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arXiv 1108.6281astro-ph.GA
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哈勃太空望远镜对星暴后类星体的成像

Hubble Space Telescope Imaging of Post-Starburst Quasars

S. L. Cales, M. S. Brotherton, Zhaohui Shang, Vardha Nicola Bennert, G. Canalizo, R. Stoll, R. Ganguly, D. Vanden Berk, C. Paul, A. Diamond-Stanic

摘要:

本文介绍了哈勃空间望远镜(\emph{HST})高级巡天照相机(ACS)宽视场通道快照计划中29个星暴后类星体(PSQs)的图像。这些宽线条的活动星系核(AGN)具有大质量($M_{burst} \sim 10^{10} M_{\odot}$)、中等年龄恒星星族(数百万年)的光谱特征。因此,它们的复合性质提供了对活动星系核-星暴联系的深入了解。我们通过半自动化的二维光剖面拟合PSF减去图像来测量类星体对宿主星系的光贡献。我们检查主机的形态,以及,模型单独的凸起和磁盘组件。\emph{HST} /ACS-F606 W图像显示了相同数量的螺旋型(13/29)和早期型(13/29)宿主,其余3种宿主的分类不确定。早期型星系中活动星系核的平均光度比旋涡星系中的大。扰动,如潮汐尾,壳,恒星形成结,和不对称被视为相互作用/合并活动的路标。在29个天体中的17个中发现了这样的扰动,并且均匀地分布在早期类型和螺旋星系中。其中两个系统显然正在与它们的同伴合并。与其他光度和红移相近的活动星系核相比,这些PSQs具有更高的早型寄主和扰动比例。我们最明亮的物体与扰动的早期型宿主星系似乎是一致的合并产品。因此,这些发光的扰动星系可能代表了合并驱动活动和星系等级演化的演化场景中的一个阶段。我们的不太明亮的物体似乎与不需要由主要合并触发的塞弗特星系一致。这些塞弗特星系中有许多是棒旋星系。

英文摘要:

We present images of 29 post-starburst quasars (PSQs) from a Hubble Space Telescope (\emph{HST}) Advanced Camera for Surveys (ACS) Wide Field Channel Snapshot program. These broad-lined active galactic nuclei (AGN) possess the spectral signatures of massive ($M_{burst} \sim 10^{10} M_{\odot}$), moderate-aged stellar populations (hundreds of Myrs). Thus, their composite nature provides insight into the AGN-starburst connection. We measure quasar-to-host galaxy light contributions via semi-automated two-dimensional light profile fits of PSF-subtracted images. We examine the host morphologies, as well as, model the separate bulge and disk components. The \emph{HST}/ACS-F606W images reveal an equal number of spiral (13/29) and early-type (13/29) hosts, with the remaining three hosts having indeterminate classifications. AGNs hosted by early-type galaxies have on average greater luminosity than those hosted by spiral galaxies. Disturbances, such as tidal tails, shells, star-forming knots, and asymmetries are seen as signposts of interaction/merger activity. Disturbances such as these were found in 17 of the 29 objects and are evenly distributed among early-type and spiral galaxies. Two of these systems are clearly merging with their companions. Compared to other AGN of similar luminosity and redshift these PSQs have a higher fraction of early-type hosts and disturbances. Our most luminous objects with disturbed early-type host galaxies appear to be consistent with merger products. Thus, these luminous disturbed galaxies may represent a phase in an evolutionary scenario for merger driven activity and of hierarchical galaxy evolution. Our less luminous objects appear to be consistent with Seyfert galaxies not requiring triggering by major mergers. Many of these Seyferts are barred spiral galaxies.

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