The gamma-ray binary HESS J0632+057 is in an unusually high X-ray and TeV emission state.
ATel #11223; Reshmi Mukherjee (Barnard College) for the VERITAS Collaboration
on 24 Jan 2018; 22:05 UT
Credential Certification: Reshmi Mukherjee (firstname.lastname@example.org)
Subjects: Gamma Ray, TeV, VHE, Binary
Observations by the VERITAS collaboration and with the Swift XRT show the
TeV and X-ray emission of the gamma-ray binary HESS J0632+057
(RA 06h32m59.26s, Dec +05d48m01.2s, J2000.0) are comparable to the
highest ever observed from this object. HESS J0632+057 (VER J0633+057 in the
VERITAS catalog) is associated with the B0pe star MWC 148 and the
X-ray source XMMU J063259.3+054801, and has also been weakly
detected at GeV energies. The binary orbital period is 315 days, and
the nature of the compact object is unknown. Correlated X-ray and
TeV flares have been observed in the past, usually peaking around
orbital phase 0.35. The system is currently at phase
0.42. Observations made with VERITAS on MJDs 58136 and 58141 detect
the source with a statistical significance in excess of 10 standard deviations in an
exposure of 4.3 hours. The integral gamma-ray flux is 5.9e-12 ± 7.7e-13
photons cm^-2 s^-1 above 350 GeV (corresponding to about 6% of the flux of the Crab
Nebula above the same energy), about twice the flux typically measured in this
orbital phase range.
Swift XRT observations on MJD 58142
show a 0.3-10 keV count rate of 0.060 ± 0.007.
We encourage multi-wavelength observations. VERITAS observations
will continue until Sep 26th, but will not be possible over the following full Moon
period. Questions regarding VERITAS should be directed to Reshmi
Mukherjee (email@example.com). The VERITAS array is located
at the Fred Lawrence Whipple Observatory in southern Arizona, USA
work made use of data supplied by the UK Swift Science Data Centre at
the University of Leicester.