Detection of Very high energy gamma-ray flare from the blazar Mrk 421 with MACE
ATel #16537; K K Yadav on behalf of MACE team (Bhabha Atomic Research Centre, Mumbai, India)
on 18 Mar 2024; 13:51 UT
Credential Certification: Kuldeep Yadav (kkyadav@barc.gov.in)
Subjects: Gamma Ray, >GeV, TeV, VHE, AGN, Blazar
MACE (Major Atmospheric Cherenkov Experiment) has detected a giant gamma-ray flaring activity from a nearby blazar Mrk 421 (z=0.031, RA: 11h 05m 37.12s, Dec: 38o 04'3.5'') at very high energies on the night of March 16, 2024. The preliminary analysis of data collected in the direction of source for a live time of about 70 minutes indicates presence of a strong gamma-ray signal with a statistical significance of nearly 12.7 sigma. The emission level is characterized by an integral flux of approximately 70% of the Crab Nebula flux in the energy range above 60 GeV. The differential energy spectrum of the source is described by a simple power law of spectral index 2.4 ± 0.1.
These preliminary results on Mrk 421, obtained with MACE, complement the stereoscopic observations of the source using two SST-1M telescopes on the night of March 13, 2024 for a live time of 3.3 hours (AteL # 16533). The MACE telescope will not be able to continue the monitoring of the source due to unavailability of dark period. However, multi-wavelength observations of the source are encouraged.
MACE is a newly commissioned large sized imaging atmospheric Cherenkov telescope located at Hanle (32.8o N, 78.9oE, 4270m above mean sea level), Ladakh, in India. It is equipped with a large quasi-parabolic light collector of 21m diameter and an imaging camera comprising of 1088 photomultiplier tubes with a pixel resolution of 0.125o (K K Yadav et al. Current Science, 2022, 123, 1428, and C. Borwankar et al. Astroparticle Physics, 2024, 102960).
