孤立星系的AMIGA样本。IV。孤立星系周围的邻居目录
The AMIGA sample of isolated galaxies. IV. A catalogue of neighbours around isolated galaxies
摘要：
研究环境对星系性质和演化的影响需要定义明确的控制样本。到目前为止，这种孤立的星系样本很小或定义不清。AMIGA项目（孤立星系的星际介质分析）试图定义一个统计上有用的样本，在本地（z < 0.05）宇宙中最孤立的星系。一个合适的大样本的AMIGA项目已经存在，孤立星系的目录（CIG，Karachentseva 1973; 1050星系），我们使用这个样本作为一个起点，以完善和执行更好的量化其隔离性能。对POSS-IE数字图像进行了分析，得出了950个CIG星系周围的最小投影半径R > 0.5 Mpc（不包括Vr = 1500 km s-1以内的星系）。我们使用LMORPHO软件确定了每个领域中亮度超过B = 17.5的所有候选星系，具有高度的置信度。我们生成了一个大约54000个潜在邻居的目录（这个样本的30%存在红移）。六百六十六个星系通过和二百八十四个失败的原始CIG隔离标准。现有的红移数据证实，我们的星表主要涉及背景人口，而不是物理上相关的邻居。我们发现，在每个CIG星系周围的大小的四个因素，在原来的隔离标准，排除邻居，对应于德尔塔Vr ~ 18000公里s-1，这是一个保守的限制。已发现CIG中的半导体显示出不同程度的隔离。我们的结论是，这是强制性的定量措施。这将是今后根据在此获得的邻区目录开展工作的主题。
英文摘要：
Studies of the effects of environment on galaxy properties and evolution require well defined control samples. Such isolated galaxy samples have up to now been small or poorly defined. The AMIGA project (Analysis of the interstellar Medium of Isolated GAlaxies) represents an attempt to define a statistically useful sample of the most isolated galaxies in the local (z < 0.05) Universe. A suitable large sample for the AMIGA project already exists, the Catalogue of Isolated Galaxies (CIG, Karachentseva 1973; 1050 galaxies), and we use this sample as a starting point to refine and perform a better quantification of its isolation properties. Digitised POSS-I E images were analysed out to a minimum projected radius R > 0.5 Mpc around 950 CIG galaxies (those within Vr = 1500 km s-1 were excluded). We identified all galaxy candidates in each field brighter than B = 17.5 with a high degree of confidence using the LMORPHO software. We generated a catalogue of approximately 54 000 potential neighbours (redshifts exist for 30% of this sample). Six hundred sixty-six galaxies pass and two hundred eighty-four fail the original CIG isolation criterion. The available redshift data confirm that our catalogue involves a largely background population rather than physically associated neighbours. We find that the exclusion of neighbours within a factor of four in size around each CIG galaxy, employed in the original isolation criterion, corresponds to Delta Vr ~ 18000 km s-1 indicating that it was a conservative limit. Galaxies in the CIG have been found to show different degrees of isolation. We conclude that a quantitative measure of this is mandatory. It will be the subject of future work based on the catalogue of neighbours obtained here.
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