Absorption-based circumgalactic medium line emission estimates
Absorption-based circumgalactic medium line emission estimates
复制标题
基于吸收的环河中线排放估算
DOI：
10.1093/mnras/stac2390
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发表时间：
2022
影响因子：
4.8
通讯作者：
McQuinn, Matthew
中科院分区：
文献类型：
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作者：
Piacitelli, Daniel R.;Solhaug, Erik;Faerman, Yakov;McQuinn, Matthew
在大型地面望远镜积分场单位(IFU)和使用紫外线敏感空间望远镜探测环绕星系介质(CGM)发射的提议的推动下，我们调查了最有希望的发射线，以及这些观测如何有助于我们对CGM及其与星系形成的关系的理解。我们将我们的排放估计与z≈0.2银河系质量晕周围离子的HST/COS吸收测量以及气体密度和温度模型联系在一起。我们还提供了简化将我们的估计扩展到其他样本和物理场景的公式。我们发现，在固定离子柱密度下主要对它们所在气体的热压敏感的OIII5007 ä和Nii6583 ä，可以用KCW，特别是30 m望远镜半径为0.5维里半径的IFU探测到。Ov630 ä和Ovi1032,1038 ä可能是最有希望的紫外线线，模型预测了银河系内部100γ−2s−1SR−1的强度&100 kpc。对Ovii的探测将确认碰撞电离图像，并限制CGM的密度分布。其他紫外线金属线限制了活跃冷却和混合的气体的数量。我们发现，如果观测到的Ovicolum中相当大一部分与混合或冷却气体有关，则可以检测到Cii978 ä和Civ1548 ä。即使是来自电离背景荧光的最小信号，类银河系星系的H-α发射也在当前IFU的范围内，而H-N>；2 Ly系列谱线太弱，无法被探测到。
Motivated by integral field units (IFUs) on large ground telescopes and proposals for ultraviolet-sensitive space telescopes to probe circumgalactic medium (CGM) emission, we survey the most promising emission lines and how such observations can inform our understanding of the CGM and its relation to galaxy formation. We tie our emission estimates to bothHST/COS absorption measurements of ions aroundz≈ 0.2 Milky Way mass haloes and models for the density and temperature of gas. We also provide formulas that simplify extending our estimates to other samples and physical scenarios. We find that Oiii5007 Å and Nii6583 Å, which at fixed ionic column density are primarily sensitive to the thermal pressure of the gas they inhabit, may be detectable with KCWI and especially IFUs on 30 m telescopes out to half a virial radius. Ov630 Å and Ovi1032,1038 Å are perhaps the most promising ultraviolet lines, with models predicting intensities >100 γ cm−2s−1sr−1in the inner 100 kpc of Milky Way-like systems. A detection of Oviwould confirm the collisionally ionized picture and constrain the density profile of the CGM. Other ultraviolet metal lines constrain the amount of gas that is actively cooling and mixing. We find that Ciii978 Å and Civ1548 Å may be detectable if an appreciable fraction of the observed Ovicolumn is associated with mixing or cooling gas. H α emission withinkpc of Milky Way-like galaxies is within reach of current IFUs even for the minimum signal from ionizing background fluorescence, while hydrogenn> 2 Ly-series lines are too weak to be detectable.