SIMBAD references

2008CBET.1285....1B - Central Bureau Electronic Telegrams, 1285, 1 (2008/March-0)

Supernova 2008ax in NGC 4490.


Abstract (from CDS):

S. Blondin, Harvard-Smithsonian Center for Astrophysics (CfA), on behalf of the CfA Supernova Group; A. V. Filippenko, R. J. Foley, and W. Li, University of California, Berkeley; and L. Dessart, Steward Observatory, University of Arizona, report that a spectrum (range 350-740 nm) of the possible supernova announced on CBET 1280, obtained on Mar. 4.37 UT by A. Vaz with the F. L. Whipple Observatory 1.5-m telescope (+ FAST), shows it to be a young, reddened, peculiar, type-II supernova. The spectrum is dominated by broad P-Cyg profiles of the Balmer series with a broad absorption around 545 nm due to He I (rest 587.6 nm). The spectrum is similar to an early spectrum of the peculiar type-II supernova 1987A taken on 1987 Feb. 25 UT (i.e., roughly two days past the neutrino outburst and 82 days before V-band maximum light; Phillips et al. 1988, A.J. 95, 1087), although the line widths and blueshifts are greater in 2008ax. Adopting a recession velocity of 589 km/s for the host galaxy of 2008ax (from The Updated Zwicky Catalogue,, the maximum absorptions in the H_beta (rest 486.1 nm), He I (rest 587.6 nm), and H_alpha (rest 656.3 nm) lines are blueshifted by roughly 23500, 22800, and 26600 km/s, respectively (cf. 16000, 14900, and 18500 km/s for the aforementioned 1987A spectrum). The peak emissions also display significant blueshifts (6700 km/s for H_alpha), as observed in the early spectra of type-II supernovae (cf. Dessart and Hillier 2005, A.Ap. 437, 667). Also, interstellar Na I D absorption at the redshift of the host galaxy is visible in the spectrum, suggesting some reddening towards 2008ax. In the comparison plot (visible at website URL, the spectrum of 2008ax is dereddened by E(B-V) = 0.6 mag to reproduce the overall spectral energy distribution of the 1987A comparison spectrum. Assuming that the host galaxy is in the Hubble flow and the supernova suffers from A_V about 2 mag of visual extinction, the discovery magnitude of 16.1 corresponds to an absolute magnitude of roughly -15.4, comparable to 1987A in its early stages [M_V = -14 on 1987 Feb. 27, adopting the apparent V-band magnitude of 4.45 reported by Hamuy et al. (1988, A.J. 95, 63) and a distance modulus of -18.5 to the LMC].

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