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First Hubble Space Telescope observations of the brightest stars in the Virgo galaxy M100 = NGC 4321As part of both the Early Release Observations from the Hubble Space Telescope (HST) and the Key Project on the Extragalactic Distance Scale, we have obtained multiwavelength BVR Wide Field/Planetary Camera-2 (WFPC2) images for the face-on Virgo cluster spiral galaxy M100 = NGC 4321. We report here preliminary results from those observations, in the form of a color-magnitude diagram for approximately 11,500 stars down to V approximately 27 mag and a luminosity function for the brightest blue stars which is found to have a slope of 0.7, in excellent agreement with previous results obtained for significantly nearer galaxies. With the increased resolution now available using WFPC2, the number of galaxies in which we can directly measure Population I stars and thereby quantify the recent evolution, as well as test stellar evolution theory, has dramatically increased by at least a factor of 100. Finally, we find that the stars are present in M100 at the colors and luminosities expected for the brightest Cepheid variables in galaxies.
Document ID
19950040554
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Freedman, Wendy L.
(Carnegie Inst. of Washington, Pasadena, CA United States)
Madore, Barry F.
(NASA Pasadena Office, Pasadena, CA United States)
Stetson, Peter B.
(Dominion Astrophysical Observatory Victoria, BC, Canada)
Hughes, Shaun M. G.
(Royal Greenwich Observatory Cambridge, United Kingdom)
Holtzman, Jon A.
(Lowell Observatory, Flagstaff, AZ United States)
Mould, Jeremy R.
(MSSO Weston, Australi, United States)
Trauger, John T.
(NASA Jet Propulsion Lab. Cal. Inst. of Tech., Pasadena, CA, United States)
Gallagher, John S., III
(Univ. of Wisconsin, Madison, WI United States)
Ballester, Gilda E.
(Univ. of Michigan, Ann Arbor, MI United States)
Burrows, Christopher J.
(Space Telescope Science Inst. Baltimore, MD, United States)
Date Acquired
August 16, 2013
Publication Date
November 1, 1994
Publication Information
Publication: Astrophysical Journal, Part 2 - Letters
Volume: 435
Issue: 1
ISSN: 0004-637X
Subject Category
Astronomy
Accession Number
95A72153
Funding Number(s)
CONTRACT_GRANT: NSF AST-91-16496
CONTRACT_GRANT: NAS5-26555
Distribution Limits
Public
Copyright
Other

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