EP251129a
GCN Circular 42942
Subject
EP251129a/GRB 251129A: NOWT Detection
Date
2025-12-02T08:20:32Z (7 hours ago)
From
Abdusamatjan Iskandar at XAO,CAS <abudu@xao.ac.cn>
Via
Web form
Shahidin Yaqup, Abdusamatjan Iskandar, Jinzhong Liu, report on behalf of optical group of the XAO:
We imaged the field of the GRB 251129A/EP 251129a (GCN Circ. 42877, 42880, 42884 ) using the Nanshan One-meter Wide-field Telescope (NOWT) at Nanshan Station of Xinjiang Astronomical Observatory (XAO). We observed from 2025-11-29 20:08:26 to 20:32:43 UTC and obtained 6 x 300 s exposure in the V filter. The stack image photometry was calibrated using nearby stars from the GAIA synthesis catalog, without correction for Galactic extinction.
We detect a source at the position (RA, DEC(J2000) = 14:57:18.88, +79:17:34.8) reported by GCN Circ.42880, with preliminary magnitude of V = 21.74+-0.64 mag.
GCN Circular 42902
Subject
EP251129a/GRB 251129A: EP-FXT follow-up observations
Date
2025-11-30T06:51:00Z (2 days ago)
From
EP Team at NAOC/CAS <ep_ta@bao.ac.cn>
Via
Web form
Y. H. Jiang, Y. Wu, C. Y. Dai (NJU), Y. Wang (PMO), H. C. Ding, T. Wu (AHNU), W. J. Zhang, Y. Liu (NAO, CAS), on behalf of the Einstein Probe (EP) team:
A follow-up observation of EP251129a / GRB 251129A (Wu et al., GCN 42884, Tan et al., GCN 42877) with the Follow-up X-ray Telescope (FXT) was performed automatically at 2025-11-29T03:16:08 (UTC), i.e. T0+2643 s, where T0 is reported by SVOM (Tan et al., GCN 42877) , with an exposure time of 5,003 s. The average FXT 0.5-10 keV spectrum of the observation can be fitted with an absorbed power law, with a fixed Galactic hydrogen column density of 2.94 x 10^20 cm^-2, an intrinsic hydrogen column density of 1.40 (-0.05/+0.05) x 10^22 cm^-2, and a photon index of 1.98 (-0.02/+0.02) . The derived average unabsorbed 0.5-10 keV flux is 1.74 (-0.02/+0.02) x 10^(-9) erg/s/cm^2.
We performed two target-of-opportunity (ToO) follow-up observations with FXT at 2025-11-29T05:26:09 (UTC, T0+10,444 s) and 2025-11-29T12:34:30 (UTC, T0+36,145 s), with an exposure time of 2,786 s and 3,091 s, respectively.
The average FXT 0.5-10 keV spectrum of the first ToO observation can be fitted with an absorbed power law, with a fixed Galactic hydrogen column density of 2.94 x 10^20 cm^-2, an intrinsic hydrogen column density of 1.04 (-0.11/+0.11) x 10^22 cm^-2, and a photon index of 2.45 (-0.05/+0.05) . The derived average unabsorbed 0.5-10 keV flux is 1.56 (-0.04/+0.04) x 10^(-10) erg/s/cm^2.
The average FXT 0.5-10 keV spectrum of the second ToO observation can be fitted with an absorbed power law, with a fixed Galactic hydrogen column density of 2.94 x 10^20 cm^-2, an intrinsic hydrogen column density of 1.49 (-0.46/+0.46) x 10^22 cm^-2, and a photon index of 3.49 (-0.23/+0.23). The derived average unabsorbed 0.5-10 keV flux is 9.20 (-0.75/+0.82) x 10^(-13) erg/s/cm^2.
Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics).
GCN Circular 42886
Subject
EP251129a: Global MASTER-Net observations report
Date
2025-11-29T05:36:20Z (3 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-Kislovodsk robotic telescope [1] located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the EP251129a ( EP Team et al., GCN 42884) errorbox 107 sec after trigger time at 2025-11-29 03:16:10 UT, with upper limit up to 17.6 mag. Observations started at twilight. The observations began at zenith distance = 44 deg. The sun altitude is -11.4 deg.
The galactic latitude b = 36 deg., longitude l = 116 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=3054702
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
167 | 2025-11-29 03:16:10 | MASTER-Kislovodsk | (14h 59m 24.03s , +79d 38m 56.6s) | C | 120 | 17.2 |
287 | 2025-11-29 03:16:10 | MASTER-Kislovodsk | (14h 59m 24.03s , +79d 38m 56.6s) | C | 360 | 17.6 | Coadd
167 | 2025-11-29 03:16:10 | MASTER-Kislovodsk | (15h 21m 34.38s , +79d 11m 04.2s) | C | 120 | 17.4 |
307 | 2025-11-29 03:18:30 | MASTER-Kislovodsk | (14h 59m 22.72s , +79d 39m 05.4s) | C | 120 | 17.0 |
307 | 2025-11-29 03:18:30 | MASTER-Kislovodsk | (15h 21m 33.89s , +79d 11m 14.4s) | C | 120 | 17.1 |
447 | 2025-11-29 03:20:49 | MASTER-Kislovodsk | (14h 59m 21.42s , +79d 39m 14.1s) | C | 120 | 16.6 |
447 | 2025-11-29 03:20:49 | MASTER-Kislovodsk | (15h 21m 32.90s , +79d 11m 24.4s) | C | 120 | 16.7 |
587 | 2025-11-29 03:23:09 | MASTER-Kislovodsk | (14h 59m 20.23s , +79d 39m 22.9s) | C | 120 | 16.4 |
707 | 2025-11-29 03:23:09 | MASTER-Kislovodsk | (14h 59m 20.29s , +79d 39m 22.8s) | C | 360 | 17.0 | Coadd
587 | 2025-11-29 03:23:09 | MASTER-Kislovodsk | (15h 21m 29.63s , +79d 11m 35.4s) | C | 120 | 14.6 |
727 | 2025-11-29 03:25:29 | MASTER-Kislovodsk | (14h 59m 19.13s , +79d 39m 30.8s) | C | 120 | 16.3 |
867 | 2025-11-29 03:27:49 | MASTER-Kislovodsk | (14h 59m 17.67s , +79d 39m 36.8s) | C | 120 | 16.1 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
[1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp.
http : // www.pereplet.ru/lipunov/625.html
GCN Circular 42884
Subject
EP251129a/GRB 251129A : Einstein Probe detection of an X-ray transient
Date
2025-11-29T05:21:00Z (3 days ago)
From
EP Team at NAOC/CAS <ep_ta@bao.ac.cn>
Via
Web form
Y. Wu, Y. H. Jiang, C. Y. Dai (NJU), Y. Wang (PMO), H. C. Ding, T. Wu (AHNU), W. J. Zhang, Y. Liu (NAO, CAS), on behalf of the Einstein Probe (EP) team:
We report on the detection of an X-ray transient by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission, designated EP251129a. The transient triggered EP-WXT (ID: 01709248891) at 2025-11-29T03:14:23 (UTC). The WXT position of the source is R.A. = 224.294 deg, DEC = 79.301 deg (J2000) with an uncertainty of 3 arcmin in radius (90% C.L. statistical and systematic).
A follow-up observation with the Follow-up X-ray Telescope (FXT) was performed automatically. Within the WXT error circle, an uncatalogued X-ray source was detected at R.A. = 224.3331 deg, DEC = 79.2903 deg (J2000) with an uncertainty of 20 arcsec in radius (90% C.L. statistical and systematic). The position of FXT is 36 arcsec from SVOM/MXT detection of GRB 251129A (Tan et al., GCN 42877), and 10 arcsec from its optical counterpart (Angulo et al., GCN 42883). Further information will be updated when the telemetry data is received.
Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics).