GCN Circular 18799

J. L. Racusin (NASA/GSFC), S. Razzaque (UJ, South Africa), and M. Axelsson (KTH, Sweden) report on behalf 
of the Fermi-LAT team: 

At 05:10:11 UT on January 1, 2016, Fermi-LAT detected high-energy emission from GRB 160101B, which was 
also detected by Fermi-GBM (trigger 473317815/160101215). 

The GBM location was initially inside the LAT field of view at an angle of 9 degrees to the LAT boresight, and 
remained in the LAT field of view until ~T0+1500 s. No significant excess is seen using standard >100 MeV 
likelihood analysis procedures. 

Using the LAT Low Energy (LLE) data selection, over 100 counts above background were detected within a 10 s 
interval coinciding with the time of the GBM emission. This data selection has insufficient spatial resolution to 
provide a reliable LAT localization. Since an excess of events were not seen using the standard analysis 
selection, this detection is likely due to low energy gamma-rays (below 100 MeV). 

The Fermi-LAT point of contact for this burst is Judith Racusin (judith.racusin@nasa.gov). 

The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 
300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many 
scientific institutions across France, Italy, Japan and Sweden.