TITLE: GCN CIRCULAR
NUMBER: 42910
SUBJECT: IceCube Alert 251130.75: Global MASTER-Net observations report
DATE: 25/11/30 23:13:22 GMT
FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru>
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-Tunka robotic telescope [1] located in Russia (Applied Physics Institute, Irkutsk State University) was pointed to the IceCube Alert 251130.75 (trigger No 31953389,15h 18m 58.08s , -05d 39m 25.2s, R=0.95) errorbox 18825 sec after notice time and 18880 sec after trigger time at 2025-11-30 23:08:10 UT, with upper limit up to 15.1 mag. Observations started at twilight. The observations began at zenith distance = 82 deg. The sun altitude is -14.8 deg.
The galactic latitude b = 41 deg., longitude l = 356 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=3056129
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
18910 | 2025-11-30 23:08:10 | MASTER-Tunka | (15h 18m 34.03s , -05d 47m 52.8s) | C | 60 | 14.5 |
18910 | 2025-11-30 23:08:10 | MASTER-Tunka | (15h 18m 53.09s , -05d 55m 00.3s) | C | 60 | 15.1 |
18984 | 2025-11-30 23:09:24 | MASTER-Tunka | (15h 18m 39.40s , -05d 48m 55.2s) | C | 60 | 14.3 |
18984 | 2025-11-30 23:09:24 | MASTER-Tunka | (15h 18m 58.71s , -05d 56m 07.2s) | C | 60 | 15.0 |
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
View this GCN Circular online at https://gcn.nasa.gov/circulars/42910.
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TITLE: GCN CIRCULAR
NUMBER: 42909
SUBJECT: IceCube-251130A - IceCube observation of a high-energy neutrino candidate track-like event
DATE: 25/11/30 19:37:39 GMT
FROM: A. Zegarelli at Ruhr University Bochum <azegarelli(a)icecube.wisc.edu>
The IceCube Collaboration (http://icecube.wisc.edu/) reports:
On 25-11-30 at 17:53:30.69 UT IceCube detected a track-like event with a high probability of being of astrophysical origin.
The event was selected by the ICECUBE_Astrotrack_GOLD alert stream.
The average astrophysical neutrino purity for Gold alerts is 50%.
This alert has an estimated false alarm rate of 1.1099 events per year due to atmospheric
backgrounds.
The IceCube detector was in a normal operating state at the time of detection.
After the initial automated alert (https://gcn.gsfc.nasa.gov/notices_amon_g_b/141654_31953389.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to:
Date: 25-11-30
Time: 17:53:30.69 UT
RA: 229.7 (+0.53/-0.52 deg 90% PSF containment) J2000
Dec: -5.53 (+0.58/-0.6 deg 90% PSF containment) J2000
We encourage follow-up by ground and space-based instruments to help identify a possible astrophysical source for the candidate neutrino.
No known gamma-ray sources listed in the Fermi 4FGL-DR4 or 3FHL catalogs are located within the 90% uncertainty region of the event.
The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica.
The IceCube realtime alert point of contact can be reached at roc(a)icecube.wisc.edu
View this GCN Circular online at https://gcn.nasa.gov/circulars/42909.
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TITLE: GCN CIRCULAR
NUMBER: 42908
SUBJECT: EP251130a: Swift-XRT counterpart detection
DATE: 25/11/30 19:00:56 GMT
FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk>
P.A. Evans (U. Leicester), J.A. Kennea (PSU), E. Ambrosi (INAF-IASFPA) , A.P.
Beardmore (U. Leicester), M.G. Bernardini (INAF-OAB), R. Brivio (INAF-OAB), D.N.
Burrows (PSU), S. Campana (INAF-OAB), M. Capalbi (INAF-OAR), A. D'Ai (INAF-IASFPA),
P. D'Avanzo (INAF-OAB), V. D'Elia (SSDC & INAF-OAR), S. Dichiara (PSU), M. Ferro
(INAF-OAB), A. Melandri (INAF-OAR), J.P. Osborne (U. Leicester), K.L. Page (U.
Leicester), M. Perri (SSDC & INAF-OAR), C. Salvaggio (INAF-OAB), T. Sbarrato
(INAF-OAB), B. Sbarufatti (INAF-OAB), M.A. Williams (PSU) report on behalf of the
Swift-XRT team:
Swift-XRT has performed follow-up observations of the Einstein Probe/WXT-detected
source EP251130a, collecting 2.0 ks of Photon Counting (PC) mode data between T0+5.8
ks and T0+11 ks after the trigger. A likely counterpart has been found. The details
of this source are:
Source 1 (SWIFT J064404.8+272302):
==================================
RA (J2000.0): 101.0203 = 06 44 04.87
Dec (J2000.0): +27.3839 = +27 23 02.0
Error: 3.9 (arcsec, radius, 90% confidence).
Detect flag: GOOD
Distance: 75 arcsec from the Einstein Probe/WXT position.
Mean rate: 0.0618 [+0.0070, -0.0068] ct s^-1
Mean flux: (2.21 [+0.25, -0.24])e-12 erg cm^-2 s^-1
Peak rate: 0.139 +/- 0.031 ct s^-1
Peak flux: (5.0 +/- 1.1)e-12 erg cm^-2 s^-1
ECF: 3.57e-11 erg cm^-2 ct^-1
assuming NH=1.80e+21 cm^-2, gamma=1.97
determined from a spectral fit.
XMM UL: 3.5e-12 erg cm^-2 s^-1, (0.3-10 keV)
so the source is 1.4-sigma above this 3-sigma upper limit.
The source may be fading, at the 2.6-sigma level. This position is consistent
with the candidate optical counterpart reported by COLIBRI (GCN 42904).
All fluxes are 0.3-10 keV, observed. For all flux conversions and comparisons with
catalogues and upper limits from other missions, we assumed a power-law spectrum
with NH=3x10^20 cm^-2 and photon index (Gamma)=1.7 unless otherwise stated.
The results of the XRT-team automatic analysis of the XRT observations, including a
position-specific upper limit calculator, are available at
https://www.swift.ac.uk/EP/EP_FIELD00085.
This circular is an official product of the Swift-XRT team.
View this GCN Circular online at https://gcn.nasa.gov/circulars/42908.
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TITLE: GCN CIRCULAR
NUMBER: 42906
SUBJECT: EP251130a: Global MASTER-Net observations report
DATE: 25/11/30 16:45:38 GMT
FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru>
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 EP251130a ( EP Team et al., GCN 42903) errorbox 16211 sec after notice time and 19018 sec after trigger time at 2025-11-30 16:24:47 UT, with upper limit up to 15.3 mag. The observations began at zenith distance = 80 deg. The sun altitude is -30.0 deg.
The galactic latitude b = 11 deg., longitude l = 188 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=3055832
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
19048 | 2025-11-30 16:24:47 | MASTER-Kislovodsk | (06h 42m 49.31s , +27d 04m 35.5s) | C | 60 | 13.6 |
19048 | 2025-11-30 16:24:47 | MASTER-Kislovodsk | (06h 42m 50.47s , +27d 27m 17.4s) | C | 60 | 15.3 |
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
View this GCN Circular online at https://gcn.nasa.gov/circulars/42906.
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TITLE: GCN CIRCULAR
NUMBER: 42904
SUBJECT: EP251030a: COLIBRÍ optical counterpart candidate
DATE: 25/11/30 15:18:49 GMT
FROM: Damien Dornic <ddornic(a)km3net.de>
Damien Dornic (CPPM), Margarita Pereyra (UNAM), Stéphane Basa (UAR Pytheas), Rosa L. Becerra (UNAM), Alan M. Watson (UNAM), Jean-Luc Atteia (IRAP), Camila Angulo (UNAM), Dalya Akl (NYUAD), Sarah Antier (IJCLAB), Nathaniel R. Butler (ASU), Jean-Grégoire Ducoin (CPPM), Francis Fortin (IRAP), Leonardo García García (UNAM), William H. Lee (UNAM), Kin Ramandeep Gill (UNAM), Noémie Globus (UNAM), Ocelotl López (UNAM), Diego López-Cámara (UNAM), Nikos Mandarakas (LAM), Francesco Magnani (CPPM), Enrique Moreno Méndez (UNAM), Ny Avo Rakotondrainibe (LAM), Fredd Sánchez Álvarez (UNAM), Benjamin Schneider (LAM) and Antonio de Ugarte Postigo (LAM):
We imaged the field of the EP251030a (Wu et al., GCN 42903) using the DDRAGO two-channel wide-field imager on the COLIBRÍ telescope. We observed from 2025-11-30T12:09:17 to 12:28 UTC (from 1.02 to 1.34 hours after the trigger) and obtained 16 minutes of simultaneous exposure in the r and z filters.
The data were reduced, coadded and analysed with the COLIBRÍ pipeline. The photometry was calibrated using nearby stars from the PanSTARRS DR1 catalog, is in the AB system, and is not corrected for Galactic extinction.
In the stacked image, we detect an uncatalogued source at the coordinates: RA = 101.0205 deg, Dec = 27.3840 deg with an uncertainty of 0.5 arcsec, compatible with the EP/FXT position (Wu et al., GCN 42903), at preliminary magnitudes of:
r = 20.69 +/- 0.03
z = 19.45 +/- 0.03
We thank the staff of the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir and the COLIBRÍ and DDRAGO engineering teams.
COLIBRÍ is an astronomical observatory developed and operated jointly by France (AMU, CNES and CNRS) and Mexico (UNAM and SECIHTI). It is located at the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir, Baja California, Mexico.
View this GCN Circular online at https://gcn.nasa.gov/circulars/42904.
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TITLE: GCN CIRCULAR
NUMBER: 42903
SUBJECT: EP251130a: Einstein Probe detection of an X-ray transient
DATE: 25/11/30 11:51:35 GMT
FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn>
T. Wu, H. C. Ding (AHNU), Y. H. Jiang, Y. Wu (NJU), Y. Wang (PMO), 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 EP251130a. The transient triggered EP-WXT (ID: 01709249022) at 2025-11-30T11:07:49 (UTC). The WXT position of the source is R.A. = 101.041 deg, DEC = 27.394 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. = 101.0242 deg, DEC = 27.3824 deg (J2000) with an uncertainty of 20 arcsec in radius (90% C.L. statistical and systematic).
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).
View this GCN Circular online at https://gcn.nasa.gov/circulars/42903.
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