标题： 星系团中星系属性的轨道依赖性 显示英文标题

标题： Orbital Dependence of Galaxy Properties in Satellite Systems of Galaxies

摘要： 我们研究了卫星星系的性质与到宿主星系的距离以及轨道运动的关系，使用的是SDSS数据。 从SDSS DR7中，我们找到3515个z<0.03的孤立卫星系统，包含8904个卫星星系。 利用这个样本，我们构建了一个包含635个卫星星系的目录，这些卫星星系与215个宿主星系相关联，其自转方向由我们对SDSS彩色图像的检查和/或文献中的光谱观测确定。 根据卫星星系相对于宿主星系自转方向的轨道运动，我们将它们分为顺行和逆行轨道子样本。 我们发现顺行轨道星系的数量几乎等于逆行轨道星系的数量：顺行轨道卫星的比例为50±2%。 卫星相对于宿主星系的速度分布几乎是对称的：卫星的整体旋转速度中值为-1±8公里/秒。 我们发现早期类型顺行轨道卫星的径向分布强烈集中在宿主星系附近，而逆行轨道卫星的分布则显示较少的集中性。 我们还发现顺行轨道的晚期类型卫星的轨道速度随着投影距离（R）减小而增加，而对于逆行轨道的卫星则相反。 在R小于宿主星系暴发半径的0.1倍时，无论是顺行还是逆行轨道情况下，轨道速度都会下降。 对于早期和晚期形态学类型的卫星来说，顺行轨道的卫星平均比逆行轨道的卫星更暗淡。 对于顺行和逆行轨道的晚期类型卫星，u-r颜色随着R减小而变得更红。 顺行和逆行轨道卫星之间的差异可能归因于它们不同的起源或经历的不同物理过程强度，这些过程通过与宿主星系的流体力学相互作用而产生。 显示英文摘要

摘要： We study the dependence of satellite galaxy properties on the distance to the host galaxy and the orbital motion using the SDSS data. From SDSS DR7 we find 3515 isolated satellite systems of galaxies at z<0.03 that contain 8904 satellite galaxies. Using this sample we construct a catalog of 635 satellites associated with 215 host galaxies whose spin directions are determined by our inspection of the SDSS color images and/or by spectroscopic observations in the literature. We divide satellite galaxies into prograde and retrograde orbit subsamples depending on their orbital motion respect to the spin direction of the host. We find that the number of galaxies in prograde orbit is nearly equal to that of retrograde orbit galaxies: the fraction of satellites in prograde orbit is 50+/-2%. The velocity distribution of satellites with respect to their hosts is found almost symmetric: the median bulk rotation of satellites is -1+/- 8 km/s. It is found that the radial distribution of early-type satellites in prograde orbit is strongly concentrated toward the host while that of retrograde ones shows much less concentration. We also find the orbital speed of late-type satellites in prograde orbit increases as the projected distance to the host (R) decreases while the speed decreases for those in retrograde orbit. At R less than 0.1 times the host virial radius the orbital speed decreases in both prograde and retrograde orbit cases. Prograde satellites are on average fainter than retrograde satellites for both early and late morphological types. The u-r color becomes redder as R decreases for both prograde and retrograde orbit late-type satellites. The differences between prograde and retrograde orbit satellites may be attributed to their different origin or the different strength of physical processes that they have experienced through hydrodynamic interactions with their host galaxies.