赛弗特2型星系M51核区50pc内的星族组成

发布时间：2018-03-15 23:24

本文选题：赛弗特星系M51　切入点：SSP拟合　出处：《南京师范大学》2013年硕士论文　论文类型：学位论文

【摘要】：星系中恒星的形成历史与星系的演化密切相关,同样,恒星形成历史与星系中心的超大质量黑洞也有着关联。有研究表明赛弗特星系中心环绕核心的区域其恒星形成率会受到压制。赛弗特2型星系M51是近邻的(8.4Mpc)、正向的漩涡星系,且其核心的活动星系核活动性较弱,这些都有利于对其核心区域的恒星星族组成进行研究。本文利用HST-STIS高空间分辨率(～2pc)的光栅光谱,研究了M51核区～50pc范围内的比恒星形成率(SSFR)的径向分布,以讨论星系核区恒星形成率与AGN的关系。主要的工作结果与结论是： (1)从HST STIS长狭缝中共获得M51的24条光谱,径向抽取,区域为其核心两侧,距离核心～50pc(从-43.5pc到43.5pc)。 (2)通过简单星族模型拟合的方法,得到了所有24条径向光谱的星族组成,即得到距M51核心～50pc内径向星族组成分布。发现M51核区年轻星族(小于108yr)的平均光谱流量占总流量的比例为12%,质量比例为0.11%,而在近邻核心(从-6pc到2pc)的范围内并不需要年轻星族。 (3)核心区域(从-6pc到2pc)范围不需要年轻星族的拟合结果,说明在该核心区域区内恒星的形成可能受到AGN反馈作用压抑。 (4)年轻星族的分布在核心两侧并不对称,即从-6pc到2pc,这或许因为M51的AGN对寄主星系的反馈也是不对称的,与M51喷流有关。
[Abstract]:Closely related to the evolution and formation history of galaxies of the same stars, a supermassive black hole at the center of the galaxy and star formation history also have relevance. Studies have shown that Seyfert galaxies around the core area of the center of the star formation rate will be suppressed. Seyfert 2 Galaxy M51 is the nearest neighbor (8.4Mpc), positive vortex galaxy, weak AGN activity and its core, which are conducive to the core area of the stellar population study. This paper using HST-STIS high spatial resolution (~ 2pc) of the grating spectrum of M51, nucleus ~ 50pc range than the star formation rate (SSFR) of the radial distribution, to discussion on the relationship between stars and galaxies nucleus formation rate and AGN.
The main results and conclusions are as follows:
(1) 24 spectra of M51 are obtained from the long slit of HST STIS, radial extraction, the region as its core, and the distance from the core to 50pc (from -43.5pc to 43.5pc).
(2) by a simple population model fitting, get all 24 radial spectra of population composition, from M51 to 50pc to the core diameter distribution is obtained. It is found that the population composition of M51 nucleus of young population (less than 108yr) the average spectral flow rate ratio is 12%, the mass ratio of 0.11%, and in the neighboring core (from -6pc to 2pc) within the range does not need the young population.
(3) the core region (from -6pc to 2pc) range does not need fitting results of young population, indicating the formation of stars in the core region in the region may be suppressed AGN feedback.
(4) the young population distribution in the core of both sides and asymmetry, from -6pc to 2pc, perhaps because feedback is asymmetric M51 AGN on the host galaxy, and M51 jet.

【学位授予单位】：南京师范大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：P152

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