The far-ultraviolet emission of early-type galaxies

被引:31
作者
Deharveng, JM [1 ]
Boselli, A [1 ]
Donas, J [1 ]
机构
[1] Lab Astrophys Marseille, F-13376 Marseille 12, France
关键词
stars : AGB and post-AGB; stars : horizontal-branch; galaxies : stellar content; galaxies : elliptical and lenticular; cD; ultraviolet : galaxies;
D O I
10.1051/0004-6361:20021082
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We have assembled a UV-flux selected sample of 82 early-type galaxies and collected additional information at other wavelengths. These data confirm a large spread of the UV-V color in the range 2 to 5. The spread in UV-V is accompanied by a spread in B-V that is mainly attributed to the range of morphological types and luminosities. A large fraction of the objects have red colors, UV-V = 4 +/- 0.4, corresponding to a weak UV-upturn as observed with IUE. If the current interpretation for the UV emission from early-type galaxies is applicable to our sample, the PAGB (Post-Asymptotic Giant Branch) tracks are the most common evolution path for the low-mass stars responsible for the UV emission. A small number of very blue (UV-V < 1.4) objects have been found that can be reasonably interpreted as harbouring some low level of star formation. In contrast to a previous sample based on IUE observations, no correlation is found between the UV - V color and the Mg-2 spectral line index; possible explanations are reviewed. The potential of a more extended UV survey like GALEX is briefly presented.
引用
收藏
页码:843 / 854
页数:12
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