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GCN Circular 12994

GRB 120226A: Fermi-LAT data analysis
2012-02-28T19:12:33Z (12 years ago)
Weikang Zheng at U.of Michigan <>
Weikang Zheng and Carl Akerlof report on behalf of the ROTSE

We analyzed the high energy LAT data of GRB 120226A (Vasileiou and
Racusin, GCN 12989) using the matched filter technique (Akerlof et al,
2010, ApJ, 725, L15; 2011 ApJ, 726, 22; Zheng et al. 2012, ApJ 745,72,
GCN 12822). We only selected the photons with energy above 100 MeV in
our pipeline analysis. Our localization result gives the coordinate of
Ra = 300.05, Dec=48.81 (J2000) with uncertainty ~0.5 degree. This
location is about 7 degrees away from GBM trigger (Ra = 304.29,Dec =
42.1) and about 9 degrees away from the LAT location (Ra = 305.30, Dec =
40.75) given in GCN 12989. Our localization is much closer to the center
of IPN location (Ra = 302.930, Dec = 48.665, K. Hurley et al. GCN
12993), about 2 degrees away.

The LAT data signal is weak, too low to claim a firm detection. Only
four photons were identified near the estimated coordinate within a 50s
time window following the GBM trigger but by extending the duration to
250s, the number of photons increases to about 10. We encourage X-ray
follow-up observations of the new location.

All the pipeline results including the skymap can be found at the
following link:
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