- ID:
- ivo://CDS.VizieR/J/MNRAS/397/1713
- Title:
- SDSS DR3 flat-spectrum radio quasars
- Short Name:
- J/MNRAS/397/1713
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We constructed a sample of 185 flat-spectrum radio quasars (FSRQs) by cross-correlating Shen et al.'s (2006MNRAS.369.1639S) Sloan Digital Sky Survey Data Release 3 (SDSS DR3) X-ray quasar sample with the Faint Images of the Radio Sky at Twenty Centimeters (FIRST) and Green Bank 6-cm survey (GB6) radio catalogues. From the spectral energy distribution (SED) constructed using multi-band (radio, UV, optical, infrared and X-ray) data, we derived the synchrotron peak frequency and peak luminosity. The black hole mass MBH and the broad-line region (BLR) luminosity (then the bolometric luminosity Lbol) were obtained by measuring the linewidth and strength of broad emission lines from SDSS spectra. We define a subsample of 118 FSRQs for which non-thermal jet emission is thought to dominate over thermal emission from the accretion disc and host galaxy.
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- ID:
- ivo://CDS.VizieR/J/other/NewA/58.61
- Title:
- SDSS DR9 galaxy clusters optical catalog
- Short Name:
- J/other/NewA/58.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new galaxy cluster catalog constructed from the Sloan Digital Sky Survey Data Release 9 (SDSS DR9) using an Adaptive Matched Filter (AMF) technique. Our catalog has 46479 galaxy clusters with richness {Lambda}_200_>20 in the redshift range 0.045<=z<0.641 in ~11500 deg^2^ of the sky. Angular position, richness, core and virial radii and redshift estimates for these clusters, as well as their error analysis, are provided as part of this catalog. In addition to the main version of the catalog, we also provide an extended version with a lower richness cut, containing 79368 clusters. This version, in addition to the clusters in the main catalog, also contains those clusters (with richness 10<{Lambda}_200_<20) which have a one-to-one match in the DR8 catalog developed by Wen et al (WHL). We obtain probabilities for cluster membership for each galaxy and implement several procedures for the identification and removal of false cluster detections. We cross-correlate the main AMF DR9 catalog with a number of cluster catalogs in different wavebands (Optical, X-ray). We compare our catalog with other SDSS-based ones such as the redMaPPer (Rykoff et al., 2014, Cat. J/ApJ/785/104, 26350 clusters) and the Wen et al. (WHL, 2012, Cat. J/ApJS/199/34) (132684 clusters) in the same area of the sky and in the overlapping redshift range. We match 97% of the richest Abell clusters (Richness group 3), the same as WHL, while redMaPPer matches ~90% of these clusters. Considering AMF DR9 richness bins, redMaPPer does not have one-to-one matches for 70% of our lowest richness clusters (20<{Lambda}_200_<40), while WHL matches 54% of these missed clusters (not present in redMaPPer). redMaPPer consistently does not possess one-to-one matches for ~20% AMF DR9 clusters with {Lambda}_200_>40, while WHL matches >=70% of these missed clusters on average. For comparisons with X-ray clusters, we match the AMF catalog with BAX, MCXC and a combined catalog from NORAS and REFLEX. We consistently obtain a greater number of one-to-one matches for X--ray clusters across higher luminosity bins (L_x_>6x10^44^erg/s) than redMaPPer while WHL matches the most clusters overall. For the most luminous clusters (L_x_>8), our catalog performs equivalently to WHL. This new catalog provides a wider sample than redMaPPer while retaining many fewer objects than WHL.
- ID:
- ivo://CDS.VizieR/J/MNRAS/422/25
- Title:
- SDSS DR7 groups, clusters and filaments
- Short Name:
- J/MNRAS/422/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have developed a multiscale structure identification algorithm for the detection of overdensities in galaxy data that identifies structures having radii within a user-defined range. Our "multiscale probability mapping" technique combines density estimation with a shape statistic to identify local peaks in the density field. This technique takes advantage of a user-defined range of scale sizes, which are used in constructing a coarse-grained map of the underlying fine-grained galaxy distribution, from which overdense structures are then identified. In this study we have compiled a catalogue of groups and clusters at 0.025<z<0.24 based on the Sloan Digital Sky Survey (SDSS), Data Release 7, quantifying their significance and comparing with other catalogues. Most measured velocity dispersions for these structures lie between 50 and 400km/s. A clear trend of increasing velocity dispersion with radius from 0.2 to 1Mpc/h is detected, confirming the lack of a sharp division between groups and clusters. A method for quantifying elongation is also developed to measure the elongation of group and cluster environments. By using our group and cluster catalogue as a coarse-grained representation of the galaxy distribution for structure sizes of <~1Mpc/h, we identify 53 filaments (from an algorithmically derived set of 100 candidates) as elongated unions of groups and clusters at 0.025<z<0.13. These filaments have morphologies that are consistent with previous samples studied.
1464. SDSS DR7 M dwarfs
- ID:
- ivo://CDS.VizieR/J/AJ/141/97
- Title:
- SDSS DR7 M dwarfs
- Short Name:
- J/AJ/141/97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a spectroscopic catalog of 70,841 visually inspected M dwarfs from the seventh data release of the Sloan Digital Sky Survey. For each spectrum, we provide measurements of the spectral type, a number of molecular band heads, and the H{alpha}, H{beta}, H{gamma}, H{delta}, and CaII-K emission lines. In addition, we calculate the metallicity-sensitive parameter {zeta} and identify a relationship between {zeta} and the g-r and r-z colors of M dwarfs. We assess the precision of our spectral types (which were assigned by individual examination), review the bulk attributes of the sample, and examine the magnetic activity properties of M dwarfs, in particular those traced by the higher order Balmer transitions. Our catalog is cross-matched to 2MASS infrared data, and contains photometric distances for each star. Finally, we identify eight new late-type M dwarfs that are possibly within 25 pc of the Sun. Future studies will use these data to thoroughly examine magnetic activity and kinematics in late-type M dwarfs and examine the chemical and dynamical history of the local Milky Way.
- ID:
- ivo://CDS.VizieR/J/ApJS/194/42
- Title:
- SDSS-DR3 MgII-based black hole masses
- Short Name:
- J/ApJS/194/42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present MgII-based black hole (BH) mass estimates for 27602 quasars with rest-frame UV spectra available in the Sloan Digital Sky Survey Data Release Three (Cat. II/259; superseded by II/294). This estimation is possible due to the existence of an empirical correlation between the radius of the broad-line region (BLR) and the continuum luminosity at 3000{AA}. We regenerate this correlation by applying our measurement method to UV spectra of low-redshift quasars in the Hubble Space Telescope/International Ultraviolet Explorer databases which have corresponding reverberation mapping estimates of the H{beta} BLR's radius. Our mass estimation method uses the line dispersion rather than the full width at half-maximum of the low-ionization MgII emission line.
- ID:
- ivo://CDS.VizieR/J/A+A/471/17
- Title:
- SDSS-DR4 nearby clusters global properties
- Short Name:
- J/A+A/471/17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Large surveys such as the Sloan Digital Sky Survey have made large amounts of spectroscopic and photometric data of galaxies available, thereby providing important information for studying galaxy evolution in dense environments. We have selected a sample of 88 nearby (z<0.1) galaxy clusters from the SDSS-DR4 with redshift information for the cluster members. In particular, we focus on the galaxy morphological distribution, the velocity dispersion profiles, and the fraction of blue galaxies in clusters. Cluster membership was determined using the available velocity information. We derived global properties for each cluster, such as their mean recessional velocity, velocity dispersion, and virial radii. Cluster galaxies were grouped into two families according to their u-r colours.
- ID:
- ivo://CDS.VizieR/J/MNRAS/452/4153
- Title:
- SDSS DR12 QSOs [OIII] doublet
- Short Name:
- J/MNRAS/452/4153
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- From the Sloan Digital Sky Survey (SDSS) Data Release 12, which covers the full Baryonic Oscillation Spectroscopic Survey (BOSS) footprint, we investigate the possible variation of the fine-structure constant over cosmological time-scales. We analyse the largest quasar sample considered so far in the literature, which contains 13175 spectra (10363 from SDSS-III/BOSS DR12+2812 from SDSS-II DR7) with redshift z<1. We apply the emission-line method on the [OIII] doublet ({lambda}{lambda}4960, 5008{AA}) and obtain {Delta}{alpha}/{alpha}=(0.9+/-1.8)x10^-5^ for the relative variation of the fine-structure constant. We also investigate the possible sources of systematics: misidentification of the lines, sky OH lines, H{beta} and broad line contamination, Gaussian and Voigt fitting profiles, optimal wavelength range for the Gaussian fits, chosen polynomial order for the continuum spectrum, signal-to-noise ratio and good quality of the fits. The uncertainty of the measurement is dominated by the sky subtraction. The results presented in this work, being systematics limited, have sufficient statistics to constrain robustly the variation of the fine-structure constant in redshift bins ({Delta}z~0.06) over the last 7.9Gyr. In addition, we study the [NeIII] doublet ({lambda}{lambda}3869, 3968{AA}) present in 462 quasar spectra and discuss the systematic effects on using these emission lines to constrain the fine-structure constant variation. Better constraints on {Delta}{alpha}/{alpha}(<10^-6^) using the emission-line method would be possible with high-resolution spectroscopy and large galaxy/qso surveys.
- ID:
- ivo://CDS.VizieR/J/ApJ/819/154
- Title:
- SDSS-DR7 QSOs with X-ray and UV luminosities
- Short Name:
- J/ApJ/819/154
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The observed relation between the soft X-ray and the optical-ultraviolet emission in active galactic nuclei (AGNs) is nonlinear and it is usually parametrized as a dependence between the logarithm of the monochromatic luminosity at 2500{AA} and at 2keV. Previous investigations have found that the dispersion of this relation is rather high (~0.35-0.4 in log units), which may be caused by measurement uncertainties, variability, and intrinsic dispersion due to differences in the AGN physical properties (e.g., different accretion modes). We show that, once optically selected quasars with homogeneous SED and X-ray detection are selected, and dust reddened and/or gas obscured objects are not included, the measured dispersion drops to significantly lower values (i.e., ~0.21-0.24dex). We show that the residual dispersion is due to some extent to variability, and to remaining measurement uncertainties. Therefore, the real physical intrinsic dispersion should be <0.21dex. Such a tight relation, valid over four decades in luminosity, must be the manifestation of an intrinsic (and universal) physical relation between the disk, emitting the primary radiation, and the hot electron corona emitting X-rays.
1469. SDSS-DR5 quasar catalog
- ID:
- ivo://CDS.VizieR/VII/252
- Title:
- SDSS-DR5 quasar catalog
- Short Name:
- VII/252
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The fourth edition of the Sloan Digital Sky Survey (SDSS) Quasar Catalog, made from the SDSS Fifth Data Release, contains 77,429 objects; this is an increase of over 30,000 entries since the previous edition (Schneider et al., Cat. <VII/243>). The catalog consists of the objects in the SDSS Fifth Data Release that have luminosities larger than M_i_=-22.0 (in a cosmology with Ho=70km.s-1.Mpc-1, {Omega}_M_=0.3, and {Omega}_{Lambda}_=0.7), have at least one emission line with FWHM larger than 1000km.s-1 or have interesting or complex absorption features, are fainter than i~15.0, and have highly reliable redshifts. The area covered by the catalog is about 5740deg^2^. The quasar redshifts range from 0.08 to 5.41, with a median value of 1.48; the catalog includes 891 quasars at redshifts greater than 4, of which 36 are at redshifts greater than 5. Approximately half of the catalog quasars have i<19; nearly all have i<21. For each object the catalog presents positions accurate to better than 0.2" 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 basic 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 about 2000; the spectra can be retrieved from the public database using the information provided in the catalog. The average SDSS colors of quasars as a function of redshift, derived from the catalog entries, are presented in tabular form. Approximately 96% of the objects in the catalog were discovered by the SDSS.
- ID:
- ivo://CDS.VizieR/J/AJ/135/10
- Title:
- SDSS-DR4/RASS source matching
- Short Name:
- J/AJ/135/10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The current view of galaxy formation holds that all massive galaxies harbor a massive black hole at their center, but that these black holes are not always in an actively accreting phase. X-ray emission is often used to identify accreting sources, but for galaxies that are not harboring quasars (low-luminosity active galaxies), the X-ray flux may be weak, or obscured by dust. To aid in the understanding of weakly accreting black holes in the local universe, a large sample of galaxies with X-ray detections is needed. We cross-match the ROSAT All Sky Survey (RASS) with galaxies from the Sloan Digital Sky Survey Data Release 4 (SDSS DR4) to create such a sample. Because of the high SDSS source density and large RASS positional errors, the cross-matched catalog is highly contaminated by random associations. We investigate the overlap of these surveys and provide a statistical test of the validity of RASS-SDSS galaxy cross-matches.
