标题： 使用斯皮策望远镜首次探测到来自超亮X射线源的[O IV]。 Ⅱ. 霍尔姆伯格二号超亮X射线源具有高亮度的证据 显示英文标题

标题： The First Detection of [O IV] from an Ultraluminous X-ray Source with Spitzer. II. Evidence for High Luminosity in Holmberg II ULX

摘要： 这是两篇研究斯皮策红外光谱仪（IRS）观测星系晕II中超亮X射线源（ULX）的第二篇。在这里我们对红外线进行了详细的光致电离建模。我们的分析表明，[O IV] 25.89 $\mu$m发射线的亮度和形态与双星系统吸积盘发出的软X射线和远紫外线（FUV）辐射的光致电离一致，与窄束流不一致。我们展示了发射星云在视线方向以及东方是物质限制的，并且可能在西方是辐射限制的。为了产生所测量到的[O IV]流量，需要超过10$^{40}$ erg s$^{-1}$的全波段亮度。我们通过建模和之前发表的研究得出结论，冲击可能对我们在星系晕II ULX中观察到的高电离线流量几乎没有贡献，甚至没有贡献。此外，我们发现伴星的光谱类型对[O IV]发射强度的预测值有令人惊讶的强大影响。这一发现可以解释一些包含黑洞双星系统的恒星形成星系中[O IV]的起源。 显示英文摘要

摘要： 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 $\mu$m 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$^{40}$ erg s$^{-1}$ 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-ionization 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.