AstroNote 2026-158

The BHTOM.space network coordinated an observing campaign to monitor SN 2025fvw, a bright nearby SN Ia supernova, reported on 2025/03/26 by K. Itagaki ( https://www.wis-tns.org/object/2025fvw/discovery-cert , http://k-itagaki.jp/images/2025fvw.jpg ). NGC 5957 was recognised as a potential host. Supernova was later classified as Type-Ia by R. Leadbeater ( https://www.wais-tns.org/ads/TNSCR-2025-1262 ).

Follow-up observations commenced on April 3rd, 2025, a little over a week after the initial discovery and finished on August 25, 2025, when the target was at ~19.2 mag in R band. During this period, approximately 600 measurements were obtained using a variety of telescopes within the BHTOM network. Photometric data were taken in both Sloan- and Johnson-like filters and subsequently transformed into Gaia Synthetic Photometry (GaiaSP) for consistency. 

The evolution of the SN 2025fvw light curve was also observed by sky surveys ZTF and ATLAS. Also, ultraviolet observations from Swift UVOT are present in the light curve available through BHTOM.space. Some archival observations of these region exist as well (ATLAS & WISE). The last registered photometric data point comes from ZTF at ~20 mag in the Sloan g’ filter (January 30, 2026).

The multi-band light curve in BHTOM shows a steady decline in all bands with a bump clearly visible across the entire spectrum at the end of April 2025.

Detailed light curves and associated statistics are presented on the webpage: https://bhtom.space/public/targets/SN2025fvw . Further details and the full photometric dataset are available for download by registered users of the BHTOM.space platform. 

Acknowledgements: BHTOM.space is based on the open-source TOM Toolkit by LCO and has been supported by the European Union's research and innovation programmes under grant agreements No 101004719 (OPTICON-RadioNet Pilot, ORP) and 101131928 (ACME).