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GRB 250522B

GCN Circular 40531

Subject
GRB 250522B: Fermi GBM Final Localization
Date
2025-05-23T00:55:12Z (7 days ago)
From
Matt Godwin <msg0028@uah.edu>
Via
Web form
The Fermi GBM team reports the detection of a likely LONG GRB

"At 17:08:52.84 UT on 22 May 2025, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 250522B (trigger 769626537/250522714).

The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 285.32, Dec = -54.30 (J2000 degrees, equivalent to J2000 19h 1m, -54d 17'),
with a statistical uncertainty of 11.40 degrees.

The angle from the Fermi LAT boresight is 80 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250522714/quicklook/glg_skymap_all_bn250522714.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250522714/quicklook/glg_healpix_all_bn250522714.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250522714/quicklook/glg_lc_medres34_bn250522714.gif"

GCN Circular 40533

Subject
Fermi GRB 250522B: Global MASTER-Net observations report
Date
2025-05-23T07:31:07Z (6 days ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
email
V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, 
G.Antipov,  A.Sankovich, Yu.Tselik, 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.Sosnovskij (CrAO),
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-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) started inspect of the Fermi GRB 250522B ( Fermi GBM team, GCN 40531) errorbox  27574 sec after notice time and 49860 sec after trigger time at 2025-05-23 06:59:53 UT, with upper limit up to  20.3 mag. The observations began at zenith distance = 29 deg. The sun  altitude  is -55.1 deg. 

The galactic latitude b = -24 deg., longitude l = 343 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2878662

We obtain a following upper limits.  

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

   49910 | 2025-05-23 06:59:53 |         MASTER-OAFA | (19h 44m 22.76s , -56d 37m 08.7s) |   C |   100 | 18.9 |        
   49920 | 2025-05-23 06:59:53 |         MASTER-OAFA | (20h 00m 53.97s , -56d 11m 31.1s) |   C |   120 | 20.2 |        
   50055 | 2025-05-23 07:02:17 |         MASTER-OAFA | (19h 44m 22.46s , -56d 38m 27.6s) |   C |   100 | 18.9 |        
   50065 | 2025-05-23 07:02:17 |         MASTER-OAFA | (20h 00m 54.27s , -56d 12m 49.5s) |   C |   120 | 20.2 |        
   50193 | 2025-05-23 07:04:35 |         MASTER-OAFA | (19h 44m 26.76s , -56d 36m 55.4s) |   C |   100 | 19.1 |        
   50203 | 2025-05-23 07:04:35 |         MASTER-OAFA | (20h 00m 57.96s , -56d 11m 17.4s) |   C |   120 | 20.3 |        
   50328 | 2025-05-23 07:06:51 |         MASTER-OAFA | (19h 44m 20.88s , -56d 37m 43.4s) |   C |   100 | 19.0 |        
   50339 | 2025-05-23 07:06:51 |         MASTER-OAFA | (20h 00m 52.54s , -56d 12m 05.3s) |   C |   120 | 20.2 |        
   50465 | 2025-05-23 07:09:07 |         MASTER-OAFA | (19h 44m 22.05s , -56d 36m 37.8s) |   C |   100 | 18.9 |        
   50475 | 2025-05-23 07:09:07 |         MASTER-OAFA | (20h 00m 53.32s , -56d 11m 00.0s) |   C |   120 | 20.2 |        
   50601 | 2025-05-23 07:11:23 |         MASTER-OAFA | (19h 44m 26.58s , -56d 37m 34.2s) |   C |   100 | 18.9 |        
   50611 | 2025-05-23 07:11:23 |         MASTER-OAFA | (20h 00m 58.26s , -56d 11m 55.7s) |   C |   120 | 20.2 |        
Filter C is a clear (unfiltred) band. 


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


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