We present measurements of the restframe UV spectral slope,
We search for features in the mass distribution of detected compact binary coalescences which signify the transition between neutron stars (NSs) and black holes (BHs). We analyze all gravitationalwave (GW) detections by the LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration (LVK) made through the end of the first half of the third observing run, and find clear evidence for two different populations of compact objects based solely on GW data. We confidently (99.3%) find a steepening relative to a single power law describing NSs and lowmass BHs below
 NSFPAR ID:
 10486132
 Publisher / Repository:
 DOI PREFIX: 10.3847
 Date Published:
 Journal Name:
 The Astrophysical Journal
 Volume:
 931
 Issue:
 2
 ISSN:
 0004637X
 Format(s):
 Medium: X Size: Article No. 108
 Size(s):
 ["Article No. 108"]
 Sponsoring Org:
 National Science Foundation
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