Distance and Reddening of the Isolated Dwarf Irregular Galaxy NGC 1156
Distance and Reddening of the Isolated Dwarf Irregular Galaxy NGC 1156
复制标题
孤立矮不规则星系 NGC 1156 的距离和红化
DOI：
10.1093/pasj/64.2.23
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发表时间：
2011
影响因子：
2.3
通讯作者：
Minjin Kim
中科院分区：
文献类型：
--
作者：
Sang Chul Kim;H. S. Park;J. Kyeong;J. Lee;C. Ree;Minjin Kim
我们提出了一个光度估计的距离和红化值矮不规则星系NGC 1156，这是在附近的宇宙中孤立的矮星系的研究的最佳目标之一。我们使用哈勃太空望远镜（HST）高级巡天相机的成像数据集，NGC 1156（26 00 - 29 00）中心区域的高分辨率通道，可在HST存档中用于本研究。根据（UB，BV）的颜色-颜色图，我们首先估计了NGC 1156的总（前景+内部）红化E（BV）= 0.35 tec0.05 mag，而之前只知道前景红化E（BV）= 0.16 mag（1984，ApJS，54，33）或0.24 mag（1998，ApJ，500，525）。根据最亮星方法，选取三颗最亮的蓝超巨星（平均B星等hB（3 B）i = 21.94）和三颗最亮的红超巨星（平均V星等hV（3 R）i = 22.76），得到了它们与NGC 1156的距离模分别为：（mM）0，BSG = 29.16 mag和.mM/ 0; RSG = 29.55 mag。通过对BSG使用1的权重和对RSG使用1.5的权重，我们最终获得了到NGC 1156的加权平均距离模数，mM/ 0 = 29.39 stec0.20 mag（距离= 7.6 stec0.7 Mpc），这与先前的估计一致。结合Karachentsev，Musella和Grimardi（1996，A&A，310，722）的测光数据，给出了NGC 1156的较小距离，并讨论了数据的局限性。
We present a photometric estimation of the distance and reddening values to the dwarf irregular galaxy NGC 1156, that is one of the best targets for the study of isolated dwarf galaxies in the nearby universe. We used imaging data sets of the Hubble Space Telescope (HST) Advanced Camera for Surveys, High Resolution Channel of the central region of NGC 1156 (26 00 � 29 00 ) available in the HST archive for this study. From the (UB, BV ) color-color diagram, we first estimated the total (foreground + internal) reddening toward NGC 1156 of E(BV ) = 0.35 ˙ 0.05 mag, whereas only the foreground reddening was previously known to be E(BV ) = 0.16 mag (1984, ApJS, 54, 33) or 0.24 mag (1998, ApJ, 500, 525). Based on the brightest-star method, selecting the three brightest blue supergiant (BSG) stars with a mean B magnitude of hB(3B)i = 21.94 and the three brightest red supergiant (RSG) stars with a mean V magnitude of hV (3R)i = 22.76, we derived the distance modulus to NGC 1156 to be (mM )0;BSG = 29.16 mag and .mM/ 0;RSG = 29.55 mag. By using weights of 1 for BSGs and 1.5 for RSGs, we finally obtained a weighted mean distance modulus to NGC 1156, .mM/ 0 = 29.39 ˙ 0.20 mag (distance = 7.6 ˙ 0.7 Mpc), which is in agreement with previous estimates. Combining the photometry data of this study with those of Karachentsev, Musella, and Grimardi (1996, A&A, 310, 722) gives a smaller distance to NGC 1156, which is discussed together with the limits of the data.