Search

Start Over Subject spectroscopy Content Level Research
2721. Stellar abundances of neutron-capture elements
ID:
ivo://CDS.VizieR/J/A+A/552/A128
Title:
Stellar abundances of neutron-capture elements
Short Name:
J/A+A/552/A128
Date:
21 Oct 2021
Publisher:
CDS
Description:
The aim of this work is to present and discuss the observations of the iron peak (Fe, Ni) and neutron-capture element (Y, Zr, Ba, La, Ce, Nd, Sm, and Eu) abundances for 276 FGK dwarfs, located in the galactic disk with metallicity -1<[Fe/H]<+0.3. Atmospheric parameters and chemical composition of the studied stars were determined from an high resolution, high signal-to-noise echelle spectra obtained with the echelle spectrograph ELODIE at the Observatoire de Haute-Provence (France). Effective temperatures were estimated by the line depth ratio method and from the H{alpha} line-wing fitting. Surface gravities (logg) were determined by parallaxes and the ionization balance of iron. Abundance determinations were carried out using the LTE approach, taking the hyperfine structure for Eu into account, and the abundance of Ba was computed under the NLTE approximation. We are able to assign most of the stars in our sample to the substructures of the Galaxy thick disk, thin disk, or Hercules stream according to their kinematics. The classification of 27 stars is uncertain. For most of the stars in the sample, the abundances of neutron-capture elements have not been measured earlier. For all of them, we provide the chemical composition and discuss the contribution from different nucleosynthesis processes.
2722. Stellar atmospheric parameters in MILES library
ID:
ivo://CDS.VizieR/J/MNRAS/374/664
Title:
Stellar atmospheric parameters in MILES library
Short Name:
J/MNRAS/374/664
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a homogeneous set of stellar atmospheric parameters (Teff, logg, [Fe/H]) for MILES, a new spectral stellar library covering the range {lambda}{lambda}3525-7500{AA} at 2.3{AA} (FWHM) spectral resolution. The library consists of 985 stars spanning a large range in atmospheric parameters, from super-metal-rich, cool stars to hot, metal-poor stars. The spectral resolution, spectral type coverage and number of stars represent a substantial improvement over previous libraries used in population synthesis models. The atmospheric parameters that we present here are the result of a previous, extensive compilation from the literature. In order to construct a homogeneous data set of atmospheric parameters we have taken the sample of stars of Soubiran, Katz & Cayrel (1998, Cat. <J/A+AS/133/221>, which has very well determined fundamental parameters, as the standard reference system for our field stars, and have calibrated and bootstrapped the data from other papers against it. The atmospheric parameters for our cluster stars have also been revised and updated according to recent metallicity scales, colour-temperature relations and improved set of isochrones.
2723. Stellar bow shock nebulae spectroscopic obs.
ID:
ivo://CDS.VizieR/J/ApJS/251/29
Title:
Stellar bow shock nebulae spectroscopic obs.
Short Name:
J/ApJS/251/29
Date:
21 Oct 2021
Publisher:
CDS
Description:
Arcuate mid-infrared nebulae known as stellar bow shock nebulae (SBNe) have been previously hypothesized to be supported by the strong stellar winds and/or luminosity of massive early-type stars. We present an optical spectroscopic survey of 84 stars identified from mid-infrared images as candidate SBN-supporting stars. Eighty-one of 84 sources, 96%, are O or early-B spectral types. K-band luminosities for a larger sample of 289 stars at the centers of bow shock nebulae are overwhelmingly consistent with OB stars. This affirms both that SBNe are supported by massive stars and that arcuate mid-infrared nebulae are reliable indicators of the presence of a massive star. The radial velocity dispersions of these systems and detections of double-lined systems indicate that at least 27 of the 74 systems with multiple observations (>36%) are candidate multiple-star systems. This rate is consistent with observed multiplicity rates of field OB stars detected with similar radial velocity surveys and lower than, but not inconsistent with, the multiplicity rates of OB stars in clusters and associations.
2724. Stellar Content of LH 9 and 10 in the LMC
ID:
ivo://CDS.VizieR/J/AJ/103/1205
Title:
Stellar Content of LH 9 and 10 in the LMC
Short Name:
J/AJ/103/1205
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present CCD photometry and spectroscopy for stars in Lucke-Hodge 9 and 10, two adjacent OB association in the northwest corner of the LMC. Our catalog contains UBV photometry (complete to ~18mag in all three filters) for 795 stars and BV-only photometry (complete to ~19mag in both filters) for an additional 434 stars.
2725. Stellar content of Tr 14 and Tr 16
ID:
ivo://CDS.VizieR/J/AJ/105/980
Title:
Stellar content of Tr 14 and Tr 16
Short Name:
J/AJ/105/980
Date:
21 Oct 2021
Publisher:
CDS
Description:
The stellar content of the region around {eta} Car is investigated using CCD photometry and spectroscopy.
2726. Stellar kinematics for NGC 2859 and NGC 4371
ID:
ivo://CDS.VizieR/J/MNRAS/446/4039
Title:
Stellar kinematics for NGC 2859 and NGC 4371
Short Name:
J/MNRAS/446/4039
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an analysis of nine S0-Sb galaxies which have (photometric) bulges consisting of two distinct components. The outer component is a flattened, kinematically cool, disc-like structure: a 'discy pseudo-bulge'. Embedded inside is a rounder, kinematically hot spheroidal structure: a `classical bulge'. This indicates that pseudo-bulges and classical bulges are not mutually exclusive phenomena: some galaxies have both. The discy pseudo-bulges almost always consist of an exponential disc (scalelengths=125-870 pc, mean size ~440 pc) with one or more disc-related subcomponents: nuclear rings, nuclear bars, and/or spiral arms. They constitute 11-59 percent of the galaxy stellar mass (mean PB/T=0.33), with stellar masses ~7x10^9^-9x10^10^ M_{sun}_. The classical-bulge components have Sersic indices of 0.9-2.2, effective radii of 25-430 pc and stellar masses of 5x10^8^-3x10^10^ M_{sun}_; they are usually <10 percent of the galaxy's stellar mass (mean B/T=0.06). The classical bulges do show rotation, but are clearly kinematically hotter than the discy pseudo-bulges. Dynamical modelling of three systems indicates that velocity dispersions are isotropic in the classical bulges and equatorially biased in the discy pseudo-bulges. In the mass-radius and mass-stellar mass density planes, classical-bulge components follow sequences defined by ellipticals and (larger) classical bulges. Discy pseudo-bulges also fall on this sequence; they are more compact than large-scale discs of similar mass. Although some classical bulges are quite compact, they are as a class clearly distinct from nuclear star clusters in both size and mass; in at least two galaxies they coexist with nuclear clusters. Since almost all the galaxies in this study are barred, they probably also host boxy/peanut-shaped bulges (vertically thickened inner parts of bars). NGC 3368 shows isophotal evidence for such a zone just outside its discy pseudo-bulge, making it a clear case of a galaxy with all three types of 'bulge'.
2727. Stellar-mass black holes in the SDSS
ID:
ivo://CDS.VizieR/J/ApJ/596/437
Title:
Stellar-mass black holes in the SDSS
Short Name:
J/ApJ/596/437
Date:
21 Oct 2021
Publisher:
CDS
Description:
We search for nearby, isolated, accreting, "stellar-mass" (3-100M_{sun}_) black holes. Models suggest a synchrotron spectrum in visible wavelengths and some emission in X-ray wavelengths. Of 3.7 million objects in the Sloan Digital Sky Survey Early Data Release, Cat. <J/AJ/123/567>, about 150,000 objects have colors and properties consistent with such a spectrum, and 87 of these objects are X-ray sources from the ROSAT All-Sky Survey (Cat. <IX/10> and <IX/29>). Thirty-two of these have been confirmed not to be black holes using optical spectra. We give the positions and colors of these 55 black hole candidates and quantitatively rank them on their likelihood to be black holes. We discuss uncertainties in the expected number of sources and the contribution of black holes to local dark matter.
2728. Stellar mass in disk-dominated galaxies
ID:
ivo://CDS.VizieR/J/ApJ/633/844
Title:
Stellar mass in disk-dominated galaxies
Short Name:
J/ApJ/633/844
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigate the correlations among stellar mass (M*), disk scale length (R_d_), and rotation velocity at 2.2 disk scale lengths (V_2.2_) for a sample of 81 disk-dominated galaxies (disk/total>=0.9) selected from the SDSS. We measure V_2.2_ from long-slit H{alpha} rotation curves and infer M* from galaxy i-band luminosities (L_i_) and g-r colors.
2729. Stellar mass-metallicity relation. I.
ID:
ivo://CDS.VizieR/J/ApJ/856/15
Title:
Stellar mass-metallicity relation. I.
Short Name:
J/ApJ/856/15
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the stellar mass-stellar metallicity relationship (MZR) in the galaxy cluster Cl0024+1654 at z~0.4 using full-spectrum stellar population synthesis modeling of individual quiescent galaxies. The lower limit of our stellar mass range is M*=10^9.7^M_{sun}_, the lowest galaxy mass at which individual stellar metallicity has been measured beyond the local universe. We report a detection of an evolution of the stellar MZR with observed redshift at 0.037+/-0.007dex per Gyr, consistent with the predictions from hydrodynamical simulations. Additionally, we find that the evolution of the stellar MZR with observed redshift can be explained by an evolution of the stellar MZR with the formation time of galaxies, i.e., when the single stellar population (SSP)-equivalent ages of galaxies are taken into account. This behavior is consistent with stars forming out of gas that also has an MZR with a normalization that decreases with redshift. Lastly, we find that over the observed mass range, the MZR can be described by a linear function with a shallow slope ([Fe/H]{propto}(0.16+/-0.03)logM*). The slope suggests that galaxy feedback, in terms of mass-loading factor, might be mass-independent over the observed mass and redshift range.
2730. Stellar MFP for massive quiescent z<0.7 galaxies
ID:
ivo://CDS.VizieR/J/ApJ/821/101
Title:
Stellar MFP for massive quiescent z<0.7 galaxies
Short Name:
J/ApJ/821/101
Date:
21 Oct 2021
Publisher:
CDS
Description:
We examine the evolution of the relation between stellar mass surface density, velocity dispersion, and half-light radius --the stellar mass fundamental plane (MFP)-- for quiescent galaxies at z<0.6. We measure the local relation from galaxies in the Sloan Digital Sky Survey and the intermediate redshift relation from ~500 quiescent galaxies with stellar masses 10<~log(M*/M_{sun}_)<~11.5. Nearly half of the quiescent galaxies in our intermediate redshift sample are compact. After accounting for important selection and systematic effects, the velocity dispersion distribution of galaxies at intermediate redshifts is similar to that of galaxies in the local universe. Galaxies at z<0.6 appear to be smaller (<~0.1dex) than galaxies in the local sample. The orientation of the stellar MFP is independent of redshift for massive quiescent galaxies at z<0.6 and the zero-point evolves by ~0.04dex. Compact quiescent galaxies fall on the same relation as the extended objects. We confirm that compact quiescent galaxies are the tail of the size and mass distribution of the normal quiescent galaxy population.

Limit your search

more »

more »

more »

more »