J/ApJ/751/122 Ages and masses for 920 LMC clusters (Popescu+, 2012)
Age and mass for 920 Large Magellanic Cloud clusters derived from 100 million
Monte Carlo simulations.
Popescu B., Hanson M.M., Elmegreen B.G.
<Astrophys. J., 751, 122 (2012)>
=2012ApJ...751..122P 2012ApJ...751..122P
ADC_Keywords: Clusters, open ; Magellanic Clouds ; Photometry, UBVRI
Keywords: galaxies: clusters: general - methods: analytical -
open clusters and associations: general
Abstract:
We present new age and mass estimates for 920 stellar clusters in the
Large Magellanic Cloud (LMC) based on previously published broadband
photometry and the stellar cluster analysis package, MASSCLEANage.
Expressed in the generic fitting formula,
d2N/dMdt∝Mαtβ, the distribution of observed
clusters is described by α=-1.5 to -1.6 and β=-2.1 to -2.2.
For 288 of these clusters, ages have recently been determined based on
stellar photometric color-magnitude diagrams, allowing us to gauge the
confidence of our ages. The results look very promising, opening up
the possibility that this sample of 920 clusters, with reliable and
consistent age, mass, and photometric measures, might be used to
constrain important characteristics about the stellar cluster
population in the LMC. We also investigate a traditional age
determination method that uses a χ2 minimization routine to fit
observed cluster colors to standard infinite-mass limit simple stellar
population models. This reveals serious defects in the derived cluster
age distribution using this method. The traditional χ2
minimization method, due to the variation of U, B, V, R colors, will
always produce an overdensity of younger and older clusters, with an
underdensity of clusters in the log(age/yr)=[7.0,7.5] range. Finally,
we present a unique simulation aimed at illustrating and constraining
the fading limit in observed cluster distributions that includes the
complex effects of stochastic variations in the observed properties of
stellar clusters.
Description:
Using the MASSCLEAN package (Popescu & Hanson 2009AJ....138.1724P 2009AJ....138.1724P) we
have built a database of integrated colors and magnitudes of stellar
clusters, MASSCLEANcolors (Popescu & Hanson 2010ApJ...713L..21P 2010ApJ...713L..21P,
2010ApJ...724..296P 2010ApJ...724..296P).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 124 288 Age and mass determination for 288 LMC clusters
with CMD age
table2.dat 113 632 Age and mass determination for 632 LMC clusters
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See also:
II/236 : UBVR CCD survey of the Magellanic clouds (Massey+, 2002)
J/A+A/555/A131 : Fundamental parameters of LMC star clusters (Palma+, 2013)
J/A+A/554/A16 : Age and metallicity relation in MC clusters (Livanou+, 2013)
J/AJ/142/48 : LMC star clusters structural parameters (Werchan+, 2011)
J/A+A/517/A50 : Ages of young SMC/LMC star clusters (Glatt+, 2010)
J/MNRAS/389/678 : Extended objects in Magellanic Clouds (Bica+, 2008)
J/MNRAS/386/1380 : BVRI photometry of LMC star clusters (Kumar+, 2008)
J/AcA/50/337 : OGLE LMC star clusters (Pietrzynski+, 2000)
J/AcA/49/521 : OGLE LMC star clusters BVI photometry (Pietrzynski+, 1999)
J/AJ/117/2244 : HST color-magnitude diagrams of the LMC (Olsen, 1999)
J/AJ/116/723 : LMC star clusters ages and metallicity (Bica+ 1998)
http://www.physics.uc.edu/~popescu/massclean : MASSCLEAN package home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 17 A17 --- Name Cluster name
19- 24 F6.3 mag VMag Integrated absolute V band magnitude (G1)
26- 30 F5.3 mag e_VMag Uncertainty in VMag
32- 37 F6.3 mag U-B Integrated (U-B)0 color index (G1)
39- 43 F5.3 mag e_U-B Uncertainty in U-B
45- 50 F6.3 mag B-V Integrated (B-V)0 color index (G1)
52- 56 F5.3 mag e_B-V Uncertainty in B-V
58- 63 F6.3 mag V-R Integrated (V-R)0 color index (G1)
65- 69 F5.3 mag e_V-R Uncertainty in V-R
71- 75 F5.2 [yr] Age1 Log of Hunter et al. 2003AJ....126.1836H 2003AJ....126.1836H age
77- 80 F4.2 [yr] Age2 Log of Glatt et al. 2010, Cat. J/A+A/517/A50,
CMD age
82- 85 F4.2 [yr] e_Age2 Uncertainty in G10Age
87- 91 F5.3 mag E(B-V) Glatt et al. 2010, Cat. J/A+A/517/A50, E(B-V)
CMD color excess
93- 96 F4.2 [yr] Age Log of MASSCLEAN derived age
98-101 F4.2 [yr] E_Age Upper uncertainty in Age
103-106 F4.2 [yr] e_Age Lower uncertainty in Age
108-112 I5 Msun Mass MASSCLEAN derived mass
114-118 I5 Msun E_Mass Upper uncertainty in Mass
120-124 I5 Msun e_Mass Lower uncertainty in Mass
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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- 17 A17 --- Name Cluster name
23- 28 F6.3 mag VMag Integrated absolute V band magnitude (G1)
30- 34 F5.3 mag e_VMag Uncertainty in VMag
36- 41 F6.3 mag U-B Integrated (U-B)0 color index (G1)
43- 47 F5.3 mag e_U-B Uncertainty in U-B
49- 54 F6.3 mag B-V Integrated (B-V)0 color index (G1)
56- 60 F5.3 mag e_B-V Uncertainty in B-V
62- 67 F6.3 mag V-R Integrated (V-R)0 color index (G1)
69- 73 F5.3 mag e_V-R Uncertainty in V-R
75- 79 F5.2 [yr] Age1 Log of Hunter et al. 2003AJ....126.1836H 2003AJ....126.1836H age
81- 84 F4.2 [yr] Age Log of MASSCLEAN derived age
86- 89 F4.2 [yr] E_Age Upper uncertainty in Age
91- 94 F4.2 [yr] e_Age Lower uncertainty in Age
96-101 I6 Msun Mass MASSCLEAN derived mass
103-107 I5 Msun E_Mass Upper uncertainty in Mass
109-113 I5 Msun e_Mass Lower uncertainty in Mass
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Global notes:
Note (G1): From Hunter et al. 2003AJ....126.1836H 2003AJ....126.1836H
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 16-Jan-2014