Search for high energy gamma-ray emission from tidal disruption events with the Fermi Large Area Telescope

Abstract

Massive black holes at galaxy center may tear apart a star when the star passes occasionally within the disruption radius, which is the so-called tidal disruption event(TDE). Most TDEs radiate with thermal emission resulted from the accretion disk, but three TDEs have been detected in bright non-thermal X-ray emission, which is interpreted as arising from the relativistic jets. Search for high-energy gamma-ray emission from one relativistic TDE (Swift J164449.3+573451) with the \textsl{Fermi} Large Area Telescope (LAT) has yielded non-detection. In this paper, we report the search for high energy emission from the other two relativistic TDEs (Swift J2058.4+0516 Swift J1112.2-8238) during the flare period. No significant GeV emission is found, with an upper limit fluence in LAT energy range being less than $1\%$ of that in X-rays. Compared with gamma-ray bursts (GRBs) and blazars, these TDEs have the lowest flux ratio between GeV emission and X-ray emission. The non-detection of high-energy emission from relativistic TDEs could be due to that the high-energy emission is absorbed by soft photons in the source. Based on this hypothesis, upper limits on the bulk Lorentz factors, $Γ\la 30$, are then obtained for the jets in these TDEs. We also search for high-energy gamma-ray emission from the nearest TDE discovered to date, ASASSN-14li. No significant GeV emission is found and an upper limit of $L(0.1-10GeV)\le 4.4\times 10^{42}$ erg s${}^{-1}$ (at $95\%$ confidence level) is obtained for the first $10^7$ s after the disruption.

Accepted by ApJ, 6 pages, 3 figures

References in corpus (6)

• Six Months of Multi-Wavelength Follow-up of the Tidal Disruption Candidate ASASSN-14li and Implied TDE Rates from ASAS-SN
• Swift J1112.2-8238: A Candidate Relativistic Tidal Disruption Flare
• Annihilation Emission from the Galactic Black Hole
• Diffuse Gamma-ray Emission from the Galactic Center - A Multiple Energy Injection Model
• Quasi-Periodic Variations in X-ray Emission and Long-Term Radio Observations: Evidence for a Two-Component Jet in Sw J1644+57
• The extension of variability properties in gamma-ray bursts to blazars

Cited by in corpus (4)

• New physical insights about Tidal Disruption Events from a comprehensive observational inventory at X-ray wavelengths
• Jets from Tidal Disruption Events
• Search for GeV and X-ray flares associated with the IceCube track-like neutrinos
• Detection of GeV emission from an ultra-long gamma-ray burst with the Fermi Large Area Telescope