The resolved outer population of NGC 6822 with WFPC2

被引:17
作者
Hutchings, JB
Cavanagh, B
Bianchi, L
机构
[1] Natl Res Council Canada, Dominion Astrophys Observ, Victoria, BC V8X 4M6, Canada
[2] Univ Victoria, Dept Phys & Astron, Victoria, BC V8W 3P6, Canada
[3] Johns Hopkins Univ, Dept Phys & Astron, Ctr Astrophys Sci, Baltimore, MD 21218 USA
关键词
D O I
10.1086/316366
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We present F336W (U), F439W (B), F555W (V), and F675W (R) Wide Field Planetary Camera 2 (WFPC2) photometry of two outer regions of the Local Group dwarf irregular galaxy NGC 6822. The northeast region is similar to 13' from the galaxy center, whereas the west region lies 10' out and within the wispy low surface brightness outer regions of the galaxy. The fields are not crowded and contain few NGC 6822 stars. We discuss the errors and uncertainties and find that the west region contains a main sequence that extends to stars of about 2 M-., with an age of about 200 Myr. The northeast region has no main sequence or stars younger than 1 Gyr but does contain some luminous red stars that are not matched in the west held. These stars are not clumped in the held. The results suggest that the west region may be a trace of a tidal event that triggered the current star formation in this isolated galaxy.
引用
收藏
页码:559 / 565
页数:7
相关论文
共 17 条
[1]  
BERTELLI G, 1994, ASTRON ASTROPHYS SUP, V106, P275
[2]  
BURROWS CJ, 1995, WIDE FIELD PLANETARY
[3]   The dwarf irregular galaxy Sextans A .1. HST photometry of the resolved stars [J].
DohmPalmer, RC ;
Skillman, ED ;
Saha, A ;
Tolstoy, E ;
Mateo, M ;
Gallagher, J ;
Hoessel, J ;
Chiosi, C ;
Dufour, RJ .
ASTRONOMICAL JOURNAL, 1997, 114 (06) :2514-&
[4]   A Wide Field Planetary Camera 2 study of the resolved stellar population of the Pegasus dwarf irregular galaxy (DDO 216) [J].
Gallagher, JS ;
Tolstoy, E ;
Dohm-Palmer, RC ;
Skillman, ED ;
Cole, AA ;
Hoessel, JG ;
Saha, A ;
Mateo, M .
ASTRONOMICAL JOURNAL, 1998, 115 (05) :1869-1887
[5]   The Local Group Dwarf Irregular Galaxy NGC 6822 .1. The stellar content [J].
Gallart, C ;
Aparicio, A ;
Vilchez, JM .
ASTRONOMICAL JOURNAL, 1996, 112 (05) :1928-&
[6]   STRUCTURE AND CONTENT OF NGC 6822 [J].
HODGE, PW .
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 1977, 33 (01) :69-&
[7]   NGC 6822, a remote stellar system [J].
Hubble, E .
ASTROPHYSICAL JOURNAL, 1925, 62 (05) :409-433
[8]   PHOTOMETRY OF NEARBY IRREGULAR GALAXY NGC 6822 [J].
KAYSER, SE .
ASTRONOMICAL JOURNAL, 1967, 72 (02) :134-&
[9]   Hot, luminous stars in selected regions of NGC 6822, M31, and M33 [J].
Massey, P ;
Armandroff, TE ;
Pyke, R ;
Patel, K ;
Wilson, CD .
ASTRONOMICAL JOURNAL, 1995, 110 (06) :2715-&
[10]   Evolved massive stars in the local group. I. Identification of red supergiants in NGC 6822, M31, AND M33 [J].
Massey, P .
ASTROPHYSICAL JOURNAL, 1998, 501 (01) :153-174