GCN Circular 30949

K. Hurley on behalf of the IPN team,

A.S.��Kozyrev, D.V.��Golovin, M.L.��Litvak, I.G.��Mitrofanov, and A.B.��Sanin 
on behalf of the MGNS/BepiColombo team, and

J.��Benkhoff on behalf of the BepiColombo team, report:

The ESA/JAXA BepiColombo mission was launched on October 20, 2018 on a 
7.2-year journey to Mercury. After arrival in late 2025, the mission 
will spend a nominal one year in Mercury orbit. The mission consists of 
two spacecraft: the JAXA-provided Mio spacecraft for the thorough 
exploration of the environment, and the ESA-led Mercury Planetary 
Orbiter, MPO, for a comprehensive exploration of the planet itself, the 
interior, and its magnetic field. The MPO contains the Mercury Gamma-Ray 
and Neutron Spectrometer (MGNS) experiment [1, 2] consisting of a 3��� 
diameter x 3��� long CeBr3 scintillator, which also has a gamma-ray burst 
detection capability. During the cruise phase so far, MGNS operated for 
about 23 months, and has detected 38 confirmed gamma-ray bursts, 21 of 
which have been localized to annuli using data from HEND/Mars Odyssey, 
which is also part of the IPN since 2002. The verification of the 
localization accuracy of this method was based on gamma-ray bursts for 
which optical afterglows were detected. Reference [3] presents 5 
gamma-ray bursts as examples of these localizations.

MGNS is now the 34th experiment to be integrated into the interplanetary 
network (IPN) since 1977, which currently consists of Konus-Wind, Mars 
Odyssey, BepiColombo, Swift, INTEGRAL and AGILE. In this configuration, 
the IPN now has two interplanetary spacecraft, which will lead to more 
precise GRB localizations.

References:

1. Mitrofanov, I.G., Kozyrev, A.S., Lisov, D.I., Litvak, M. L., et al. 
(2021). Space Science Reviews. Volume 217, Issue 5, article id.67A.

2. https://np.cosmos.ru/index.php/en-us/instruments/mgns

3. The links below show maps with localization annuli from MGNS-HEND 
data for 5 gamma-ray bursts: GRB 190530A, GRB 200219C, GRB 200415A, GRB 
200716C and GRB 210112A.

http://l503.iki.rssi.ru/owncloud/index.php/s/bXsgMFb9afifHzz

http://l503.iki.rssi.ru/owncloud/index.php/s/mPC5lrPy2pYLmbz

http://l503.iki.rssi.ru/owncloud/index.php/s/FcbgOtcA5pEx3nD

http://l503.iki.rssi.ru/owncloud/index.php/s/58JCvMJ6x5uzbbU

http://l503.iki.rssi.ru/owncloud/index.php/s/g4miSw176EHU7bL