AstroNote 2026-118

We report on the multi-band photometric monitoring campaign of 6 spectroscopically confirmed supernovae, conducted through the BHTOMnetwork.

SN 2026afewas first discovered by the ZTF (r-band) on January 15, 2026 (Wise et al. 2026). It has been classified as a type Ia-pec supernova with z = 0.01, based on the spectrum taken by SPRAT on the Liverpool Telescope (Wise et al. 2026). The BHTOM network monitored the object from around peak brightness onward in griBVRI optical bands. During the peak brightness, it was also observed by Swift, and the automated Swift UVOT pipeline suggests the UVOT observation is consistent with the supernova light curve. Detailed light curves and associated statistics of SN 2026afe are presented on the webpage: https://bhtom.space/public/targets/SN2026afe.

SN 2025zjxwas first discovered by Pan-STARRS (w-P1) on September 29, 2025 (Chambers et al. 2025). It was classified as a Type II with z = 0.0078 supernova based on optical spectra obtained on October 2, 2025, using the GMOS spectrograph on the Gemini-N telescope (Andrews et al. 2025). The BHTOM network initiated follow-up observations two days after classification and monitored the target until 14 December 2025 in the grizVRI bands, until it became too faint for detection. Detailed light curves and associated statistics of SN 2025zjx are presented on the webpage: https://bhtom.space/public/targets/SN2025zjx.

SN 2025mbwas first discovered by ATLAS (o-band) on January 15, 2025 (Tonry et al. 2025). It has been classified as Type IIb based on the strong Hydrogen emission lines with z=0.005 (Kaur and Foley, 2025). The BHTOM network initiated follow-up observations in grizBRV optical bands on January 16, 2025, and ended on November 15, 2025, covering all the states of the supernova. The supernova has now faded, and the most recent observations appear consistent with the host galaxy. Detailed light curves and associated statistics of SN 2025mb are presented on the webpage: https://bhtom.space/public/targets/AT2025mb.

SN 2026btiwas first discovered by ZTF (g-band) on January 28, 2026 (Sollerman et al. 2026). It was classified as a Type IIn Supernova based on the presence of the narrow hydrogen emission lines in the optical spectra (Rose et al. 2026). The BHTOM network initiated multi-band follow-up observations three days after the initial discovery. The light curve exhibits a general decline; however, given its Type IIn nature, potential fluctuations or rebrightenings cannot be ruled out, and monitoring will continue until the supernova falls below detection limits. Detailed light curves and associated statistics of SN 2026bti are presented on the webpage: https://bhtom.space/public/targets/AT2026bti/.

SN 2025aarnwas first discovered by GOTO (L-GOTO) on October 17, 2025 (O'Neill et al. 2025). It has been classified as a Type II supernova based on the optical spectrum with broad, albeit shallow Balmer P-Cygni lines on a blue continuum (Pursiainen et al. 2025). Redshift of value 0.01685 was measured from the template match of the optical spectrum (Dong et al. 2025). It was followed up by the BHTOM network from October 20, 2025, covering the peak and decline phase. The light curve shows a sudden drop ~40 days after peak and has now faded completely in the optical bands. It was observed in grizRB bands, and observations are still going on.  Detailed light curves and associated statistics of SN 2025aarn are presented on the webpage: https://bhtom.space/public/targets/AT2025aarn.

SN 2025aoxwas first discovered by XOSS (CL) on January 31, 2025 (Zhang et al. 2025). It was classified as a Type Ia-SC supernova with z = 0.04 (Johansson et al. 2025). The BHTOM network initiated follow-up observations in grizRI optical bands on February 9, 2025, and covered the decline phase. The light curve shows a possible late-time bump. It is unclear whether this feature is significant, and its origin remains uncertain, requiring dedicated analysis. Detailed light curves and associated statistics of SN 2025aox are presented on the webpage: https://bhtom.space/public/targets/AT2025aox.

The targets are observed by the LCO Network, 51-cm Slooh Australia Telescope (Australia), 50-cm University of Zielona Góra Observatory (Chile), 1.2-meter Kryoneri Observatory (Greece), 40-cm GoChile-GoT1 Telescope (Chile), 60-cm REM Telescope (Chile), 41-cm School Astronomical Observatory Bolecina (Poland), 68-cm Horten Telescope (Norway), 70-cm Planetarium Slaskie Telescope (Poland), 30-cm SUTO-Otivar Telescope (Spain), 60-cm UwB Astronomical Observatory Telescope (Poland), 80-cm Joan Oró Telescope (Spain), 50-cm OAUJ CDK Telescope (Poland) and 80-cm Moletai Observatory (Lithuania). Photometric observations were transformed into Gaia Synthetic Photometry (GaiaSP) for consistency.

Data accessed through the BHTOM networkis subject to its Terms and Conditions available here. Public links to the light curves are provided here in the spirit of open science and collaborative research; full downloads are available to registered users upon creating a free account at BHTOM.

We share these resources because we believe in free data accessibility and the value of broad scientific collaboration. In return, we kindly ask that researchers who find these light curves useful to properly acknowledge the BHTOM project. Proper credit is essential to sustaining the collaborative spirit that makes this data possible.

Researchers planning to use these data are warmly encouraged to reach out to the BHTOM team in advance at contact@bhtom.space.

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).