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1381. Library of FOE spectra of late-type stars
ID:
ivo://CDS.VizieR/J/ApJS/123/283
Title:
Library of FOE spectra of late-type stars
Short Name:
J/ApJS/123/283
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a library of Penn State Fiber Optic Echelle (FOE) observations of a sample of field stars with spectral types F to M and luminosity classes V to I. The spectral coverage is from 3800 to 10000{AA} with a nominal resolving power of 12,000. These spectra include many of the spectral lines most widely used as optical and near-infrared indicators of chromospheric activity such as the Balmer lines (H{alpha} to H{delta}), Ca II H & K, the Mg I b triplet, Na I D_1_, D_2_, He I D_3_, and Ca II IRT lines. There are also a large number of photospheric lines, which can also be affected by chromospheric activity, and temperature-sensitive photospheric features such as TiO bands. The spectra have been compiled with the goal of providing a set of standards observed at medium resolution. We have extensively used such data for the study of active chromosphere stars by applying a spectral subtraction technique. However, the data set presented here can also be utilized in a wide variety of ways ranging from radial velocity templates to study of variable stars and stellar population synthesis. This library can also be used for spectral classification purposes and determination of atmospheric parameters (T_eff_, logg, [Fe/H]). A digital version of all the fully reduced spectra is available via ftp and the World Wide Web (WWW) in FITS format.
1382. Library of Spectra (0.5 to 2.5um) of Cool Stars
ID:
ivo://CDS.VizieR/J/A+AS/146/217
Title:
Library of Spectra (0.5 to 2.5um) of Cool Stars
Short Name:
J/A+AS/146/217
Date:
21 Oct 2021
Publisher:
CDS
Description:
The present catalogue contains 182 low resolution optical spectra, 145 medium resolution (R~1100) near-IR spectra, and 112 merged optical+near-IR spectra that range from about 510 to 2450 nm. The observed stars are luminous cool objects: the sample includes red giants, red supergiants, oxygen rich and carbon rich long period variables (asymptotic giant branch stars), as well as a few Galactic Bulge and LMC/SMC stars. The optical data were acquired on the so-called 74 inch Telescope at Mount Stromlo Observatory. The near-IR data were acquired with the Cryogenic Array Spectrometer and Imager CASPIR on the 2.3 meter Australian National University Telescope at Siding Spring Observatory. Optical and near-IR data for variable objects have been merged only when both were taken less than 15 days apart; but both spectral ranges are also provided separately. The spectra are corrected for telluric absorption. However, in regions where the transmission of the Earth atmosphere is close to zero the fluxes recovered remain highly uncertain. The flux calibration is based on a series of reference stars, for which a theoretical intrinsic energy distribution was assumed. An absolute flux calibration (to about 10% accuracy) was only achieved in exceptional cases; in the other cases, the absolute fluxes can be off their real values by an order of magnitude due to slit losses (for the programme star and/or the reference star) and to non-photometric wheather. Uncertainties in the relative values of fluxes along each spectrum are described in the paper.
1383. Library of UES spectra late-type stars
ID:
ivo://CDS.VizieR/J/A+AS/128/485
Title:
Library of UES spectra late-type stars
Short Name:
J/A+AS/128/485
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a library of Utrecht echelle spectrograph (UES) observations of a sample of F, G, K and M field dwarf stars covering the spectral range from 4800{AA} to 10600{AA} with a resolution of 55000. These spectra include some of the spectral lines most widely used as optical and near-infrared indicators of chromospheric activity such as H{beta}, MgI b triplet, NaI D{1}, D{2}, HeI D{3}, H{alpha}, and CaII IRT lines, as well as a large number of photospheric lines which can also be affected by chromospheric activity. The spectra have been compiled with the aim of providing a set of standards observed at high-resolution to be used in the application of the spectral subtraction technique to obtain the active-chromosphere contribution to these lines in chromospherically active single and binary stars. This library can also be used for spectral classification purposes. A digital version with all the spectra is available via ftp and the World Wide Web (WWW) (http://www.ucm.es/OTROS/Astrof/fgkmsl/UESfgkmsl.html) in FITS format.
1384. Li, C and O abundances of FGK stars
ID:
ivo://CDS.VizieR/J/AJ/159/90
Title:
Li, C and O abundances of FGK stars
Short Name:
J/AJ/159/90
Date:
21 Oct 2021
Publisher:
CDS
Description:
Abundances of lithium, carbon, and oxygen have been derived using spectral synthesis for a sample of 249 bright F, G, and K Northern Hemisphere dwarf stars from the high-resolution spectra acquired with the Vilnius University Echelle Spectrograph (VUES) at the Moletai Astronomical Observatory of Vilnius University. The sample stars have metallicities, effective temperatures, and ages between -0.7-0.4dex, 5000-6900K, 1-12Gyr, accordingly. We confirm a so far unexplained lithium abundance decrease at supersolar metallicities --A(Li) in our sample stars, which drop by 0.7dex in the [Fe/H] range from +0.10 to +0.55dex. Furthermore, we identified stars with similar ages, atmospheric parameters, and rotational velocities, but with significantly different lithium abundances, which suggests that additional specific evolutionary factors should be taken into account while interpreting the stellar lithium content. Nine stars with predominantly supersolar metallicities, i.e., about 12% among 78 stars with C and O abundances determined, have the C/O number ratios larger than 0.65, thus may form carbon-rich rocky planets. Ten planet-hosting stars, available in our sample, do not show a discernible difference from the stars with no planets detected regarding their lithium content.
1385. Lick AGN monitoring 2011: light curves
ID:
ivo://CDS.VizieR/J/ApJS/217/26
Title:
Lick AGN monitoring 2011: light curves
Short Name:
J/ApJS/217/26
Date:
21 Oct 2021
Publisher:
CDS
Description:
In the Spring of 2011 we carried out a 2.5 month reverberation mapping campaign using the 3m Shane telescope at Lick Observatory, monitoring 15 low-redshift Seyfert 1 galaxies. This paper describes the observations, reductions and measurements, and data products from the spectroscopic campaign. The reduced spectra were fitted with a multicomponent model in order to isolate the contributions of various continuum and emission-line components. We present light curves of broad emission lines and the active galactic nucleus (AGN) continuum, and measurements of the broad H{beta} line widths in mean and rms spectra. For the most highly variable AGNs we also measured broad H{beta} line widths and velocity centroids from the nightly spectra. In four AGNs exhibiting the highest variability amplitudes, we detect anticorrelations between broad H{beta} width and luminosity, demonstrating that the broad-line region "breathes" on short timescales of days to weeks in response to continuum variations. We also find that broad H{beta} velocity centroids can undergo substantial changes in response to continuum variations; in NGC 4593, the broad H{beta} velocity shifted by ~250km/s over a 1 month period. This reverberation-induced velocity shift effect is likely to contribute a significant source of confusion noise to binary black hole searches that use multi-epoch quasar spectroscopy to detect binary orbital motion. We also present results from simulations that examine biases that can occur in measurement of broad-line widths from rms spectra due to the contributions of continuum variations and photon-counting noise.
1386. Lick indices for FGK stars
ID:
ivo://CDS.VizieR/J/MNRAS/442/220
Title:
Lick indices for FGK stars
Short Name:
J/MNRAS/442/220
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present FEROS-Lick/SDSS, an empirical data base of Lick/SDSS spectral indices of FGK stars to be used in population synthesis projects for discriminating different stellar populations within the integrated light of galaxies and globular clusters. From about 2500 FEROS stellar spectra obtained from the European Southern Observatory Science Archive Facility, we computed line-strength indices for 1085 non-supergiant stars with atmospheric parameter estimates from the AMBRE project. Two samples of 312 dwarfs and of 83 subgiants} with solar chemical composition and no significant {alpha}-element abundance enhancement are used to compare their observational indices with the predictions of the Lick/SDSS library of synthetic indices. In general, the synthetic library reproduces very well the behaviour of observational indices as a function of temperature, but in the case of low-temperature (T_eff_<~5000K) dwarfs; low-temperature subgiants are not numerous enough to derive any conclusion. Several possible causes of the disagreement are discussed and promising theoretical improvements are presented.
1387. Lick indices for metal-rich stars
ID:
ivo://CDS.VizieR/J/ApJ/637/1102
Title:
Lick indices for metal-rich stars
Short Name:
J/ApJ/637/1102
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present empirical calibrations that provide estimates of stellar metallicity, effective temperature, and surface gravity as a function of Lick IDS indices. These calibrations have been derived from a training set of 261 stars for which (1) high-precision measurements of [Fe/H], Teff, and log(g) have been made using spectral-synthesis analysis of HIRES spectra, and (2) Lick indices have also been measured.
1388. Lick indices for 51 stars
ID:
ivo://CDS.VizieR/J/MNRAS/435/952
Title:
Lick indices for 51 stars
Short Name:
J/MNRAS/435/952
Date:
21 Oct 2021
Publisher:
CDS
Description:
A method that is widely used to analyse stellar populations in galaxies is to apply the theoretically derived responses of stellar spectra and line indices to element abundance variations, which are hereafter referred to as response functions. These are applied in a differential way, to base models, in order to generate spectra or indices with different abundance patterns. In this paper, sets of such response functions for three different stellar evolutionary stages are tested with new empirical [Mg/Fe] abundance data for the medium-resolution Isaac Newton Telescope library of empirical spectra (MILES). Recent theoretical models and observations are used to investigate the effects of [Fe/H], [Mg/H] and overall [Z/H] on spectra, via ratios of spectra for similar stars. The global effects of changes in abundance patterns are investigated empirically through direct comparisons of similar stars from MILES, highlighting the impact of abundance effects in the blue part of the spectrum, particularly for lower temperature stars. It is found that the relative behaviour of iron-sensitive line indices are generally well predicted by response functions, whereas Balmer line indices are not. Other indices tend to show large scatter about the predicted mean relations. Implications for element abundance and age studies in stellar populations are discussed and ways forward are suggested to improve the match with the behaviour of spectra and line-strength indices observed in real stars.
1389. Lick indices of EDCSN galaxies
ID:
ivo://CDS.VizieR/J/A+A/499/47
Title:
Lick indices of EDCSN galaxies
Short Name:
J/A+A/499/47
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a comprehensive analysis of the stellar population properties (age, metallicity and the alpha-element enhancement [E/Fe]) and morphologies of red-sequence galaxies in 24 clusters and groups from z~0.75 to z~0.45. The dataset, consisting of 215 spectra drawn from the ESO Distant Cluster Survey, constitutes the largest spectroscopic sample at these redshifts for which such an analysis has been conducted. Analysis reveals that the evolution of the stellar population properties of red-sequence galaxies depend on their mass: while the properties of most massive are well described by passive evolution and high-redshift formation, the less massive galaxies require a more extended star formation history. We show that these scenarios reproduce the index-sigma relations as well as the galaxy colours. The two main results of this work are (1) the evolution of the line-strength indices for the red-sequence galaxies can be reproduced if 40% of the galaxies with sigma<175km/s entered the red-sequence between z=0.75 to z=0.45, in agreement with the fraction derived in studies of the luminosity functions, and (2) the percentage of galaxies in the red-sequence with early-type morphologies (E/S0) decreases by 20% from z=0.75 to z=0.45. This can be understood if the red-sequence gets populated at later times with disc galaxies with quenched star formation. We conclude that the processes quenching star formation do not necessarily produce a simultaneous morphological transformation of the galaxies entering the red-sequence.
1390. Lick indices of M31 globular clusters
ID:
ivo://CDS.VizieR/J/AJ/143/14
Title:
Lick indices of M31 globular clusters
Short Name:
J/AJ/143/14
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present absorption line indices measured in the integrated spectra of globular clusters both from the Galaxy and from M31. Our samples include 41 Galactic globular clusters, and more than 300 clusters in M31. The conversion of instrumental equivalent widths into the Lick system is described, and zero-point uncertainties are provided. Comparison of line indices of old M31 clusters and Galactic globular clusters suggests an absence of important differences in chemical composition between the two cluster systems. In particular, CN indices in the spectra of M31 and Galactic clusters are essentially consistent with each other, in disagreement with several previous works. We reanalyze some of the previous data, and conclude that reported CN differences between M31 and Galactic clusters were mostly due to data calibration uncertainties. Our data support the conclusion that the chemical compositions of Milky Way and M31 globular clusters are not substantially different, and that there is no need to resort to enhanced nitrogen abundances to account for the optical spectra of M31 globular clusters.

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