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181. A spectroscopic census of A2029 members
ID:
ivo://CDS.VizieR/J/ApJ/872/192
Title:
A spectroscopic census of A2029 members
Short Name:
J/ApJ/872/192
Date:
21 Oct 2021
Publisher:
CDS
Description:
A rich spectroscopic census of members of the local massive cluster A2029 includes 1215 members of A2029 and its two infalling groups, A2033 and the Southern Infalling Group. The two infalling groups are identified in spectroscopic, X-ray, and weak-lensing maps. We identify active galactic nuclei (AGNs), star-forming galaxies, E+A galaxies, and quiescent galaxies based on the spectroscopy. The fractions of AGN and post-starburst E+A galaxies in A2029 are similar to those of other clusters. We derive the stellar mass (M_*_)-metallicity relation of A2029 based on 227 star-forming members; A2029 members within 10^9^M_{sun}_<M_*_<10^9.5^M_{sun}_ are more metal-rich than Sloan Digital Sky Survey galaxies within the same mass range. We utilize the spectroscopic index D_n_4000, a strong age indicator, to trace past and future evolution of the A2029 system. The median D_n_4000 of the members decreases as the projected clustercentric distance increases for all three subsystems. The D_n_4000-M_*_ relations of the members in A2029 and its two infalling groups differ significantly, indicating the importance of stochastic effects for understanding the evolution of cluster galaxy populations.
182. A spectroscopic survey of field RHB stars
ID:
ivo://CDS.VizieR/J/AJ/155/240
Title:
A spectroscopic survey of field RHB stars
Short Name:
J/AJ/155/240
Date:
21 Oct 2021
Publisher:
CDS
Description:
A metallicity, chemical composition, and kinematic survey has been conducted for a sample of 340 candidate field red horizontal-branch (RHB) stars. Spectra with high resolution and high signal-to-noise ratio were gathered with the McDonald Observatory 2.7 m Tull and the Hobby-Eberly Telescope echelle spectrographs, and were used to determine effective temperatures, surface gravities, microturbulent velocities, [Fe/H] metallicities, and abundance ratios [X/Fe] for seven {alpha} and Fe-group species. The derived temperatures and gravities confirm that at least half of the candidates are true RHB stars, with (average) parameters T_eff_~5000 K and log g~2.5. From the {alpha} abundances alone, the thin and thick Galactic populations are apparent in our sample. Space motions for 90% of the program stars were computed from Hipparcos and Gaia parallaxes and proper motions. Correlations between chemical compositions and Galactic kinematics clearly indicate the existence of both thin-disk and thick-disk RHB stars.
183. asPIC1.1 catalogue
ID:
ivo://CDS.VizieR/J/A+A/653/A98
Title:
asPIC1.1 catalogue
Short Name:
J/A+A/653/A98
Date:
22 Feb 2022
Publisher:
CDS
Description:
The ESA PLAnetary Transits and Oscillations of stars (PLATO) mission will search for terrestrial planets in the habitable zone of solar-like stars. Because of telemetry limitations PLATO targets need to be pre-selected. In this paper we present an all sky catalog that will be fundamental to select the best PLATO fields and the most promising target stars, derive their fundamental parameters, analyze the instrumental performances and then plan and optimize follow-up observations. This catalog also represents a valuable resource for the general definition of stellar samples optimized for the search of transiting planets. We used Gaia Data Release 2 (DR2) astrometry and photometry and 3D maps of the local interstellar medium to isolate FGK (V<=13) and M(V<=16) dwarfs and subgiant stars. We present the first public release of the all sky PLATO Input Catalog (asPIC1.1) containing a total of 2675539 stars among which 2378177 FGK dwarfs and subgiants and 297362 M dwarfs. The median distance in our sample is 428pc for FGK stars and 146 pc for M dwarfs, respectively. We derived the reddening of our targets and developed an algorithm to estimate stellar fundamental parameters (Teff, radius, mass) from astrometric and photometric measurements. We show that our overall (internal+external) uncertainties on the stellar parameters determination is ~230K (4%) for the effective temperatures, ~0.1R_{sun}_ (9%) for the stellar radii and ~0.1M_{sun}_ (11%) for the stellar mass. We release a special target list containing all known planet hosts cross-matched with our catalog.
184. Associated MgII absorbers
ID:
ivo://CDS.VizieR/J/ApJ/679/239
Title:
Associated MgII absorbers
Short Name:
J/ApJ/679/239
Date:
21 Oct 2021
Publisher:
CDS
Description:
We studied a sample of 415 associated (z_abs_~z_em_; relative velocity with respect to QSO in units of c, {beta}<0.01) MgII absorption systems with 1.0<=z_abs_<=1.86, in the spectra of SDSS DR3 QSOs, to determine the dust content and ionization state in the absorbers. We also compared these properties to those of a similarly selected sample of 809 intervening systems ({beta}>0.01), so as to understand their origin. Normalized, composite spectra were derived for absorption line measurements, for the full sample and for several subsamples, chosen on the basis of the line strengths and other absorber and QSO properties. From these, and from the equivalent widths in individual spectra, we conclude that the associated MgII absorbers have higher ionization (higher ratios of the strengths of CIV and MgII lines), than the intervening absorbers. The ionization decreases with increasing {beta}. Average extinction curves were obtained for the subsamples by comparing their geometric mean QSO spectra with those of matching (in z_em_ and i magnitude) samples of QSOs without absorption lines. There is clear evidence for SMC-like dust attenuation in these systems; the 2175{AA} absorption feature is absent. The extinction is almost twice that observed in intervening systems. We reconfirm that QSOs with nonzero FIRST radio flux are intrinsically redder than the QSOs with no detection in the FIRST survey.
185. A standard stellar library. II.
ID:
ivo://CDS.VizieR/J/A+AS/130/65
Title:
A standard stellar library. II.
Short Name:
J/A+AS/130/65
Date:
21 Oct 2021
Publisher:
CDS
Description:
A standard library of theoretical stellar spectra intended for multiple synthetic photometry applications including spectral evolutionary synthesis is presented. The grid includes M dwarf model spectra, hence complementing the first library version established in Paper I (Lejeune et al., 1997, Cat. <J/A+AS/125/229>). It covers the following wide ranges of fundamental parameters: Teff: 50,000 to 2000K, logg: 5.5 to -1.02, and [Fe/H]: +1.0 to -5.0. A correction procedure is also applied to the theoretical spectra in order to provide color-calibrated flux distributions over a large domain of effective temperatures. Empirical Teff-color calibrations are constructed between 11500K and 2000K, and semi-empirical calibrations for non-solar abundances ([Fe/H]=-3.5 to +1.0) are established. Model colors and bolometric corrections for both the original and the corrected spectra, synthesized in the UBV(RI)c(JHKLL'M) system, are given for the full range of stellar parameters. Synthetic colors: ---------------- Synthetic UBV(RI)c(JHKLM) colors have been computed from both the original and the corrected model flux distributions presented in Paper I (1997A&AS..125..229L; see catalog <J/A+AS/125/229>), as the files lcb98ori.dat and lcb98cor.dat respectively; the results are also presented in individual files lcb98xxx.ori and lcb98xxx.cor, where xxx designates the metallicity (ex: 'm15' --> [Fe/H]=-1.5). For each file, we give synthetic colors computed from energy-weighted and photon-weighted stellar fluxes. Semi-empirical calibrations: --------------------------- Empirical ([Fe/H]=0.0) and semi-empirical (-3.5<=[Fe/H]<=+1.0) Teff-colors (UBVRIJHKLM) calibrations are given in Tables 1 to 10.
186. A star catalog for the open cluster NGC 188
ID:
ivo://CDS.VizieR/J/PASP/116/1012
Title:
A star catalog for the open cluster NGC 188
Short Name:
J/PASP/116/1012
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present new BVRI broadband photometry for the old open cluster NGC 188, based on an analysis of 299 CCD images either obtained by us, donated by colleagues, or retrieved from public archives.
187. ASTEP catalog of EB* and variable stars
ID:
ivo://CDS.VizieR/J/ApJS/226/21
Title:
ASTEP catalog of EB* and variable stars
Short Name:
J/ApJS/226/21
Date:
21 Oct 2021
Publisher:
CDS
Description:
We used the large photometric database of the ASTEP program, whose primary goal was to detect exoplanets in the southern hemisphere from Antarctica, to search for eclipsing binaries (EcBs) and variable stars. 673 EcBs and 1166 variable stars were detected, including 31 previously known stars. The resulting online catalogs give the identification, the classification, the period, and the depth or semi-amplitude of each star. Data and light curves for each object are available at http://astep-vo.oca.eu/.
188. Asteroides phase curves using SLOAN MOC
ID:
ivo://CDS.VizieR/J/A+A/657/A80
Title:
Asteroides phase curves using SLOAN MOC
Short Name:
J/A+A/657/A80
Date:
22 Feb 2022
Publisher:
CDS
Description:
Large photometric surveys are producing, and will continue doing it, massive amounts of data on small bodies. Usually,these data will be sparsely obtained at arbitrary (and unknown) rotational phases. Therefore, new methods to process such data need to be developed to make the most of those large catalogs. We aim to produce a method to create phase curves of small bodies considering the uncertainties introduced not only by the nominal errors in the magnitudes, but also the effect introduced by rotational variations.We use as a benchmark the data from the SLOAN Moving Objects Catalog with the objective to construct phase curves of all small bodies in there, in the u, g, r, i, and z, filters. We will obtain from the phase curves the absolute magnitudes and set up with them the absolute colors, which are the colors of the asteroids not affected by changes in phase angle. We select objects with >3 observations taken in, at least, one filter and spanned over a minimum of 5 degrees in phase angle. We developed a method that combines Monte Carlo simulations and Bayesian inference to estimate the absolute magnitudes using the HG12 photometric system. We obtained almost 15000 phase curves, about 12000 including all five filters. The absolute magnitudes and absolute colors are compatible with previously published data, supporting our method.Conclusions. The method we developed is fully automatic and well suited to be run on large amounts of data. Moreover, it includes the nominal uncertainties in the magnitudes and the whole distribution of possible rotational states of the objects producing, possibly,less precise values, i.e., larger uncertainties, but more accurate, i.e., closer to the real value. To the best of our knowledge, this work is the first to include the effect of rotational variations in such a way.
189. Astrometric catalog around ultracool dwarfs
ID:
ivo://CDS.VizieR/J/A+A/565/A21
Title:
Astrometric catalog around ultracool dwarfs
Short Name:
J/A+A/565/A21
Date:
21 Oct 2021
Publisher:
CDS
Description:
We describe the astrometric reduction of images obtained with the FORS2/VLT camera in the framework of an astrometric planet search around 20 M/L-transition dwarfs. We present the correction of systematic errors, the achieved astrometric performance, and a new astrometric catalogue containing the faint reference stars in 20 fields located close to the galactic plane. Remote reference stars are used both to determine the astrometric trajectories of the nearby planet search targets and to identify and correct systematic errors. We detected three types of systematic errors in the FORS2 astrometry: the relative motion of the camera's two CCD chips, errors that are correlated in space, and an error contribution of yet unexplained origin. The relative CCD motion has probably a thermal origin and usually is 0.001-0.010px (0.1-1mas), but sometimes amounts to 0.02-0.05px (3-6mas). This instability and space- correlated errors are detected and mitigated using reference stars. The third component of unknown origin has an amplitude of 0.03-0.14mas and is independent of the observing conditions. We find that a consecutive sequence of 32 images of a well-exposed star over 40min at 0.6arcsec seeing results in a median r.m.s. of the epoch residuals of 0.126mas. Overall, the epoch residuals are distributed according to a normal law with a {chi}^2^ value near unity. We compiled a catalogue of 12000 stars with I-band magnitudes of 16-22 located in 20 fields, each covering 2x2'. It contains I-band magnitudes, ICRF positions with 40-70mas precision, and relative proper motions and absolute trigonometric parallaxes with a precision of 0.1mas/yr and 0.1mas at the bright end, respectively. This work shows that an astrometric accuracy of ~100 micro-arcseconds over two years can be achieved with a large optical telescope in a survey covering several targets and varying observing conditions.
190. Astrometric orbit of DENIS-P J082303.1-49120
ID:
ivo://CDS.VizieR/J/A+A/556/A133
Title:
Astrometric orbit of DENIS-P J082303.1-49120
Short Name:
J/A+A/556/A133
Date:
21 Oct 2021
Publisher:
CDS
Description:
Little is known about the existence of extrasolar planets around ultracool dwarfs. Furthermore, binary stars with Sun-like primaries and very low-mass binaries composed of ultracool dwarfs show differences in the distributions of mass ratio and orbital separation that can be indicative of distinct formation mechanisms. Using FORS2/VLT optical imaging for high precision astrometry we are searching for planets and substellar objects around ultracool dwarfs to investigate their multiplicity properties for very low companion masses. Here we report astrometric measurements with an accuracy of one tenth of a milli-arcsecond over two years that reveal orbital motion of the L1.5 dwarf DENIS-P J082303.1-491201 (having 7.5+/-1% of the Sun's mass) caused by a companion with a mass of 28+/-2 Jupiter masses that revolves about its host on an eccentric orbit in 246.4+/-1.4days. This new system is nearby at 20.77+/-0.08pc and has the smallest mass ratio (0.36+/-0.02) of known very low-mass binaries with a characterised orbit. With this discovery we demonstrate 100 micro-arcsecond astrometry over an arc-minute field and over several years that is sufficient to discover sub-Jupiter mass planets around ultracool dwarfs. We also show that the achieved parallax accuracy of <0.4% makes it possible to remove distance as a dominant source of uncertainty in the modelling of ultracool dwarfs.