4.5.2. VHE Observations and Results

The final results from VHE data analysis of GRB 201015A have not been published yet. Preliminary information reported here have been released in [216,217]. Observations of GRB 201015A were performed by the MAGIC telescopes starting 33 s after the trigger time, under dark conditions, with a zenith angle ranging from 24◦ up to 48◦ , and lasted for about 4 h. In the second half of the data, taking the presence of passing clouds affected the observation for ∼0.45 h. These data were removed and the remaining ones were analyzed with the standard MAGIC analysis software. Offline analysis showed a possible excess with a 3.5*σ* significance at the GRB position (see Figure 26) and a significant spot in the sky map. The energy threshold of the analysis is calculated to be 140 GeV from Monte Carlo simulated *γ*-ray data.

**Figure 26.** GRB 201015A: distribution of the angular distance *θ* <sup>2</sup> between the reconstructed event arrival directions and the nominal source position. The gray histogram represents background events while the black point with blue crosses are the *γ*-like events. The vertical dashed line describes the *θ* 2 cut value and defines the region in which excess events and signal significance are calculated. From [217].
