2008A&A...481..635L


C.D.S. - SIMBAD4 rel 1.7 - 2019.11.21CET23:52:32

2008A&A...481..635L - Astronomy and Astrophysics, volume 481, 635-644 (2008/4-3)

A comparison of the s- and r-process element evolution in local dwarf spheroidal galaxies and in the Milky Way.

LANFRANCHI G.A., MATTEUCCI F. and CESCUTTI G.

Abstract (from CDS):

We study the nucleosynthesis of several neutron capture elements (barium, europium, lanthanum, and yttrium) in local group dwarf spheroidal (dSph) galaxies and in the Milky Way by comparing the predictions of detailed chemical evolution models with the observed data. We analyse the differences in the abundance patterns of these two types of galaxies in order to understand their formation and evolution. We compare the evolution of [Ba/Fe], [Eu/Fe], [La/Fe], [Y/Fe], [Ba/Y], [Ba/Eu], [Y/Eu], and [La/Eu] observed in dSph galaxies and in our Galaxy with predictions of detailed chemical evolution models. The models for all dSph galaxies and for the Milky Way are able to reproduce several observational features of these galaxies, such as a series of abundance ratios and the stellar metallicities distributions. The Milky Way model adopts the two-infall scenario, whereas the most important features of the models for the dSph galaxies are the low star-formation rate and the occurrence of intense galactic winds. We predict that the [s-r/Fe] ratios in dSphs are generally different than the corresponding ratios in the Milky Way, at the same [Fe/H] values. This is interpreted as a consequence of the time-delay model coupled with different star formation histories. In particular, the star-formation is less efficient in dSphs than in our Galaxy and it is influenced by strong galactic winds. Our predictions are in very good agreement with the available observational data. The time-delay model for the galactic chemical enrichment coupled with different histories of star formation in different galaxies allow us to succesfully interpret the observed differences in the abundance ratios of s- and r-process elements, as well as of α-elements in dSphs and in the Milky Way. These differences strongly suggest that the main stellar populations of these galaxies could not have had a common origin and, consequently, that the progenitors of local dSphs might not be the same objects as the building blocks of our Galaxy.

Abstract Copyright:

Journal keyword(s): stars: abundances - galaxies: Local Group - galaxies: evolution - galaxies: dwarf - galaxies: formation

Simbad objects: 12

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Number of rows : 12

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NAME Sculptor Dwarf Galaxy G 01 00 09.4 -33 42 32   9.79 8.6 8.81   ~ 1063 4
2 2MASS J01001630-3342371 * 01 00 16.2939480511 -33 42 37.233911181   18.86 16.995   15.525 C 13 0
3 SCMS 822 * 01 00 17.0895890704 -33 45 13.860920066   19.14 18.152   17.140 ~ 13 0
4 NAME Fornax Dwarf Spheroidal G 02 39 59.3 -34 26 57   9.02 7.4     ~ 1409 1
5 NAME Carina dSph G 06 41 36.7 -50 57 58   22.14 11.0 19.47   ~ 956 0
6 NAME Leo I dSph G 10 08 28.12 +12 18 23.4   11.3 10.0     ~ 1010 1
7 NAME Dwarf Elliptical Galaxy in Sex G 10 13 02.9 -01 36 53   12 10.4     ~ 670 0
8 NAME Leo B G 11 13 28.13 +22 09 10.1   12.9 12.0     ~ 705 0
9 NAME UMi Galaxy G 15 09 11.34 +67 12 51.7   13.60 10.6     ~ 1141 0
10 NAME Dra dSph G 17 20 14.335 +57 55 16.39   12.40 10.6     ~ 1125 1
11 NAME SDG G 18 55 03.1 -30 28 42   4.5 3.6     ~ 1651 2
12 NAME Local Group GrG ~ ~           ~ 6685 0

    Equat.    Gal    SGal    Ecl

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2019.11.21-23:52:32

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