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951. The Parkes quarter-Jansky flat-spectrum sample
ID:
ivo://CDS.VizieR/J/A+A/386/97
Title:
The Parkes quarter-Jansky flat-spectrum sample
Short Name:
J/A+A/386/97
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a new sample of quarter-Jansky flat-spectrum radio sources selected to search for high-redshift quasars and to study the evolution of the flat-spectrum quasar population. The sample comprises 878 radio sources selected from the Parkes catalogues with spectral indices {alpha}^5GHz^_2.7GHz_>=-0.4 where S_{nu}{prop.to}{nu}^{alpha}. The sample covers all right ascensions and the declination range from -80.0{deg} to +2.5{deg}, excluding low galactic latitudes (|b|<10{deg}) and the Magellanic Cloud regions. We have obtained improved radio source positions, firstly to reconfirm the majority of the existing identifications, and secondly, using digitized sky-survey data and deep B, Gunn-i and Gunn-z CCD-imaging, to find optical identifications for 223 previously-unidentified sources. We present the final catalogue of 878 flat-spectrum sources: 827 are compact radio sources identified with galaxies, quasars and BL Lac objects, 38 have either extended radio structure or are identified with Galactic objects (PN, HII or non-compact radio source), 4 are obscured by Galactic stars, and 9 (1 per cent of the total sample) remain unidentified.
952. The quasars MMT-BOSS pilot survey
ID:
ivo://CDS.VizieR/J/ApJS/199/3
Title:
The quasars MMT-BOSS pilot survey
Short Name:
J/ApJS/199/3
Date:
21 Oct 2021
Publisher:
CDS
Description:
The SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), a five-year spectroscopic survey of 10000deg^2^, achieved first light in late 2009. One of the key goals of BOSS is to measure the signature of baryon acoustic oscillations (BAOs) in the distribution of Ly{alpha} absorption from the spectra of a sample of ~150000 z>2.2 quasars. Along with measuring the angular diameter distance at z~2.5, BOSS will provide the first direct measurement of the expansion rate of the universe at z>2. One of the biggest challenges in achieving this goal is an efficient target selection algorithm for quasars in the redshift range 2.2<z<3.5, where their colors tend to overlap those of the far more numerous stars. During the first year of the BOSS survey, quasar target selection (QTS) methods were developed and tested to meet the requirement of delivering at least 15 quasars/deg^2^ in this redshift range, with a goal of 20 out of 40 targets/deg^2^ allocated to the quasar survey. To achieve these surface densities, the magnitude limit of the quasar targets was set at g<=22.0 or r<=21.85. We have defined a uniformly selected subsample of 20 targets/deg^2^, for which the selection efficiency is just over 50% (~10 z>2.20 quasars/deg^2^). This "CORE" subsample will be fixed for Years Two through Five of the survey. In this paper, we describe the evolution and implementation of the BOSS QTS algorithms during the first two years of BOSS operations (through 2011 July), in support of the science investigations based on these data, and we analyze the spectra obtained during the first year. During this year, 11263 new z>2.20 quasars were spectroscopically confirmed by BOSS, roughly double the number of previously known quasars with z>2.20. Our current algorithms select an average of 15 z>2.20 quasars/deg^2^ from 40 targets/deg^2^ using single-epoch SDSS imaging.
953. The Roma BZCAT - 5th edition
ID:
ivo://CDS.VizieR/VII/274
Title:
The Roma BZCAT - 5th edition
Short Name:
VII/274
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Roma-BZCAT is now at the 5th Edition which contains coordinates and multi-frequency data of 3561 sources, about 30% more than in the 1st edition, either confirmed blazars or exhibiting characteristics close to this type of sources. With respect to the previous editions, this new edition has relevant changes in the sources' classification and has a new format for the notes in the tables. We emphasize that all the sources in the Roma-BZCAT have a detection in the radio band. Moreover, a complete spectroscopic information is published and could be accessed by us for all of them, with the exception of BL Lac candidates. Consequently, peculiar sources as the so called "radio quiet BL Lacs", which are reported in some other catalogues, are not included here because of possible contamination with hot stars and other extragalactic objects.
954. The SDSS-DR3 damped Ly{alpha} survey
ID:
ivo://CDS.VizieR/J/ApJ/635/123
Title:
The SDSS-DR3 damped Ly{alpha} survey
Short Name:
J/ApJ/635/123
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results from a damped Ly{alpha} survey of the Sloan Digital Sky Survey, Data Release 3 (Cat. <II/259>). We have discovered over 500 new damped Ly{alpha} systems at z>2.2, and the complete statistical sample for z>1.6 has more than 600 damped Ly{alpha} galaxies.
955. The SDSS-DR7 quasar catalog
ID:
ivo://CDS.VizieR/VII/260
Title:
The SDSS-DR7 quasar catalog
Short Name:
VII/260
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the fifth edition of the Sloan Digital Sky Survey (SDSS) Quasar Catalog, which is based upon the SDSS Seventh Data Release. The catalog, which contains 105783 spectroscopically confirmed quasars, represents the conclusion of the SDSS-I and SDSS-II quasar survey. The catalog consists of the SDSS objects that have luminosities larger than M_i_=-22.0 (in a cosmology with H_0_=70km/s/Mpc, {Omega}_M_=0.3, and {Omega}_{Lambda}=0.7), have at least one emission line with FWHM larger than 1000km/s or have interesting/complex absorption features, are fainter than i~15.0, and have highly reliable redshifts. The catalog covers an area of ~9380deg^2^. The quasar redshifts range from 0.065 to 5.46, with a median value of 1.49; the catalog includes 1248 quasars at redshifts greater than 4, of which 56 are at redshifts greater than 5. The catalog contains 9210 quasars with i<18; slightly over half of the entries have i<19. For each object the catalog presents positions accurate to better than 0.1"rms per coordinate, five-band (ugriz) CCD-based photometry with typical accuracy of 0.03mag, and information on the morphology and selection method. The catalog also contains radio, near-infrared, and X-ray emission properties of the quasars, when available, from other large-area surveys. The calibrated digital spectra cover the wavelength region 3800-9200{AA} at a spectral resolution of ~2000; the spectra can be retrieved from the SDSS public database using the information provided in the catalog. Over 96% of the objects in the catalog were discovered by the SDSS. We also include a supplemental list of an additional 207 quasars with SDSS spectra whose archive photometric information is incomplete.
956. The SDSS DR5/XMM-Newton quasar survey
ID:
ivo://CDS.VizieR/J/ApJS/183/17
Title:
The SDSS DR5/XMM-Newton quasar survey
Short Name:
J/ApJS/183/17
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a catalog of 792 Fifth Data Release Sloan Digital Sky Survey quasars with optical spectra that have been observed serendipitously in the X-rays with the XMM-Newton. These quasars cover a redshift range of z=0.11-5.41 and a magnitude range of i=15.3-20.7. Substantial numbers of radio-loud (70) and broad absorption line (51) quasars exist within this sample. Significant X-ray detections at >=2{sigma} account for 87% of the sample (685 quasars), and 473 quasars are detected at >=6{sigma}, sufficient to allow X-ray spectral fits. For detected sources, ~60% have X-ray fluxes between F_2-10keV_=(1-10)x10^-14^erg/cm^2^/s. We fit a single power law, a fixed power law with intrinsic absorption left free to vary, and an absorbed power-law model to all quasars with X-ray signal-to-noise ratio >=6, resulting in a weighted mean photon index {Gamma}=1.91+/-0.08, with an intrinsic dispersion {sigma}_{Gamma}_=0.38.
957. The SDSS Reverberation Mapping (SDSS-RM) project
ID:
ivo://CDS.VizieR/J/ApJS/241/34
Title:
The SDSS Reverberation Mapping (SDSS-RM) project
Short Name:
J/ApJS/241/34
Date:
07 Mar 2022 07:38:42
Publisher:
CDS
Description:
We present a detailed characterization of the 849 broad-line quasars from the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project. Our quasar sample covers a redshift range of 0.1<z<4.5 and is flux-limited to i_PSF_<21.7 without any other cuts on quasar properties. The main sample characterization includes: (1) spectral measurements of the continuum and broad emission lines for individual objects from the coadded first-season spectroscopy in 2014, (2) identification of broad and narrow absorption lines in the spectra, and (3) optical variability properties for continuum and broad lines from multi-epoch spectroscopy. We provide improved systemic redshift estimates for all quasars and demonstrate the effects of the signal-to-noise ratio on the spectral measurements. We compile measured properties for all 849 quasars along with supplemental multi-wavelength data for subsets of our sample from other surveys. The SDSS-RM sample probes a diverse range in quasar properties and shows well-detected continuum and broad-line variability for many objects from first-season monitoring data. The compiled properties serve as the benchmark for follow-up work based on SDSS-RM data.
958. The third realization of the ICRF, ICRF3
ID:
ivo://CDS.VizieR/J/A+A/644/A159
Title:
The third realization of the ICRF, ICRF3
Short Name:
J/A+A/644/A159
Date:
21 Oct 2021
Publisher:
CDS
Description:
A new realization of the International Celestial Reference Frame (ICRF) is presented based on the work achieved by a working group of the International Astronomical Union (IAU) mandated for this purpose. This new realization follows the initial realization of theICRF completed in 1997 and its successor, ICRF2, adopted as a replacement in 2009. The new frame, referred to as ICRF3, is based on nearly 40 years of data acquired by very long baseline interferometry at the standard geodetic and astrometric radio frequencies (8.4 and 2.3GHz), supplemented with data collected at higher radio frequencies (24GHz and dual-frequency 32 and 8.4GHz) over the past 15 years. State-of-the-art astronomical and geophysical modeling has been used to analyze these data and derive source positions. The modeling integrates, for the first time, the effect of the galactocentric acceleration of the solar system (directly estimated from the data) which, if not considered, induces significant deformation of the frame due to the data span. The new frame includes positions at 8.4GHz for 4536 extragalactic sources. Of these, 303 sources, uniformly distributed on the sky, are identified as "defining sources" and as such serve to define the axes of the frame. Positions at 8.4GHz are supplemented with positions at 24GHz for 824 sources and at 32GHz for 678 sources. In all, ICRF3 comprises 4588 sources, with three-frequency positions available for 600 of these. Source positions have been determined independently at each of the frequencies in order to preserve the underlying astrophysical content behind such positions. They are reported for epoch 2015.0 and must be propagated for observations at other epochs for the most accurate needs, accounting for the acceleration toward the Galactic center, which results in a dipolar proper motion field of amplitude 0.0058 milliarcsecond/yr (mas/yr). The frame is aligned onto the International Celestial Reference System to within the accuracy of ICRF2 and shows a median positional uncertainty of about 0.1mas in right ascension and 0.2 mas in declination, with a noise floor of 0.03mas in the individual source coordinates. A subset of 500 sources is found to have extremely accurate positions, in the range of 0.03 to 0.06mas, at the traditional 8.4GHz frequency. Comparing ICRF3 with the recently released Gaia Celestial Reference Frame 2 in the optical domain, there is no evidence for deformations larger than 0.03 mas between the two frames, in agreement with the ICRF3 noise level. Significant positional offsets between the three ICRF3 frequencies are detected for about 5% of the sources.Moreover, a notable fraction (22%) of the sources shows optical and radio positions that are significantly offset. There are indications that these positional offsets may be the manifestation of extended source structures. This third realization of the ICRF was adopted by the IAU at its 30th General Assembly in August 2018 and replaced the previous realization, ICRF2, on January 1, 2019.
959. The UV-bright Quasar Survey (UVQS) DR1
ID:
ivo://CDS.VizieR/J/AJ/152/25
Title:
The UV-bright Quasar Survey (UVQS) DR1
Short Name:
J/AJ/152/25
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the first data release (DR1) from our UV-bright Quasar Survey for new z~1 active galactic nuclei (AGNs) across the sky. Using simple GALEX UV and WISE near-IR color selection criteria, we generated a list of 1450 primary candidates with FUV<18.5mag. We obtained discovery spectra, primarily on 3m-class telescopes, for 1040 of these candidates and confirmed 86% as AGNs, with redshifts generally at z>0.5. Including a small set of observed secondary candidates, we report the discovery of 217 AGNs with FUV<18mag that previously had no reported spectroscopic redshift. These are excellent potential targets for UV spectroscopy before the end of the Hubble Space Telescope mission. The main data products are publicly available through the Mikulski Archive for Space Telescopes.
960. The XMM-ATLAS catalogues
ID:
ivo://CDS.VizieR/J/A+A/577/A121
Title:
The XMM-ATLAS catalogues
Short Name:
J/A+A/577/A121
Date:
21 Oct 2021
Publisher:
CDS
Description:
Wide area X-ray and far infrared surveys are a fundamental tool to investigate the link between AGN growth and star formation, especially in the low-redshift universe (z<1). The Herschel Terahertz Large Area survey (H-ATLAS) has covered 550deg^2^ in five far-infrared and sub-mm bands, 16deg^2^ of which have been presented in the Science Demonstration Phase (SDP) catalogue. Here we introduce the XMM-Newton observations in H-ATLAS SDP area, covering 7.1deg^2^ with flux limits of 2*10^-15^, 6*10^-15^, and 9*10^-15^erg/s/cm^2^ in the 0.5-2, 0.5-8 and 2-8keV bands, respectively. We present the source detection and the catalogue, which includes 1700, 1582 and 814 sources detected by emldetect in the 0.5-8, 0.5-2 and 2-8keV bands, respectively; the number of unique sources is 1816. We extract spectra and derive fluxes from power-law fits for 398 sources with more than 40 counts in the 0.5-8keV band. We compare the best-fit fluxes with the catalogue ones, obtained by assuming a common photon index of Gamma=1.7; we find no bulk difference between the fluxes, and a moderate dispersion of s=0.33dex. Using wherever possible the fluxes from the spectral fits, we derive the 2-10keV Log N-Log S, which is consistent with a Euclidean distribution. Finally, we release computer code for the tools developed for this project.