2006CBET..647....1H

A. Harutyunyan, S. Benetti, M. Turatto, E. Cappellaro, and N. Elias-Rosa, Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Padova; and G. Andreuzzi, Telescopio Nazionale Galileo (TNG), report that a spectrum of 2006gy (cf. CBET 644), obtained on Sept. 26.07 UT with the 3.5-m TNG (+ DOLORES; range 340-920 nm, resolution 1.2 nm), shows it to be a type-II supernova caught soon after explosion. The spectrum, heavily contaminated by the parent galaxy, seems dominated by a relatively red continuum with overimposed H-beta with a P-Cyg profile, and H-alpha with a complex profile consisting of three emission components: a narrow unresolved one, an intermediate (FWHM about 2500 km/s) one, and a broad one (FWHM about 9500 km/s). The He I 587.6-nm emission is also present. An interstellar Na I D absorption feature is visible in the host-galaxy rest frame with an equivalent width of about 0.6 nm. Adopting the recession velocity of 5945 km/s (as measured from the Na I D absorption) for the parent galaxy, the expansion velocity derived from the H-beta minimum is about 4500 km/s.