| タイトル | The First Detection of [O IV] from an Ultraluminous X-ray Source with Spitzer |
| 本文（外部サイト） | http://hdl.handle.net/2060/20090012461 |
| 著者（英） | Kallman, T. R.; Dudik, R. P.; Weaver, K. A.; Berghea, C. T. |
| 著者所属（英） | NASA Goddard Space Flight Center |
| 発行日 | 2009-01-01 |
| 言語 | eng |
| 内容記述 | This is the second of two papers examining Spitzer Infrared Spectrograph (IRS) observations of the ultraluminous X-ray source (ULX) in Holmberg II. Here we perform detailed photoionization modeling of the infrared lines. Our analysis suggests that the luminosity and morphology of the [O IV] 25.89 micron emission line is consistent with photoionization by the soft X-ray and far ultraviolet (FUV) radiation from the accretion disk of the binary system and inconsistent with narrow beaming. We show that the emission nebula is matter-bounded both in the line of sight direction and to the east, and probably radiation-bounded to the west. A bolometric luminosity in excess of 10(exp 40) erg/s would be needed to produce the measured [O IV] flux. We use modeling and previously published studies to conclude that shocks likely contribute very little, if at all, to the high-excitation line fluxes observed in the Holmberg II ULX. Additionally, we find that the spectral type of the companion star has a surprisingly strong effect on the predicted strength of the [O IV] emission. This finding could explain the origin of [O IV] in some starburst systems containing black hole binaries. |
| NASA分類 | Astronomy |
| 権利 | Copyright, Distribution as joint owner in the copyright |
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