Population synthesis models for cluster galaxies at redshifts of 0. 4 to 0. 55

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1991

OSTI ID:5223784

Walsh, D E.P.

Stellar population synthesis models were built for use with optical spectra with approx. 10A resolution. These make use of metal rich evolutionary tracks and the results compare very well with Galactic bulge giant data. It is suggested that most V band light in old populations comes from main sequence turnoff stars, not giants. Attention is drawn to important differences between two popular libraries of stellar spectra. Good fits are found for local giant elliptical galaxy spectra with metallicities Z approx. = 0.03 and ages approx. = 13 Gyr. There is no need to provide supplementary blue stars to produce the flux between 3160 and 4000A. The red cluster galaxies with z between 0.38 to 0.55 are redder than expected, but there are some considerable discrepancies between photometric and spectral data which make this uncertain. If the redness is real, either extinction or a metallicity higher than anticipated is required. The bluer cluster galaxies have undergone bursts of star formation with up to 20 pct of their stellar mass residing in stars younger than approx. 1 Gyr. These bursts may be the origin for the observed dispersion in the color magnitude relationship for early type galaxies.

• Research Organization: Princeton Univ., NJ (United States)
• OSTI ID: 5223784
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
DATA
EMISSION SPECTRA
GALAXIES
INFORMATION
MAIN SEQUENCE STARS
MATHEMATICAL MODELS
NUMERICAL DATA
RED SHIFT
SPECTRA
STAR EVOLUTION
STAR MODELS
STARS
THEORETICAL DATA