Program: GS-2007B-Q-53
Title: | The ABCs of BCDs |
PI: | Eduardo Unda-Sanzana |
Co-I(s): | Ovidiu Vaduvescu, Marshall McCall, Henry Lee |
Abstract
Recent studies of the near-infrared (NIR) properties of dwarf irregular
galaxies (dIs) and blue compact dwarfs (BCDs) 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 z~1.
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). Moreover, 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.
Based on these results, it has become possible to trace the evolution of
BCDs with respect to dIs, and in so doing to pinpoint the physical parameters
controlling dwarf evolution.
In the present application the authors propose to scrutinize the evolution
of BCDs with respect of dIs even further. We propose to use GMOS on Gemini
South to measure oxygen abundances in 10 BCDs in Fornax cluster. This
proposal has two main science objectives: to evaluate the chemical evolution
of "clean" 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 the Virgo and Fornax clusters. Masses and
gas fractions for cluster BCDs and a control sample of field dIs are being
quantified through 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