J/ApJ/794/60 SDSS RGB stars distances (Tan+, 2014)
Red giant stars from the Sloan Digital Sky Survey.
II. Distances.
Tan K., Chen Y., Carrell K., Zhao J., Zhao G.
<Astrophys. J., 794, 60 (2014)>
=2014ApJ...794...60T 2014ApJ...794...60T (SIMBAD/NED BibCode)
ADC_Keywords: Stars, giant ; Milky Way ; Stars, distances ; Photometry, SDSS ;
Abundances, [Fe/H] ; Effective temperatures ; Isochrones
Keywords: Galaxy: stellar content - stars: distances
Abstract:
We present distance determinations for a large and clean sample of red
giant branch stars selected from the ninth data release of the Sloan
Digital Sky Survey (Adelman-McCarthy et al. 2012ApJS..203...21A 2012ApJS..203...21A,
Cat. V/139). The distances are calculated based on both observational
cluster fiducials and theoretical isochrones. Distributions of
distances from the two methods are very similar with peaks at about
10 kpc and tails extending to more than 70 kpc. We find that distances
from the two methods agree well for the majority of the sample stars;
though, on average, distances based on isochrones are 10% higher than
those based on fiducials. We test the accuracy of our distance
determinations using 332 stars from 10 Galactic globular and open
clusters. The average relative deviation from the literature cluster
distances is 4% for the fiducial-based distances and 8% for the
isochrone-based distances, both of which are within the uncertainties.
We find that the effective temperature and surface gravity derived
from low-resolution spectra are not accurate enough to essentially
improve the performance of distance determinations. However, for stars
with significant extinction, effective temperature may help to better
constrain their distances to some extent. We make our sample stars and
their distances available from an online catalog. The catalog
comprises 17941 stars with reasonable distance estimations reaching to
more than 70 kpc, which is suitable for the investigation of the
formation and evolution of the Galaxy, especially the Galactic halo.
Description:
Our sample stars were selected from the SDSS DR9 database, which
includes stars obtained during the original SDSS, the Sloan Extension
for Galactic Understanding and Exploration (SEGUE; Yanny et al. 2009,
J/AJ/137/4377) in SDSS-II, and SEGUE-2 (Rockosi et al., in preparation)
in SDSS-III. First, we limited our sample to stars whose spectra have
signal-to-noise ratios (S/Ns) larger than 10. To eliminate early-type
stars, we selected stars with effective temperatures between 3000 and
10000 K. Then, stars with surface gravities less than 3.5 and (g-r)0
between 0.4 and 1.0 were selected to ensure that most of the sample
stars were RGB stars.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 146 17941 Parameters of the Sample Stars
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See also:
V/139 : The SDSS Photometric Catalog, Release 9
(Adelman-McCarthy+, 2012)
J/AJ/137/4377 : List of SEGUE plate pairs (Yanny+, 2009)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Plate SDSS plate identifier
6- 10 I5 d MJD Modified Julian Date of the observation
12- 14 I3 --- Fiber SDSS fiber identifier
16- 23 F8.4 deg RAdeg Right Ascension in decimal degrees (J2000)
25- 32 F8.4 deg DEdeg Declination in decimal degrees (J2000)
34- 38 F5.2 [-] [Fe/H] Metallicity
40- 43 F4.2 [-] e_[Fe/H] Uncertainty in [Fe/H]
45- 48 I4 K Teff Effective temperature
50- 52 I3 K e_Teff Uncertainty in Teff
54- 57 F4.2 [cm/s2] log(g) Log of the surface gravity
59- 62 F4.2 [cm/s2] e_log(g) Uncertainty in log(g)
64- 69 F6.1 km/s HRV Heliocentric radial velocity
71- 76 F6.3 mag gmag SDSS g band magnitude; extinction corrected
78- 82 F5.3 mag g-r SDSS (g-r) color; extinction corrected
84- 88 F5.3 mag e_gmag Uncertainty in gmag
90- 94 F5.3 mag e_rmag Uncertainty in the r band magnitude
96-101 F6.2 kpc Dfid Distance based on fiducials
103-107 F5.2 kpc e_Dfid Uncertainty in Dfid
109-114 F6.2 kpc Dall Distance based on isochrones; all parameters
included
116-120 F5.2 kpc e_Dall Uncertainty in Dall
122-127 F6.2 kpc D4 Distance based on isochrones (1)
129-133 F5.2 kpc e_D4 Uncertainty in D4
135-140 F6.2 kpc D3 Distance based on isochrones (2)
142-146 F5.2 kpc e_D3 Uncertainty in D3
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Note (1): With [Fe/H], (g-r)0, and Teff included.
Note (2): With only [Fe/H] and (g-r)0 included.
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History:
From electronic version of the journal
References:
Chen et al., Paper I, 2014ApJ...795...52C 2014ApJ...795...52C
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 27-Apr-2017