Astronomy and Astrophysics – Astrophysics
Scientific paper
2004-05-27
Astronomy and Astrophysics
Astrophysics
18 pages, 10 figures, MNRAS, accepted for publication
Scientific paper
10.1111/j.1365-2966.2004.08070.x
The bottom line of this study is (i) to check whether normal (quiescent) and interacting EGs have a different behavior in the popular diagnostic planes such as Hb vs. [MgFe] (and others); (ii) to seek whether the signature of mergers and/or interactions may mirror in some specific changes of the indices that could un-equivocally hint for burts of stellar activity; (iii) to evaluate the intensity of those bursts or secondary episodes of star formation; (iv) to explore whether other alternatives can exist, i.e. distinct from obvious ones resting on large age range. The data show that both normal, field and interacting galaxies have the same scattered but smooth distribution in the Hb vs. [MgFe] diagnostic plane. There are two interpretations for this: (1) EGs span larges ranges of ages and metallicities. (2) The bulk population of stars is old but subsequent episodes of star formation scatter the object in the diagnostic planes. Both these interpretation are not able to reproduce the observed distribution. The above schemes are too demanding because of the many ad hoc ingredients that have to be introduced. Furthermore they neglect the observationally grounded hint that the stellar content of EGs is likely enhanced in alfa-elements. We propose here a new scheme, in which the bulk dispersion of galaxies in the index-index plane is caused by a different mean degree of enhancement. The possibility that EGs span large ranges of [alpha/Fe] and metallicities but narrow ranges of ages for the bulk population favors the monolithic scheme.
Chiosi Cesare
Tantalo Rosaria
No associations
LandOfFree
Star formation history in early-type galaxies. I. The line absorption indices diagnostics 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 Star formation history in early-type galaxies. I. The line absorption indices diagnostics, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Star formation history in early-type galaxies. I. The line absorption indices diagnostics will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-269736