论文标题
在季后赛星系中,主动银河核是推动变化还是乘车的星系?
Are Active Galactic Nuclei in Post-Starburst Galaxies Driving the Change or Along for the Ride?
论文作者
论文摘要
我们介绍了对12个震惊的季后星系星系的10 ks快照Chandra观测值的分析,该观察结果为恒星后星系中活跃的银河核(AGN)活性的未解决问题提供了一个窗口,及其在从活跃的恒星形成到静止状态的星系过渡中的作用。尽管7/12星系具有统计学上的显着检测(还有2个边缘检测),但最亮仅获得了10个光子。鉴于该样品中的硬度比各种多种多样,我们选择采用一种正向建模的方法来限制这些星系的内在光度和遮挡,而不是堆叠。我们根据计数和频谱形状的总数和光谱形状的总数来限制被模糊的幂律的内在光度,其本身主要是由晦涩的,硬度比与数据一致。我们还测试了热模型。尽管所有星系都具有与观测值一致的幂律模型,但三分之一的星系更适合作为模糊的幂律,而另外三分之一则更适合作为热发射。如果这些后星星的星系在过渡的早期包含AGN,那么这些星系主要局限于较低的遮阳度($ n_h \ leq10^{23} $ cm $ $^{ - 2} $)和较低的发光度($ l_ {$ l_ {2-10〜 \ rm kev} \ rm kev} \ leq \ leq10^$ s $ s $ s $ s $但是,两个星系显然是明显遮盖的AGN。该样品中至少有一半显示了至少低光度AGN活性的证据,尽管没有一个可以辐射驱动剩余的分子气储存库。因此,这些AGN更有可能乘坐,因为通过推动过渡的相同过程喂食气体。
We present an analysis of 10 ks snapshot Chandra observations of 12 shocked post-starburst galaxies, which provide a window into the unresolved question of active galactic nuclei (AGN) activity in post-starburst galaxies and its role in the transition of galaxies from actively star forming to quiescence. While 7/12 galaxies have statistically significant detections (with 2 more marginal detections), the brightest only obtained 10 photons. Given the wide variety of hardness ratios in this sample, we chose to pursue a forward modeling approach to constrain the intrinsic luminosity and obscuration of these galaxies rather than stacking. We constrain intrinsic luminosity of obscured power-laws based on the total number of counts and spectral shape, itself mostly set by the obscuration, with hardness ratios consistent with the data. We also tested thermal models. While all the galaxies have power-law models consistent with their observations, a third of the galaxies are better fit as an obscured power-law and another third are better fit as thermal emission. If these post-starburst galaxies, early in their transition, contain AGN, then these are mostly confined to a lower obscuration ($n_H \leq10^{23}$ cm$^{-2}$) and lower luminosity ($L_{2-10~ \rm keV}\leq10^{42}$erg s$^{-1}$). Two galaxies, however, are clearly best fit as significantly obscured AGN. At least half of this sample show evidence of at least low luminosity AGN activity, though none could radiatively drive out the remaining molecular gas reservoirs. Therefore, these AGN are more likely along for the ride, having been fed gas by the same processes driving the transition.