论文标题
吸收线通过三个本地组矮星系光环搜索
Absorption Line Search Through Three Local Group Dwarf Galaxy Halos
论文作者
论文摘要
矮星系几乎缺少来自恒星磁盘的所有重子和金属，这些磁盘被认为处于绑定的光晕或被驱逐出病毒半径之外。带有$ M _ {\ rm H} \ SIM 10^9-10^{10} $ $ M _ {\ odot} $的星系的病毒温度与C IV离子的碰撞电离平衡温度相似。我们搜索了从六个视线中的C IV吸收的紫外线吸收，沿抗M31方向和本地组的外围搜索了三个小矮星系（$ d \ $ 1.3 mpc; sextans a，sextans a，sextans b和ngc 3109）。仅在六个视线之一中检测到C IV Doublet，朝向六片A，其中$ \ log n（{\ rm c iv}）$ = $ 13.06 \ pm 0.08 $。这与我们的气态光环模型一致，在该模型中，光环气体质量取决于冷却速率，反馈和恒星形成速率。摄影的包含是必不可少的成分。该模型还可以重现其他矮人样品中O VI吸收的较高检测率（除本地组之外），并且只能在$ \ sim 0.5r _ {\ rm vir} $中检测到C IV。
Dwarf galaxies are missing nearly all of their baryons and metals from the stellar disk, presumed to be in a bound halo or expelled beyond the virial radius. The virial temperature for galaxies with $M_{\rm h} \sim 10^9 - 10^{10}$ $M_{\odot}$ is similar to the collisional ionization equilibrium temperature for the C IV ion. We searched for UV absorption from C IV in six sightlines toward three dwarf galaxies in the anti-M31 direction and at the periphery of the Local Group ($D \approx$ 1.3 Mpc; Sextans A, Sextans B, and NGC 3109). The C IV doublet is detected in only one of six sightlines, toward Sextans A, with $\log N({\rm C IV})$ = $13.06 \pm 0.08$. This is consistent with our gaseous halo models, where the halo gas mass is determined by the cooling rate, feedback, and the star formation rate; the inclusion of photoionization is an essential ingredient. This model can also reproduce the higher detection rate of O VI absorption in other dwarf samples (beyond the Local Group), and with C IV only detectable within $\sim 0.5R_{\rm vir}$.
