MACE detection of very high energy gamma-ray flare from the radio galaxy NGC 1275
ATel #15823; K. K. Yadav (Bhabha Atomic Research Centre, Mumbai, India)
on 23 Dec 2022; 13:02 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Kuldeep Yadav (kkyadav@barc.gov.in)
Subjects: Gamma Ray, >GeV, TeV, VHE, AGN, Transient
The MACE (Major Atmospheric Cherenkov Experiment) telescope has detected very high energy gamma-ray signal from the radio galaxy NGC 1275 (RA=03:19:48.1, DEC=+41:30:42, J2000.0, z=0.0179) during its recent flaring episode reported by Fermi-LAT, MAGIC and LST-1 collaborations (Atel # 15819, 15820). The MACE was deployed for monitoring the source on the night of December 21-22, 2022 (MJD 59934.597 â 59934.773) for a total observation time of approximately 250 minutes in the zenith angle range of 10 - 30 degree. Preliminary analysis of clean data indicates detection of 2706 +- 404 gamma-like events from NGC 1275 with a statistical significance of approximately 6.7 sigma by the MACE telescope. The measured flux level is observed to vary from 78% to 35% of the Crab Nebula flux.
The MACE telescope is an imaging atmospheric Cherenkov telescope at Hanle (32.8 deg N, 78.9 deg E, 4270 m asl), Ladakh, India. The telescope has recently been commissioned after its first successful light in April 2021 (K K Yadav et al. Current Science, 2022, 123, 1428). It is equipped with a large quasi-parabolic light collector of 21m diameter and 25m focal length. The imaging camera of telescope is an array of 1088 photomultiplier tubes with a pixel resolution of 0.125 deg.
The preliminary data analysis has been performed by P. Chandra (chandrap@barc.gov.in), C. Borwankar (chinmay@barc.gov.in), M. Khurana (mkhurana@barc.gov.in), A. Tolamatti (anilkumart@barc.gov.in) and K K Singh (kksastro@barc.gov.in).