J/ApJ/777/82 Ks luminosity of AGB stars in LMC clusters (Ko+, 2013)
Ks-band luminosity evolution of the asymptotic giant branch population based
on star clusters in the Large Magellanic Cloud.
Ko Y., Lee M.G., Lim S.
<Astrophys. J., 777, 82 (2013)>
=2013ApJ...777...82K 2013ApJ...777...82K
ADC_Keywords: Magellanic Clouds ; Photometry, infrared ; Stars, giant
Keywords: galaxies: evolution; galaxies: star clusters: general;
infrared: stars; Magellanic Clouds; stars: AGB and post-AGB
Abstract:
We present a study of Ks-band luminosity evolution of the asymptotic
giant branch (AGB) population in simple stellar systems using star
clusters in the Large Magellanic Cloud (LMC). We determine physical
parameters of LMC star clusters including center coordinates, radii,
and foreground reddenings. Ages of 83 star clusters are derived from
isochrone fitting with the Padova models, and those of 19 star
clusters are taken from the literature. The AGB stars in 102 star
clusters with log(age)=7.3-9.5 are selected using near-infrared
color-magnitude diagrams based on Two Micron All Sky Survey
photometry. Then we obtain the Ks-band luminosity fraction of AGB
stars in these star clusters as a function of ages. The Ks-band
luminosity fraction of AGB stars increases, on average, as age
increases from log(age)∼8.0, reaching a maximum at log(age)∼8.5, and
it decreases thereafter. There is a large scatter in the AGB
luminosity fraction for given ages, which is mainly due to stochastic
effects. We discuss this result in comparison with five simple stellar
population models. The maximum Ks-band AGB luminosity fraction for
bright clusters is reproduced by the models that expect the value of
0.7-0.8 at log(age)=8.5-8.7. We discuss the implication of our results
with regard to the study of size and mass evolution of galaxies.
Description:
We redetermined the centers and radii of LMC star clusters based on
the center coordinates presented in Bica et al. (2008, J/MNRAS/389/678).
We used optical (UBVI) and near-infrared (JHKs) point source catalogs
of the LMC. The Magellanic Clouds Photometric Survey (MCPS; Zaritsky
et al. 1997AJ....114.1002Z 1997AJ....114.1002Z) obtained drift-scan images using 1m Las
Campanas Swope Telescope and Great Circle Camera in UBVI. In order to
distinguish AGB stars from other populations, we used a near-infrared
point source catalog from the Two Micron All Sky Survey (2MASS;
Skrutskie et al. 2006, VII/233). We also used 2MASS Atlas Images to
estimate the integrated luminosity of the star clusters, retrieving
the Ks-band images of our sample clusters using 2MASS interactive
image service.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 76 102 Physical parameters of 102 star clusters in the LMC
table2.dat 107 102 The properties of AGB populations in 102 star
clusters in the LMC
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See also:
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
VII/183 : The Cluster System of the LMC (Kontizas+ 1990)
J/MNRAS/436/136 : Ages and masses of LMC clusters (de Grijs+, 2013)
J/MNRAS/430/676 : Massive clusters in the LMC (Baumgardt+, 2013)
J/A+A/555/A131 : Parameters of star clusters in the LMC (Palma+, 2013)
J/ApJ/761/16 : Sun IR colors from Line-Depth Ratios (Casagrande+, 2012)
J/A+A/543/A75 : Near-IR spectra of LMC globular clusters (Lyubenova+, 2012)
J/ApJ/751/122 : Ages and masses for 920 LMC clusters (Popescu+, 2012)
J/ApJ/749/124 : Spectroscopy on LMC clusters (Colucci+, 2012)
J/AJ/142/48 : LMC star clusters structural parameters (Werchan+, 2011)
J/AJ/139/878 : RGB stars in 8 LMC clusters (Sharma+, 2010)
J/A+A/517/A50 : Ages of young SMC/LMC star clusters (Glatt+, 2010)
J/MNRAS/404/1639 : MILES base models + new line index system (Vazdekis+, 2010)
J/A+A/510/A19 : K-band spectra of 6 LMC globular clusters (Lyubenova+, 2010)
J/AJ/137/4810 : LMC-SAGE AGB star candidates (Srinivasan+, 2009)
J/MNRAS/389/678 : Extended objects in Magellanic Clouds (Bica+, 2008)
J/MNRAS/386/1380 : BVRI photometry of LMC star clusters (Kumar+, 2008)
J/A+A/448/181 : IR colours of AGB and post-AGB stars (Groenewegen+, 2006)
J/AJ/128/1606 : Magellanic Clouds Photom. Survey: the LMC (Zaritsky+, 2004)
J/A+A/392/1 : Spectrophotom. of simulated Stellar Pop. (Schulz+, 2002)
J/AcA/50/337 : OGLE LMC star clusters (Pietrzynski+, 2000)
J/A+AS/141/371 : Low-mass stars evolutionary tracks (Girardi+, 2000)
J/AJ/116/723 : LMC star clusters ages and metallicity (Bica+ 1998)
J/MNRAS/272/391 : Globular clusters in the Magellanic Clouds (Ferraro+, 1995)
J/A+AS/106/275 : Theoretical isochrones (Bertelli+ 1994)
J/AJ/99/784 : IR photometry of LMC long-period variables (Hughes+ 1990)
J/ApJ/348/98 : LMC AGB stars IRAS fluxes (Reid+ 1990)
http://irsa.ipac.caltech.edu/applications/2MASS/IM/interactive.html :
Interactive 2MASS Image Service
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Name Name of star cluster
10- 11 I2 h RAh [4/6] Hour of Right ascension (J2000)
13- 14 I2 min RAm Minute of Right ascension (J2000)
16- 20 F5.2 s RAs Second of Right ascension (J2000)
22 A1 --- DE- [-] Sign of the Declination (J2000)
23- 24 I2 deg DEd [63/74] Degree of Declination (J2000)
26- 27 I2 arcmin DEm Arcminute of Declination (J2000)
29- 32 F4.1 arcsec DEs Arcsecond of Declination (J2000)
35 I1 --- r [0/1]? Reference for position (1)
37- 42 F6.2 arcsec Rad [12/156] Cluster radius
44- 47 F4.1 arcsec e_Rad [4/4.5]?=99.9 Uncertainty in Rad
50 I1 --- r_Rad [0/1]? Reference of Rad (1)
52- 55 F4.2 [yr] logAge [7.3/9.5] Log of the age
57- 60 F4.2 [yr] E_logAge [0.01/0.2] Upper error in logAge
62- 65 F4.2 [yr] e_logAge [0.01/0.8]?=9.99 Lower error in logAge
68 I1 --- r_logAge [0/5]? Reference in logAge (2)
70- 73 F4.2 mag E(B-V) [0/0.3] Foreground reddening E(B-V)
75- 76 I2 --- r_E(B-V) [0/99]? Reference of E(B-V) (3)
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Note (1): Reference as follows:
0 = This study;
1 = Bica et al. (2008, J/MNRAS/389/678).
Note (2): Reference as follows:
0 = This study;
2 = Goudfrooij et al. (2011ApJ...737....4G 2011ApJ...737....4G);
3 = Elson & Fall (1985ApJ...299..211E 1985ApJ...299..211E) and
Girardi et al. (1995A&A...298...87G 1995A&A...298...87G);
4 = Pietrzynski & Udalski (2000, J/AcA/50/337)
5 = Popescu et al. (2012, J/ApJ/751/122).
Note (3): Reference as follows:
0 = This study;
6 = Haschke et al. (2011AJ....141..158H 2011AJ....141..158H).
99 = Assumption without references.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Name Name of star cluster
10- 15 F6.3 mag Ksmag [6.18/11.82] Star cluster integrated
Ks band magnitude
17- 21 F5.3 mag e_Ksmag [0.002/0.07] Photometric error in Ksmag
23- 28 F6.2 10+4Lsun LKs [0.9/171.1] Star cluster integrated
Ks band luminosity
30- 33 F4.2 10+4Lsun E_LKs Upper error in LKs
35- 39 F5.2 10+4Lsun e_LKs Lower error in LKs
41- 42 I2 --- Nagb [1/10] Number of AGB stars in cluster
44- 47 F4.2 --- Fagb [0/3.7] Normalized number of field AGB stars
around cluster
49- 53 F5.2 10+4Lsun Lagb [0.6/31] Ks band luminosity of AGB stars
in cluster
55- 59 F5.2 10+4Lsun e_Lagb Uncertainty in Lagb
61- 65 F5.2 10+4Lsun Lagc [0/27] Ks band luminosity of AGB stars
in cluster after field subtraction
67- 71 F5.2 10+4Lsun e_Lagc [0/12] Uncertainty in Lagc
73- 77 F5.3 --- fL [0/1] Ks band luminosity fraction of AGB
stars in cluster
79- 83 F5.3 --- E_fL Upper error in fL
85- 89 F5.3 --- e_fL Lower error in fL
91- 95 F5.3 --- fLc [0/1] Ks band luminosity fraction of AGB
stars in cluster after field subtraction
97-101 F5.3 --- E_fLc Upper error in fLc
103-107 F5.3 --- e_fLc Lower error in fLc
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 07-Apr-2015