OUTFLOWS IN SODIUM EXCESS OBJECTS

OUTFLOWS IN SODIUM EXCESS OBJECTS
复制标题

钠过量对象的流出

DOI：
--
复制
发表时间：
2015
期刊：
影响因子：
--
通讯作者：
S. Yi
S. Yi
中科院分区：
--
文献类型：
--
作者：
Jongwon Park;Hyunjin Jeong;S. Yi

文献摘要

被引文献

相似文献

货车Dokkum和Conroy重新研究了在一些巨大的椭圆星系中发现的8200 nm处出乎意料的强Na i线，并将其解释为异常底部重的初始质量函数的证据。Jeong等人后来发现大量星系在5900 nm处显示出同样非凡的Na-D双重吸收线（Na-D过量天体：近地天体），并表明它们的起源可能因不同类型的星系而异。虽然Na-D过量似乎与晚型星系中的星际介质有关，但外观光滑的早型近地天体很少或没有尘埃消光，因此没有令人信服的迹象表明星际介质的贡献。为了进一步验证这一发现，我们测量了多普勒成分的Na-D线。我们假设，ISM将有一个更好的机会（虽然不确定）显示蓝移多普勒离开大部分的恒星人口由于流出造成的星星形成或活动星系核活动。许多晚型近地天体的Na-D线明显出现蓝移，这与以前的解释一致，即在这些天体中发现的Na-D过量与星星形成造成的气体外流有关。相反，看上去光滑的早期型近地天体没有显示出任何明显的多普勒成分，这也与Jeong等人的解释相一致，即早期型近地天体中Na-D过量可能与ISM活动无关，而纯粹是恒星来源。
Van Dokkum and Conroy revisited the unexpectedly strong Na i lines at 8200 Å found in some giant elliptical galaxies and interpreted them as evidence for an unusually bottom-heavy initial mass function. Jeong et al. later found a large population of galaxies showing equally extraordinary Na D doublet absorption lines at 5900 Å (Na D excess objects: NEOs) and showed that their origins can be different for different types of galaxies. While a Na D excess seems to be related to the interstellar medium (ISM) in late-type galaxies, smooth-looking early-type NEOs show little or no dust extinction and hence no compelling signs of ISM contributions. To further test this finding, we measured the Doppler components in the Na D lines. We hypothesized that the ISM would have a better (albeit not definite) chance of showing a blueshift Doppler departure from the bulk of the stellar population due to outflow caused by either star formation or AGN activities. Many of the late-type NEOs clearly show blueshift in their Na D lines, which is consistent with the former interpretation that the Na D excess found in them is related to gas outflow caused by star formation. On the contrary, smooth-looking early-type NEOs do not show any notable Doppler components, which is also consistent with the interpretation of Jeong et al. that the Na D excess in early-type NEOs is likely not related to ISM activities but is purely stellar in origin.