- ID:
- ivo://CDS.VizieR/J/A+A/623/A80
- Title:
- Open clusters in APOGEE and GALAH surveys
- Short Name:
- J/A+A/623/A80
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Open clusters are ideal laboratories to investigate a variety of astrophysical topics, from the properties of the Galactic disk to stellar evolutionary models. Knowing their metallicity and possibly detailed chemical abundances is therefore important. However, the number of systems with chemical abundances determined from high resolution spectroscopy is still small. To increase the number of open clusters with radial velocities and chemical abundances determined from high resolution spectroscopy we used publicly available catalogues of surveys in combination with Gaia data. Open cluster stars have been identified in the APOGEE and GALAH spectroscopic surveys by cross-matching their latest data releases with stars for which high-probability astrometric membership has been derived in many clusters on the basis of the Gaia second data release. Radial velocities have been determined for 131 and 14 clusters from APOGEE and GALAH data, respectively. This is the first radial velocity determination from high resolution spectra for 16 systems. Iron abundances have been obtained for 90 and 14 systems from APOGEE and GALAH samples, respectively. To our knowledge 66 of these clusters (57 in APOGEE and 9 in GALAH) do not have previous determinations in the literature. For 90 and 7 clusters in the APOGEE and GALAH samples, respectively, we have also determined average abundances for Na, Mg, Al, Si, Ca, Cr, Mn, and Ni.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/523/A11
- Title:
- Open clusters towards the Galactic center
- Short Name:
- J/A+A/523/A11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the framework of the study of the Galactic metallicity gradient and its time evolution, we present new high-resolution spectroscopic observations obtained with FLAMES and the fiber link to UVES at VLT of three open clusters (OCs) located within ~7kpc from the Galactic Center (GC): NGC 6192, NGC 6404, NGC 6583. We also present new orbit determination for all OCs with Galactocentric distances (R_gc_)<=8kpc and metallicity from high-resolution spectroscopy. We have derived memberships of a group of evolved stars for each clusters, obtaining a sample of 4, 4, and 2 member stars in NGC 6192, NGC 6404, and NGC 6583, respectively. Using standard LTE analysis we derived stellar parameters and abundance ratios for the iron-peak elements Fe, Ni, Cr, and for the {alpha}-elements Al, Mg, Si, Ti, Ca. We calculated the orbits of the OCs currently located within 8kpc from the GC, and discuss their implication on the present-time radial location. The average metallicities of the three clusters are all oversolar: [Fe/H]= +0.12+/-0.04 (NGC 6192), +0.11+/-0.04 (NGC 6404), +0.37+/-0.03 (NGC 6583). They are in qualitative agreement with their galactocentric distances, being all internal OCs, and thus expected to be metal richer than the solar neighborhood. The abundance ratios of the other elements over iron [X/Fe] are consistent with solar values. The clusters we have analysed, together with other OC and Cepheid data, confirm a steep gradient in the inner disk, a signature of an evolutionary rate different than in the outer disk.
- ID:
- ivo://CDS.VizieR/J/MNRAS/421/2982
- Title:
- Optical and UV colors of Coma galaxies
- Short Name:
- J/MNRAS/421/2982
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present and analyse optical and ultraviolet (UV) colours for passive and optically-red Coma cluster galaxies for which we have spectroscopic age and element abundance estimates. Our sample of 150 objects covers a wide range in mass, from giant ellipticals down to the bright end of the dwarf-galaxy regime. Galaxies with ongoing star formation have been removed using strict H{alpha} emission-line criteria. We focus on the colours FUV-i, NUV-i, FUV-NUV, u*-g and g-i. We find that all of these colours are correlated with both luminosity and velocity dispersion at the >5{sigma} level, with FUV-i and FUV-NUV becoming bluer with increasing 'mass' while the other colours become redder. We perform a purely empirical analysis to assess what fraction of the variation in each colour can be accounted for by variations in the average stellar populations, as traced by the optical spectra.
- ID:
- ivo://CDS.VizieR/J/A+A/423/983
- Title:
- Optical constants for meteoritic nano-diamonds
- Short Name:
- J/A+A/423/983
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used different spectroscopic techniques to obtain a consistent quantitative absorption spectrum of a sample of meteoritic nano-diamonds in the wavelength range from the vacuum ultraviolet (0.12um) to the far infrared (100um). The nano-diamonds have been isolated by a chemical treatment from the Allende meteorite (Braatz et al. 2000, Meteorit. Planet. Sci., 35, 75). Electron energy loss spectroscopy (EELS) extends the optical measurements to higher energies and allows the derivation of the optical constants (n & k) by Kramers-Kronig analysis.
- ID:
- ivo://CDS.VizieR/J/ApJ/723/1542
- Title:
- Optical high-resolution spectroscopy of WTTSs
- Short Name:
- J/ApJ/723/1542
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high-resolution spectroscopic observations for a sample of 19 weak-line T Tauri stars (WTTSs). Based on these observations and data of 108 WTTSs taken from the literature, we derive lithium abundances for 127 WTTSs. Investigation of a possible relation between lithium and rotation in WTTSs shows that: (1) rapidly rotating WTTSs have comparatively lower lithium abundances than their slower rotating counterparts; (2) in the spectral-type range G0-K0, most of the WTTSs share the same Li content irrespective of their Teff; and (3) active late-type binaries do not obey the correlation between lithium abundances and rotation periods, since the tidally locked rotation of the late-type binary system leads naturally to slower lithium destruction rates.
- ID:
- ivo://CDS.VizieR/J/AJ/130/1345
- Title:
- Optical-infrared colors of CORALS QSOs
- Short Name:
- J/AJ/130/1345
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The presence of dust in quasar absorbers, such as damped Ly{alpha} (DLA) systems, may cause the background QSO to appear reddened. We investigate the extent of this potential reddening by comparing the optical-to-infrared colors of QSOs with and without intervening absorbers. Our QSO sample is based on the Complete Optical and Radio Absorption Line System (CORALS) survey of Ellison and coworkers. The CORALS data set consists of 66 radio-selected QSOs at z_em_>=2.2 with complete optical identifications. We have obtained near-simultaneous B- and K-band magnitudes for a subset of the CORALS sample and supplemented our observations with further measurements published in the literature. In total, we have B-K colors for 42 of the 66 QSOs, of which 14 have intervening DLA systems. To account for redshift-related color changes, the B-K colors are normalized using the Sloan Digital Sky Survey QSO composite.
- ID:
- ivo://CDS.VizieR/B/ocl
- Title:
- Optically visible open clusters and Candidates
- Short Name:
- B/ocl
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have compiled a new catalogue of open clusters in the Galaxy which updates the previous catalogues of Lynga (1987, Cat. VII/92) and of Mermilliod (1995, in Information and On-Line Data in Astronomy, ed. D. Egret & M. A. Albrecht (Dordrecht: Kluwer), 127) (included in the WEBDA database, http://obswww.unige.ch/webda). New objects and new data, in particular, data on kinematics (proper motions) that were not present in the old catalogues, have been included. Virtually all the clusters (2167) presently known were included, which represents an increment of about 986 objects relative to the Lynga (1987, VII/92) catalogue. The catalogue is presented in a single table containing all the important data, which makes it easy to use. In total, 99.7% of the objects have estimates of their apparent diameters, and 74.5% have distance, E(B-V) and age determinations. Concerning the data on kinematics, 54.7% have their mean proper motions listed, 25% their mean radial velocities, and 24.2% have both information simultaneously.
- ID:
- ivo://CDS.VizieR/J/ApJS/151/313
- Title:
- Optical spectra in star-forming regions
- Short Name:
- J/ApJS/151/313
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high-resolution optical spectra (at ~0.6-1.8km/s) of interstellar CN, CH, CH+, CaI, KI, and CaII absorption toward 29 lines of sight in three star-forming regions, {rho} Oph, Cep OB2, and Cep OB3. The observations and data reduction are described. The agreement between earlier measurements of the total equivalent widths and our results is quite good. However, our higher resolution spectra reveal complex structure and closely blended components in most lines of sight. The velocity component structure of each species is obtained by analyzing the spectra of the six species for a given sight line together. The tabulated column densities and Doppler parameters of individual components are determined by using the method of profile fitting. Total column densities along lines of sight are computed by summing results from profile fitting for individual components and are compared with column densities from the apparent optical depth method. A more detailed analysis of these data and their implications will be presented in a companion paper.
- ID:
- ivo://CDS.VizieR/J/AZh/83/265
- Title:
- Optical spectral variability of IRAS 20508+2011
- Short Name:
- J/AZh/83/265
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on high-resolution spectra we revealed variability of the optical spectrum of the cool star identified with the IR source IRAS 20508+2011. Over the five years of our observations, the radial velocity derived from photospheric absorption lines varied in the interval V_r_=15-30km/s. In the same time, the H(alpha) profile varied from an intense bell-shaped emission line with a small absorption to 2-peaked emission with a central absorption feature below the continuum level. At all but one epoch, the positions of the metallic photospheric lines were systematically shifted relative to the H(alpha) emission: Delta V_r_=V_r_(met)-V_r_(Halpha,emis)~-23km/s. The NaD doublet lines shown a complex profile with broad (half-width about 120km/s) emission and photospheric absorption, as well as an interstellar component. We used model atmospheres to determine the physical parameters and chemical composition of the star's atmosphere: Teff=4800K, logg=1.5, Vt=4.0km/s and metallicity [Fe/H]=-0.36. We detected overabundances of oxygen [O/Fe]=+1.79 (with the ratio [C/O]~-0.9), and alpha-process elements, as well as a deficit of heavy metals. The totality of the parameters suggests that the optical component of IRAS 20508+2011 is an "O-rich" AGB star with luminosity M_v_~-3mag that is close to its evolution transition to the post-AGB stage.
- ID:
- ivo://CDS.VizieR/J/ApJ/680/939
- Title:
- Optical spectra of 24um galaxies in COSMOS. I.
- Short Name:
- J/ApJ/680/939
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study zCOSMOS-bright optical spectra for 609 Spitzer MIPS 24um-selected galaxies with S_24um_>0.30mJy and I<22.5 (AB mag) over 1.5deg^2^ of the COSMOS field.
