J/ApJ/456/174 Intermediate-Mass Population in NGC 604 (Hunter+ 1996)
The intermediate stellar mass population in NGC 604 determined from Hubble
Space Telescope Images
Hunter D.A., Baum W.A., O'Neil E.J.JR., Lynds R.
<Astrophys. J. 456, 174 (1996)>
=1996ApJ...456..174H 1996ApJ...456..174H
ADC_Keywords: H II regions ; Stars, giant ; Photometry
Keywords: galaxies: individual (M33) - galaxies: photometry -
galaxies: star clusters - galaxies: stellar content - HII regions -
ISM: individual (NGC 604) - stars: luminosity function, mass function
Abstract:
We present photometry of stars in the giant H II region NGC 604 in
M33. The photometry is measured from Hubble Space Telescope images
through the F336W, F555W, and F814W broadband filters. Color-
magnitude diagrams of the stars in NGC 604 show a main sequence
detected down to an M_F555W,0 of -1 (nearly 6M☉). In addition,
there are luminous stars that are probably blue and red supergiants.
Based on the previously known presence of Wolf-Rayet stars, we take
the age of the cluster to be 3-5Myr. We measure an initial mass
function for intermediate-mass stars (6.5-18M☉) that has a
slope of -1.6±0.7. This slope is, within the uncertainties, similar
to those found for OB associations in the Milky Way and Magellanic
Clouds. The density of the luminous stars in NGC 604 is also
comparable to that of OB associations in those galaxies even though
the total number of stars is greater in NGC 604. A few subclamps have
densities that are higher by as much as a factor of 10. A comparison
with R136 in the LMC emphasizes that the formation of a large number
of massive stars does not necessarily entail a high concentration of
those stars.
Objects:
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RA (2000) DE Designation(s)
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01 34 32.8 +30 47 04 NGC 604
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 90 34484 Photometry
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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- 6 I6 --- Star *Star identification number
8- 13 F6.1 pix X X pixel coord relative to Fig. 1 in paper
15- 20 F6.1 pix Y Y pixel coord relative to Fig. 1 in paper
22- 27 F6.2 mag F336W ?=100.00 F336W magnitude
29- 34 F6.2 mag e_F336W ?=100.00 F336W magnitude uncertainty
36- 41 F6.2 mag F555W ?=100.00 F555W magnitude
43- 48 F6.2 mag e_F555W ?=100.00 F555W magnitude uncertainty
50- 55 F6.2 mag F814W ?=100.00 F814W magnitude
57- 62 F6.2 mag e_F814W ?=100.00 F814W magnitude uncertainty
64- 69 F6.2 mag F336W-F555W ?=100.00 F336W-F555W color
71- 76 F6.2 mag e_F336W-F555W ?=100.00 F336W-F555W color uncertainty
78- 83 F6.2 mag F555W-F814W ?=100.00 F555W-F814W color
85- 90 F6.2 mag e_F555W-F814W ?=100.00 F555W-F814W color uncertainty
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Note on Star: Star identification number. The first significant digit is the
chip number; the second is the stellar group number (cluster or
background); and the rest is the individual star number.
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Origin: AAS CD-ROM series, Volume 6, 1996 Lee Brotzman [ADS] 22-Apr-96
(End) [CDS] 05-Sep-1996