http://arxiv.org/abs/2105.14026
We consider collisions between stars moving near the speed of light around supermassive black holes (SMBHs), with mass $M_{\bullet}\gtrsim10^8\,M_{\odot}$, without being tidally disrupted. The overall rate for collisions taking place in the inner $\sim1$ pc of galaxies with $M_{\bullet}=10^8,10^9,10^{10}\,M_{\odot}$ are $\Gamma\sim5,0.07,0.02$ yr$^{-1}$, respectively. We further calculate the differential collision rate as a function of total energy released, energy released per unit mass lost, and galactocentric radius. The most common collisions will release energies on the order of $\sim10^{49}-10^{51}$ erg, with the energy distribution peaking at higher energies in galaxies with more massive SMBHs. Depending on the host galaxy mass and the depletion timescale, the overall rate of collisions in a galaxy ranges from a small percentage to several times larger than that of core-collapse supernovae (CCSNe) for the same host galaxy. In addition, we show example light curves for collisions with varying parameters, and find that the peak luminosity could reach or even exceed that of superluminous supernovae (SLSNe), although with light curves with much shorter duration. Weaker events could initially be mistaken for low-luminosity supernovae. In addition, we note that these events will likely create streams of debris that will accrete onto the SMBH and create accretion flares that may resemble tidal disruption events (TDEs).
B. Hu and A. Loeb
Tue, 1 Jun 21
38/72
Comments: 9 pages, 6 figures
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