Evidence for the Preferential Disruption of Moderately Massive Stars by Supermassive Black Holes
Abstract

Tidal disruption events (TDEs) provide a unique opportunity to probe the stellar populations around supermassive black holes (SMBHs). By combining light-curve modeling with spectral line information and knowledge about the stellar populations in the host galaxies, we are able to constrain the properties of the disrupted star for three TDEs. The TDEs in our sample have UV spectra, and measurements of the UV Niiito Ciiiline ratios enabled estimates of the nitrogen-to-carbon abundance ratios for these events. We show that the measured nitrogen line widths are consistent with originating from the disrupted stellar material dispersed by the central SMBH. We find that these nitrogen-to-carbon abundance ratios necessitate the disruption of moderately massive stars (≳1–2M). We determine that these moderately massive disruptions are overrepresented by a factor of ≳102when compared to the overall stellar population of the post-starburst galaxy hosts. This implies that SMBHs are preferentially disrupting higher mass stars, possibly due to ongoing top-heavy star formation in nuclear star clusters or to dynamical mechanisms that preferentially transport higher mass stars to their tidal radii.

Authors:
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Award ID(s):
Publication Date:
NSF-PAR ID:
10361626
Journal Name:
The Astrophysical Journal
Volume:
924
Issue:
2
Page Range or eLocation-ID:
Article No. 70
ISSN:
0004-637X
Publisher:
DOI PREFIX: 10.3847
National Science Foundation
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