GRB 241201A

J. Joshi (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of GRB 241201A which was also detected by Fermi/GBM (Fermi-GBM Team, GCN Circ. 38403
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 ), and GRBAlpha (Dafcikova et al., GCN Circ. 38437
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 ).

The source was clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve showed two peaks of emission with the strongest peak at 2024-12-01 14:55:59.35 UTC. The measured peak count rate associated with the burst is 599 (+82, -62) counts/s above the background in the combined data of all quadrants, with a total of 1960 (+359, -389) counts. The local mean background count rate was 1849 (+16, -8) counts/s. We measure a T90 of 7.6 (+0.8, -0.6) s from the cumulative Veto light curve.

CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project.

CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb

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.

We report a possible detection of the long-duration GRB 241201A (Fermi/GBM detection: GCN 38403
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 ) by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; https://ui.adsabs.harvard.edu/abs/2023A%26A...677A..40P/abstract).

We note that GRBAlpha did not detect the initial bright peak but only the secondary one ~10 s later. The Fermi/GBM location of this burst was not occulted by the Earth or Moon at the trigger time. The non-detection of the initial peak could be due to a significantly decreased effective area caused by the variable attitude of the satellite.

The detection peak time is at 2024-12-01 14:56:06.7 UTC. The T90 duration measured by GRBAlpha is 1.5 s and the overall significance during T90 reaches 7.8 sigma.

The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB241201A_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.

V.Lipunov, E.Gorbovskoy, N.Tiurina,  P.Balanutsa, , D.Vlasenko, I.Panchenko,
A.Kuznetsov,  G.Antipov,  A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, Ya.Kechin,
V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU),
O.Gress, N.Budnev (ISU),
C.Francile,  F. Podesta, R.Podesta, E. Gonzalez  (Observatorio Astronomico Felix Aguilar (OAFA),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity)
D.Buckley (SAAO),
R.Rebolo (The Instituto de Astrofisica de Canarias),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) 

MASTER-Tunka robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the Fermi GRB 241201A ( Fermi GBM team, GCN 38403
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 ) errorbox  14079 sec after notice time and 14110 sec after trigger time at 2024-12-01 18:51:09 UT, with upper limit up to  19.9 mag. The observations began at zenith distance = 79 deg. The sun  altitude  is -53.3 deg. 

The galactic latitude b = 63 deg., longitude l = 275 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2691073

We obtain a following upper limits.  

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

   14141 | 2024-12-01 18:51:09 |        MASTER-Tunka | (11h 48m 39.15s , +06d 53m 47.2s) |   C |    60 | 19.3 |        
   14201 | 2024-12-01 18:51:09 |        MASTER-Tunka | (11h 48m 39.15s , +06d 53m 47.2s) |   C |   180 | 19.8 |  Coadd 
   14579 | 2024-12-01 18:58:27 |        MASTER-Tunka | (11h 46m 11.74s , +05d 01m 12.0s) |   C |    60 | 19.0 |        
   14639 | 2024-12-01 18:58:27 |        MASTER-Tunka | (11h 46m 11.73s , +05d 01m 12.1s) |   C |   180 | 19.6 |  Coadd 
   14728 | 2024-12-01 19:00:56 |        MASTER-Tunka | (11h 55m 50.65s , +06d 54m 27.7s) |   C |    60 | 19.4 |        
   14788 | 2024-12-01 19:00:56 |        MASTER-Tunka | (11h 55m 50.64s , +06d 54m 27.8s) |   C |   180 | 19.8 |  Coadd 
   14956 | 2024-12-01 19:04:45 |        MASTER-Tunka | (12h 03m 54.69s , +06d 53m 20.5s) |   C |    60 | 19.2 |        
   15016 | 2024-12-01 19:04:45 |        MASTER-Tunka | (12h 03m 54.67s , +06d 53m 20.7s) |   C |   180 | 19.8 |  Coadd 
   15029 | 2024-12-01 19:05:58 |        MASTER-Tunka | (11h 48m 42.69s , +06d 54m 06.9s) |   C |    60 | 19.2 |        
   15322 | 2024-12-01 19:10:50 |        MASTER-Tunka | (11h 46m 08.97s , +05d 00m 58.9s) |   C |    60 | 19.4 |        
   15468 | 2024-12-01 19:13:16 |        MASTER-Tunka | (11h 55m 58.43s , +06d 54m 49.9s) |   C |    60 | 19.5 |        
   15541 | 2024-12-01 19:14:30 |        MASTER-Tunka | (11h 53m 27.89s , +05d 00m 10.0s) |   C |    60 | 19.5 |        
   15601 | 2024-12-01 19:14:30 |        MASTER-Tunka | (11h 53m 27.89s , +05d 00m 09.9s) |   C |   180 | 19.9 |  Coadd 
   15613 | 2024-12-01 19:15:41 |        MASTER-Tunka | (12h 01m 27.44s , +05d 01m 21.4s) |   C |    60 | 19.3 |        
   15673 | 2024-12-01 19:15:41 |        MASTER-Tunka | (12h 01m 27.43s , +05d 01m 21.6s) |   C |   180 | 19.9 |  Coadd 
   15685 | 2024-12-01 19:16:53 |        MASTER-Tunka | (12h 03m 58.03s , +06d 53m 52.1s) |   C |    60 | 19.4 |        
   16624 | 2024-12-01 19:32:32 |        MASTER-Tunka | (11h 46m 08.42s , +05d 02m 28.5s) |   C |    60 | 19.3 |        
   16696 | 2024-12-01 19:33:45 |        MASTER-Tunka | (11h 55m 58.00s , +06d 55m 15.8s) |   C |    60 | 19.6 |        
   16769 | 2024-12-01 19:34:57 |        MASTER-Tunka | (11h 53m 21.59s , +05d 00m 20.6s) |   C |    60 | 19.5 |        
   16842 | 2024-12-01 19:36:10 |        MASTER-Tunka | (12h 01m 30.45s , +05d 00m 28.6s) |   C |    60 | 19.3 |        
   16914 | 2024-12-01 19:37:23 |        MASTER-Tunka | (12h 03m 57.99s , +06d 56m 01.3s) |   C |    60 | 19.5 |        
   17358 | 2024-12-01 19:44:46 |        MASTER-Tunka | (11h 44m 31.08s , +03d 07m 24.0s) |   C |    60 | 19.5 |        
   17430 | 2024-12-01 19:45:59 |        MASTER-Tunka | (11h 53m 27.91s , +05d 02m 25.5s) |   C |    60 | 19.6 |        
   17503 | 2024-12-01 19:47:11 |        MASTER-Tunka | (12h 01m 23.85s , +05d 01m 30.2s) |   C |    60 | 19.6 |        
Filter C is a clear (unfiltred) band. 


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

T. Preis, B. Biltzinger, J. Burgess & J. Greiner (all MPE Garching) report:

The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
754757764 at 14:55:59 on 01 Dec. 2024 were automatically fitted for spectrum
and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427;
Berlato et al. 2019, ApJ 873, 60).

The best-fit position is:
RA(2000.0) = 189.8 deg
Decl.(2000.0) = -0.7 deg
The 1 sigma statistical error radius is 2.6 deg.
We estimate an additional systematic error of 1 deg.

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB241201622/

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB241201622/healpix

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB241201622/json

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

At 14:55:59 UT on 1 Dec 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 241201A (trigger 754757764.155878 / 241201622).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 179.9, Dec = 3.2 (J2000 degrees, equivalent to J2000 11h 59m, 3d 12'), with a statistical uncertainty of 2.6 degrees.

The angle from the Fermi LAT boresight is 26.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241201622/quicklook/glg_skymap_all_bn241201622.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/bn241201622/quicklook/glg_healpix_all_bn241201622.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241201622/quicklook/glg_lc_medres34_bn241201622.gif