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arXiv 1701.07641astro-ph.GA
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星系群中的赝凸起:环境在长期演化中的作用

Pseudo bulges in galaxy groups: the role of environment in secular evolution

Preetish K. Mishra, Yogesh Wadadekar, Sudhanshu Barway

摘要:

我们研究的流量有限的样本$\sim$ 5000 SDSS星系的包含伪隆起的星系的分数对环境的依赖性。我们已经分为经典的和伪的凸起类别的基础上,他们的位置在科门迪图。赝凸起被认为是由内部过程形成的,是星系长期演化的结果。我们试图理解长期进化对环境和形态的依赖。根据星系群成员的不同,将盘状+球星系样本分为三类:星系群中的中心星系、卫星星系和孤立的场星系,我们发现,卫星星系和场星系的赝球比例几乎相等。中心星系中的假核球宿主所占比例几乎是伴星系和场星系中假核球所占比例的一半。当只有星系被认为是螺旋或S0时,这种趋势也是有效的。使用投影的第五近邻密度作为局部环境的度量,我们寻找伪凸起分数对环境密度的依赖性。伴星系和场星系的赝球分数对环境的依赖性很弱或没有。然而,部分的伪隆起主办的中央星系减少,增加当地的环境密度。我们没有发现赝球光度对环境的依赖性。我们的研究结果表明,区分凸起类型的过程是环境的函数,而负责形成伪凸起的过程似乎是独立的环境。

英文摘要:

We examine the dependence of the fraction of galaxies containing pseudo bulges on environment for a flux limited sample of $\sim$5000 SDSS galaxies. We have separated bulges into classical and pseudo bulge categories based on their position on the Kormendy diagram. Pseudo bulges are thought to be formed by internal processes and are a result of secular evolution in galaxies. We attempt to understand the dependence of secular evolution on environment and morphology. Dividing our sample of disc+bulge galaxies based on group membership into three categories: central and satellite galaxies in groups and isolated field galaxies, we find that pseudo bulge fraction is almost equal for satellite and field galaxies. Fraction of pseudo bulge hosts in central galaxies is almost half of the fraction of pseudo bulges in satellite and field galaxies. This trend is also valid when only galaxies are considered only spirals or S0. Using the projected fifth nearest neighbour density as measure of local environment, we look for the dependence of pseudo bulge fraction on environmental density. Satellite and field galaxies show very weak or no dependence of pseudo bulge fraction on environment. However, fraction of pseudo bulges hosted by central galaxies decreases with increase in local environmental density. We do not find any dependence of pseudo bulge luminosity on environment. Our results suggest that the processes that differentiate the bulge types are a function of environment while processes responsible for the formation of pseudo bulges seem to be independent of environment.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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