We study the properties of the galaxies hosting the first 19 tidal disruption events (TDEs) detected with the Zwicky Transient Facility (ZTF) within the context of a carefully constructed, representative host galaxy sample. We find that the ZTF sample of TDE hosts is dominated by compact “green valley” galaxies. After we restrict the comparison sample to galaxies with a similar concentration, as measured by the Srsic index, we find this green valley overrepresentation is even larger. That is, concentrated red sequence galaxies are not producing TDEs at elevated levels. We present host galaxy spectra that show that E + A galaxies are overrepresented in the ZTF sample by a factor of ≈22, which is lower than previous TDE host galaxy studies have found. We find that this overrepresentation can be fully accounted for when taking into account the masses, colors, and Srsic indices of the ZTF TDE hosts. The combination of both green colors and high Srsic index of the typical TDE host galaxy could be explained if the TDE rate is temporarily enhanced following a merger that leads to a higher central concentration of stars.

我们研究了在精心构建的代表性宿主星系样本的背景下，使用茨维克瞬变设施（ZTF）检测到的前19个潮汐破坏事件（TDE）所在的星系的属性。我们发现，TDE宿主的ZTF样本主要由紧凑的“绿谷”星系主导。在将比较样本限制为浓度相似的星系（通过Srsic指数测量）后，我们发现此绿色山谷超额表示量甚至更大。也就是说，浓缩的红色序列星系不会产生高水平的TDE。我们提供的宿主星系光谱表明，E + A星系在ZTF样本中的代表度为≈22，这比以前的TDE宿主星系研究发现的要低。我们发现，在考虑到群众时，可以充分考虑到这种过剩的代表，ZTF TDE主机的颜色和Srsic索引。如果合并后会导致TDE速率暂时升高，从而导致更高的恒星中心集中度，则可以解释典型TDE宿主星系的绿色和高Srsic指数的组合。