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The ACS Virgo Cluster Survey. XIII. SBF Distance Catalog and the Three-dimensional Structure of the Virgo Cluster*
Simona Mei,John P. Blakeslee,Patrick Côté,John L. Tonry,Michael J. West,Laura Ferrarese,Andrés Jordán,Eric W. Peng,André Anthony, andDavid Merritt
© 2007. The American Astronomical Society. All rights reserved. Printed in U.S.A.
The Astrophysical Journal,Volume 655,Number 1Citation Simona Meiet al 2007ApJ655 144DOI 10.1086/509598
Simona Mei
AFFILIATIONS
Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD
GEPI, Observatoire de Paris, Section de Meudon, Meudon Cedex, France
University of Paris 7 Denis Didevot, Paris Cedex 05, France
John P. Blakeslee
AFFILIATIONS
Department of Physics and Astronomy, Washington State University, Pullman, WA
Patrick Côté
AFFILIATIONS
Herzberg Institute of Astrophysics, National Research Council, Victoria, BC, Canada
John L. Tonry
AFFILIATIONS
Institute of Astronomy, University of Hawaii, Honolulu, HI
Michael J. West
AFFILIATIONS
Gemini Observatory, La Serena, Chile
Department of Physics and Astronomy, University of Hawaii, Hilo, HI
Laura Ferrarese
AFFILIATIONS
Herzberg Institute of Astrophysics, National Research Council, Victoria, BC, Canada
Andrés Jordán
AFFILIATIONS
European Southern Observatory, Garching, Germany
Eric W. Peng
AFFILIATIONS
Herzberg Institute of Astrophysics, National Research Council, Victoria, BC, Canada
André Anthony
AFFILIATIONS
Herzberg Institute of Astrophysics, National Research Council, Victoria, BC, Canada
David Merritt
AFFILIATIONS
Department of Physics, Rochester Institute of Rochester, NY 14623
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- Received2006 June 19
- Accepted2006 September 19
Abstract
The ACS Virgo Cluster Survey consists ofHST ACS imaging for 100 early-type galaxies in the Virgo Cluster, observed in the F475W (≈SDSSg) and F850LP (≈SDSSz) filters. We derive distances for 84 of these galaxies using the method of surface brightness fluctuations (SBFs), present the SBF distance catalog, and use this database to examine the three-dimensional distribution of early-type galaxies in the Virgo Cluster. The SBF distance moduli have a mean (random) measurement error of 0.07 mag (0.5 Mpc), or roughly 3 times better than previous SBF measurements for Virgo Cluster galaxies. Five galaxies lie at a distance ofd ≈ 23 Mpc and are members of the W' cloud. The remaining 79 galaxies have a narrow distribution around our adopted distance of ⟨d⟩ = 16.5 ± 0.1 (random mean error) ±1.1 Mpc (systematic). The rms distance scatter of this sample is σ(d) = 0.6 ± 0.1 Mpc, with little or no dependence on morphological type or luminosity class (i.e., 0.7 ± 0.1 and 0.5 ± 0.1 Mpc for the giants and dwarfs, respectively). The back-to-front depth of the cluster measured from our sample of early-type galaxies is 2.4 ± 0.4 Mpc (i.e., ±2 σ of the intrinsic distance distribution). The M87 (cluster A) and M49 (cluster B) subclusters are found to lie at distances of 16.7 ± 0.2 and 16.4 ± 0.2 Mpc, respectively. There may be a third subcluster associated with M86. A weak correlation between velocity and line-of-sight distance may be a faint echo of the cluster velocity distribution not having yet completely virialized. In three dimensions, Virgo's early-type galaxies appear to define a slightly triaxial distribution, with axis ratios of (1 : 0.7 : 0.5). The principal axis of the best-fit ellipsoid is inclined ~20°-40° from the line of sight, while the galaxies belonging to the W' cloud lie on an axis inclined by ~10°-15°.
Footnotes
- *
Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.
