TITLE: GCN CIRCULAR NUMBER: 36550 SUBJECT: GRB 240527B: Fermi-LAT detection DATE: 24/05/27 23:09:39 GMT FROM: Rahul Gupta at NASA/GSFC <rahulbhu.c157@gmail.com> R. Gupta (NASA/GSFC), F. Longo (University and INFN, Trieste), and A. Holzmann (DF, University of Buenos Aires, Argentina) report on behalf of the Fermi-LAT Collaboration: At 14:03:51.50 on May, 27, 2024 Fermi-LAT detected high-energy emission from GRB 240527B which was also detected by Fermi-GBM (trigger 738511436 / 240527586, GCN 36546). The best LAT on-ground location is found to be RA, Dec = 128.10, -14.48 (J2000) with an error radius of 0.19 deg (90 % containment, statistical error only). This was 77 deg from the LAT boresight at the time of the trigger. The data from the Fermi-LAT show a significant increase in the event rate that is spatially and temporally correlated with the trigger with high significance. The photon flux above 100 MeV in the time interval 0-3000 s after the GBM trigger is (6.2 +/- 3.0) E-7 ph/cm2/s. The estimated photon index above 100 MeV is - 1.6+/- 0.2. The highest-energy photon is a 4.0 GeV event which is observed about 1200 seconds after the GBM trigger. A Swift ToO has been approved. The Fermi-LAT point of contact for this burst is Rahul Gupta ( rahul.gupta@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. View this GCN Circular online at https://gcn.nasa.gov/circulars/36550. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...