Skip to main content
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 36396

IceCube-240424A: GRANDMA Optical Upper Limit of Fermi J2151.3+0220
2024-05-05T10:09:59Z (13 days ago)
Dalya Akl at American Uni. SHJ <>
Web form
D. Akl (AUS), T. Pradier (Unistra/IPHC), T. Jegou du Laz (Caltech), M. Molham (NRIAG), S. Antier (OCA), I. Tosta e Melo (UniCT-DFA), P. Hello (IJCLAB), S. Karpov (FZU), M. Coughlin (UMN), C. Andrade (UMN), P-A Duverne (APC), D. Turpin (CEA-Saclay/Irfu), N. Guessoum (AUS), E. G. Elhosseiny (NRIAG), D. Dornic (CPPM), M. Pillas, J. Dibasso (Berkeley), W. Corradi, N. Sasaki, F. Navarete, L. De Almeida, L. Fraga (LNA), Z. Benkhaldoun, A. Kaeouch (OUCA, KNC) on behalf of GRANDMA collaboration:

We observed the localization region of the neutrino event IceCube-240424A (Zegarelli, GCN 36283; Mand, GCN 36309) primarily at the location of the gamma-ray source Fermi J2151.3+0220 (Garrappa et. al, GCN 36349; RA: 327.83 deg, DEC: 2.34 deg). We considered T0 as 2024-04-24 01:49:26.0 UT.

We did not find any optical counterpart in our images within a 10 arcmin radius around the J2151.3+0220 position for the ASO telescope, and within a 5 arcmin radius for the OPD telescope.

In the following table, we report a subset of the preliminary photometry of our observations of J2151.3+0220. Upper limits are reported in the Vega system.

| T-T0 [day] |      MJD       | Telescope | Exposure  | Filter | Upperlimit (5 sig.) | 
|    6.07    | 60430.15036744 |    ASO    |  17x180s  |   L    |         21.8        |  
|    7.19    | 60431.26727265 |    OPD    |  10x180s  |   R    |         20.8        |
|    7.21    | 60431.28910205 |    OPD    |  10x200s  |   R    |         21.1        |
|    7.24    | 60431.31329227 |    OPD    |  12x250s  |   R    |         21.4        |

ASO and OPD data have been calibrated in V and in R, respectively, using the Gaia DR3 Synphot catalog

All the data have been reduced by a single data processing pipeline STDPIPE (Karpov et al., 2022).

GRANDMA is a worldwide coordinated telescope network ( devoted to the observation of transients in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS497, 5518). Kilonova-Catcher (KNC) is the citizen science program of GRANDMA (
Looking for U.S. government information and services? Visit