Spectroscopic confirmation and photometry of the nova candidate PNV J00424067+4115451

ATel #15840; A. Vinokurov, A. Valeev, R. Uklein, O. Maslennikova, A. Sarkisyan (SAO RAS)
on 2 Jan 2023; 21:39 UT
Credential Certification: Azamat Valeev (azamat@sao.ru)

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ATels #15833,#15836 reported the discovery of PNV J00424067+4115451, a new nova candidate in M31. Here, we present the results of our recent optical spectroscopy and photometry of the object.

Spectroscopic observations were carried out on 2022 Dec. 30 (MJD=59943.78) with the multi-mode focal reducer SCORPIO-2 mounted at the primary focus of a 6-m SAO RAS telescope. Three subexposures of 300s were obtained with a VPHG1200@540 grism covering the spectral range of about 3650-7300ÅÅ with resolution of 4.5Å. Spectroscopy has revealed a prominent blue continuum with high-order Balmer absorption lines together with deep Fe II, Ca II and relatively weak Na I and Si II absorptions. Emission components in a P-Cyg profile are clearly visible in the Hγ, Hβ, Hα and some Fe II lines, for example Fe II 4924,5018. The FWHMs of the emission components are in range of 1000-1200 km/s, and absorption minimum of the lines is blueshifted by 1050 ± 100 km/s from the emission peak.

Direct imaging of the M31 nuclear region in filters B, V and Rc were carried out approximately 1.5 hours before the spectroscopy (MJD=59943.71) using the CCD photometer of the 1-m SAO RAS telescope. The seeing was 1.8-2.3 arcsec during observations. 60 sec exposure per filter were obtained. The measured magnitudes are B = 17.20 ± 0.07, V = 16.81 ± 0.12, Rc = 16.67 ± 0.17. The Rc magnitude indicates an increase in the brightness of the object compared to the values reported by K. Hornoch et al. in ATel #15836.

Based on the obtained spectrum and photometry, we classify PNV J00424067+4115451 as Fe II class Nova which has not yet reached its maximum brightness at the time of our observations.

The work was 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".

The spectrum with the line identification