Volume 502, Number 2, August I 2009
|Page(s)||L9 - L12|
|Published online||02 July 2009|
Letter to the Editor
The young stellar population at the center of NGC 205
European Southern Observatory, Casilla 19001, Santiago, Chile e-mail: email@example.com
2 Universidad de Concepción, Casilla 160-C, Concepción, Chile
3 Istituto Nazionale di Astrofisica – Osservatorio Astronomico di Bologna, 40127 Bologna, Italy
Accepted: 22 June 2009
Context. NGC 205 is a peculiar dwarf elliptical galaxy hosting in its center a population of young blue stars. Their origin is still matter of debate, the central fresh star formation activity possibly being related to dynamical interactions between NGC 205 and M 31.
Aims. The star formation history in the central 30´´ (~120 pc) around the NGC 205 central nucleus is investigated in order to obtain clues to the origin of the young stellar population.
Methods. Deep HST/ACS CCD photometry is compared with theoretical isochrones and luminosity functions to characterize the stellar content of the region under study and compute the recent SF rate.
Results. Our photometry reveals a previously undetected blue plume of young stars clearly distinguishable down to . Our analysis suggests that were produced between approximately 62 Myr and 335 Myr ago in the NGC 205 inner regions, with a latest minor episode occurring ~25 Myr ago. This implies a star formation rate of ~ /yr over this period.
Conclusions. The excellent fit of the observed luminosity function of young main sequence stars obtained with a model having a constant star formation rate argues against a tidally triggered star formation activity over the last ~300 Myr. Rather, a constant SF may be consistent with NGC 205 being on its first interaction with M 31.
Key words: galaxies: evolution / galaxies: dwarf / galaxies: individual: NGC 205 dE
© ESO, 2009
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.