J/ApJ/679/404 Star clusters in M82 (Mayya+, 2008)
HST ACS imaging of M82: a comparison of mass and size distribution functions
of the younger nuclear and older disk clusters.
Mayya Y.D., Romano R., Rodriguez-Merino L.H., Luna A., Carrasco L.,
Rosa-Gonzalez D.
<Astrophys. J., 679, 404-419 (2008)>
=2008ApJ...679..404M 2008ApJ...679..404M
ADC_Keywords: Associations, stellar ; Photometry, HST ; Extinction
Keywords: catalogs - galaxies: individual (M82) - galaxies: star clusters
Abstract:
We present the results obtained from an objective search for stellar
clusters, both in the currently active nuclear starburst region, and
in the poststarburst disk of M82. Images obtained with the Advanced
Camera for Surveys (ACS) on board the Hubble Space Telescope (HST) in
F435W (B), F555W (V), and F814W (I) filters were used in the search
for the clusters. We detected 653 clusters, of which 393 are located
outside the central 450pc in the poststarburst disk of M82. The
luminosity function of the detected clusters shows an apparent
turnover at B=22mag (MB=-5.8), which we interpret from Monte Carlo
simulations as due to incompleteness in the detection of faint
clusters, rather than an intrinsic lognormal distribution. We derived
a photometric mass of every detected cluster from models of simple
stellar populations assuming a mean age of either 8 (nuclear clusters)
or 100 (disk clusters) million years old. The mass functions of the
disk (older) and the nuclear (younger) clusters follow power laws, the
former being marginally flatter (α=1.5±0.1) than the latter
(α=1.8±0.1). The distribution of sizes (FWHM) of clusters
brighter than the apparent turnover magnitude (mass≳2x104M☉)
can be described by a lognormal function.
Description:
The data were obtained by the Hubble Heritage Team using the ACS Wide
Field Channel in 2006 March, and released in fits format. Observations
consisted of 96 individual exposures in F435W, F555W, F814W, and F658N
filters covering a field of view of 8'x8' centered on the galaxy
nucleus, and cover the entire optical disk of the galaxy.
Objects:
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RA (2000) DE Designation(s)
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09 55 52.2 +69 40 49 M82 = NAME CIGAR GALAXY = NGC 3034
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 66 653 Photometric properties of detected star clusters
in M82
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See also:
J/AJ/121/768 : BVIJH photometry of M82 (de Grijs+, 2001)
J/ApJ/619/270 : Young super star clusters in the starburst of M82 (Melo+,
2005)
J/ApJ/667/L145 : HST Photometry of M82 region B (Smith+, 2007)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- [MRR2008] Object identification (1)
6- 10 F5.2 mag Bmag HST/ACS F435W (B band) magnitude
12- 15 F4.2 mag e_Bmag Formal SExtractor error in Bmag (2)
17- 20 F4.2 mag B-V ? The (B-V) color index
22- 25 F4.2 mag V-I The (V-I) color index
27- 30 F4.2 mag AV The V band extinction
32- 35 F4.2 mag e_AV ? Error in AV
37- 42 F6.2 mag BMAG The absolute B band magnitude
44- 47 F4.2 mag e_BMAG ? Formal SExtractor error in BMag (2)
49- 52 F4.2 [solMass] logM Log of cluster mass
54- 57 F4.2 [solMass] e_logM ? Error in logM
59- 66 A8 --- OID Other identification (3)
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Note (1): The IDs run from 1N to 265N for the nuclear clusters, followed by
1D to 393D for the disk ones (5 nuclear clusters 84N, 139N, 147N, 149N
and 258N were rejected as the error on at least one of the colors was
unreasonably high). The clusters are arranged in increasing order of B
magnitude, separately for the nuclear and disk sources.
Note (2): The systematic errors due to an improper background subtraction,
which affects a magnitude measurement, and not a color measurement,
could be as large as 0.2∼mag for sources fainter than B=21 mag.
Note (3): the first letter indicate the source catalog.
M = Melo et al. (2005, Cat. J/ApJ/619/270)
H = O'Connell & Mangano (1978ApJ...221...62O 1978ApJ...221...62O) (<[OM78] A> in Simbad);
B = Smith et al. (2006MNRAS.370..513S 2006MNRAS.370..513S) (<[SWG2006] BN-N> or
<[SWG2006] A1, F or L> in Simbad)
Only sources that can be associated uniquely with a cluster in our
list are identified.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 08-Oct-2010