A high-excitation H II region in the faint dwarf elliptical galaxy A 0951+68

被引:19
作者
Johnson, RA
Lawrence, A
Terlevich, R
Carter, D
机构
[1] UNIV EDINBURGH,ROYAL OBSERV,INST ASTRON,EDINBURGH EH9 3HJ,MIDLOTHIAN,SCOTLAND
[2] ROYAL GREENWICH OBSERV,CAMBRIDGE CB3 0EZ,ENGLAND
[3] LIVERPOOL JOHN MOORES UNIV,ASTROPHYS GRP,LIVERPOOL L3 5UX,MERSEYSIDE,ENGLAND
关键词
H II regions; galaxies; individual; A; 0951; 68;
D O I
10.1093/mnras/287.2.333
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We present the results of BVRI imaging and optical spectroscopy of the dwarf galaxy A 0951 + 68. The images reveal that, although this galaxy is classified as a dwarf elliptical, it has some properties that are similar to dwarf irregular galaxies. It contains two bright knots of emission, one of which is red and unresolved, and the other blue and resolved. The blue knot also shows a high-excitation emission-line spectrum. The observed line ratios indicate that this is an H II region, though with some line ratios that are border-line with those in AGN. The emission-line luminosity is consistent with ionization by a single, very luminous O star, or several smaller O stars, but the extended blue light in the knot shows that this has occurred as part of a substantial recent star formation event. We find that the metal abundance, while low compared to typical large galaxies, actually seems to be high for such a low-luminosity dwarf. The position of A 0951 in the literature is incorrect, and we provide the correct value.
引用
收藏
页码:333 / 340
页数:8
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