arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0807.0741astro-ph
收藏

NGC 7070 A和ESO 2400100壳星系的XMM-牛顿X射线和光学监视器远UV观测

XMM-Newton X-ray and Optical Monitor far UV observations of NGC 7070A and ESO 2400100 shell galaxies

G. Trinchieri, R. Rampazzo, C. Chiosi, R. Grutzbauch, A. Marino, R. Tantalo

摘要:

我们目前的XMM-牛顿X射线观测的两个壳星系,NGC 7070 A和ESO 2400100,和远紫外线观测获得的光学监测这些和一个额外的壳星系,NGC 474,我们也有近和远紫外线数据从GALEX。我们的目标是深入了解其恒星形成历史和热气含量所追踪的整体演化。X射线和远紫外数据被用来推导它们的X射线空间和光谱特性以及它们的紫外光度分布。我们使用专门开发的模型来研究恒星形成的最后一幕的年龄(紫外光)颜色和线强度指数。X射线空间和光谱分析表明,这两个对象的显着差异。NGC 7070 A在2-10 keV波段的主要成分是低光度核源,log LX =41.7 erg s^{-1}。在ESO 2400100中,X射线发射是由于低温等离子体以及来自单个源的集体发射的贡献。ESO 2400100的光学监视器图像显示了一个双核,一个比另一个更蓝。这可能是由于最近在北核区域的恒星形成事件。紫外辐射的延伸与所有星系的光学范围一致,在不同的过滤器中具有不同的意义。通过(紫外光学)颜色和谱线强度指数分析证实了双核的存在,这表明ESO 2400100正在吸积一个暗淡的伴星。我们探讨了吸积过程中X射线光度随时间的演化。我们讨论了气体的存在和年龄之间的联系,因为气体要么在聚结之前被检测到,要么在聚结之后几个Gyr(>3)被检测到。

英文摘要:

We present XMM-Newton X-ray observations of two shell galaxies, NGC 7070A and ESO 2400100, and far UV observations obtained with the Optical Monitor for these and for an additional shell galaxy, NGC 474, for which we also have near and far UV data from GALEX. We aim at gaining insight on the overall evolution traced by their star formation history and by their hot gas content. The X-ray and the far UV data are used to derive their X-ray spatial and spectral characteristics and their UV luminosity profiles. We use models developed ad hoc to investigate the age of the last episode of star formation from the (UV - optical) colors and line strength indices. The X-ray spatial and spectral analysis show significant differences in the two objects. A low luminosity nuclear source is the dominant component in NGC 7070A log L_X=41.7 erg s^{-1} in the 2-10 keV band. In ESO 2400100, the X-ray emission is due to a low temperature plasma with a contribution from the collective emission of individual sources. In the Optical Monitor image ESO 2400100 shows a double nucleus, one bluer than the other. This probably results from a very recent star formation event in the northern nuclear region. The extension of the UV emission is consistent with the optical extent for all galaxies, at different degrees of significance in different filters. The presence of the double nucleus, corroborated by the (UV - optical) colors and line strength indices analysis, suggests that ESO 2400100 is accreting a faint companion. We explore the evolution of the X-ray luminosity during accretion processes with time. We discuss the link between the presence of gas and age, since gas is detected either before coalescence or several Gyr (>3) after (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。

↑