J/ApJ/700/103 Ages of star clusters in M33 (Park+, 2009)
Ages of M33 star clusters based on the Hubble space Telescope/WFPC2 photometry.
Park W.-K., Park H.S., Lee M.G.
<Astrophys. J., 700, 103-113 (2009)>
=2009ApJ...700..103P 2009ApJ...700..103P
ADC_Keywords: Associations, stellar ; Galaxies, nearby ; Cross identifications
Keywords: galaxies: individual (M33) - galaxies: photometry -
galaxies: star clusters
Abstract:
We present a result of age estimation for star clusters in M33. We
obtain color-magnitude diagrams (CMDs) of resolved stars in 242 star
clusters from the Hubble Space Telescope/Wide Field Planetary Camera 2
images. We estimate ages of 100 star clusters among these, by fitting
the Padova theoretical isochrones to the observational CMDs. Age
distribution of the star clusters shows a dominant peak at log(t)∼7.8.
Majority of star clusters are younger than log(t)=9.0, while 10 star
clusters are older than log(t)∼9.0. There is only one cluster younger
than log(t)=7 in this study, which is in contrast with the results
based on the integrated photometry of star clusters in the previous
studies. Radial distribution of the cluster ages shows that young- to
intermediate-age clusters are found from the center to the outer
region, while old clusters are distributed farther from the M33
center. We briefly discuss the implication of the results with regard
to the formation of the M33 cluster system.
Description:
We used HST/WFPC2 images of M33 fields available in the HST archive.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 77 100 Ages of M33 star clusters
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See also:
B/hst : HST Archived Exposures Catalog (STScI, 2007)
J/ApJ/699/839 : Newly identified star clusters in M33. II. (San+, 2009)
J/AJ/134/447 : Catalog of star cluster candidates in M33 (Sarajedini+, 2007)
J/AJ/134/2168 : BVI photometry of M33 star clusters (Park+, 2007)
J/A+A/444/831 : New star clusters in M33 (Bedin+, 2005)
J/A+A/366/498 : VI photometry of M33 star clusters (Chandar+, 2001)
J/ApJS/122/431 : Star Clusters in M33 (Chandar+, 1999)
J/AcA/48/455 : Globular Clusters in M31 and M33 (Mochejska+, 1998)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- [PL2007] Cluster ID number from Park & Lee 2007, Cat.
J/AJ/134/2168
5- 7 F3.1 [yr] log(t) Log of estimated age
8 A1 --- u_log(t) [:] Uncertainty flag on log(t) (1)
10- 12 F3.1 [yr] E_log(t) Upper error of log(t)
14- 16 F3.1 [yr] e_log(t) Lower error of log(t)
18- 22 F5.3 --- Z Metallicity Z used during isochrone fitting
24- 27 F4.2 mag E(B-V) The reddening used during isochrone fitting
29- 32 F4.2 mag e_E(B-V) Error in E(B-V)
34- 36 F3.1 arcsec Radius Member star selection radius
38- 77 A40 --- OName Cross-identification with previous catalogs (2)
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Note (1): Indicates the young age limit of the star cluster.
Note (2): Other identifications from references below:
B- = Bedin et al. (2005, Cat. J/A+A/444/831; <[BPB2005] NNN> for Simbad);
CBF- = Chandar et al. (1999, Cat. J/ApJS/122/431; 2001, Cat. J/A+A/366/498,
in Simbad);
CS- = Christian & Schommer (1982ApJS...49..405C 1982ApJS...49..405C; <[CS82] ANN> in Simbad);
MKKSS- = Mochejska et al. (1998, Cat. J/AcA/48/455; <[MKK98] M 33 NN> in
Simbad);
MD- = Melnick & D'Odorico (1978A&AS...34..249M 1978A&AS...34..249M; <[MD78] NN> in Simbad);
SBGHS- = Sarajedini et al. (2007AJ....133..290S 2007AJ....133..290S; <[SBG2007] NN> in Simbad);
SM- = Sarajedini & Mancone (2007, Cat. J/AJ/134/447; <[SM2007] NNN> in
Simbad) except numbers greater than 451 which are from:
http://www.mancone.net/m33_catalog/
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 12-Jul-2011