Flaring activity from Mrk 421 observed by HAWC

ATel #15389; Hugo Ayala (PSU)
on 21 May 2022; 16:01 UT
Credential Certification: Hugo Alberto Ayala Solares (hgayala@psu.edu)

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The HAWC Observatory has measured an increased gamma-ray activity from the direction of the BL Lac Markarian 421 (z=0.031) on the previous transit, May 20-21, 2022:

Day: 2022-05-20, (MJD 59719)

Duration: 6.2 hrs, from 2022-05-20 22:32:11 to 2022-05-21 04:48:09 (UT)

Preliminary Flux level: (5.33 +/- 1.13) X 10-11 cm^-2s^-1 [>1 TeV] (2.76 +/- 0.58 CU)

HAWC continuously monitors this source and will keep reporting in case that the enhance activity follows. Follow-up observations are encouraged. All flux values are obtained from a maximum likelihood fit under the assumption of a fixed spectral shape with power law index of 2.2 and exponential cut-off at 5 TeV.

The HAWC contact people for this analysis are Jose Andres Garcia-Gonzalez (IF-UNAM, jagarcia@fisica.unam.mx, ITESM-EIC, anteus79@tec.mx), Hugo Ayala (hgayala@psu.edu) and Israel Martinez (UMD, imc@umd.edu). HAWC is a TeV gamma ray water Cherenkov array located in the state of Puebla, Mexico, that monitors two thirds of the sky every day with an instantaneous field of view of ~2 sr.