//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29748 SUBJECT: GRB 210403A: Swift detection of a burst DATE: 21/04/03 08:40:22 GMT FROM: Kim Page at U.of Leicester K. L. Page (U Leicester) and A. Y. Lien (GSFC/UMBC) report on behalf of the Neil Gehrels Swift Observatory Team: At 08:27:13 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 210403A (trigger=1040345). Swift did not slew immediately to the burst due to an observing constraint. The BAT on-board calculated location is RA, Dec 2.767, -32.999 which is RA(J2000) = 00h 11m 04s Dec(J2000) = -32d 59' 56" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multi-peaked structure with a duration of about 140 sec. The peak count rate was ~1200 counts/sec (15-350 keV), at ~0 sec after the trigger. Due to a Sun observing constraint, Swift cannot slew to the BAT position until 21:34 UT on 2021 April 14. There will thus be no XRT or UVOT data for this trigger before this time. Burst Advocate for this burst is K. L. Page (klp5 AT leicester.ac.uk). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29751 SUBJECT: Swift GRB210403.35: Global MASTER-Net observations report DATE: 21/04/03 13:20:29 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov, D. Cheryasov (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State University) MASTER-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the Swift GRB210403.35 (trigger No 1040345,00h 11m 04.08s , -32d 59m 56.4s, R=0.05) errorbox 1478 sec after notice time and 1500 sec after trigger time at 2021-04-03 08:52:14 UT, with upper limit up to 18.8 mag. The observations began at zenith distance = 85 deg. The sun altitude is -25.4 deg. The galactic latitude b = -80 deg., longitude l = 356 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1582518 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 1591 | MASTER-OAFA | C | 180 | 16.2 | 2025 | MASTER-OAFA | C | 180 | 17.0 | 2205 | MASTER-OAFA | C | 540 | 18.0 | Coadd 3222 | MASTER-OAFA | C | 180 | 17.8 | 3422 | MASTER-OAFA | C | 180 | 17.9 | 3621 | MASTER-OAFA | C | 180 | 18.0 | 3801 | MASTER-OAFA | C | 540 | 18.8 | Coadd 3820 | MASTER-OAFA | C | 180 | 18.0 | 4020 | MASTER-OAFA | C | 180 | 18.1 | 4219 | MASTER-OAFA | C | 180 | 18.1 | 4419 | MASTER-OAFA | C | 180 | 18.0 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29754 SUBJECT: GRB 210403A: Swift-BAT refined analysis DATE: 21/04/03 20:57:12 GMT FROM: Scott Barthelmy at NASA/GSFC H. A. Krimm (NSF), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL), (i.e. the Swift-BAT team): Using the data set from T-61 to T+242 sec from the recent telemetry downlink, we report further analysis of BAT GRB 210403A (trigger #1040345) (K.Page, et al., GCN Circ. 29748). The BAT ground-calculated position is RA, Dec = 2.813, -33.024 deg which is RA(J2000) = 00h 11m 15.2s Dec(J2000) = -33d 01' 27.2" with an uncertainty of 2.6 arcmin, (radius, sys+stat, 90% containment). The partial coding was 80%. The lightcurve has multiple peaks starting at T-40 sec and ending at T+140 sec. T90 (15-350 keV) is 168.3 +- 9.2 sec (estimated error including systematics). The time-averaged spectrum from T-41.51 to T+137.18 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 0.93 +- 0.52, and Epeak of 37.4 +- 4.8 keV (chi squared 52.21 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 2.7 +- 0.2 x 10^-06 erg/cm2 and the 1-sec peak flux measured from T+0.18 sec in the 15-150 keV band is 1.1 +- 0.2 ph/cm2/sec. A fit to a simple power law gives a photon index of 2.13 +- 0.10 (chi squared 73.02 for 57 d.o.f.). All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/1040345/BA/