Program: GS-2008A-Q-49
Title: | The ABCs of BCDs: Hydra Cluster |
PI: | Ovidiu Vaduvescu |
Co-I(s): | Marshall McCall, Jose Manuel Vilchez, Henry Lee, Eduardo Unda-Sanzana |
Abstract
Recent studies of the near-infrared (NIR) properties of dwarf irregular
galaxies (dIs) and blue compact dwarfs (BCDs) observed in the field and
nearby clusters have provided improved estimates for the NIR luminosity
of old stellar populations in these galaxies (Vaduvescu et al, 2005, Vaduvescu,
Richer & McCall, 2006). Knowledge of the evolutionary status of BCDs is pivotal
to understanding the origin of other kinds of dwarfs, most especially dwarf
spheroidals (dSphs), and the nature of faint blue galaxies at higher redshifts.
Recent chemical studies of dwarfs have shown that field dIs and Virgo
BCDs appear to share a common relation between the oxygen abundance
and the luminosity in K (Vaduvescu, McCall & Richer, 2007). The correlation
between metallicity and the gas fraction appears to be the same for BCDs as
for dIs, suggesting that BCD evolution is similar to that of dIs. An incoming run
on Gemini-South is expected to bring new data for about 6 BCDs in Fornax
Cluster. Based on these results, we will be able to start tracing the evolution
of BCDs with respect to dIs in different environments, and in so doing to
pinpoint the physical parameters controlling dwarf evolution.
In the present application we propose to scrutinize the evolution of BCDs
with respect of dIs in a new environment. We propose to use GMOS on Gemini
South in Band 3 conditions in order to measure accurate oxygen abundances in
about 6-10 BCDs in Hydra cluster. This proposal has two main science objectives:
to study the chemical evolution of BCDs with respect to dIs, and to evaluate the
effect of the environment on the evolution of BCDs. An additional result of this study
will be the comparison of the chemical evolution of BCDs in three cluster enviromnets:
Virgo, Fornax and Hydra, which will make the object of a paper in progress. Masses
and gas fractions for cluster BCDs are being quantified in parallel, via NIR imaging.
Publications using this program's data
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[data]
[ADS] Searching for star-forming galaxies in the Fornax and Hydra clusters