Volume 375, Number 2, August IV 2001
|Page(s)||359 - 365|
|Section||Cosmology (including clusters of galaxies)|
|Published online||15 August 2001|
WFPC2 observations of two dwarf spheroidal galaxies in the M 81 group*
Special Astrophysical Observatory, Russian Academy of Sciences, N. Arkhyz, KChR, 369167, Russia
2 Isaac Newton Institute, SAO Branch Chile
3 Kitt Peak National Observatory, National Optical Astronomy Observatories, PO Box 26732, Tucson, AZ 85726, USA
4 Departamento de Fisica, Grupo de Astronomia, Universidad de Concepcion, Casilla 160-C, Concepcion, Chile
5 Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
6 Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195, USA
7 UCO/Lick Observatory, University of California at Santa Cruz, Santa Cruz, CA 95064, USA
8 Astronomical Observatory of Kiev University, 04053, Observatorna 3, Kiev, Ukraine
9 Astronomy Department, Wesleyan University, Middletown, CT 06459, USA
10 Department of Astronomy, University of Michigan, 830 Dennison Building, Ann Arbor, MI 48109, USA
Corresponding author: I. D. Karachentsev, email@example.com
Accepted: 17 May 2001
We have obtained HST WFPC2 and ground-based images of two low surface brightness dwarf spheroidal galaxies in the M 81 group, FM1 and KKH57. Their colour-magnitude diagrams show red giant branches with tips at and , respectively. The derived true distance moduli, and , agree well with the mean distance modulus of the M 81 group, . Absolute V magnitudes of the galaxies (-11.46 and -10.85), their colours ( and 0.80), and central surface brightnesses ( = 24.8 and 24.4 mag/) are in the range of other dSph companions of M 81, M 31, and Milky Way. With two new objects the maximum projected radius of the dwarf spheroidal subsystem around M 81 is 380 kpc.
Key words: galaxies: dwarf / galaxies: stellar content / galaxies: distances and redshifts / galaxies: individual: M 81 group: FM1 and KKH57
Based on observations made with the NASA/ESA Hubble Space Telescope. The Space Telescope Science Institute is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS 5-26555. Based in part on observations obtained with the Apache Point Observatory 3.5-meter telescope, which is owned and operated by the Astrophysical Research Consortium.
© ESO, 2001
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.