VERITAS detection of unprecedented gamma-ray flare from the blazar VER J0521+211
ATel #13522; John Quinn (University College Dublin) for the VERITAS Collaboration
on 25 Feb 2020; 20:25 UT
Credential Certification: Deirdre Horan (deirdre@llr.in2p3.fr)
Subjects: Gamma Ray, >GeV, TeV, VHE, AGN, Blazar
The VERITAS Collaboration reports the detection of a flare in
very-high-energy (VHE; >100 GeV) gamma rays from the blazar
VER J0521+211 (05h21m45s +21d12m51.4s, J2000) for observations made
on 2020 February 25 (MJD 58904.12 - 58904.24). A preliminary analysis
of the data indicates a steadily rising flux, reaching >130% the
VHE flux from the Crab Nebula as the source set.
VER J0521+211 typically has a VHE flux
∼7% Crab but has been seen to flare to ∼50% Crab.
A coordinated Swift/VERITAS campaign also resulted in simultaneous Swift observations that
show an elevated X-ray state with a 0.3-10 keV flux that is ∼10× that of observations taken
in prior weeks and months. For more details see the
Swift VERJ0521+212 monitoring site.
VER J0521+21, associated
with RGB J0521.8+2112, is classified as an intermediate BL Lac (IBL)
object and its redshift is uncertain.
Multiwavelength observations are encouraged.
Questions regarding the VERITAS observations should be directed to
John Quinn (john.quinn@ucd.ie). VERITAS (the Very Energetic Radiation
Imaging Telescope Array System) is located at the Fred Lawrence Whipple
Observatory in southern Arizona, USA, and is most sensitive to gamma
rays between ∼85 GeV and ∼30 TeV. For further information see
the VERITAS web site.
