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2891. Q1700-MD94 CI(1-0) datacube with NOEMA
ID:
ivo://CDS.VizieR/J/A+A/657/L15
Title:
Q1700-MD94 CI(1-0) datacube with NOEMA
Short Name:
J/A+A/657/L15
Date:
21 Mar 2022 09:37:17
Publisher:
CDS
Description:
We use a combination of new NOrthern Extended Millimeter Array (NOEMA) observations of the pair of [CI] transitions, the CO(7-6) line, and the dust continuum, in addition to ancillary CO(1-0) and CO(3-2) data, to study the molecular gas properties of Q1700-MD94, a massive, main-sequence galaxy at z~2. We find that for a reasonable set of assumptions for a typical massive star-forming galaxy, the CO(1-0), the [CI](1-0) and the dust continuum yield molecular gas masses that are consistent within a factor of ~2. The global excitation properties of the molecular gas as traced by the [CI] and CO transitions are similar to those observed in other massive, star-forming galaxies at z~2. Our large velocity gradient (LVG) modeling using RADEX of the CO and [CI] spectral line energy distributions (SLEDs) suggests the presence of relatively warm (Tkin=41K), dense (n_H2_=8x10^3^cm^-3^) molecular gas, comparable to the high-excitation molecular gas component observed in main-sequence, star-forming galaxies at z~1. The galaxy size in the CO(1-0) and CO(7-6) line emission are comparable, which suggests that the highly-excited molecular gas is distributed throughout the disk powered by intense star formation activity. To confirm this scenario will require spatially resolved observations of the CO and [CI] lines which can now be obtained with NOEMA upgraded capabilities.
2892. QMW IRAS galaxy catalogue
ID:
ivo://CDS.VizieR/J/MNRAS/253/485
Title:
QMW IRAS galaxy catalogue
Short Name:
J/MNRAS/253/485
Date:
21 Oct 2021
Publisher:
CDS
Description:
This study presents a highly complete and reliable IRAS 60-micron galaxy catalog covering 82 percent of the sky. IRAS color conditions are used to exclude galactic sources, including the remaining cirrus sources. All sources flagged as extended, confused, or having a poor correlation coefficient with a point-source template are examined with the raw IRAS data and accurate fluxes determined using mapping routines. The completeness, reliability, and flux accuracy of the catalog are discussed. Identifications are made with existing optical galaxy catalogs and with galaxy redshift surveys in the literature. It is estimated that redshifts are available for 79 percent of the galaxies in the catalog with V less than 5000km/s, and the 3D distribution of such galaxies is displayed. The dipole component of the surface-brightness distribution of galaxies in the catalog is discussed.
2893. QSO-galaxy pairs from SDSS
ID:
ivo://CDS.VizieR/J/MNRAS/447/3856
Title:
QSO-galaxy pairs from SDSS
Short Name:
J/MNRAS/447/3856
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present photometric and spectroscopic measurements of 53 QSO-galaxy pairs from the Sloan Digital Sky Survey (SDSS), where nebular emission lines from a 0<z<0.84 foreground galaxy are detected in the fibre spectra of a background QSO, bringing the overall sample to 103 QSO-galaxy pairs detected in the SDSS. We here study the nature of these systems. Detected foreground galaxies appear at impact parameters between 0.37 and 12.68 kpc. The presence of oxygen and Balmer emission lines allows us to determine the emission line metallicities for our sample, which are on average supersolar in value. Star formation rates for our sample are in the range 0.01-12M_{sun}_/yr. We utilize photometric redshift fitting techniques to estimate the M* values of our galaxies (logM*=7.34-11.54), and extrapolate this relationship to those galaxies with no imaging detections. Where available, we measure the absorption features present in the QSO spectrum due to the foreground galaxy and the relationships between their rest equivalent widths. We report an anticorrelation between impact parameter and E(B-V)(g-i), as well as a correlation between galaxy colour (u- r) and E(B-V)(g-i). We find that our sample is one of late-type, star-forming galaxies comparable to field galaxies in a similar redshift range, providing important clues to better understand absorption systems. These galaxies represent a sample of typical galaxies in the local Universe for which abundances, extinction, morphology, and absorption properties may be measured using background QSOs with great potential for follow-up observations.
2894. QSO J1721+8842 spectra
ID:
ivo://CDS.VizieR/J/A+A/657/A113
Title:
QSO J1721+8842 spectra
Short Name:
J/A+A/657/A113
Date:
22 Feb 2022
Publisher:
CDS
Description:
High-redshift binary quasars provide key insights into mergers and quasar activity, and are useful tools for probing the spatial kinematics and chemistry of galaxies along the line-of-sight. However, only three sub-10-kpc binaries have been confirmed above z=1. Gravitational lensing would provide a way to easily resolve such binaries, study them in higher resolution, and provide more sightlines, though the required alignment with a massive foreground galaxy is rare. Through image deconvolution of StanCam Nordic Optical Telescope (NOT) monitoring data, we reveal two further point sources in the known, z~2.38, quadruply lensed quasar (quad), J1721+8842. An ALFOSC/NOT long-slit spectrum shows that the brighter of these two sources is a quasar with z=2.369+/-0.007 based on the CIII] line, while the CIII] redshift of the quad is z=2.364+/-0.003. Lens modelling using point source positions rules out a single source model, favouring an isothermal lens mass profile with two quasar sources separated by ~6.0kpc (0.73") in projection. Given the resolving ability from lensing and current lensed quasar statistics, this discovery suggests a large population of undiscovered, unlensed sub-10-kpc binaries. We also analyse spectra of two images of the quad, showing narrow Ly{alpha} emission within the trough of a proximate damped Lyman-{alpha} absorber (PDLA). An apparent mismatch between the continuum and narrow line flux ratios provides a new potential tool for simultaneously studying microlensing and the quasar host galaxy. Signs of the PDLA are also seen in the second source, however a deeper spectrum is still required to confirm this. Thanks to the multiple lines-of-sight from lensing and two quasar sources, this system offers simultaneous sub-parsec and kpc-scale probes of a PDLA.
2895. 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.
2896. QSOs orientation modeling
ID:
ivo://CDS.VizieR/J/ApJ/427/125
Title:
QSOs orientation modeling
Short Name:
J/ApJ/427/125
Date:
21 Oct 2021
Publisher:
CDS
Description:
We discuss the statistics of projection on the sky of a simple model for radio sources. The model has a core and two hot spots at unequal distance with an overall structure which is bent at the core. We examine the distributions or the observed sizes and bend angles in 114 quasars and 78 radio galaxies with z<2, from our own data. We find that the observations are well matched by this model with (a) a size distribution matching the observed one, (b) core-hotspot length differences between 0 and 45kpc, and (c) bend angles distributed between 0deg and ~25deg, where quasars are seen within 50deg of the source axis, and radio galaxies are seen at greater angles. We discuss the implications of these fits to unified models and source evolution.
2897. Quantified H I morphology of WHISP sample
ID:
ivo://CDS.VizieR/J/MNRAS/416/2437
Title:
Quantified H I morphology of WHISP sample
Short Name:
J/MNRAS/416/2437
Date:
21 Oct 2021
Publisher:
CDS
Description:
The morphology of the atomic hydrogen (HI) disc of a spiral galaxy is the first component to be disturbed by a gravitational interaction such as a merger between two galaxies. We use a simple parametrization of the morphology of HI column density maps of the Westerbork observations of neutral Hydrogen in Irregular and SPiral galaxies (WHISP) project to select those galaxies that are likely undergoing a significant interaction. Merging galaxies occupy a particular part of parameter space defined by Asymmetry (A), the relative contribution of the 20 per cent brightest pixels to the second-order moment of the column density map (M20) and the distribution of the second-order moment over all the pixels (GM). Based on their HI morphology, we find that 13 per cent of the WHISP galaxies are in an interaction (Concentration-M20) and only 7 per cent are based on close companions in the data cube. This apparent discrepancy can be attributed to the difference in visibility time-scales: mergers are identifiable as close pairs for 0.5 Gyr but are identifiable for ~1Gyr by their disturbed HI morphology. Expressed as volume merger rates, the two estimates agree very well: 7 and 6.8x10^-3^mergers/Gyr/Mpc^3^ for paired and morphologically disturbed HI discs, respectively.
2898. Quantified HI morphology. VI. NUV/FUV
ID:
ivo://CDS.VizieR/J/MNRAS/427/3159
Title:
Quantified HI morphology. VI. NUV/FUV
Short Name:
J/MNRAS/427/3159
Date:
21 Oct 2021
Publisher:
CDS
Description:
Extended ultraviolet (XUV) discs have been found in a substantial fraction of late-type - S0, spiral and irregular - galaxies. Similarly, most late-type spirals have an extended gas disc, observable in the 21-cm radio line (HI). The morphology of galaxies can be quantified well using a series of scale-invariant parameters; concentration-asymmetry-smoothness (CAS), Gini, M_20_, and G_M_ parameters. In this series of papers, we apply these to HI column density maps to identify mergers and interactions, lopsidedness and now XUV discs. In this paper, we compare the quantified morphology and effective radius (R_50_) of the Westerbork observations of neutral Hydrogen in Irregular and SPiral galaxies Project (WHISP) HI maps to those of far- and near-ultraviolet images obtained with GALEX, to explore how close the morphology and scales of HI and UV in these discs correlate. We find that XUV discs do not stand out by their effective radii in UV or HI. However, the concentration index in far-ultraviolet (FUV) appears to select some XUV discs. And known XUV discs can be identified via a criterion using asymmetry and M_20_; 80 per cent of XUV discs are included but with 55 per cent contamination. This translates into 61 candidate XUV disc out of our 266 galaxies, 23 per cent consistent with previous findings. Otherwise, the UV and HI morphology parameters do not appear closely related.
2899. Quasar and radio galaxies flux densities
ID:
ivo://CDS.VizieR/J/A+A/319/757
Title:
Quasar and radio galaxies flux densities
Short Name:
J/A+A/319/757
Date:
21 Oct 2021
Publisher:
CDS
Description:
The tables described below contain the data used in the analysis. The data have been taken from various sources in the literature. The references to the data can be found in the paper. Table 1 contains the data of the 3C radio galaxy sample. Table 2 contains the data of the 3C quasar sample. Table 3 contains the data of the 4C quasar sample. The tables list the name of the object, its redshift, the value of the Q-parameter (ratio between the core and extended flux at 5 GHz observed frequency), and the flux densities at various frequencies.
2900. Quasar candidates selected from the SDSS
ID:
ivo://CDS.VizieR/J/AJ/137/3884
Title:
Quasar candidates selected from the SDSS
Short Name:
J/AJ/137/3884
Date:
21 Oct 2021
Publisher:
CDS
Description:
We explore the multidimensional, multiwavelength selection of quasars from mid-infrared (MIR) plus optical data, specifically from Spitzer-Infrared Array Camera (IRAC) and the Sloan Digital Sky Survey (SDSS). Traditionally, quasar selection relies on cuts in two-dimensional color space despite the fact that most modern surveys (optical and IR) are done in more than three bandpasses. In this paper, we apply modern statistical techniques to combined Spitzer MIR and SDSS optical data, allowing up to eight-dimensional (8-D) color selection of quasars. Using a Bayesian selection method, we catalog 5546 quasar candidates to an 8.0{mu}m depth of 56{mu}Jy over an area of ~24{deg}^2^. Roughly 70% of these candidates are not identified by applying the same Bayesian algorithm to 4-color SDSS optical data alone. The 8-D optical+MIR selection on this data set recovers 97.7% of known type 1 quasars in this area and greatly improves the effectiveness of identifying 3.5<z<5 quasars which are challenging to identify (without considerable contamination) using MIR data alone.