J/A+A/532/A147 HST photometry in extragalactic star clusters (Larsen+, 2011)
Resolved photometry of extragalactic young massive star clusters.
Larsen S.S., de Mink S.E., Eldridge J.J., Langer N., Bastian N.,
Seth A., Smith L.J., Brodie J., Efremov Y.N.
<Astron. Astrophys. 532, A147 (2011)>
=2011A&A...532A.147L 2011A&A...532A.147L
ADC_Keywords: Galaxies, nearby ; Associations, stellar ; Photometry, HST
Keywords: open clusters and associations: general -
galaxies: star clusters: general - galaxies: spiral -
Hertzsprung-Russell and C-M diagrams
Abstract:
We present colour-magnitude diagrams (CMDs) for a sample of seven
young massive clusters in the galaxies NGC 1313, NGC 1569, NGC 1705
and NGC 5236. The clusters have ages in the range 5-50 million years
and masses of 105-106M☉. Although crowding prevents us from
obtaining photometry in the inner regions of the clusters, we are
still able to measure up to 30-100 supergiant stars in each of the
richest clusters, along with the brighter main sequence stars. The
resulting CMDs and luminosity functions are compared with photometry
of artificially generated clusters, designed to reproduce the
photometric errors and completeness as realistically as possible. In
agreement with previous studies, our CMDs show no clear gap between
the H-burning main sequence and the He-burning supergiant stars,
contrary to predictions by common stellar isochrones. In general, the
isochrones also fail to match the observed number ratios of
red-to-blue supergiant stars, although the difficulty of separating
blue supergiants from the main sequence complicates this comparison.
In several cases we observe a large spread (1-2mag) in the
luminosities of the supergiant stars that cannot be accounted for by
observational errors. This spread can be reproduced by including an
age spread of 10-30 million years in the models. However, age spreads
cannot fully account for the observed morphology of the CMDs and other
processes, such as the evolution of interacting binary stars, may also
play a role.
Description:
These tables contain the PSF-fitting photometry in the HST/ACS filters
F435W, F555W and F814W for each cluster.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 88 7 Data for the clusters analysed in this paper
table4.dat 78 365 Photometry for NGC1569-A
table5.dat 78 449 Photometry for NGC1569-B
table6.dat 78 489 Photometry for NGC1705-1
table7.dat 78 201 Photometry for NGC1313-F3-1
table8.dat 78 122 Photometry for NGC5236-F1-1
table9.dat 78 98 Photometry for NGC5236-F1-3
table10.dat 78 100 Photometry for NGC7793-F1-1
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See also:
J/A+AS/139/393 : Young Massive Star Clusters. II. (Larsen, 1999)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Cluster Cluster name
14- 15 I2 h RAh Right ascension (J2000)
17- 18 I2 min RAm Right ascension (J2000)
20- 24 F5.2 s RAs Right ascension (J2000)
26 A1 --- DE- Declination sign (J2000)
27- 28 I2 deg DEd Declination (J2000)
30- 31 I2 arcmin DEm Declination (J2000)
33- 36 F4.1 arcsec DEs Declination (J2000)
38- 40 F3.1 Mpc Dist Cluster distance
41 A1 --- r_Dist Distance reference (1)
43- 46 F4.1 mag Vmag V magnitude of cluster
48- 51 F4.2 mag AB Absorption in B band
53- 56 F4.2 [yr] logAge Age of cluster
58- 64 E7.2 Msun Mass Estimated mass of cluster
66 A1 --- l_MTO [~] Limit flag on MTO
67- 70 F4.1 Msun MTO Main sequence turn-off mass
72- 76 F5.3 arcsec FWHM1 FWHM size of cluster in arcsec
77 A1 --- --- [/]
78- 80 F3.1 pc FWHM2 FWHM size of cluster in parsecs
82- 85 F4.2 --- eta Best fitting parameter η (2)
87- 88 I2 --- Tb [2/10] Number of the table containing the
individual photometry
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Note (1): References as follows:
a = Mendez et al. (2002AJ....124..213M 2002AJ....124..213M)
b = Thim et al. (2003ApJ...590..256T 2003ApJ...590..256T)
c = Carignan (1985ApJS...58..107C 1985ApJS...58..107C)
d = Grocholski et al. (2008ApJ...686L..79G 2008ApJ...686L..79G)
e = Tosi et al. (2001AJ....122.1271T 2001AJ....122.1271T)
Note (2): η is the parameter that determines how steeply the envelope
falls off at large radii.
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Byte-by-byte Description of file: table[4-9].dat table10.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- Seq Allframe sequential number within the cluster
7- 12 F6.2 pix Xpos X coordinate on CCD image
14- 19 F6.2 pix Ypos Y coordinate on CCD image
21- 26 F6.3 arcsec oRA Offset in right ascension relative to cluster centre
28- 33 F6.3 arcsec oDE Offset in Declination relative to cluster centre
35- 41 F7.3 mag F435W ?=99.999 F435W absolute magnitude (1)
43- 49 F7.3 mag F555W F555W absolute magnitude
51- 57 F7.3 mag F814W F814W absolute magnitude
59- 64 F6.3 mag e_F435W ?=99.999 Error on F435W magnitude (1)
66- 71 F6.3 mag e_F555W Error on F555W magnitude
73- 78 F6.3 mag e_F814W Error on F814W magnitude
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Note (1): A value of 99.999 indicates that no photometry is available in F435W
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Acknowledgements:
Soeren Larsen, s.s.larsen(at)astro-uu.nl
(End) S. Larsen [Astronomical Inst., Utrecht], P. Vannier [CDS] 28-Jun-2011