*4.4. GRB 201015A*

GRB 201015A was detected by *Swift*-BAT and followed-up by MAGIC, which reported an excess at the level of >3*σ* in [75,90]. MAGIC observation started from 33 s after *T*0, lasting for about 4 h under good weather conditions. The evidence of emission is found above an energy threshold of ∼140 GeV. This GRB has some properties similar to GRB 190829A, in particular, the isotropic energy release *<sup>E</sup>*iso∼10<sup>50</sup> erg; however, it is located at a much farther distance *z* = 0.423, resulting in a stronger flux attenuation due to the EBL. With the publication of MAGIC data on this GRB, a more detailed comparison with GRB 190829A will be possible, giving more insights into VHE GRBs with rather low luminosity.

The observations performed by MAGIC and H.E.S.S. established the presence of a VHE emission component in both the early and late afterglow phase. For the former, the fast repositioning and reaction of the MAGIC telescopes played a fundamental role. For the latter, the merit is the well-thought strategy based on observational results from other bands. In both cases, these results have proved to be complementary, providing insights into the nature of GRBs and their VHE detectability at different times, constituting an important lesson for the future observation strategies of next-generation VHE facilities.
