-Compton (SSC) models. We categorized all our sources according to a new physical classification scheme based on the generally accepted paradigm for Active Galactic Nuclei and on the results of this SED study.
- ID:
- ivo://CDS.VizieR/J/ApJ/663/81
- Title:
- SED of hard X-ray selected AGN in XMDS
- Short Name:
- J/ApJ/663/81
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the SEDs of a hard X-ray selected sample containing 136 sources with F(2-10)keV>10^-14^erg/cm^2^/s; 132 are AGNs. The sources are detected in a 1deg^2^ area of the XMM-Newton Medium Deep Survey where optical data from the VVDS and CFHTLS and infrared data from the SWIRE survey are available. Based on a SED fitting technique we derive photometric redshifts with {sigma}(1+z)=0.11 and 6% of outliers and identify AGN signatures in 83% of the objects. This fraction is higher than derived when a spectroscopic classification is available. The remaining 17% of AGNs show star-forming galaxy SEDs (SF class).
- ID:
- ivo://CDS.VizieR/J/ApJ/709/1407
- Title:
- SED of the Fermi blazars
- Short Name:
- J/ApJ/709/1407
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We complied the optical, X-ray, and {gamma}-ray data for 54 Fermi blazars and studied the relationship between the broadband spectral index {alpha}_ox_ and {alpha}_x{gamma}_, as well as the relationship between the intrinsic composite spectral indices {alpha}_xox_ and {alpha}_{gamma}x{gamma}_ for this sample. The relationship between {alpha}_xox_ and {alpha}_{gamma}x{gamma}_ reveals that flat spectrum radio quasars and low-energy peaked BL Lacertae follow a continuous trend, which is consistent with previous results, whereas high-energy peaked BL Lacertae follow a separate distinct trend. Even so, a unified scheme is also revealed from {alpha}_xox_-{alpha}_{gamma}x{gamma}_ diagram when all three subclasses of blazars are considered.
- ID:
- ivo://CDS.VizieR/J/MNRAS/495/1853
- Title:
- SED-selected AGN in the VIPERS field
- Short Name:
- J/MNRAS/495/1853
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The detection of X-ray emission constitutes a reliable and efficient tool for the selection of active galactic nuclei (AGNs), although it may be biased against the most heavily absorbed AGNs. Simple mid-infrared (IR) broad-band selection criteria identify a large number of luminous and absorbed AGNs, yet again host contamination could lead to non-uniform and incomplete samples. Spectral energy distribution (SED) decomposition is able to decouple the emission from the AGN versus that from star-forming regions, revealing weaker AGN components. We aim to identify the obscured AGN population in the VIMOS Public Extragalactic Redshift Survey in the Canada-France-Hawaii Telescope Legacy Survey W1 field through SED modelling. We construct SEDs for 6860 sources and identify 160 AGNs at a high confidence level using a Bayesian approach. Using optical spectroscopy, we confirm the nature of ~85 per cent of the AGNs. Our AGN sample is highly complete (~92 per cent) compared to mid-IR colour-selected AGNs, including a significant number of galaxy-dominated systems with lower luminosities. In addition to the lack of X-ray emission (80 per cent), the SED fitting results suggest that the majority of the sources are obscured. We use a number of diagnostic criteria in the optical, IR, and X-ray regimes to verify these results. Interestingly, only 35 per cent of the most luminous mid-IR-selected AGNs have X-ray counterparts suggesting strong absorption. Our work emphasizes the importance of using SED decomposition techniques to select a population of type II AGNs, which may remain undetected by either X-ray or IR colour surveys.
- ID:
- ivo://CDS.VizieR/J/ApJ/729/22
- Title:
- SEDs of galaxy cluster members
- Short Name:
- J/ApJ/729/22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a study of AGNs and their host galaxies found in low-redshift galaxy clusters. We fit model spectral energy distributions (SEDs) to the combined visible and mid-infrared (MIR) photometry of cluster members and use these model SEDs to determine stellar masses and star formation rates (SFRs). We identify two populations of AGNs, the first based on their X-ray luminosities (X-ray AGNs) and the second based on the presence of a significant AGN component in their model SEDs (IR AGNs). We find that the two AGN populations are nearly disjoint; only 8 out of 44 AGNs are identified with both techniques.