论文标题
XGASS：在全球HI光谱中对不对称的强大量化及其与环境过程的关系
xGASS: Robust quantification of asymmetries in global HI spectra and their relationship to environmental processes
论文作者
论文摘要
我们介绍了扩展的Galex Arecibo SDSS调查（XGASS）的全球HI光谱中的不对称分析，这是一种恒星质量选择的和气体分数的调查，代表了当地宇宙中星系的HI性质。我们证明，HI频谱中的不对称性与其信号到噪声密切相关，这意味着与以前的工作中所做的相反，不同样品的不对称分布无法在面值时比较。我们开发了一种说明噪声引起的不对称性的方法，发现XGASS检测到的典型星系表现出高于单独归因于噪声的不对称性，其中37％的样本显示在80％置信度下的不对称性大于10％。我们发现，与在恒星质量和信噪比中匹配的对称对应物相比，不对称星系的HI质量平均少29％。我们还提供了明确的证据表明，与中心的卫星星系相比，卫星星系表现出更多的不对称HI光谱，与孤立的中心相比，该组中央星系显示出HI不对称率略高。所有这些结果都支持一种场景，在这种情况下，环境过程，尤其是负责去除气体的人，是XGASS中不对称的主要驱动因素。
We present an analysis of asymmetries in global HI spectra from the extended GALEX Arecibo SDSS Survey (xGASS), a stellar mass-selected and gas fraction-limited survey which is representative of the HI properties of galaxies in the local Universe. We demonstrate that the asymmetry in a HI spectrum is strongly linked to its signal-to-noise meaning that, contrary to what was done in previous works, asymmetry distributions for different samples cannot be compared at face value. We develop a method to account for noise-induced asymmetry and find that the typical galaxy detected by xGASS exhibits higher asymmetry than what can be attributed to noise alone, with 37% of the sample showing asymmetry greater than 10% at an 80% confidence level. We find that asymmetric galaxies contain, on average, 29% less HI mass compared to their symmetric counterparts matched in both stellar mass and signal-to-noise. We also present clear evidence that satellite galaxies, as a population, exhibit more asymmetric HI spectra than centrals and that group central galaxies show a slightly higher rate of HI asymmetries compared to isolated centrals. All these results support a scenario in which environmental processes, in particular those responsible for gas removal, are the dominant driver of asymmetry in xGASS.
