Supernova 2006D

SN 2006 D was the tenth supernova discovered by BRASS. This SN was found in galaxy MCG -01-33-34 (MRK 1337, IRAS 12499-0930, PGC 043690), located at R.A. 12^o52'34.7", Dec -09^o46'36" (2000.0). Discovery was made on 2006 Jan 11.19 UT, through images made at the robotic CEAMIG-REA Observatory. Confirmation from IAU came though IAU Circular # 8658 (Jan 13, 2006) with further references available in CBET 362, CBET 366, ATEL 689.

MCG -01-33-34 is a spiral galaxy of morphological class SAB(s)ab pec? according to NASA Extragalactic Database (NED). Its apparent dimensions are 1.2 x 0.8 arcmin, which means that it is seen almost quase "face-on". Its recession speed and redshift are respectively (2556 +/- 5) km/s and (0.00853 +/- 0.00002) (same source), which implies that its distance is about 36.5 megaparsec (some 119 million light years), assuming a value of 70 km/s.Mpc for the Hubble constant. Taking into account that figure plus the apparent magnitude measured at discovery (15.5) we estimated SN 2006D' s absolute magnitude as -17.3.

Further to our discovery, spectra obtained in the 320 - 1000 nm band by Nearby Supernovae Factory on January 14.6 UT with the 2.2-m telescope of the University of Hawaii showed that SN 2006D was a Type Ia supernova about one week before maximum, which made this SN particularly important for further observations. Spectra showed a striking carbon signature of C II 657.8 nm, plus features of C II 426.7, 472.0 and 723.3 nm. Doppler shift was estimated as about 12 000 km/s.

Our own post-discovery magnitude estimates have indicated a brightening of 1.3 magnitudes in only five days from discovery with a trend for further strenghtening over the next few days. Monitoring persists at the moment this text is being written.