[ Previous | Next | ADS ]

HAWC observation of Mrk421 reaching peak TeV flux in month-long enhanced activity

ATel #11194; J. A. Garcia-Gonzalez (UNAM, Ciudad de Mexico, Mexico), I. Martinez-Castellanos (UMD, College Park, USA) on behalf of the HAWC collaboration
on 17 Jan 2018; 22:12 UT
Credential Certification: Colas Riviere (riviere@umd.edu)

Subjects: Gamma Ray, TeV, VHE, AGN, Blazar

Referred to by ATel #: 11199, 11216

Since December 2017 the HAWC observatory has observed an increased TeV gamma-ray emission from Markarian 421. During this period we have observed a series of flaring episodes, the last one reaching a flux above 1TeV of (1.2 +/- 0.2) x 10^-10 (~6 equivalent Crab units) between 2018-01-17 06:39 and 09:47 UTC. This is about 10 times the all-time averaged flux measured by HAWC and the highest one since the beginning of this enhanced period.

This is a follow-up of ATel #11077. Enhanced emission has also been reported by FACT (ATel #11086 and #11184), and MAXI/GSC (ATel #11186).

HAWC will continue to monitor this source. The next transit will occur between 6:35 and 12:54 UTC. 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) 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.