■ [Extragalactic nova] M31 2011-01a : observation start
We started observations of extragalactic nova M31 2011-01a since Jan. 9. We roughly measured the apparent peak magnitude of 15.3 mag in V-band. This indicates that this nova is one of the very bright nova. It roughly takes 10 days to decrease by 2 magnitudes. Thus, this nova is classified into very fast nova. This very fast decline is consistent with high peak luminosity. We will continue the observations of this nova.
■ [Extragalactic nova] M31 2010-09b : update
We update the light curve of M31 2010-09b. We can roughly estimate of the t2 ~ 10, which takes days decrease of 2 magnitude in the light curves. The low decline rate indicates that this nova is a very fast nova, like U Sco, V2491 Cyg, V1500 Cyg and so on.
■ [Extragalactic nova] M31 2010-09b : Observations Start
We performed the photometric observations of M31 2010-09b using 1.5m-Kanata telescope equipped with HOWPol. This nova was discovered of 17.3 mag in the nearby galaxy M31 on 2010 Sep. 30.566 by the amatuer nova survey persons, Nishiyama and Kabashima (CBET 2472). Despite of the early discovery of this nova (ATEL 2896), our preliminary results indicate that the brightness rapidly decrease with time. This results suggest that M31 2010-09b may be a class of very fast novae (Payne-Gaposchkin 1958). But, the object is not so moreluminous than M31 2009-10b (CBET 1971, Kanata ObsLog on 2009 Oct. 19). This means that this nova may be reddened by the galactic dust or a possible candidate of the recurrent nova, like U Sco. Shafter et al. reported that the spectrum exhibits the HeII 4686 line and the FeII line series on Oct. 1.39, which indicates that this nova is a possible hybrid nova (ATEL 2898). This class object will be rapidly fading out. We will observe this object until limit.