GCN Circular 43429
Subject
GRB 260114A: VLT/MUSE spectroscopic observations
Event
Date
2026-01-16T21:38:14Z (12 days ago)
From
Andrea Saccardi at CEA/Irfu <andrea.saccardi@cea.fr>
Via
Web form
A. Saccardi (CEA/Irfu), D. B. Malesani (DAWN/NBI and Radboud), B. Schneider (LAM), G. Corcoran (UCD), H. Fausey (Baylor), L. Izzo (INAF/OACn & DARK/NBI), A. J. Levan (Radboud and Warwick), A. Martin-Carrillo (UCD), G. Tagliaferri (INAF/OAB), N. R. Tanvir (Leicester) report on behalf of the Stargate collaboration:
We observed the field of the short GRB 260114A (Eyles-Ferris et al., GCN 43396; Bissaldi, GCN 43400; Ren et al., GCN 43402; Wang et al., GCN 43404; Ridnaia et al., GCN 43413) using the ESO/VLT UT4 (Yepun) equipped with the MUSE integral-field spectrograph, covering 1'x1' centered around the XRT position. The observation mid time was 2026 Jan 15.155 UT (16.05 hr after the Swift/BAT trigger).
In proximity of the X-ray localization (Beardmore et al., GCN 43412), several objects are visible in archival images of the field, for some of which we report redshifts. These measurements are based on identification of emission lines due to, among others, [O III], Hbeta, and the [O II] doublet. The redshift of the first object in the list has been already reported by Yang et al. (GCN 43410).
Three of the objects have redshift close to z = 0.52, reinforcing that this is the likely GRB redshift.
We note the presence of a star in chance alignment with the galaxy at z = 0.524. Its spectrum easily identifies it as an early M star, and its PSF is unresolved down to ~0.5" seeing in our HAWK-I image (Schneider et al., GCN 43423).
| RA (J2000) | Dec (J2000) | Redshift | Comments |
| ----------- | ----------- | -------- | --------- |
| 04:58:23.43 | -08:00:50.5 | 0.524 | GCN 43410 |
| 04:58:23.57 | -08:00:52.2 | 0.514 | |
| 04:58:23.60 | -08:01:00.4 | 0.523 | |
| 04:58:22.72 | -08:00:47.7 | 0.288 | |
| 04:58:23.41 | -08:00:49.7 | 0 | M star |
A finding chart showing the positions of the above objects is posted at the following link (the XRT position is taken from https://www.swift.ac.uk/xrt_positions/):
https://sid.erda.dk/share_redirect/Ba6h5nsfin
We thank Phil Evans (Leicester) for insightful clarifications about the XRT localization. We also acknowledge excellent support from the observing staff at Paranal, in particular Thomas Rivinius, Julien Drevon, Camila de Sa Freitas, Rodrigo Romero.