标题： X射线对星系的调查 显示英文标题

标题： An X-ray Survey of Galaxies in Pairs

摘要： 从对成对星系X射线辐射的首次调查中报告了结果。 样本包括来自Karachentsev（1972）的成对星系目录中的五十二对星系，其坐标与ROSAT位置敏感比例计数器定点观测重叠。 早期类型成对星系的平均观测log l_x为41.35 +/-0.21，而使用孤立早期类型星系的l_x-l_b关系预测的平均log l_x为42.10 +/-0.19。 以95%的置信度，成对星系在X射线波段比孤立星系暗淡，对于相同的l_b。 混合成对样本的显著一部分也似乎同样暗淡。 空间分析显示，两种类型的成对星系的X射线辐射通常具有约10-50 kpc的范围，远小于星系团的星际介质，因此很可能起源于星系本身。 CPG 564，最明亮的早期类型成对星系，X射线光度为4.7x10^42 ergs/sec，是一个例外。 它的X射线辐射范围大于169 kpc，半高全宽约为80 kpc，与星际介质预期的范围相当。 该样本在l_x和l_b之间仅显示出较弱的相关性，约81%的置信度，可能是由于星系内部气体含量的变化所致。 尽管检测率较低，仅为22%，但未发现l_x与成对速度差、分离度或远红外光度之间的相关性。 显示英文摘要

摘要： Results are reported from the first survey of X-ray emission from galaxies in pairs. The sample consists of fifty-two pairs of galaxies from the Catalog of Paired Galaxies Karachentsev (1972) whose coordinates overlap ROSAT Position Sensitive Proportional Counter pointed observations. The mean observed log l_x for early-type pairs is 41.35 +/-0.21 while the mean log l_x predicted using the l_x-l_b relationship for isolated early-type galaxies is 42.10 +/-0.19. With 95% confidence, the galaxies in pairs are underluminous in the X-ray, compared to isolated galaxies, for the same l_b. A significant fraction of the mixed pair sample also appear similarly underluminous. A spatial analysis shows that the X-ray emission from pairs of both types typically has an extent of ~10 - 50 kpc, much smaller than group intergalactic medium and thus likely originates from the galaxies. CPG 564, the most X-ray luminous early-type pair, 4.7x10^42 ergs/sec, is an exception. The extent of it's X-ray emission, >169 kpc, and HWHM, ~80 kpc, is comparable to that expected from an intergalactic medium. The sample shows only a weak correlation, ~81% confidence, between l_x and l_b, presumably due to variations in gas content within the galaxies. No correlation between l_x and the pair velocity difference, separation, or far-infrared luminosity is found though the detection rate is low, 22%.