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17161. VLTS. Properties of O dwarf in 30 Dor
ID:
ivo://CDS.VizieR/J/A+A/601/A79
Title:
VLTS. Properties of O dwarf in 30 Dor
Short Name:
J/A+A/601/A79
Date:
21 Oct 2021
Publisher:
CDS
Description:
The VLT-FLAMES Tarantula Survey has observed hundreds of O-type stars in the 30 Doradus region of the Large Magellanic Cloud (LMC). We study the properties of 105 apparently single O-type dwarfs. To determine stellar and wind parameters, we used the IACOB-GBAT package, an automatic procedure based on a large grid of atmospheric models calculated with the FASTWIND code. In addition to classical techniques, we applied the Bayesian BONNSAI tool to estimate evolutionary masses. We provide a new calibration of effective temperature vs. spectral type for O-type dwarfs in the LMC, based on our homogeneous analysis of the largest sample of such objects to date and including all spectral subtypes. Good agreement with previous results is found, although the sampling at the earliest subtypes could be improved. Rotation rates and helium abundances are studied in an evolutionary context. We find that most of the rapid rotators (vsini higher than 300km/s) in our sample have masses below 25 MSun and intermediate rotation-corrected gravities (logg_c_ between 3.9 and 4.1). Such rapid rotators are scarce at higher gravities (i.e. younger ages) and absent at lower gravities (larger ages). This is not expected from theoretical evolutionary models, and does not appear to be due to a selection bias in our sample. We compare the estimated evolutionary and spectroscopic masses, finding a trend that the former is higher for masses below 20M_{sun}_. This can be explained as a consequence of limiting our sample to the O-type stars, and we see no compelling evidence for a systematic mass discrepancy. For most of the stars in the sample we were unable to estimate the wind-strength parameter (hence mass-loss rates) reliably, particularly for objects with luminosity lower than logL/L_{sun}_ about 5.1. Ultraviolet spectroscopy is needed to undertake a detailed investigation of the wind properties of these dwarfs.
17162. VLT Survey Telescope ATLAS
ID:
ivo://CDS.VizieR/II/350
Title:
VLT Survey Telescope ATLAS
Short Name:
II/350
Date:
21 Oct 2021
Publisher:
CDS
Description:
The VLT Survey Telescope ATLAS survey is an optical ugriz survey aiming to cover ~4700deg^2^ of the southern sky to similar depths as the Sloan Digital Sky Survey (SDSS). From reduced images and object catalogues provided by the Cambridge Astronomical Surveys Unit, we first find that the median seeing ranges from 0.8-arcsec FWHM (full width at half-maximum) in i to 1.0-arcsec in u, significantly better than the 1.2-1.5arcsec seeing for SDSS. The 5{sigma} mag limit for stellar sources is r_AB_=22.7 and in all bands these limits are at least as faint as SDSS. SDSS and ATLAS are more equivalent for galaxy photometry except in the z band where ATLAS has significantly higher throughput. We have improved the original ESO magnitude zero-points by comparing m<16 star magnitudes with the AAVSO Photometric All-Sky Survey in gri, also extrapolating into u and z, resulting in zero-points accurate to ~+/-0.02mag. We finally compare star and galaxy number counts in a 250deg^2^ area with SDSS and other count data and find good agreement. ATLAS data products can be retrieved from the ESO Science Archive, while support for survey science analyses is provided by the OmegaCAM Science Archive, operated by the Wide-Field Astronomy Unit in Edinburgh.
17163. VLT/VIMOS spectroscopy in GOODS-South field
ID:
ivo://CDS.VizieR/J/A+A/512/A12
Title:
VLT/VIMOS spectroscopy in GOODS-South field
Short Name:
J/A+A/512/A12
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the full data set of the VIsible Multi-Object Spectrograph (VIMOS) spectroscopic campaign of the ESO/GOODS program in the Chandra Deep Field South (CDFS), which complements the FORS2 ESO/GOODS spectroscopic campaign. The ESO/GOODS spectroscopic programs are aimed at reaching signal-to-noise ratios adequate to measure redshifts for galaxies with AB magnitudes in the range ~24-25 in the B and R band using VIMOS, and in the z band using FORS2.
17164. Vmag/plx relation for Hyades stars
ID:
ivo://CDS.VizieR/J/other/NewA/8.645
Title:
Vmag/plx relation for Hyades stars
Short Name:
J/other/NewA/8.6
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this paper, relation was established for Hyades stars between their apparent magnitudes and parallaxes. The precision criteria of this relation are very satisfactory. The importance of this relation was illustrated through its usages as: (1) A criterion for membership of the cluster, (2) a generating function for evaluating some parameters of the cluster.
17165. VMC DR4 - VISTA Magellanic System survey
ID:
ivo://wfau.roe.ac.uk/vmcDR4-dsa
Title:
VMC DR4 - VISTA Magellanic System survey
Date:
04 Dec 2019 13:42:27
Publisher:
WFAU, Institute for Astronomy, University of Edinburgh
Description:
The VMC survey aims to obtain YJKs band photometry across the system down to Ks=20.3 at S/N=10. This sensitivity corresponds to the bottom of the red giant branch field stellar population and allows us to determine the global spatially resolved star formation history with unprecedented quality and to construct a three-dimensional map of the system. A wide-area encompassing the D25 as well as major features delineated by the distribution of stars and HI gas, will both trace the structure of the galaxies and signatures of past and present interactions. Contemporary optical and kinematic observations of comparable sensitivity will provide the community with a superior database for future studies of the system and will give us an excellent insight as to what has happened elsewhere in the Universe.
17166. VMC DR3 - VISTA Magellanic System survey
ID:
ivo://wfau.roe.ac.uk/vmcDR3-dsa
Title:
VMC DR3 - VISTA Magellanic System survey
Short Name:
VMC DR3
Date:
04 Dec 2019 13:42:19
Publisher:
WFAU, Institute for Astronomy, University of Edinburgh
Description:
The VMC survey aims to obtain YJKs band photometry across the system down to Ks=20.3 at S/N=10. This sensitivity corresponds to the bottom of the red giant branch field stellar population and allows us to determine the global spatially resolved star formation history with unprecedented quality and to construct a three-dimensional map of the system. A wide-area encompassing the D25 as well as major features delineated by the distribution of stars and HI gas, will both trace the structure of the galaxies and signatures of past and present interactions. Contemporary optical and kinematic observations of comparable sensitivity will provide the community with a superior database for future studies of the system and will give us an excellent insight as to what has happened elsewhere in the Universe.
17167. VMC DR2 - VISTA Magellanic System survey
ID:
ivo://wfau.roe.ac.uk/vmcDR2-dsa
Title:
VMC DR2 - VISTA Magellanic System survey
Short Name:
VMC DR2
Date:
04 Dec 2019 13:42:10
Publisher:
WFAU, Institute for Astronomy, University of Edinburgh
Description:
The VMC survey aims to obtain YJKs band photometry across the system down to Ks=20.3 at S/N=10. This sensitivity corresponds to the bottom of the red giant branch field stellar population and allows us to determine the global spatially resolved star formation history with unprecedented quality and to construct a three-dimensional map of the system. A wide-area encompassing the D25 as well as major features delineated by the distribution of stars and HI gas, will both trace the structure of the galaxies and signatures of past and present interactions. Contemporary optical and kinematic observations of comparable sensitivity will provide the community with a superior database for future studies of the system and will give us an excellent insight as to what has happened elsewhere in the Universe.
17168. VMC DR1 - VISTA Magellanic System survey
ID:
ivo://wfau.roe.ac.uk/vmcDR1-dsa
Title:
VMC DR1 - VISTA Magellanic System survey
Short Name:
VMC DR1
Date:
04 Dec 2019 13:41:53
Publisher:
WFAU, Institute for Astronomy, University of Edinburgh
Description:
The VMC survey aims to obtain YJKs band photometry across the system down to Ks=20.3 at S/N=10. This sensitivity corresponds to the bottom of the red giant branch field stellar population and allows us to determine the global spatially resolved star formation history with unprecedented quality and to construct a three-dimensional map of the system. A wide-area encompassing the D25 as well as major features delineated by the distribution of stars and HI gas, will both trace the structure of the galaxies and signatures of past and present interactions. Contemporary optical and kinematic observations of comparable sensitivity will provide the community with a superior database for future studies of the system and will give us an excellent insight as to what has happened elsewhere in the Universe.
17169. VMC Survey. VII. 30 Doradus reddening map
ID:
ivo://CDS.VizieR/J/A+A/554/A33
Title:
VMC Survey. VII. 30 Doradus reddening map
Short Name:
J/A+A/554/A33
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this paper we present a detailed reddening map of the central 30 Doradus region of the Large Magellanic Cloud; for both community use and as a test of the methods used for future use on a wider area. The reddening, a measurement of dust extinction, acts as a tracer of the interstellar medium (ISM). Near-infrared (NIR) photometry of the red clump stars is used to measure reddening as their fixed luminosity and intermediate age make extinction the dominant cause of colour and magnitude variance. The star formation history derived previously from these data is used to produce an intrinsic colour to act as a zero point in converting colour to reddening values E(J-Ks) which are subsequently converted to visual extinction A_V_. Presented is a dust map for the 30 Doradus field in both A_V_ and E(J-Ks). This map samples a region of 1{deg}x1.5{deg}, containing ~1.5x10^5^ red clump stars which probe reddening up to A_V_~6mag. We compare our map with maps from the literature, including optical extinction maps and radio, mid- and far-infrared maps of atomic hydrogen and dust emission. Through estimation of column density we locate molecular clouds.
17170. VMC survey. XIV. SFR in SMC
ID:
ivo://CDS.VizieR/J/MNRAS/449/639
Title:
VMC survey. XIV. SFR in SMC
Short Name:
J/MNRAS/449/639
Date:
21 Oct 2021
Publisher:
CDS
Description:
We analyse deep images from the VISTA survey of the Magellanic Clouds in the YJKs filters, covering 14deg^2^ (10 tiles), split into 120 subregions, and comprising the main body and Wing of the Small Magellanic Cloud (SMC). We apply a colour-magnitude diagram reconstruction method that returns their best-fitting star formation rate SFR(t), age-metallicity relation (AMR), distance and mean reddening, together with 68 percent confidence intervals. The distance data can be approximated by a plane tilted in the East-West direction with a mean inclination of 39{deg}, although deviations of up to +/-3kpc suggest a distorted and warped disc. After assigning to every observed star a probability of belonging to a given age-metallicity interval, we build high-resolution population maps. These dramatically reveal the flocculent nature of the young star-forming regions and the nearly smooth features traced by older stellar generations. They document the formation of the SMC Wing at ages <0.2Gyr and the peak of star formation in the SMC Bar at ~40Myr. We clearly detect periods of enhanced star formation at 1.5 and 5Gyr. The former is possibly related to a new feature found in the AMR, which suggests ingestion of metal-poor gas at ages slightly larger than 1Gyr. The latter constitutes a major period of stellar mass formation. We confirm that the SFR(t) was moderately low at even older ages.

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