Follow-up observations of AT 2025qmf, a possible nova in M31

ATel #17285; R. Fidrich (HAA/VSS, Budakeszi, Hungary), A. S. Vinokurov (SAO RAS), T. Tordai (HAA/VSS, Budapest, Hungary), O. I. Spiridonova (SAO RAS)
on 14 Jul 2025; 11:11 UT
Credential Certification: Alexander Vinokurov (vinokurov@sao.ru)

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We present the results of optical photometry of AT 2025qmf discovered by Robert Fidrich in the field of M31 on 2025 July 6.34904UT near 17.70 magnitude.

Over the past week AT 2025qmf dimmed gradually almost by 2 magnitudes. The B-V and V-R color indices of AT 2025qmf (0.62 and 0.52, respectively) suggest that the transient is unlikely to be a cataclysmic variable or a long-period variable. Observations were made with the 0.51m CDK reflector (iTelescope.net network), Utah Desert Remote Observatory at Great Basin Desert, Beryl Junction, Utah, USA (T26 the table below), the 0.43m CDK reflector, Alnitak Remote Observatory at Nerpio, Spain (A1) and the 1m Zeiss-1000 telescope at SAO RAS (Z1).

JD-2460000 | Mag | Filter | Telescope

862.85 | 17.706 ± 0.029 | LV | T26

864.58 | 18.09 ± 0.05 | LV | A1

864.60 | 17.58 ± 0.05 | R | A1

865.52 | 19.29 ± 0.07 | B | Z1

865.52 | 18.67 ± 0.03 | V | Z1

865.87 | 18.87 ± 0.10 | LV | T26

866.64 | 19.02 ± 0.11 | V | A1

866.64 | 18.50 ± 0.11 | R | A1

867.86 | 19.07 ± 0.14 | LV | T26

868.90 | 19.67 ± 0.22 | LV | T26

Filter key: Johnson filters B, V and R; LV refer to Luminance filter, calibrated using V comparison stars.

Spectroscopy and additional photometric observations (especially with H-alpha and Johnson or Cousins R-band) of this nova candidate in M31 are strongly encouraged to confirm the nature of this transient.

The observations made using the Alnitak Remote Observatories robotic telescope network, were supported by ARTA program. The Zeiss-1000 observations and calibrations were performed as part of the government contract of the SAO RAS approved by the Ministry of Science and Higher Education of the Russian Federation. Observations with the SAO RAS telescopes are supported by the Ministry of Science and Higher Education of the Russian Federation. The renovation of telescope equipment is currently provided within the national project "Science and Universities".