The nature of LINER galaxies: Ubiquitous hot old stars and rare accreting black holes-猫眼课题宝

DOI：

10.1051/0004-6361/201322062

发表时间：

2013-08

期刊：

Proceedings of the International Astronomical Union

影响因子：

通讯作者：

中科院分区：

其他

文献类型：

作者：

R. Singh;G. Ven;K. Jahnke;M. Lyubenova;J. Falcón-Barroso;J. Falcón-Barroso;João Alves;R. C. Fernandes;L. Galbany;R. García-Benito;B. Husemann;R. Kennicutt;R. Marino;I. Márquez;J. Masegosa;D. Mast;A. Pasquali;Sebastián F. Sánchez;J. Walcher;Vivienne Wild;L. Wisotzki;B. Ziegler

摘要镓通常含有电离气体，有时也会出现所谓的低电离核发射线区（LINER）。30年来，这被归因于一个中心质量吸积的低光度超大质量黑洞（更常被称为活动星系核或AGN），使LINER星系成为最大的AGN子群体，在数量上超过了更高的AGN光度的塞弗特星系和类星体。然而，这造成了一个严重的问题。虽然推断出的能量平衡是合理的，但许多LINER显然不包含活动星系核的任何其他独立特征。使用来自CALIFA调查的积分场光谱数据，我们将观察到的径向表面亮度轮廓与活动星系核照明的预期进行了比较。对于48个星系LINER类发射，我们表明，径向发射线表面亮度轮廓是不一致的电离中心点源，因此不能单独由于活动星系核。对于过量的LINER类辐射，最可能的解释是在被称为后AGB的短暂但非常热和充满活力的阶段中，演化的恒星电离。这就引出了一个全新的解释。后AGB恒星无处不在，它们的电离效应应该在每个存在气体和恒星年龄大于1 Gyr的星系中都可以观察到，除非来自年轻热恒星或AGN的更强辐射场超过它们。这意味着，具有LINER类发射的星系不是由属性定义的一类，而是由缺乏属性定义的一类。这也解释了为什么LINER辐射主要在有老恒星和很少有星星形成的大质量星系中观察到。

Abstract Galaxies, which often contain ionised gas, sometimes also exhibit a so-called low-ionisation nuclear emission line region (LINER). For 30 years, this was attributed to a central mass-accreting supermassive black hole (more commonly known as active galactic nucleus or AGN) of low luminosity, making LINER galaxies the largest AGN sub-population, which dominate in numbers over higher AGN-luminosity Seyfert galaxies and quasars. This, however, poses a serious problem. While the inferred energy balance is plausible, many LINERs clearly do not contain any other independent signatures of an AGN. Using integral field spectroscopic data from the CALIFA survey, we compare the observed radial surface brightness profiles with what is expected from illumination by an AGN. For 48 galaxies with LINER-like emission we show, that the radial emission-line surface brightness profiles are inconsistent with ionisation by a central point-source and hence cannot be due to an AGN alone. The most probable explanation for the excess LINER-like emission is ionisation by evolved stars during the short but very hot and energetic phase known as post-AGB. This leads us to an entirely new interpretation. Post-AGB stars are ubiquitous and their ionising effect should be potentially observable in every galaxy with gas present and with stars older than ~1 Gyr, unless a stronger radiation field from young hot stars or an AGN outshines them. This means, that galaxies with LINER-like emission are not a class defined by a property but rather by the absence of a property. It also explains why LINER emission is observed mostly in massive galaxies with old stars and little star formation.

The nature of LINER galaxies: Ubiquitous hot old stars and rare accreting black holes

文献摘要

被引文献

相似文献