TNS Classification Report No. 20207 [ 2025TNSCR.260....1L ]
Date Received (UTC): 2025-01-19 19:41:06 Sender: Daniele Malesani
Group: None
Andrew J. Levan (Radboud), Jillian C. Rastinejad (Northwestern), Daniele B. Malesani (DAWN/ NBI and Radboud), Wen-fai Fong (Northwestern), Nial R. Tanvir (Leicester) report/s a classification of object: SN 2025kg
Type: SN Ic-BLRedshift: 0.176
Remarks: In contrast to earlier observations which showed a hot, blue continuum (Zhu et al., GCN 38908), it is now characterised by a redder shape. In addition, broad features are now visible in the spectrum with high signal to noise. Both the spectral shape and broad features resemble those found in broad-lined type Ic supernovae. Our findings find further support for the conclusions based on NOT spectroscopic observations (Xu et al., GCN 38394, and are also consistent with the optical re-brightening reported by Eyles-Ferris et al. (GCN 38983). On this basis we therefore conclude that the FXT and FBOT EP250108a is related to the core-collapse of a massive star. The earlier bright blue emission may be consistent with a rapidly cooling black body, similar to that seen in GRB/XRF 060218 (Campana et al. 2006, doi:10.1038/nature04892; Pian et al. 2006, doi:10.1038/nature05082), although it appears to last for a much longer period (days instead of hours) in the case of EP250108a.
The following Classification spectrum was provided:
Obsdate: 2025-01-19 01:29:02
Instrument: GMOS-S
Telescope: Gemini South
Details of the object and its spectra can be viewed here: https://www.wis-tns.org/object/2025kg
Date Received (UTC): 2025-01-19 19:41:06 Sender: Daniele Malesani
Group: None
Andrew J. Levan (Radboud), Jillian C. Rastinejad (Northwestern), Daniele B. Malesani (DAWN/ NBI and Radboud), Wen-fai Fong (Northwestern), Nial R. Tanvir (Leicester) report/s a classification of object: SN 2025kg
Type: SN Ic-BLRedshift: 0.176
Remarks: In contrast to earlier observations which showed a hot, blue continuum (Zhu et al., GCN 38908), it is now characterised by a redder shape. In addition, broad features are now visible in the spectrum with high signal to noise. Both the spectral shape and broad features resemble those found in broad-lined type Ic supernovae. Our findings find further support for the conclusions based on NOT spectroscopic observations (Xu et al., GCN 38394, and are also consistent with the optical re-brightening reported by Eyles-Ferris et al. (GCN 38983). On this basis we therefore conclude that the FXT and FBOT EP250108a is related to the core-collapse of a massive star. The earlier bright blue emission may be consistent with a rapidly cooling black body, similar to that seen in GRB/XRF 060218 (Campana et al. 2006, doi:10.1038/nature04892; Pian et al. 2006, doi:10.1038/nature05082), although it appears to last for a much longer period (days instead of hours) in the case of EP250108a.
The following Classification spectrum was provided:
Obsdate: 2025-01-19 01:29:02
Instrument: GMOS-S
Telescope: Gemini South
Details of the object and its spectra can be viewed here: https://www.wis-tns.org/object/2025kg