SN 2000cx: a peculiar type-Ia supernova

The LOSS KAIT team has discovered a bright supernova in NGC 524. The SN was discovered and confirmed on July 17.5 (mag about 14.5) and Jul 18.4 (mag about 14.3), respectively (vsnet-campaign-sn 15). H. Yamaoka commented that the type of the host galaxy (S0) and the reported magnitudes suggest that it was of type Ia just before maximum which can be estimated around mag 14 (vsnet-campaign-sn 16). R. Modic reported their observation to [ vsnet-obs 28691] that it was bright at about 13.6mag on July 20 (vsnet-campaign-sn 18). Weidong Li commented that it was too bright for its recession velocity and getting a spectrum to check whether it is SN 1991T-like is interesting, since the host galaxy is of type S0 but looks very much like an Elliptical, and no SN 1991T-like Ia had been found in E galaxies yet (vsnet-campaign-sn 23). According to IAUC 7463, the object turned out to be of a peculiar type Ia SN, like SN 1991T. SN 2000cx is the first-ever example of bright SNeIa in the early-type galaxy ( vsnet-campaign-sn 24).

K. Krisciunas reported his observation and commented that it is curious that the B-V color has stayed so constant (vsnet-alert 5156, vsnet-campaign-sn 28). This supernova reached the maximum at about 13.1mag around the end of July (vsnet-campaign-sn 30, 36), and then, started fading (vsnet-campaign-sn 39, 42, 45, 46, 51, 61, 66, 84, 93, 103). The object showed relatively rapid fading during August (vsnet-campaign-sn 54). According to the mail forwarded by H. Yamaoka, we can see a light curve of SN 2000cx presented by O. Trondal (see, vsnet-campaign-sn 68).