J/MNRAS/426/1475 CaT in 903 globular clusters (Usher+, 2012)
The SLUGGS survey: calcium triplet-based spectroscopic metallicities for
over 900 globular clusters.
Usher C., Forbes D.A., Brodie J.P., Foster C., Spitler L.R., Arnold J.A.,
Romanowsky A.J., Strader J., Pota V.
<Mon. Not. R. Astron. Soc., 426, 1475-1495 (2012)>
=2012MNRAS.426.1475U 2012MNRAS.426.1475U
ADC_Keywords: Galaxies, nearby ; Clusters, globular ; Photometry, SDSS ;
Spectroscopy
Keywords: globular clusters: general - galaxies: abundances -
galaxies: star clusters: general - galaxies: stellar content
Abstract:
Although the colour distribution of globular clusters in massive
galaxies is well known to be bimodal, the spectroscopic metallicity
distribution has been measured in only a few galaxies. After
redefining the calcium triplet index-metallicity relation, we use
our relation to derive the metallicity of 903 globular clusters in 11
early-type galaxies. This is the largest sample of spectroscopic
globular cluster metallicities yet assembled. We compare these
metallicities with those derived from Lick indices finding good
agreement. In six of the eight galaxies with sufficient numbers of
high-quality spectra we find bimodality in the spectroscopic
metallicity distribution. Our results imply that most massive
early-type galaxies have bimodal metallicity as well as colour
distributions. This bimodality suggests that most massive early-type
galaxies experienced two periods of star formation.
Description:
As part of the ongoing SAGES Legacy Unifying Globulars and Galaxies
Survey (SLUGGS; Brodie et al., in preparation), we studied the GC
systems of 11 nearby (D<30Mpc) early-type galaxies. For most of the
galaxies in our sample we used Subaru Suprime-Cam gri imaging,
supplemented with other wide-field and Hubble Space Telescope imaging.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 48 11 Galaxy properties
table3.dat 89 903 Calcium triplet measurements and metallicities
(corrected version of 23-03-2016)
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See also:
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
J/MNRAS/385/361 : NGC 821 globular clusters BVRcIc photometry (Spitler+, 2008)
J/AJ/137/4956 : Globular clusters around NGC 1407 (Romanowsky+, 2009)
J/MNRAS/415/3393 : Stars and globulars in NGC4494 (Foster+, 2011)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Galaxy Galaxy name
9- 10 A2 --- Type Hubble type of galaxy
12- 15 I4 km/s Vsys Systemic velocity from Cappellari et al.
(2011, Cat. J/MNRAS/413/813)
17- 21 F5.2 mag (M-m) Distance modulus (1)
23- 26 F4.1 Mpc Dist Distance (1)
28- 32 F5.1 mag KMAG Absolute 2MASS K-band magnitude (2)
34- 37 F4.2 mag AB B-band foreground Galactic extinction from
Schlegel et al. (1998ApJ...500..525S 1998ApJ...500..525S)
39- 41 I3 --- Ngc [7/202] number of GCs with CaT measurements
43- 46 F4.2 mag g-i ?=- g-i colour split between subpopulations
from literature (3)
48 A1 --- r_g-i Reference for g-i (4)
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Note (1): distance modulus and distance from Cappellari et al. (2011,
Cat. J/MNRAS/413/813) based on surface brightness fluctuations (SBF) of
Tonry et al. (2001ApJ...546..681T 2001ApJ...546..681T).
* For NGC 4365 the SBF distance of Mei et al. (2007ApJ...655..144M 2007ApJ...655..144M) is used.
We assume that NGC 1400 and NGC 1407 are parts of the same group and use the
mean of their distance moduli.
* NGC 1400, NGC 1407 and NGC 3115 are not parts of the Cappellari et al. (2011,
Cat. J/MNRAS/413/813) study so their radial velocities were taken from NED,
while their distances are taken from Tonry et al. (2001ApJ...546..681T 2001ApJ...546..681T) with
the same -0.06mag distance modulus offset.
Note (2): from Cappellari et al. (2011, Cat. J/MNRAS/413/813) calculated from
the 2MASS (Skrutskie et al. 2006, Cat. VII/233) total K-band apparent
magnitude and the distance modulus in column (M-m), corrected for foreground
extinction.
Note (3): NGC 4365 shows evidence for colour trimodality;
see Blom, Spitler & Forbes (2012, Cat. J/MNRAS/420/37b).
NGC 7457 appears unimodal; see Hargis et al. (2011ApJ...738..113H 2011ApJ...738..113H).
Note (4): Colour split references as follows:
a = Spitler et al. (2008, Cat. J/MNRAS/385/361)
b = Pota et al. (2013, Cat. J/MNRAS/428/389)
c = this work
d = Foster et al. (Cat. J/MNRAS/415/3393)
e = Hargis et al. (2011ApJ...738..113H 2011ApJ...738..113H)
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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- 14 A14 --- Name Globular cluster name, NGCNNNN_GCNNN (1)
16- 25 F10.6 deg RAdeg Right ascension in decimal degrees (J2000)
27- 36 F10.6 deg DEdeg Declination in decimal degrees (J2000)
38- 41 F4.2 mag g-i g-i colour index
43- 46 F4.2 mag e_g-i rms uncertainty on g-i
48- 52 F5.2 mag imag i magnitude
54- 57 F4.2 mag e_imag rms uncertainty on imag
59- 63 F5.2 0.1nm CaT CaT index measurement corrected from S/N bias
65- 68 F4.2 0.1nm e_CaT Error on CaT (lower value)
70- 73 F4.2 0.1nm E_CaT Error on CaT (upper value)
75- 79 F5.2 [Sun] [Z/H] Total metallicity
81- 84 F4.2 [Sun] e_[Z/H] Error on [Z/H] (lower value)
86- 89 F4.2 [Sun] E_[Z/H] Error on [Z/H] (upper value)
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Note (1): same as in Pota et al. (2013, J/MNRAS/428/389) except for the GCs in
NGC 4494, where "NGC4494_" has been appended to the IDs from Foster et al.
(Cat. J/MNRAS/415/3393, [FSR2011] GCNNN in Simbad) and NGC3115_Star28.
For NGC 1407, NGC1407_GC370, NGC1407_GC371, NGC1407_GC372 and NGC1407_GC373
are a continuation of Pota et al. (2013, J/MNRAS/428/389) notation.
In NGC4494, the corrected version includes NGC4494_GC2 and NGC4494_GC3 which
were erroneously not included in the published version catalogue.
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History:
* 02-Aug-2013: From electronic version of the journal
* 23-Mar-2016: Corrected version of table3 (source names) from author
(End) Patricia Vannier [CDS] 09-Apr-2013