Speaker
Description
The observation of very high energy ($\rm VHE: >100GeV$) photon from $\gamma$-ray bursts (GRBs) can advance our understanding of their radiation mechanism, the evolution of host-galaxies, violations of Lorentz invariance, extragalactic background light, and intergalactic magnetic field. Recently the measurements on VHE emission from afterglow phase have blossomed and borne fruit while results of the prompt emission is null. It's important to observe prompt emissions by ground-based instruments which take advantage of wide field of view and high duty cycle. Up to now, of the total 6 GRBs reported with VHE $\gamma$-ray emissions, $\rm GRB~190829A$ is the nearest one. The detection of its VHE emission was announced by HESS at about 4h 20m after the burst. While during its prompt phase, $\rm GRB~190829A$ was at the edge of the field of view of LHAASO. Benefiting by the high altitude of 4430 m and the triggerless observation mode, the energy threshold of LHAASO is largely reduced to tens of GeV. This work presents the search for VHE $\gamma$-ray emission from $\rm GRB~190829A$ with the triggerless data taken by the first pond of LHAASO-WCDA. The analysis shows no indication of VHE emission neither in the prompt nor in $\rm2$ hours afterglow phase, thus $95\%$ upper limits are yielded.
Keywords
GRB, VHE Gamma ray emission, LHAASO
| Subcategory | Experimental Results |
|---|---|
| Collaboration | Lhaaso |
