AAS 206th Meeting, 29 May - 2 June 2005
Session 12 Dwarf Irregular and Starburst Galaxies
Poster, Monday, 9:20am-6:30pm, Tuesday, 10:00am-7:00pm, May 30, 2005, Ballroom A

Previous   |   Session 12   |   Next

[12.04] Spitzer/IRS spectroscopy of Blue Compact Dwarf Galaxies

Y. Wu (Cornell University), V. Charmandaris (Cornell University,University of Crete, Chercheur Associe'Obs), L. Hao, H. Spoon (Cornell University), B. Brandl (Leiden Observatory), J. Bernard-Salas, J. Houck (Cornell University)

Blue Compact Dwarfs (BCD), is a subclass of dwarf galaxies which are dominated by a recent burst of star formation, responsible for their blue optical colors. Recently,mid-IR imaging and spestroscopy of a handful such systems revealed the presence of dusty embedded sources as well as ionic line emission in their spectra consistent with a hard radiation field from massive young stars. However, the shape and strength the Polycyclic Aromatic Hydrocarbons (PAH) bands, which is a nearly ubiquitous tracer of starformation, varied substantially.

Using the unprecedented sensitivity of the Infrared Spectrograph (IRS)* on the Spitzer Space Telescope we have observed, as part of the IRS GTO program, a sample of BCDs with metallicities ranging from 1/40th to nearly solar. Based on the 5-38micron IRS spectra, as well as the 16 and 22micron peak-up images we compare the spectral slope and mid-IR luminosity of our targets with known values of typical starburst galaxies. Measuring the PAH equivalent width (EW) at 6.2micron as well as various ionic lines, we explore a number of correlations between the mid-IR colors the PAH EW and the metallicity of the galaxies. We will present preliminary results of our findings.

*The IRS was a collaborative venture between Cornell University and Ball Aerospace Corporation funded by NASA through the Jet Propulsion Laboratory and the Ames Research Center.

Previous   |   Session 12   |   Next

Bulletin of the American Astronomical Society, 37 #2
© 2005. The American Astronomical Soceity.