Hostname: page-component-797576ffbb-42xl8 Total loading time: 0 Render date: 2023-12-09T09:38:56.289Z Has data issue: false Feature Flags: { "corePageComponentGetUserInfoFromSharedSession": true, "coreDisableEcommerce": false, "useRatesEcommerce": true } hasContentIssue false

Disentangling the Stellar Populations of Fornax Dwarf Spheroidal

Published online by Cambridge University Press:  11 July 2011

M. Cesetti*
Department of Astronomy, University of Padova, Italy Osservatorio Astronomico di Padova – INAF, Padova, Italy
E.V. Held
Osservatorio Astronomico di Padova – INAF, Padova, Italy
M. Gullieuszik
Royal Observatory of Belgium, Brussels, Belgium
L. Rizzi
Joint Astronomy Centre, Hilo, Hawaii, USA
G. Battaglia
European Southern Observatory, Garching, Germany
A. Cole
School of Mathematics and Physics, University of Tasmania, Hobart, Australia
G. Da Costa
Research School of Astronomy and Astrophysics, Australian National University, Australia
M. Mateo
Department of Astronomy, University of Michigan, Ann Arbor, MI, USA
E. Olszewski
Steward Observatory, University of Arizona, Tucson, USA
E. Tolstoy
Kapteyn Astronomical Institute, Groningen, The Netherlands
M. Walker
Institute of Astronomy, University of Cambridge, UK
Get access


We studied the stellar populations of Fornax dwarf spheroidal galaxy using HST/WFPC2 imaging of 7 galaxy fields. Our observations reach the oldest main-sequence turn-off, revealing distinct stars formation episodes and allowing us to address the evolution of this prototype dwarf spheroidal galaxy known to have experienced an extended history of star formation. From our HST data, spatial gradients in the stellar content of Fornax emerge with greater clarity. The outermost fields show only stars with ages between 7–12Gyr, while the intermediate region hosts a stellar population between 4–10Gyr, and stars younger of 2 Gyr are found in the innermost fields. A clearly visible gap in the subgiant branch points to bimodality in the main star formation episode. Our observations also indicate that the inner clump detected by Coleman et al. (2004) is characterized by the presence of young stars with age about 1.8 Gyr.

Research Article
© EAS, EDP Sciences, 2011

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)


Battaglia, G., et al., 2006, A&A, 459, 423
Coleman, M., et al., 2004, AJ, 127, 832CrossRef
Dolphin, A.E., 2009, PASP, 121, 655CrossRef
Olszewski, E.W., Mateo, M., Harris, J., Walker, M.G., Coleman, M.G. & Da Costa, G.S., 2006, AJ, 131, 912CrossRef