Astronomy and Astrophysics – Astrophysics
Scientific paper
1997-04-02
Astronomy and Astrophysics
Astrophysics
14 pages, 2 tables, 2 figures ApJ Letters, in press
Scientific paper
10.1086/310632
In this paper, we show that the optically bright stars above the tip of the first red giant branch (TRGB) in the color magnitude (CM) diagrams of nearby dwarf elliptical (dE) galaxies, commonly interpreted as indication of the existence of an intermediate-age population, may, in certain circumstances, be an artifact of observational effects on a pure old population system. For this purpose, model CM diagrams have been computed simulating the observational effects that can be found in different regions of a Local Group dE galaxy. The starting synthetic CM diagram represents a pure old system, with star formation extending only from 15 to 12 Gyr ago. Based on those model diagrams, we analyze the conclusions that a hypothetical ground-based observer might reach concerning the presence of a population of stars above the tip of the red giant branch (TRGB) that could be interpreted as an intermediate-age population, by using two age indicators extensively employed in the literature: i) the bolometric magnitude at the tip of the asymptotic giant branch (AGB) phase, and ii) the ratio of AGB to red giant branch (RGB) stars present in the CM diagram. Our analysis shows that, if observational effects are overlooked, application of both methods would result in finding a fictitious intermediate-age population in the inner regions of the galaxy, where crowding is more severe.
Aparicio Antonio
Martinez-Delgado David
No associations
LandOfFree
Luminous red stars in Local Group dwarf elliptical galaxies: an intermediate-age population? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Luminous red stars in Local Group dwarf elliptical galaxies: an intermediate-age population?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Luminous red stars in Local Group dwarf elliptical galaxies: an intermediate-age population? will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-464950