J/ApJS/122/431 Star Clusters in M33 (Chandar+, 1999)
Star Clusters in M33. I. Detection, Morphology, and Photometry
Chandar R., Bianchi L., Ford H. C.
<Astrophys. J. Suppl. Ser. 122, 431 (1999)>
=1999ApJS..122..431C 1999ApJS..122..431C
ADC_Keywords: Clusters, globular; Clusters, open; Galaxies, nearby;
Photometry, UBV; Photometry, ultraviolet
Mission_Name: HST
Keywords: galaxies: evolution - galaxies: individual (M33) - galaxies:
star clusters
Abstract:
In this paper we present the discovery of 60 star clusters in 20
multiband Hubble Space Telescope (HST) WFPC2 fields in M33. The fields
sample a variety of environments, from outer regions to spiral arms
and central regions, as well as a range of galactocentric distances.
The HST spatial resolution allowed us to penetrate the crowded, spiral
arm regions of M33 yielding the first unbiased, representative sample
of star clusters for this galaxy. We discuss the separation of
clusters from stellar sources, and from other extended sources such as
star-forming regions, H II regions, and supernova remnants. For the
clusters we present multiband images and discuss morphology, location,
and integrated photometry. Measured cluster colors and magnitudes are
presented. The cluster density in our sample as a function of
galactocentric distance yields an estimate of 690 total clusters in
M33.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 102 61 The M33 cluster sample
table3.dat 101 60 M33 star cluster photometry
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See also:
J/AcA/48/455 : M31 + M33 globular clusters photometry (Mochejska+, 1998)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Seq ? Cluster number (except for the nucleus)
7- 13 A7 --- Name Cluster Identification
15 I1 h RAh Right Ascension (J2000)
17- 18 I2 min RAm Right Ascension (J2000)
20- 25 F6.3 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- 37 F5.2 arcsec DEs Declination (J2000)
44- 47 F4.2 kpc GDist ? Galactocentric distance
54- 95 A42 --- Morph Morphology of cluster
100-102 A3 --- Loc Location notes (1)
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Note (1):
1 = On spiral arm
2 = Off spiral arm
1/2 = in between
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Seq Cluster number
4- 10 A7 --- Name Cluster Identification
11- 16 F6.3 mag Vmag V band magnitude within a 2.2'' radius
18- 22 F5.3 mag e_Vmag Uncertainty in the V band
23 A1 --- n_Vmag Flag on the V measurement (1)
25- 27 F3.1 arcsec Rad ? Radius of the cluster
29- 34 F6.3 mag B-V ? B-V color within Rad radii
37- 41 F5.3 mag e_B-V ? Uncertainty in B-V
43- 48 F6.3 mag U-B ? U-B color within Rad radii
51- 55 F5.3 mag e_U-B ? Uncertainty in U-B
58- 63 F6.3 mag U-V ? U-V color within Rad radii
65- 69 F5.3 mag e_U-V ? Uncertainty in U-V
72- 77 F6.3 mag FUV ? Far-Ultraviolet magnitude within Rad radii
79- 83 F5.3 mag e_FUV ? Uncertainty in the Far-UV
84 A1 --- n_FUV Flag on the Far-UV observations (2)
86-105 A20 --- Com Comments
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Note (1): Cluster PM 4-1 has severe cosmic ray contamination within the 2.2''
radius used for photometry. The cosmic ray DN were subtracted out manually,
but this leaves residual errors. Hence, the error on the V
magnitude for this cluster is larger than for the others.
Note (2): UV magnitude for this object measured in a 1.0'' radius
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History:
From ApJ electronic edition
(End) Greg Schwarz (AAS) 31-Jan-2000