[vsnet-grb-info 25522] GRB 200415A: ASIM observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27622
SUBJECT: GRB 200415A: ASIM observation
DATE:    20/04/22 12:39:03 GMT
FROM:    Martino Marisaldi at U of Bergen, Norway  <martino.marisaldi at uib.no>

M. Marisaldi (University of Bergen), A. Mezentsev (University of Bergen), 
N. Østgaard (University of Bergen), V. Reglero (University of Valencia) 
and T. Neubert (DTU Space) report on behalf of the ASIM Team:

At 08:48:05.557 UT on 15 April 2020, the Atmosphere-Space Interactions Monitor (ASIM)
mission triggered on the very bright GRB 200415A (GCN Circ. 27579, 27580, 
27585, 27586, 27587, 27590, 27595, 27596, 27597, 27599).
Photon by photon data with <1 microsecond time resolution have been
collected for a time interval of two seconds centered at the trigger time.

As seen by the Modular X- and Gamma-Ray Sensor (MXGS) onboard ASIM
the burst consists of a bright peak about 6 ms in duration, followed by a steadily
decaying tail at least 200 ms long. The emission is detected in both 
the MXGS Low Energy Detector (LED), sensitive in the range 0.05 to 0.4 MeV,
and in the High Energy Detector (HED), sensitive in the range 0.3 to >30 MeV. 
Significant emission is observed up to several MeV. 
Further data analysis is ongoing and will be published elsewhere.

ASIM is an ESA mission onboard the International Space Station dedicated to the 
observation of Terrestrial Gamma-ray Flashes (TGFs) and Transient Luminous Events (TLEs) 
operative since June 2018 (Neubert et al., Space Sci Rev (2019) 215:26 
https://doi.org/10.1007/s11214-019-0592-z ). 
The payload includes the Modular X- and Gamma-Ray Sensor (MXGS) 
(Østgaard et al., Space Sci Rev (2019) 215:23 https://doi.org/10.1007/s11214-018-0573-7 ), 
and the the Modular Multispectral Imaging Array  (MMIA) 
(Chanrion et al., Space Sci Rev (2019) 215:28 https://doi.org/10.1007/s11214-019-0593-y ). 
The ASIM Science Data Centre (ASDC) website is https://asdc.space.dtu.dk/