Supernova 2008M

The thirteenth supernova found by BRASS was SN 2008M, located in galaxy ESO 121-026 at R.A. 06h21m38.75s and Dec -59d44m23.7s (2000.0). Discovery was made on 2008 Jan 15.12 through images made at the CEAMIG-REA Observatory, Belo Horizonte, Brazil. Confirmation came through IAU CBET #1214, dated January 18.

ESO 121-026, in Southern constellation Pictor, is a barred spiral galaxy of morphological class SB(rs)c, according to NASA Extragalactic Database (NED). Its apparent dimensions are 3.2 x 2.0 arcmin. Its recession velocity and redshift are (2267 +/- 4) km/s and ( 0.007562 +/- 0.000013) respectively, also according to NED data. Those figures imply in a distance of about 32.4 megaparsec (close to 105.6 million light years), assuming a value of 70 km/s.Mpc for the Hubble constant. Given that estimated distance plus the apparent magnitude at discovery (15.5), we may estimate the absolute magnitude of SN 2006co as -17 at discovery.

Astrometric position of SN 2008M is: R.A. 06h21m41s.28, Dec -59d43'45".4 (2000.0). Previous images from Digitized Sky Survey plates shows a faint H II region close to the position of 2008M. Further to our discovery (on Jan 28), G. Folatelli and F. Olivares (University of Chile) and N. Morrell (Las Campanas Observatory) reported on spectrograms (range 350-840 nm) of 2008M obtained on Jan. 27.2 UT with the European Southern Observatory 3.6-m telescope at La Silla. SN 2008M is a type-II supernova, a few days after explosion. Its spectrum presents a blue continuum with P-Cyg features due to the Balmer series lines. The H-alpha line is dominated by the emission component. The maximum absorption of the H-beta line indicates an expansion velocity of about 8500 km/s.