2006CBET..636....1B

S. Blondin, K. Masters, M. Modjaz, R. Kirshner, and P. Challis, Harvard-Smithsonian Center for Astrophysics; and T. Matheson, National Optical Astronomy Observatory, report that spectra (range 350-740 nm) of 2006fp (cf. CBET 625, IAUC 8750), obtained on Sept. 19.29 and 20.28 UT by P. Berlind with the F. L. Whipple Observatory 1.5-m telescope (+ FAST), show an object with a reddened continuum and narrow Balmer emission lines (FWHM about 300 km/s), as well as other emission lines from the underlying host galaxy. There might be a weak, slightly broadened (FWHM < 1000 km/s) component in the H_alpha emission line, in which case either this object could be a type-IIn supernova or it corresponds to an outburst of a luminous blue variable (LBV). However, adopting a recession velocity of 1490 km/s for the host galaxy (from "The Updated Zwicky Catalog", http://tdc-www.harvard.edu/uzc/), and assuming no peculiar motion (because of its location in the northern quiet Hubble flow region), the discovery magnitude of 17.7 corresponds to an absolute magnitude of roughly -14, which is more consistent with an LBV than a supernova (see also Van Dyk et al. 2000, PASP 112, 1532, regarding SN 1997bs). Moreover, cross-correlations with a library of template spectra shows that 2006fp is most similar to 1999bw (cf. IAUC 7152) and 2001ac (cf. IAUC 7597), both of which were underluminous with respect to other type-IIn supernovae. Last, the intermediate-width component in H_alpha, if present, is 2-4 times more narrow than seen in other type-IIn supernovae. Therefore, 2006fp is more likely to correspond to an outburst of a luminous blue variable rather than a true supernova. Also, interstellar Na I D absorption at the redshift of the host galaxy is visible in the spectrum with an equivalent width of 0.4 nm.