J/AJ/115/1801 VRI photometry of M87 globular clusters (Harris+ 1998)
M87, globular clusters, and galactic winds: issues in giant galaxy formation.
Harris W.E., Harris G.L.H., McLaughlin D.E.
<Astron. J. 115, 1801 (1998)>
=1998AJ....115.1801H 1998AJ....115.1801H (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Photometry, UBVRI
Keywords: galaxies: elliptical and lenticular, cD - galaxies: evolution -
galaxies: star clusters
Abstract:
We have used the high-resolution camera at the Canada-France-Hawaii
Telescope to obtain VRI photometry of the globular clusters in the
innermost 140 of the M87 halo. The results are used to discuss several
issues concerning the formation and evolution of globular cluster
systems in supergiant elliptical galaxies like M87. Our principal
results are as follows: (1) From our deep R-band photometry of the
cluster population, we find no significant change in the globular
cluster luminosity function (GCLF) with galactocentric radius, for
cluster masses M≥105M☉. This result places constraints on
current theoretical predictions of the rate of cluster evolution by
tidal shocking and evaporation, indicating that the main effects of
dynamical evolution may be felt only on lower mass clusters
(≲105M☉) that are below the faint limit of most current
observations. (2) Combining our V-I color indices with other data in
the literature, we derive the metallicity gradient and mean
metallicity of the clusters from r=9" out to r∼500" (∼0.7-35kpc).
Within the core radius rc=1' of the globular cluster system, the
metallicity distribution is uniform, but at larger radii the mean
metallicity declines steadily as Z/Z☉∼r-0.9. (3) The various
options for explaining the existence of high specific frequency
galaxies like M87 are evaluated. (4) We offer a new explanation for
the large observed SN range among the brightest cluster elliptical
galaxies (BCGs). It is suggested that these central supergiant E
galaxies formed in an exceptionally turbulent or high-density
environment which favored a very rapid initial star formation burst.
From a total sample of 30 BCGs, we derive empirical scaling relations
that relate to this hypothesis. Our analysis favors the view that BCGs
began forming at redshifts z≳5, distinctly earlier than most other
galaxies.
Objects:
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RA (2000) DE Designation(s)
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12 30 49.4 +12 23 28 M 87 = NGC 4486
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 32 80 Photometry of brightest clusters
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See also:
J/ApJS/73/671 : M87 globular clusters BVI photometry (Couture+, 1990)
J/AJ/106/493 : Globular clusters in M87 (Lee+, 1993)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 5 F5.2 mag Rmag R magnitude
7- 12 F6.2 arcsec Xpos X position (1)
14- 20 F7.2 arcsec Ypos Y position (1)
22- 25 F4.2 mag V-R ? V-R colour index
27- 30 F4.2 mag R-I ? R-I colour index
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Note (1): Fiducial directions are marked on the borders of Fig.2, with the
galaxy center at (0,0).
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History: From AJ electronic version
(End) James Marcout, Patricia Bauer [CDS] 12-Aug-1998