首页> 外文期刊>The Astrophysical journal >GIANT GALAXIES, DWARFS, AND DEBRIS SURVEY. I. DWARF GALAXIES AND TIDAL FEATURES AROUND NGC?7331
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GIANT GALAXIES, DWARFS, AND DEBRIS SURVEY. I. DWARF GALAXIES AND TIDAL FEATURES AROUND NGC?7331

机译:巨型星系,矮人和碎片调查。 I.NGC周围的矮星系和潮汐特征?7331

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The Giant GAlaxies, Dwarfs, and Debris Survey (GGADDS) concentrates on the nearby universe to study how galaxies have interacted in groups of different morphology, density, and richness. In these groups, we select the dominant spiral galaxy and search its surroundings for dwarf galaxies and tidal interactions. This paper presents the first results from deep wide-field imaging of NGC?7331, where we detect only four low-luminosity candidate dwarf companions and a stellar stream that may be evidence of a past tidal interaction. The dwarf galaxy candidates have surface brightnesses of μ r ≈ 23-25?mag?arcsec–2 with (g – r)0 colors of 0.57-0.75?mag in the Sloan Digital Sky Survey filter system, consistent with their being dwarf spheroidal (dSph) galaxies. A faint stellar stream structure on the western edge of NGC?7331 has μ g ≈ 27?mag?arcsec–2 and a relatively blue color of (g – r)0 = 0.15?mag. If it is tidal debris, then this stream could have formed from a rare type of interaction between NGC?7331 and a dwarf irregular or transition-type dwarf galaxy. We compare the structure and local environments of NGC?7331 to those of other nearby giant spirals in small galaxy groups. NGC?7331 has a much lower (~2%) stellar mass in the form of early-type satellites than found for M31 and lacks the presence of nearby companions like luminous dwarf elliptical galaxies or the Magellanic Clouds. However, our detection of a few dSph candidates suggests that it is not deficient in low-luminosity satellites.
机译:巨型星系,小矮星和碎片调查(GGADDS)专注于附近的宇宙,研究星系如何在不同形态,密度和丰富度的群体中相互作用。在这些组中,我们选择占优势的螺旋星系,并在其周围搜索矮星系和潮汐相互作用。本文介绍了NGC?7331的深广域成像的第一个结果,其中我们仅检测到四个低发光度候选矮伴星和恒星流,这可能是过去的潮汐相互作用的证据。在斯隆数字天空测量系统中,候选星系的表面亮度为μr≈23-25?mag?arcsec–2,(g – r)0颜色为0.57-0.75?mag,这与它们的矮球形( dSph)星系。 NGC?7331西边缘的微弱恒星流结构具有μg≈27?mag?arcsec–2和相对蓝色(g – r)0 = 0.15?mag。如果是潮汐碎片,则该流可能是由NGC?7331与矮小的不规则或过渡型矮星系之间的罕见相互作用形成的。我们将NGC?7331的结构和局部环境与小星系群中其他附近的巨大旋涡的结构和局部环境进行了比较。 NGC?7331的早期卫星形式的恒星质量要比M31的低得多(约2%),并且缺少像发光的矮椭圆形星系或麦哲伦星云等附近的伴星。但是,我们检测到一些dSph候选物表明它在低发光度卫星中并不缺乏。

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