- ID:
- ivo://CDS.VizieR/J/ApJS/238/29
- Title:
- IGRINS spectral library
- Short Name:
- J/ApJS/238/29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a library of high-resolution (R~45000) and high signal-to-noise ratio (S/N>=200) near-infrared spectra for stars of a wide range of spectral types and luminosity classes. The spectra were obtained with the Immersion GRating INfrared Spectrograph covering the full range of the H (1.496-1.780{mu}m) and K (2.080-2.460{mu}m) atmospheric windows. The targets were primarily selected for being MK standard stars covering a wide range of effective temperatures and surface gravities, with metallicities close to the solar value. Currently, the library includes flux-calibrated and telluric-absorption-corrected spectra of 84 stars, with prospects for expansion to provide denser coverage of the parametric space. Throughout the H and K atmospheric windows, we identified spectral lines that are sensitive to Teff or logg and defined corresponding spectral indices. We also provide their equivalent widths (EWs). For those indices, we derive empirical relations between the measured EWs and the stellar atmospheric parameters. Therefore, the derived empirical equations can be used to calculate the Teff and logg of a star without requiring stellar atmospheric models.
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- ID:
- ivo://CDS.VizieR/J/ApJ/659/122
- Title:
- Improved distances to type Ia supernovae
- Short Name:
- J/ApJ/659/122
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an updated version of the multicolor light-curve shape method to measure distances to Type Ia supernovae (SNe Ia), incorporating new procedures for K-correction and extinction corrections. We also develop a simple model to disentangle intrinsic color variations and reddening by dust and expand the method to incorporate U-band light curves and to more easily accommodate prior constraints on any of the model parameters. We apply this method to 133 nearby SNe Ia, including 95 objects in the Hubble flow (cz>=2500km/s), which give an intrinsic dispersion of less than 7% in distance. The Hubble flow sample, which is of critical importance to all cosmological uses of SNe Ia, is the largest ever presented with homogeneous distances.
- ID:
- ivo://CDS.VizieR/J/ApJ/862/33
- Title:
- Improved & expanded membership catalog for NGC752
- Short Name:
- J/ApJ/862/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The nearby open cluster NGC 752 presents a rare opportunity to study stellar properties at ages >1Gyr. However, constructing a membership catalog for it is challenging; most surveys have been limited to identifying its giants and dwarf members earlier than mid-K. We supplement past membership catalogs with candidates selected with updated photometric and proper-motion criteria, generating a list of 258 members, a >50% increase over previous catalogs. Using a Bayesian framework to fit MESA Isochrones & Stellar Tracks evolutionary models to literature photometry and the Tycho-Gaia Astrometric Solution data available for 59 cluster members, we infer the age of and distance to NGC 752: 1.34+/-0.06Gyr and 438_-6_^+8^pc. We also report the results of our optical monitoring of the cluster using the Palomar Transient Factory. We obtain rotation periods for 12 K and M cluster members, the first periods measured for such low-mass stars with a well-constrained age >1Gyr. We compare these new periods to data from the younger clusters Praesepe and NGC 6811, and to a theoretical model for angular momentum loss, to examine stellar spin-down for low-mass stars over their first 1.3Gyr. While on average NGC 752 stars are rotating more slowly than their younger counterparts, the difference is not significant. Finally, we use our spectroscopic observations to measure H{alpha} for cluster stars, finding that members earlier than ~M2 are magnetically inactive, as expected at this age. Forthcoming Gaia data should solidify and extend the membership of NGC 752 to lower masses, thereby increasing its importance for studies of low-mass stars.
- ID:
- ivo://CDS.VizieR/J/A+A/523/A17
- Title:
- Individual stars in Fornax dSph center
- Short Name:
- J/A+A/523/A17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- For the first time we show the detailed, late-stage, chemical evolution history of a small nearby dwarf spheroidal galaxy in the Local Group. We present the results of a high-resolution (R~20000, {lambda}=5340-5620; 6120-6701) FLAMES/GIRAFFE abundance study at ESO/VLT of 81 photometrically selected, red giant branch stars in the central 25' of the Fornax dwarf spheroidal galaxy. We also carried out a detailed comparison of the effects of recent developments in abundance analysis (e.g., spherical models vs. plane-parallel) and the automation that is required to efficiently deal with such large data sets. We present abundances of alpha-elements (Mg, Si, Ca, and Ti), iron-peak elements (Fe, Ni, and Cr), and heavy elements (Y, Ba, La, Nd, and Eu).
- ID:
- ivo://CDS.VizieR/J/ApJS/152/251
- Title:
- Indo-US library of coude feed stellar spectra
- Short Name:
- J/ApJS/152/251
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained spectra for 1273 stars using the 0.9m coude feed telescope at Kitt Peak National Observatory. This telescope feeds the coude spectrograph of the 2.1m telescope. The spectra have been obtained with the No.5 camera of the coude spectrograph and a Loral 3Kx1K CCD. Two gratings have been used to provide spectral coverage from 3460 to 9464{AA}, at a resolution of ~1{AA} FWHM and at an original dispersion of 0.44{AA}/pix. For 885 stars we have complete spectra over the entire 3460 to 9464{AA} wavelength region (neglecting small gaps of less than 50{AA}), and partial spectral coverage for the remaining stars. The 1273 stars have been selected to provide broad coverage of the atmospheric parameters T_eff_, logg, and [Fe/H], as well as spectral type. The goal of the project is to provide a comprehensive library of stellar spectra for use in the automated classification of stellar and galaxy spectra and in galaxy population synthesis. In this paper we discuss the characteristics of the spectral library, viz., details of the observations, data reduction procedures, and selection of stars. We also present a few illustrations of the quality and information available in the spectra. The first version of the complete spectral library is now publicly available from the National Optical Astronomy Observatory (NOAO) via ftp and http, at http://www.noao.edu/cflib .
- ID:
- ivo://CDS.VizieR/J/AJ/153/35
- Title:
- Infrared spectroscopy of symbiotic stars. XI.
- Short Name:
- J/AJ/153/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Employing new infrared radial velocities, we have computed spectroscopic orbits of the cool giants in four southern S-type symbiotic systems. The orbits for two of the systems, Hen 3-461 and Hen 3-828, have been determined for the first time, while orbits of the other two, SY Mus and AR Pav, have previously been determined. For the latter two systems, we compare our results with those in the literature. The low mass of the secondary of SY Mus suggests that it has gone through a common envelope phase. Hen 3-461 has an orbital period of 2271 days, one of the longest currently known for S-type symbiotic systems. That period is very different from the orbital period proposed previously from its photometric variations. The other three binaries have periods between 600 and 700 day, values that are typical for S-type symbiotic orbits. Basic properties of the M giant components and the distance to each system are determined.
- ID:
- ivo://CDS.VizieR/J/ApJ/799/136
- Title:
- IN-SYNC. II. Candidate young stars in NGC 1333
- Short Name:
- J/ApJ/799/136
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The initial velocity dispersion of newborn stars is a major unconstrained aspect of star formation theory. Using near-infrared spectra obtained with the APOGEE spectrograph, we show that the velocity dispersion of young (1-2Myr) stars in NGC 1333 is 0.92+/-0.12km/s after correcting for measurement uncertainties and the effect of binaries. This velocity dispersion is consistent with the virial velocity of the region and the diffuse gas velocity dispersion, but significantly larger than the velocity dispersion of the dense, star-forming cores, which have a subvirial velocity dispersion of 0.5km/s. Since the NGC 1333 cluster is dynamically young and deeply embedded, this measurement provides a strong constraint on the initial velocity dispersion of newly formed stars. We propose that the difference in velocity dispersion between stars and dense cores may be due to the influence of a 70{mu}G magnetic field acting on the dense cores or be the signature of a cluster with initial substructure undergoing global collapse.
- ID:
- ivo://CDS.VizieR/J/ApJ/807/27
- Title:
- IN-SYNC. III. Radial velocities of IC348 stars
- Short Name:
- J/ApJ/807/27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Most field stars will have encountered the highest stellar density and hence the largest number of interactions in their birth environment. Yet the stellar dynamics during this crucial phase are poorly understood. Here we analyze the radial velocities measured for 152 out of 380 observed stars in the 2-6Myr old star cluster IC 348 as part of the SDSS-III APOGEE. The radial velocity distribution of these stars is fitted with one or two Gaussians, convolved with the measurement uncertainties including binary orbital motions. Including a second Gaussian improves the fit; the high-velocity outliers that are best fit by this second component may either (1) be contaminants from the nearby Perseus OB2 association, (2) be a halo of ejected or dispersing stars from IC 348, or (3) reflect that IC 348 has not relaxed to a Gaussian velocity distribution. We measure a velocity dispersion for IC 348 of 0.72+/-0.07km/s (or 0.64+/-0.08km/s if two Gaussians are fitted), which implies a supervirial state, unless the gas contributes more to the gravitational potential than expected. No evidence is found for a dependence of this velocity dispersion on distance from the cluster center or stellar mass. We also find that stars with lower extinction (in the front of the cloud) tend to be redshifted compared with stars with somewhat higher extinction (toward the back of the cloud). This data suggest that the stars in IC 348 are converging along the line of sight. We show that this correlation between radial velocity and extinction is unlikely to be spuriously caused by the small cluster rotation of 0.024+/-0.013km/s/arcmin or by correlations between the radial velocities of neighboring stars. This signature, if confirmed, will be the first detection of line of sight convergence in a star cluster. Possible scenarios for reconciling this convergence with IC 348's observed supervirial state include: (a) the cluster is fluctuating around a new virial equilibrium after a recent disruption due to gas expulsion or a merger event, or (b) the population we identify as IC 348 results from the chance alignment of two sub-clusters converging along the line of sight. Additional measurements of tangential and radial velocities in IC 348 will be important for clarifying the dynamics of this region and informing models of the formation and evolution of star clusters.
- ID:
- ivo://CDS.VizieR/J/A+A/565/A49
- Title:
- Integrated spectroscopy of 6 LMC clusters
- Short Name:
- J/A+A/565/A49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To increase the number of studied star clusters (SCs) of the Large Magellanic Cloud (LMC), we present flux-calibrated integrated spectra in the optical range ({lambda}=3700-6800{AA}) for six poorly studied LMC SCs of IVA type. This type corresponds to the age range between 200 and 400Myr. We also aim at creating a new template spectrum representative of this age range at the metallicity level of the LMC. Foreground reddening E(B-V) values and ages are derived by applying the template matching method that consists of comparing the line strengths and continuum distribution of the cluster spectra with those of template cluster spectra with known properties. The equivalent width (EW) of the Balmer lines and the diagnostic diagrams involving the sum of EWs of selected spectral lines were also employed as age indicators. For the first time we provide estimates of the clusters' reddenings and ages. As expected, all the clusters appear to be of nearly the same age, their mean value being (400+/-100)Myr, while the resulting mean E(B-V) values range between 0.00 and 0.10mag. The present cluster sample complements previous ones in an effort to gather a spectral library with several clusters per age bin. By averaging the reddening-corrected integrated spectra, weighted by their signal-to-noise (S/N) ratios, a new high S/N ratio template spectrum of 400Myr has been created.
- ID:
- ivo://CDS.VizieR/VII/236
- Title:
- Interacting galaxies catalogue
- Short Name:
- VII/236
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The present edition unifies two parts of Catalogue of interacting galaxies by B.A. Vorontsov-Velyaminov (1959VV....C......0V, 1970, 1977A&AS...28....1V). It contains 852 known interacting VV-systems and 1162 new objects taken from the comments on the galaxies in Morphological catalogues of galaxies by Vorotsov-Velyaminov et al. (1962, 1963, 1964, 1968, 1974, Cats. <VII/62>, <VII/100>) with numbers from VV853 to VV2014. The classification of interacting galaxies is given in accord with the suggestion s of Vorotsov-Velyaminov. The catalogue contains new information for the galaxies included taken from the NEDA-NASA/IPAC extragalactic data base.