[vsnet-grb-info 21925] MAGIC follow-up of the X-ray =?utf-8?Q?fla?= =?utf-8?Q?res_of_LS_I_+61=BA303?= dete

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  24024
SUBJECT: MAGIC follow-up of the X-ray flares of LS I +61º303 dete
DATE:    19/03/28 17:50:39 GMT
FROM:    Razmik Mirzoyan at MPI/MAGIC  <Razmik.Mirzoyan at mpp.mpg.de>

R. Mirzoyan, D. Hadasch, A. López-Oramas report on behalf of the MAGIC
collaboration:

The MAGIC telescopes have observed the direction (RA=+02:40:37h,
DEC=+61:14:45deg,
J2000.0) coincident with the location of the gamma-ray binary LS I +61º 303
(RA:+02:40:31.00,
DEC:+61:13:45, J2000.0) in the very-high-energy (VHE; >100 GeV) range on
March
23, 2019. The MAGIC observations were triggered by the flaring activity in
X-rays
measured by Swift-BAT on March 23, 2019 at 20:30:47 UT (S. D. Barthelmy et
al., GCN
circ. 23989, 2019) and by Swift-XRT at 20:32:12.5 UT. The preliminary
Swift-BAT analysis

showed multiple short spikes with a total duration of about 20 sec and a
peak rate of about 2400

counts/sec (15-350 keV) 3 seconds after the trigger. The analysis of the
MAGIC
data taken ~20 minutes later on March 23, 2019 between 20:52:13.7 UTC (MJD
58565.8696)

and 21:12:00.9 UTC (MJD 58565.8833) did not show any significant detection
of LS I +61º 303

at VHE (significance (Li&Ma) < 0.5 sigma). After 0.33 hours of observations
the integral flux

upper limit for energies above 300 GeV is 2e-11 cm^-2 s^-1.

The MAGIC contact persons for these observations are Razmik Mirzoyan
( <mailto:Razmik.Mirzoyan at mpp.mpg.de> Razmik.Mirzoyan at mpp.mpg.de), Daniela
Hadasch ( <mailto:hadasch at icrr.u-tokyo.ac.jp> hadasch at icrr.u-tokyo.ac.jp)
and
Alicia López-Oramas ( <mailto:aloramas at iac.es> aloramas at iac.es).