GRB 240612A

The Fermi GBM team reports the detection of a likely LONG GRB

At 12:04:28 UT on 12 Jun 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240612A (trigger 739886673.980364 / 240612503).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 316.4, Dec = 5.4 (J2000 degrees, equivalent to J2000 21h 05m, 5d 24'), with a statistical uncertainty of 2.5 degrees.

The angle from the Fermi LAT boresight is 86.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240612503/quicklook/glg_skymap_all_bn240612503.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240612503/quicklook/glg_healpix_all_bn240612503.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240612503/quicklook/glg_lc_medres34_bn240612503.gif

V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik,  D. Vlasenko,
G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij
(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. Gress, N.M. Budnev, O.Ershova
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),

V. Yurkov, A. Gabovich
(Blagoveschensk Educational State University)

MASTER-Amur robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Blagoveshchensk State Pedagogical University) started inspect of the Fermi GRB 240612A ( Fermi GBM team, GCN 36662
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 ) errorbox  8847 sec after notice time and 8878 sec after trigger time at 2024-06-12 14:32:27 UT, with upper limit up to  17.8 mag. Observations started at twilight.  The observations began at zenith distance = 70 deg. The sun  altitude  is -15.7 deg. 

The galactic latitude b = -27 deg., longitude l = 55 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2490981

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

    8909 | 2024-06-12 14:32:27 |         MASTER-Amur | (21h 00m 29.19s , +08d 49m 16.4s) |   C |    60 | 17.5 |        
    8909 | 2024-06-12 14:32:27 |         MASTER-Amur | (21h 07m 21.39s , +09d 14m 48.4s) |   C |    60 | 13.6 |        
    9096 | 2024-06-12 14:35:34 |         MASTER-Amur | (20h 54m 47.89s , +06d 55m 07.6s) |   C |    60 | 17.6 |        
    9096 | 2024-06-12 14:35:34 |         MASTER-Amur | (21h 01m 34.45s , +07d 20m 09.7s) |   C |    60 | 14.0 |        
    9470 | 2024-06-12 14:41:48 |         MASTER-Amur | (20h 50m 40.50s , +05d 00m 24.4s) |   C |    60 | 17.8 |        
    9470 | 2024-06-12 14:41:48 |         MASTER-Amur | (20h 57m 29.28s , +05d 25m 51.2s) |   C |    60 | 13.5 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.

M. Dafcikova, J. Ripa, M. Kolar (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Duriskova, L. Szakszonova, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal,  A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory),  T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.

The long-duration GRB 240612A (Fermi/GBM detection: GCN 36662
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 ; INTEGRAL/SPI-ACS peak detection at 2024-06-12 ~12:04:29 UT) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; https://ui.adsabs.harvard.edu/abs/2023A%26A...677A..40P/abstract).

The detection was confirmed at the peak time 2024-06-12 12:04:30.2 UTC. The T90 duration measured by GRBAlpha is 5 s and the overall significance during T90 reaches 7.3 sigma.

The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB240612A_GCN.pdf

All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/
GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume.