J/AJ/142/126 CN and CH in SDSS Galactic globular clusters (Smolinski+, 2011)
A survey of CN and CH variations in Galactic globular clusters from Sloan
Digital Sky Survey spectroscopy.
Smolinski J.P., Martell S.L., Beers T.C., Lee Y.S.
<Astron. J., 142, 126 (2011)>
=2011AJ....142..126S 2011AJ....142..126S
ADC_Keywords: Clusters, globular ; Photometry, SDSS ; Spectroscopy
Keywords: globular clusters: individual (M2, M3, M13, M15, M53, M71, M92,
NGC 5053) - stars: abundances - stars: evolution
Abstract:
We present a homogeneous survey of the CN and CH band strengths in
eight Galactic globular clusters observed during the course of the
Sloan Extension for Galactic Understanding and Exploration sub-survey
(SEGUE) of the Sloan Digital Sky Survey. We confirm the existence of a
bimodal CN distribution among red giant branch (RGB) stars in all of
the clusters with metallicity greater than [Fe/H]=-1.7; the lowest
metallicity cluster with an observed CN bimodality is M53, with
[Fe/H]~=-2.1. There is also some evidence for individual CN groups on
the subgiant branches of M92, M2, and M13, and on the RGBs of M92 and
NGC 5053. Finally, we quantify the correlation between overall cluster
metallicity and the slope of the CN band strength-luminosity plot as a
means of further demonstrating the level of CN enrichment in cluster
giants. Our results agree well with previous studies reported in the
literature.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 72 8 Globular cluster photometric properties
(as drawn from the literature)
table3.dat 79 589 Line indices of adopted true member stars
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See also:
VII/103 : Galactic Globular Clusters (Monella 1985)
VII/151 : Galactic Globular Clusters Structure Parameters (Webbink 1985)
J/A+A/486/437 : CN and CH line strengths in 8 Galactic GlCl (Kayser+, 2008)
J/AJ/125/197 : CN abundances of the 47 Tuc main sequence (Harbeck+, 2003)
J/ApJ/700/523 : Galactic star clusters in SDSS. II. Colors. (An+, 2009)
J/A+A/524/A44 : CN and CH line strengths in 12 globulars (Pancino+, 2010)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Cluster Cluster name
10- 17 A8 --- CName Cluster name as in table3
19- 20 I2 h RAh Right ascension (J2000)
22- 23 I2 min RAm Right ascension (J2000)
25- 29 F5.2 s RAs Right ascension (J2000)
31 A1 --- DE- Declination sign (J2000)
32- 33 I2 deg DEd Declination (J2000)
35- 36 I2 arcmin DEm Declination (J2000)
38- 41 F4.1 arcsec DEs Declination (J2000)
43- 47 F5.1 deg GLON Galactic longitude
49- 53 F5.1 deg GLAT Galactic latitude
55- 59 F5.2 mag (m-M)0 Extinction corrected distance modulus (1)
61- 65 F5.3 mag E(B-V) Interstellar reddening, from Schlegel et al.
(1998ApJ...500..525S 1998ApJ...500..525S)
66 A1 --- n_E(B-V) [c] c if E(B-V) from Grundahl et al.
(2002A&A...395..481G 2002A&A...395..481G)
68- 72 F5.2 arcmin rt Tidal radius
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Note (1): From Harris (1996AJ....112.1487H 1996AJ....112.1487H, Cat. VII/195). Note that the Harris
values have been updated from http://www.physics.mcmaster.ca/~harris/mwgc.dat.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- CName Cluster name
10- 23 A14 --- specID spSpec name (Plate-MJD-Fiber) (1)
25- 29 F5.3 mag g-r Intrinsic SDSS (g-r) color index
31- 36 F6.3 mag gmag SDSS g band magnitude
38- 42 F5.3 mag e_gmag Uncertainty in gmag
44- 49 F6.3 --- S3839 Raw S(3839) CN index (2)
51- 55 F5.3 --- e_S3839 Uncertainty in S3839
57- 62 F6.3 --- dS3839 Temperature-corrected S(3839) CN index
64- 69 F6.3 --- CH4300 CH index
71- 75 F5.3 --- e_CH4300 Uncertainty in CH4300
77- 79 A3 --- Type Luminosity class
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Note (1): spSpec name, which identifies the star on the spectral plate in
the form of spectroscopic plug-plate number (four digits), Modified
Julian Date (five digits), and fiber used (three digits).
Note (2): raw S(3839) CN index, which for AGB, RGB, and SGB stars was
calculated using the definition from Norris et al.
(1981ApJ...244..205N 1981ApJ...244..205N) and for MS stars was calculated using the
definition from Harbeck et al. (2003, Cat. J/A+A/125/197).
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 28-Nov-2012