TITLE: GCN CIRCULAR NUMBER: 27454 SUBJECT: GRB 200326B: AstroSat LAXPC detection DATE: 20/03/27 12:41:54 GMT FROM: Tilak Katoch at TIFR H. M. Antia, Tilak Katoch, Parag Shah and Dhiraj Dedhia TIFR, Mumbai, India. Analysis of AstroSat LAXPC data showed the detection of a long GRB 200326B. The light curve showed a double peak profile triggered at T0 = 21h 13m 52s UT on 26 Mar 2020, with T90=10 sec for the first peak followed by a second smaller peak of similar duration about 10 s later. The measured peak count rate above the background associated with the burst is 158 +/- 24 cts/s in LAXPC10 and 171 +/- 20 cts/s in LAXPC20 at T0+3 sec. The total counts in the first peak are 542 +/- 71 cts in LAXPC10 and 773 +/- 54 in LAXPC20. Both LAXPC instruments (LAXPC10 and LAXPC20) have registered this burst profile in the light curve. For LAXPC20 the nominal energy range is 3-100 keV, but due to lower gain in LAXPC10 the energy range is about 30-400 keV. The background subtracted light curve with 1 sec time-bin is available at the web-site: https://www.tifr.res.in/~astrosat_laxpc/grb200326blc.jpg LAXPC was built by TIFR in collaboration with the Indian Space Research Organisation. The Indian Space Research Organisation funded, managed and facilitated the project.