NOAO >   Observing Info >   Approved Programs >   2002B-0159

Small NOAO Logo

Proposal Information for 2002B-0159


PI: Akihiko Tomita, Wakayama University, atomita@center.wakayama-u.ac.jp
Address: Wakayama 640-8510, Japan

CoI: Deidre Hunter, Lowell Observatory
CoI: Tsutomu T. Takeuchi, Natl. Astron. Obs. Japan
CoI: Kohji Yoshikawa, Kyoto University
CoI: Hiroyuki Hirashita, Arcetri Observatory

Title: Blue Compact Dwarfs: Young-to-Old Ratio

Abstract: Infrared imaging and color-magnitude diagram analysis show that Blue Compact Dwarfs (BCDs), once thought to be young galaxies, contain an old stellar population. But, how large is the contribution of the old population? We are proposing to obtain the data necessary to determine the relative contribution of the young (younger than 1 Gyr) and old (older than 1 Gyr) stellar populations in a sample of BCDs. We use area- integrated, low dispersion spectra with a wide wavelength coverage. We have developed a spectral decomposition method to extract the relative contribution of present and past stellar populations from these spectra. The analysis of color-magnitude diagrams is another tool to explore the star formation history. However, it is very difficult to measure faint stars, which are crucial to quantitatively evaluating the amount of the old population. The present-to-past ratio of the star formation rate has been estimated from broad-band imaging, but that analysis must assume a parametric star formation history. Our approach bridges these two techniques. The young-to-old ratio is an important information to understanding how these galaxies evolve and their relationship to faint blue galaxies at intermediate redshifts.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



NOAO >   Observing Info >   Approved Programs >   2002B-0159

noaoprop-help@noao.edu

Small NOAO Logo