2006CBET..648....1P

J. L. Prieto, Ohio State University; and P. Garnavich, A. Chronister, and P. Connick, University of Notre Dame, report that they obtained spectra of 2006gy (cf. CBET 644, 647) with the Kitt Peak 4-m telescope (+ RC spectrograph) on Sept. 26.4 UT. The spectra show a strong red continuum with broad Balmer emission and broad He I emission at 600 nm. Deep, narrow interstellar absorption lines of Na I and Ca II from the host galaxy are clearly seen. The equivalent width of the Na I absorption in the host galaxy is 0.51 nm, suggesting that the continuum color derives from heavy dust extinction. The spectrum is suggestive of a dust-extinguished type-IIn event. However, the Balmer lines are symmetric, which is unusual for supernovae in their early phases. The source showed no offset from the galaxy core in the 4-m TV guider. The brightening event could be an active-galactic-nucleus (AGN) outburst from a strongly extincted galaxy core. Comparing the Na I absorption from the Milky Way and host with the Milky Way reddening, the line-of-sight visual extinction is estimated to be about 2 magnitudes. Given the estimated apparent magnitude of the event (CBET 644), the absolute magnitude of a supernova would be -22, which is more consistent with an AGN.