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1891. The MgII cross-section of red galaxies
ID:
ivo://CDS.VizieR/J/ApJ/727/47
Title:
The MgII cross-section of red galaxies
Short Name:
J/ApJ/727/47
Date:
21 Oct 2021
Publisher:
CDS
Description:
We describe a search for MgII(2796, 2803) absorption lines in Sloan Digital Sky Survey (SDSS) spectra of QSOs whose lines of sight pass within impact parameters {rho}~200kpc of galaxies with photometric redshifts of z=0.46-0.6 and errors {Delta}z~0.05. The galaxies selected have the same colors and luminosities as the Luminous Red Galaxy (LRG) population previously selected from the SDSS. A search for MgII lines within a redshift interval of +/-0.1 of a galaxy's photometric redshift shows that absorption by these galaxies is rare: the covering fraction is f({rho})~10%-15% between {rho}=20kpc and {rho}=100kpc, for MgII lines with rest equivalent widths of W_r_>=0.6{AA}, falling to zero at larger {rho}. There is no evidence that W_r_ correlates with impact parameter or galaxy luminosity.
1892. The [OIII] emission line in SDSS AGNs
ID:
ivo://CDS.VizieR/J/ApJ/737/71
Title:
The [OIII] emission line in SDSS AGNs
Short Name:
J/ApJ/737/71
Date:
21 Oct 2021
Publisher:
CDS
Description:
We use homogeneous samples of radio-quiet Seyfert 1 galaxies and QSOs selected from the Sloan Digital Sky Survey to investigate the connection between the velocity shift and the equivalent width (EW) of the [OIII]{lambda}5007 emission line, and their correlations with physical parameters of active galactic nuclei (AGNs). We find a significant and negative correlation between the EW of the core component, EW(core), and the blueshift of either the core (the peak), the wing, or the total profile of [OIII] emission; it is fairly strong for the blueshift of the total profile in particular. However, both quantities (EW and velocity shift) generally have only weak, if any, correlations with fundamental AGN parameters such as the nuclear continuum luminosity at 5100{AA} (L_5100_), black hole mass (M_BH_), and the Eddington ratio (L/L_Edd_); these correlations include the classical Baldwin effect of EW(core), an inverse Baldwin effect of EW(wing), and the relationship between velocity shifts and L/L_Edd_. Our findings suggest that both the large object-to-object variation in the strength of [OIII] emission and the blueshift-EW(core) connection are not governed primarily by fundamental AGN parameters such as L_5100_, M_BH_, and L/L_Edd_. We propose that the interstellar medium conditions of the host galaxies play a major role instead in the diversity of the [OIII] properties in active galaxies. This suggests that the use of [OIII]{lambda}5007 luminosity as a proxy of AGN luminosity does not depend strongly on the above-mentioned fundamental AGN parameters.
1893. The OPTX project: CLANS, CLASXS and CDF-N
ID:
ivo://CDS.VizieR/J/ApJS/179/1
Title:
The OPTX project: CLANS, CLASXS and CDF-N
Short Name:
J/ApJS/179/1
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the redshift catalogs for the X-ray sources detected in the Chandra Deep Field-North (CDF-N), the Chandra Large Area Synoptic X-ray Survey (CLASXS), and the Chandra Lockman Area North Survey (CLANS). The catalogs for the CDF-N and CLASXS fields include redshifts from previous work, while the redshifts for the CLANS field are all new. For fluxes above 10^-14^ergs/cm^2^/s (2-8keV) we have redshifts for 76% of the sources. We extend the redshift information for the full sample using photometric redshifts. The goal of the OPTX Project is to use these three surveys, which are among the most spectroscopically complete surveys to date, to analyze the effect of spectral type on the shape and evolution of the X-ray luminosity functions and to compare the optical spectral types with the X-ray spectral properties. We also present the CLANS X-ray catalog. The nine ACIS-I fields cover a solid angle of ~0.6deg^2^ and reach fluxes of 7x10^-16^ergs/cm^2^/s (0.5-2keV) and 3.5x10^-15^ergs/cm^2^/s (2-8keV). We find a total of 761 X-ray point sources. In addition, we present the optical and infrared photometric catalog for the CLANS X-ray sources, as well as updated optical and infrared photometric catalogs for the X-ray sources in the CLASXS and CDF-N fields.
1894. The PHLEK survey: oxygen & helium abundances
ID:
ivo://CDS.VizieR/J/ApJ/896/77
Title:
The PHLEK survey: oxygen & helium abundances
Short Name:
J/ApJ/896/77
Date:
11 Mar 2022
Publisher:
CDS
Description:
We present Keck NIRSPEC and Keck NIRES spectroscopy of sixteen metal-poor galaxies that have pre-existing optical observations. The near-infrared (NIR) spectroscopy specifically targets the HeI{lambda}10830{AA} emission line, due to its sensitivity to the physical conditions of the gas in HII regions. We use these NIR observations, combined with optical spectroscopy, to determine the helium abundance of sixteen galaxies across a metallicity range 12+log_10_(O/H)=7.13-8.00. This data set is combined with two other samples where metallicity and helium abundance measurements can be secured: star-forming galaxies selected from the Sloan Digital Sky Survey spectroscopic database, and existing low-metallicity systems in the literature. We calculate a linear fit to these measurements, accounting for intrinsic scatter, and report a new determination of the primordial helium number abundance, y_P_=0.0805_-0.0017_^+0.0017^, which corresponds to a primordial helium mass fraction Y_P_=0.2436_-0.0040_^+0.0039^. Using our determination of the primordial helium abundance in combination with the latest primordial deuterium measurement, (D/H)_P_x10^5^=2.527+/-0.030, we place a bound on the baryon density {Omega}_b_h^2^=0.0215_-0.0005_^+0.0005^ and the effective number of neutrino species N_eff_=2.85_-0.25_^+0.28^. These values are in 1.3{sigma} agreement with those deduced from the Planck satellite observations of the temperature fluctuations imprinted on the cosmic microwave background.
1895. Thermonuclear X-ray bursts. II. Eddington limit
ID:
ivo://CDS.VizieR/J/ApJ/747/77
Title:
Thermonuclear X-ray bursts. II. Eddington limit
Short Name:
J/ApJ/747/77
Date:
21 Oct 2021
Publisher:
CDS
Description:
Time-resolved X-ray spectroscopy of thermonuclear bursts observed from low-mass X-ray binaries offer a unique tool to measure neutron-star masses and radii. In this paper, we continue our systematic analysis of all the X-ray bursts observed with Rossi X-ray Timing Explorer from X-ray binaries. We determine the events that show clear evidence for photospheric radius expansion and measure the Eddington limits for these accreting neutron stars using the bolometric fluxes attained at the touchdown moments of each X-ray burst. We employ a Bayesian technique to investigate the degree to which the Eddington limit for each source remains constant between bursts. We find that for sources with a large number of radius expansion bursts, systematic uncertainties are at a 5%-10% level. Moreover, in six sources with only pairs of Eddington-limited bursts, the distribution of fluxes is consistent with a ~10% fractional dispersion. This indicates that the spectroscopic measurements of neutron-star masses and radii using thermonuclear X-ray bursts can reach the level of accuracy required to distinguish between different neutron-star equations of state, provided that uncertainties related to the overall flux calibration of X-ray detectors are of comparable magnitude.
1896. The RMS survey: ^13^CO observations of YSOs
ID:
ivo://CDS.VizieR/J/A+A/487/253
Title:
The RMS survey: ^13^CO observations of YSOs
Short Name:
J/A+A/487/253
Date:
21 Oct 2021
Publisher:
CDS
Description:
MSX names, positions, observational rms values and molecular line parameters obtained from Gaussian fits to all detected components made towards the RMS sample of massive young stellar object candidates located in the southern Galactic plane.
1897. The RMS survey: water masers of YSOs
ID:
ivo://CDS.VizieR/J/A+A/507/795
Title:
The RMS survey: water masers of YSOs
Short Name:
J/A+A/507/795
Date:
21 Oct 2021
Publisher:
CDS
Description:
The red MSX source (RMS) survey has identified a large sample of candidate massive young stellar objects (MYSOs) and ultra compact (UC) HII regions from a sample of ~2000 MSX and 2MASS colour selected sources. To search for H_2_O masers towards a large sample of young high mass stars and to investigate the statistical correlation of H_2_O masers with the earliest stages of massive star formation. We have used the Mopra Radio telescope to make position-switched observations towards ~500 UCHII regions and MYSOs candidates identified from the RMS survey and located between 190{deg}<l<30{deg}. These observations have a 4{sigma} sensitivity of ~1Jy and a velocity resolution of ~0.4km/s.
1898. The role of the host star's metallicity
ID:
ivo://CDS.VizieR/J/A+A/624/A94
Title:
The role of the host star's metallicity
Short Name:
J/A+A/624/A94
Date:
21 Oct 2021
Publisher:
CDS
Description:
Most of our current understanding of the planet formation mechanism is based on the planet metallicity correlation derived mostly from solar-type stars harbouring gas-giant planets. To achieve a more extensive grasp on the substellar formation process, we aim to analyse in terms of their metallicity a diverse sample of stars (in terms of mass and spectral type) covering the whole range of possible outcomes of the planet formation process (from planetesimals to brown dwarfs and low-mass binaries). Our methodology is based on the use of high-precision stellar parameters derived by our own group in previous works from high-resolution spectra by using the iron ionisation and equilibrium conditions. All values were derived in an homogeneous way, except for the M dwarfs where a methodology based on the use of pseudo equivalent widths of spectral features was used. Our results show that as the mass of the substellar companion increases the metallicity of the host star tends to lower values. The same trend is maintained when analysing stars with low-mass stellar companions and a tendency towards a wide range of host star's metallicity is found for systems with low-mass planets. We also confirm that more massive planets tend to orbit around more massive stars. The core-accretion formation mechanism for planet formation achieves its maximum efficiency for planets with masses in the range 0.2 and 2M_{Jup}_. Substellar objects with higher masses have higher probabilities of being formed as stars. Low-mass planets and planetesimals might be formed by core-accretion even around low-metallicity stars.
1899. 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.
1900. 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.