arXivDaily arXiv每日学术速递 周一至周五更新
北美退伍军人节(Veterans Day),12 日无更新
arXiv 0903.0634astro-ph.COastro-ph.GA
收藏

斯隆数字巡天II中的活动星系:星系和活动演化

Active Galaxies in the Sloan Digital Sky Survey II: galaxy and activity evolution

Pietro M. Reviglio, David J. Helfand

摘要:

本文是基于FIRST和SDSS巡天的系列论文中的第二篇,我们以本地宇宙中约15万个星系为样本,研究了SDSS(~2 Gyrs)回视时间内星系形态和核活动的演化。我们展示了一个演变的无线电功率的强度和光谱发射线的AGN的典型,以及在其主机的形态。这种演化对于亮度较低的系统来说似乎更为显著,可能是恒星形成过程中尺寸缩小的低红移尾部,活动星系核活动和超大质量黑洞形成-这表明,沿着哈勃序列的星系的内禀性质的差异可能源于它们的势阱深度的不同,这导致了不同的演化路径,因为不同的势阱深度导致了不同的演化路径。气体流入的时间表这种原初的坍缩以及随后由棒波和密度波不稳定性所介导的长期演化,可能使不同质量的星系在本研究所示的局域宇宙中具有不同的活动水平和形态特征。在这样一个假设的协议,我们发现,跟踪无线电发射的恒星形成是逐步更加集中在更先进的恒星形成星系,我们表明,星系所处的环境中起着较小的作用,在塑造的功能和活动的大多数系统。

英文摘要:

In this second paper of a series of papers based on the FIRST and SDSS surveys we investigate the evolution of galaxy morphology and nuclear activity in the look-back time of the SDSS (~2 Gyrs) for a sample of ~150000 galaxies in the local universe. We demonstrate an evolution in the strength of the radio power and the spectroscopic emission-lines typical of AGN, as well as in the morphology of their hosts. Such evolution appears more substantial for less luminous systems, and is possibly the low-redshift tail of the downsizing in star-formation, AGN activity and supermassive black hole build-up observed in higher redshift surveys.This suggests that the differences in intrinsic properties of galaxies along the Hubble Sequence may arise from the difference in the depth of their potential wells which leads to different evolutionary paths because of different timescales for gas infall. This primordial infall and the following secular evolution mediated by bar and density wave instabilities may bring galaxies of different mass to have the different activity levels and morphological features in the local universe shown in this study. In agreement with such a hypothesis, we find that star-formation as traced by radio emission is progressively more centrally concentrated in more evolved star-forming galaxies and we show that the environment in which a galaxy resides plays a lesser role in shaping the features and activity for the majority of systems.

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。

↑