J/A+A/534/A136 Halo red giants from the SEGUE survey (Martell+, 2011)
Building the Galactic halo from globular clusters: evidence from chemically
unusual red giants.
Martell S.L., Smolinski J.P., Beers T.C., Grebel E.K.
<Astron. Astrophys. 534, A136 (2011)>
=2011A&A...534A.136M 2011A&A...534A.136M
ADC_Keywords: Clusters, globular ; Stars, halo ; Stars, giant ; Abundances ;
Photometry, SDSS
Keywords: stars: abundances - Galaxy: halo - Galaxy: formation
Abstract:
We present a spectroscopic search for halo field stars that
originally formed in globular clusters. Using moderate-resolution
SDSS-III/SEGUE-2 spectra of 561 red giants with typical halo
metallicities (-1.8≤[Fe/H]≤-1.0), we identify 16 stars, 3% of the
sample, with CN and CH bandstrength behavior indicating depleted
carbon and enhanced nitrogen abundances relative to the rest of the
data set. Since globular clusters are the only environment known
in which stars form with this pattern of atypical light-element
abundances, we claim that these stars are second-generation globular
cluster stars that have been lost to the halo field via normal cluster
mass-loss processes.
Description:
Table 1 lists SDSS identifiers, astrometry and photometry, stellar
parameters and survey name for 2519 stars observed as part of the
SDSS-II/SEGUE-1 and SDSS-III/SEGUE-2 surveys. The stars in this table
were selected as red giants with halo-like metallicities
(-1.8<[Fe/H]←1.0) and reasonably clean spectra (mean S/N per pixel
between 4000 and 4100A greater than 15).
Table 3 lists SDSS identifiers, CN and CH bandstrength indices, CN
bandstrength class, absolute r magnitudes, heliocentric and
Galactocentric distances, and survey name, for the same stars as in
Table 1.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 100 2519 Photometry, stellar parameters, and survey name
for each star in the final data set from this
study and the final data set from
Martell & Grebel (2010A&A...519A..14M 2010A&A...519A..14M)
table3.dat 58 2519 Measured values for the same stars as in Table 1
--------------------------------------------------------------------------------
See also:
http://www.sdss.org : SDSS Home Page
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- --- [SDSS]
6- 24 A19 --- SDSS Unique SDSS identifier, JHHMMSS.ss+DDMMSS.s
26- 29 I4 --- Plate SDSS plug-plate number
31- 35 I5 --- MJD Modified Julian date of observation
37- 39 I3 --- Fiber Fiber number
41- 42 I2 h RAh Right ascension (J2000)
44- 45 I2 min RAm Right ascension (J2000)
47- 51 F5.2 s RAs Right ascension (J2000)
53 A1 --- DE- Declination sign (J2000)
54- 55 I2 deg DEd Declination (J2000)
57- 58 I2 arcmin DEm Declination (J2000)
60- 64 F5.2 arcsec DEs Declination (J2000)
66- 70 F5.2 mag g0 Dereddened apparent g magnitude
72- 76 F5.3 mag (g-r)0 Dereddened apparent (g-r) color index
78- 82 F5.2 [Sun] [Fe/H] Metallicity
84- 87 I4 K Teff Effective temperature
89- 92 F4.2 [cm/s2] logg Surface gravity
94- 99 A6 --- --- [SEGUE-]
100 A1 --- S [12] Survey name : SEGUE-1 or SEGUE-2
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- Plate SDSS plug-plate number
6- 10 I5 --- MJD Modified Julian date of observation
12- 14 I3 --- Fiber Fiber number
16- 21 F6.3 mag S(CN) CN bandstrength index at 3883Å (1)
23- 27 F5.3 mag S(CH) CH bandstrength index at 4320Å (2)
29- 34 A6 --- CN CN class, as "Normal" or "Strong"
36- 40 F5.2 mag rMAG Absolute r magnitude
42- 45 F4.1 kpc Dist Heliocentric distance
47- 50 F4.1 kpc rGC Galactocentric distance
52- 57 A6 --- --- [SEGUE-]
58 A1 --- S [12] Survey name : SEGUE-1 or SEGUE-2
--------------------------------------------------------------------------------
Note (1): CN bandstrength index, S(3839) (Norris et al. 1981ApJ...244..205N 1981ApJ...244..205N)
Note (2): CH bandstrength index, S(CH) (Martell et al. 2008PASP..120....7M 2008PASP..120....7M)
--------------------------------------------------------------------------------
Acknowledgements:
Sarah Martell, martell(at)ari.uni-heidelberg.de
History:
* 19-Sep-2011: Original version
* 11-Mar-2013: Complete SDSS names added in table1 (supplied by Sarah Martell)
(End) Martell [ARI/ZAH, Heidelberg], Patricia Vannier [CDS] 19-Sep-2011