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首页> 外文期刊>The Astrophysical journal >THE l.0 MEGAPARSEC GALAXY PAIR SAMPLE IN LOW-DENSITY REGIONS
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THE l.0 MEGAPARSEC GALAXY PAIR SAMPLE IN LOW-DENSITY REGIONS

机译：低密度区域中的l.0 MEGAPARSEC银河系样品

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Using complete redshift catalogs, we have compiled a list of galaxy pairs based so1ely on a pair's pro- jected separation, r_P, and velocity difference, ΔV. We have made high-velocity precision H I observations of each galaxy in the sample and have reported these in the literature. Due to the nature of the redshift catalogs, we are able to quantitatively evaluate the effects of isolation and number density of surround- ing galaxies on each pair in the sample. For the close galaxy pairs (r < l00 kpc), the degree of isolation (a measure of the number of near neighbors) has little effect on the medianΔV . This median is about 55 km s~-1 for the 25 close pairs (if medium-density close pairs are omittedΔV is even smal1er, but the difference is not statistically significant). The effect of isolation is strong for the entire sample of galaxy pairs with separations as large as 1.0 Mpc. For these larger separation pairs, re1axation of strict isolation requirements introduces small groups into the sample, which dramatically increases the medianΔV . We find little evidence of an increase in the median AV with decreasing r_P, nor with increasing total lumi- nosity. For our isolated pairs in low-density regions, the overall medianΔV is only 30 km s 1. For similar separations and isolation criteria, galaxy satellites with larger 1uminosity ratios (i.e., less dynami- cal friction) in higher density regions have AV approximately twice as large. We conjecture that our orbits are highly eccentric, so that the indirect effect of dynamical friction leads to predominant1y small ΔV . However, the halos of our galaxies may also be of low density (although highly extended).
机译：使用完整的红移目录，我们仅根据一对对的预计间隔r_P和速度差ΔV编制了一个银河对列表。我们已经对样本中的每个星系进行了高速精密H I观测，并在文献中进行了报道。由于红移目录的性质，我们能够定量评估样本中每对星系的隔离和周围星系的数量密度的影响。对于近距离的星系对（r <100 kpc），隔离度（衡量近邻的数量）对中位数ΔV影响很小。 25个近距离对的中值约为55 km s〜-1（如果省略中等密度的近距离对，ΔV会更小，但差异在统计学上并不显着）。隔离效果对整个星系对样本（间隔高达1.0 Mpc）很强。对于这些较大的分离对，严格隔离要求的取消给样品引入了小组，这大大增加了中值ΔV。我们几乎没有发现r_P降低或总亮度增加时中位数AV增加的证据。对于我们在低密度区域中的孤立对，总中值ΔV仅为30 km s1。对于类似的分离和隔离标准，在较高密度区域中具有较大1辐射比（即较小的动摩擦）的星系卫星的AV大约为两倍一样大。我们推测，我们的轨道是高度偏心的，因此动摩擦的间接影响导致ΔV占主导地位。但是，我们星系的光晕也可能是低密度的（尽管高度扩展）。

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