MONITORING OF LUMINOUS BLUE VARIABLES CANDIDATES IN M31

Abstract

We present the results of spectroscopic and photometric study of Luminous Blue Variable (LBV) candidates in the Andromeda galaxy. Two targets in M31 galaxy J004526.62+415006.3 and J004425.18+413452.2 from Massey's list [1] have been observed with the 6-m Russian telescope BTA from 2012 to 2017 in the optical range. Photometric data in BVR lters for all objects obtained at
Schmidt telescope at NAO Rozhen Bulgaria from 2015 to 2018. Using these data in combination with other archive photometric data we show photometrical curve and produce multi-epoch spectral energy distributions (SED) of these stars. Taking into account an inherent property of LBVs that their bolometric luminosity of LBV stars are constant we determine the stellar temperatures and radii in different LBV states, as well as the extinction. We have obtained estimates bolometric magnitudes M_bol= --10,4^m and M_bol =-8,4^m for J004526.62+415006.3 and J004425.18+413452.2 respectively. Both objects showed photometric and spectral variability that confirm their classification as LBV.