IceCube-250706A
GCN Circular 40994
Subject
IceCube-250706A - IceCube observation of a high-energy neutrino candidate track-like event
Date
2025-07-06T20:52:56Z (a day ago)
Edited On
2025-07-07T13:29:40Z (6 hours ago)
From
A. Zegarelli at Ruhr University Bochum <azegarelli@icecube.wisc.edu>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of A. Zegarelli at Ruhr University Bochum <azegarelli@icecube.wisc.edu>
Via
Web form
The IceCube Collaboration (http://icecube.wisc.edu/) reports:
On 25-07-06 at 13:14:40.04 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 0.2382 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/141104_37015490.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to:
Date: 25-07-06
Time: 13:14:40.04 UT
RA: 266.00 (+0.57/-0.59 deg 90% PSF containment) J2000
Dec: 38.97 (+0.49/-0.47 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@icecube.wisc.edu
GCN Circular 41003
Subject
IceCube-250706A: COLIBRÍ optical upper limits
Date
2025-07-07T08:47:45Z (11 hours ago)
From
Sarah Antier at OCA <sarah.antier@oca.eu>
Via
Web form
Noémie Globus (UNAM), Sarah Antier (OCA/IJCLAB), Rosa L. Becerra (U Roma), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Alan M. Watson (UNAM), Jean-Luc Atteia (IRAP), Fredd Alvarez (UNAM), Camila Angulo (UNAM), Dalya Akl (AUS), Nathaniel R. Butler (ASU) , Damien Dornic (CPPM), Jean-Grégoire Ducoin (CPPM), Francis Fortin (IRAP), Leonardo García García (UNAM), Ramandeep Gill (UNAM), Kin Ocelotl López (UNAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Enrique Moreno Méndez (UNAM), Margarita Pereyra (UNAM), N. A. Rakotondrainibe (LAM), Benjamin Schneider (LAM), Antonio de Ugarte Postigo (LAM) report:
We observed the field of the IceCube-250706A (GCN 40994) (goldtrack) event with the DDRAGO wide-field imager on the COLIBRÍ telescope at the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir in Mexico on the night of 2025-07-07 UTC.
COLIBRÍ tiled the IceCube error region, starting at 03:43:42 UTC, e.g T+14.5 h after the trigger, for about 1h distributed over 4 tiles (26x26 arcmin); the maximum exposure at a single sky location was 16x60 s.
The data were coadded with the COLIBRÍ pipeline and analysed in STDWeb/STDPipe (Karpov 2025).
Comparing our observations (and after performing image subtraction) against Pan-STARRS DR2, we detect no evident uncatalogued sources within the observed field to a 5-sigma limiting AB magnitude of:
i > 21.6 for the first tile (3 min exp.), centered on (RA, Dec) = (17:43:12.00, +38:46:11.6)
i > 21.1 for the second tile (3 min exp.), centered on (RA, Dec) = (17:43:12.00 +39:10:12.0)
i > 21.9 for the third tile (16 min exp.), centered on (RA, Dec) = (17:44:48.00, +39:10:12.0)
i > 22.3 for the fourth tile (16 min exp.), centered on (RA, Dec) = (17:44:48.00, +38:46:12.0)
These values are not corrected for the Galactic extinction.
We thank the staff of the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir and the COLIBRÍ and DDRAGO engineering teams.