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GCN Circular 24024

MAGIC follow-up of the X-ray flares of LS I +61�303 dete
2019-03-28T17:50:39Z (5 years ago)
Razmik Mirzoyan at MPI/MAGIC <>
R. Mirzoyan, D. Hadasch, A. L�pez-Oramas report on behalf of the MAGIC

The MAGIC telescopes have observed the direction (RA=+02:40:37h,
J2000.0) coincident with the location of the gamma-ray binary LS I +61� 303
DEC:+61:13:45, J2000.0) in the very-high-energy (VHE; >100 GeV) range on
23, 2019. The MAGIC observations were triggered by the flaring activity in
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
data taken ~20 minutes later on March 23, 2019 between 20:52:13.7 UTC (MJD

and 21:12:00.9 UTC (MJD 58565.8833) did not show any significant detection
of LS I +61� 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
( <>, Daniela
Hadasch ( <>
Alicia L�pez-Oramas ( <>
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