TNS Classification Report No. 23210 [ 2026TNSCR1062....1H ]
Date Received (UTC): 2026-03-13 13:28:39 Sender: Brian Hsu
Group: AZTEC
Brian Hsu (U of Arizona), M. Shrestha (Monash U), D. J. Sand (U of Arizona), Jennifer Andrews (Gemini-N/NOIRLab), N. Franz (U of Arizona), J. Pearson (U of Arizona), C. Christy (U of Arizona), C. L. Ransome (U of Arizona), Bhagya Subrayan (U of Arizona), K. Bostroem (U of Arizona), G. Hosseinzadeh (UCSD), N. Smith (U of Arizona) on behalf of the AZTEC collaboration report/s a classification of object: AT 2026fgk
Type: AfterglowRedshift: 0.153
Remarks: We report the classification of AT 2026fgk as the possible optical counterpart to GRB 260310A (Konno et al., GCN 43974; Lipunov et al., GCN 43978, discovered by GOTO; O'Neill et al. 2026, TNS Discovery Report 294132) based on the optical spectrum obtained on UT 2025-03-13T06:02:23.850 using the B&C spectrograph on the 90-inch Bok telescope. The optical counterpart is clearly visible. The optical spectrum shows a featureless red continuum, although there is a strong, narrow emission line at 7566 Angstroms that we attribute to H-alpha from the candidate host galaxy at z = 0.153, which is in agreement with the redshift obtained by Hinds et al., GCN 43977. Additional follow-up observations are encouraged.
The following Classification spectrum was provided:
Obsdate: 2025-03-13 06:02:24
Instrument: BC-Bok
Telescope: Bok Telescope
Remarks: The strong emission line near 5577 Angstrom is an unsubtracted sky line and not associated with the candidate host galaxy.
Details of the object and its spectra can be viewed here: https://www.wis-tns.org/object/2026fgk
Date Received (UTC): 2026-03-13 13:28:39 Sender: Brian Hsu
Group: AZTEC
Brian Hsu (U of Arizona), M. Shrestha (Monash U), D. J. Sand (U of Arizona), Jennifer Andrews (Gemini-N/NOIRLab), N. Franz (U of Arizona), J. Pearson (U of Arizona), C. Christy (U of Arizona), C. L. Ransome (U of Arizona), Bhagya Subrayan (U of Arizona), K. Bostroem (U of Arizona), G. Hosseinzadeh (UCSD), N. Smith (U of Arizona) on behalf of the AZTEC collaboration report/s a classification of object: AT 2026fgk
Type: AfterglowRedshift: 0.153
Remarks: We report the classification of AT 2026fgk as the possible optical counterpart to GRB 260310A (Konno et al., GCN 43974; Lipunov et al., GCN 43978, discovered by GOTO; O'Neill et al. 2026, TNS Discovery Report 294132) based on the optical spectrum obtained on UT 2025-03-13T06:02:23.850 using the B&C spectrograph on the 90-inch Bok telescope. The optical counterpart is clearly visible. The optical spectrum shows a featureless red continuum, although there is a strong, narrow emission line at 7566 Angstroms that we attribute to H-alpha from the candidate host galaxy at z = 0.153, which is in agreement with the redshift obtained by Hinds et al., GCN 43977. Additional follow-up observations are encouraged.
The following Classification spectrum was provided:
Obsdate: 2025-03-13 06:02:24
Instrument: BC-Bok
Telescope: Bok Telescope
Remarks: The strong emission line near 5577 Angstrom is an unsubtracted sky line and not associated with the candidate host galaxy.
Details of the object and its spectra can be viewed here: https://www.wis-tns.org/object/2026fgk