J/MNRAS/327/1116 VI photometry of Sombrero globular clusters (Larsen+, 2001)
Hubble Space Telescope photometry of globular clusters in the Sombrero galaxy.
Larsen S.S., Forbes D.A., Brodie J.P.
<Mon. Not. R. Astron. Soc. 327, 1116 (2001)>
=2001MNRAS.327.1116L 2001MNRAS.327.1116L
ADC_Keywords: Clusters, globular ; Photometry
Keywords: galaxies: individual: M104 (NGC 4594) - galaxies: spiral -
galaxies: star clusters
Abstract:
We explore the rich globular cluster (GC) system of the nearby Sa
galaxy M104, the "Sombrero" (NGC 4594), using archive Wide Field
Planetary Camera 2 data. The GC colour distribution is found to be
bimodal at the >99 per cent confidence level, with peaks at
(V-I)0=0.96±0.03 and 1,21±0.03. The inferred metallicities are
very similar to those of GCs in our Galaxy and M31. However, the
Sombrero reveals a much enhanced number of red (metal-rich) GCs
compared to other well-studied spirals. Because the Sombrero is
dominated by a huge bulge and only has a modest disc, we associate the
two subpopulations with the halo and bulge components, respectively.
Thus our analysis supports the view that the metal-rich GCs in spirals
are associated with the bulge rather than with the disc. The Sombrero
GCs have typical effective (half-light) radii of ∼2pc with the red
ones being ∼30 per cent smaller than the blue ones. We identify many
similarities between the GC system of the Sombrero and those of both
late-type spirals and early-type galaxies. Thus both the GC system and
the Hubble type of the Sombrero galaxy appear to be intermediate in
their nature.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 49 193 Data for clusters in the Sombrero
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See also:
VII/13 : Globular-Cluster Catalog (Arp 1965)
VII/44 : Star Clusters Associations II. Globular Clusters (Ruprecht+ 1981)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- [LFB2001] Cluster designation (1)
7- 8 I2 h RAh Right ascension (J2000.0)
10- 11 I2 min RAm Right ascension (J2000.0)
13- 17 F5.2 s RAs Right ascension (J2000.0)
19 A1 --- DE- Declination sign (J2000.0)
20- 21 I2 deg DEd Declination (J2000.0)
23- 24 I2 arcmin DEm Declination (J2000.0)
26- 29 F4.1 arcsec DEs Declination (J2000.0)
31- 35 F5.2 mag Vmag V magnitude (2)
37- 40 F4.2 mag (V-I)0 Dereddened V-I colour index (2)
42- 46 F5.2 pc Reff ?=99.99 Estimated effective (half-light)
cluster radius
47 A1 --- u_Reff [)] Uncertainty flag for objects fainter
than V=23.5
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Note (1): Prefixes C, H1 and H2 denote objects in the central, outer and inner
halo pointings, respectively.
Note (2): V and (V-I)0 have been corrected for a foreground extinction of
AV=0.17 and E(V-I)=0.086mag.
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History:
From electronic version of the journal
(End) James Marcout, Patricia Bauer [CDS] 30-Jan-2002