arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1306.2338astro-ph.CO
收藏

CALIFA早型星系的星云辐射和Lyman连续谱光子逃逸分数

Nebular emission and the Lyman continuum photon escape fraction in CALIFA early-type galaxies

P. Papaderos, J. M. Gomes, J. M. Vilchez, C. Kehrig, M. D. Lehnert, B. Ziegler, S. F. Sanchez, B. Husemann, A. Monreal-Ibero, R. Garcia-Benito, J. Bland-Hawthor… 展开作者

P. Papaderos, J. M. Gomes, J. M. Vilchez, C. Kehrig, M. D. Lehnert, B. Ziegler, S. F. Sanchez, B. Husemann, A. Monreal-Ibero, R. Garcia-Benito, J. Bland-Hawthorn, C. Coritjo, A. de Lorenzo-Caceres, A. del Olmo, J. Falcon-Barroso, L. Galbany, J. Iglesias-Paramo, A. R. Lopez-Sanchez, I. Marquez, M. Molla, D. Mast, G. van de Ven, L. Wisotzki, the CALIFA collaboration

摘要:

利用CALIFA巡天的深积分场光谱数据对32个邻近早型星系的暖星际介质进行了研究。我们提出了一个尝试性的细分我们的样本ETGs分为两组,根据他们的哈等效宽度(EW)和莱曼连续(LyC)光子逃逸分数(PLF)。类型i ETG显示出几乎恒定的EW和PLF~0,这表明后AGB星的光电离是其微弱的双核星云发射的主要驱动力。II型ETG的特征在于非常低的、向外增加的EW,以及在它们的中心处大至约0.9的PLF。这样的性质指向低的且向内减小的WIM密度和/或体积填充因子。我们认为,由于广泛的LyC光子泄漏,发射线的亮度和电子战减少了至少一个数量级的II型ETG核。因此,这些ETG的线弱点本身并没有令人信服的证据表明它们只包含“弱”(亚爱丁顿吸积)的活动星系核(AGN)。事实上,LyC光子逃逸,这迄今尚未被考虑,可能构成一个关键因素,在理解为什么许多ETG的活动星系核活动在无线电连续谱和/或X射线波长的突出签名只显示微弱的发射线和活动星系核活动的微弱签名在其光谱。的LyC光子逃逸,结合稀释的核电子战的视线整合通过一个三轴恒星主机,可以系统地阻碍检测活动星系核的气体贫乏的星系球状体通过光学发射线光谱。我们进一步发现,i型和ii型ETG在其平均BPT线比率方面差异很小(约0.4 dex),这在两种情况下都是LINER的特征。这可能暗示了ETG中WIM的特定3D属性的投影亮度加权BPT比的简并性。(节略)

英文摘要:

We use deep integral field spectroscopy data from the CALIFA survey to study the warm interstellar medium (WIM) of 32 nearby early-type galaxies (ETGs). We propose a tentative subdivision of our sample ETGs into two groups, according to their Ha equivalent width (EW) and Lyman continuum (LyC) photon escape fraction (PLF). Type i ETGs show nearly constant EWs and a PLF~0, suggesting that photoionization by post-AGB stars is the main driver of their faint extranuclear nebular emission. Type ii ETGs are characterized by very low, outwardly increasing EWs, and a PLF as large as ~0.9 in their centers. Such properties point to a low, and inwardly decreasing WIM density and/or volume filling factor. We argue that, because of extensive LyC photon leakage, emission-line luminosities and EWs are reduced in type ii ETG nuclei by at least one order of magnitude. Consequently, the line weakness of these ETGs is by itself no compelling evidence for their containing merely "weak" (sub-Eddington accreting) active galactic nuclei (AGN). In fact, LyC photon escape, which has heretofore not been considered, may constitute a key element in understanding why many ETGs with prominent signatures of AGN activity in radio continuum and/or X-ray wavelengths show only faint emission lines and weak signatures of AGN activity in their optical spectra. The LyC photon escape, in conjunction with dilution of nuclear EWs by line-of-sight integration through a triaxial stellar host, can systematically impede detection of AGN in gas-poor galaxy spheroids through optical emission-line spectroscopy. We further find that type i and ii ETGs differ little (~0.4 dex) in their mean BPT line ratios, which in both cases are characteristic of LINERs. This potentially hints at a degeneracy of the projected, luminosity-weighted BPT ratios for the specific 3D properties of the WIM in ETGs. (abridged)

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。

↑