Volume 415, Number 3, March I 2004
|Page(s)||915 - 929|
|Published online||13 February 2004|
Simulating the recent star formation history in the halo of NGC 5128*
European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching, Germany e-mail: firstname.lastname@example.org
2 INAF, Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, 35122 Padova, Italy e-mail: email@example.com
3 Departamento de Astronomía y Astrofísica, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22, Chile and Princeton University Observatory, Peyton Hall, Princeton, NJ 08544-1001, USA
Corresponding author: M. Rejkuba, firstname.lastname@example.org
Accepted: 6 November 2003
Simulated color-magnitude diagrams are used to investigate the recent star formation history in NGC 5128. The comparison of the simulations with the observed UV color-magnitude diagram for a field in the north-eastern shell, where recent star formation is present, constrains the initial mass function (IMF) and the duration of the star formation episode. The star formation burst is still on-going or at most has stopped some 2 Myr ago. The look-back time on the main sequence is set by the incompleteness of the U-band observations at , and is of the order of 50 Myr. The post main sequence phases have a look-back time up to 100 Myr, setting the maximum observable time for the star formation in this field. The comparison of the observed and simulated luminosity functions and the number of post main sequence vs. total number of stars favours models with active star formation in the last 100 Myr. The data are best fitted by an IMF with Salpeter slope (), and are also consistent with slopes in the range of . They exclude steeper IMF slopes. The mean star formation rate for a Salpeter IMF in the range of masses within the last 100 Myr is .
Key words: galaxies: elliptical and lenticular, cD / galaxies: stellar content / stars: fundamental parameters / galaxies: individual: NGC 5128
© ESO, 2004
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.