Electronic Telegram No. 1725
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
CBAT@CFA.HARVARD.EDU (science)
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SUPERNOVAE 2009aj, 2009ao, AND 2009au
     M. Stritzinger, N. Morrell, G. Folatelli, R. Covarrubias and M. M.
Phillips, on behalf of the Carnegie Supernova Project and the Millennium
Center for Supernova Studies, report that optical spectra of 2009aj (cf.
CBET 1704) -- obtained on Feb. 26.1, Mar. 11.1, and Mar. 15.1 UT with the
du Pont telescope (+ WFCCD), Magellan BAADE telescope (+ IMACS), and CLAY
telescope (+ LDSS3) -- show it to be a type-II supernova currently around
maximum and reminiscent of SN 1983K (Niemela et al. 1985, Ap.J. 289, 52).
The initial du Pont spectrum consists of a strong blue continuum with weak
emission lines attributed to H_alpha, H_beta, H_gamma, and H_delta.  In the
subsequent two spectra, the hydrogen lines grow in strength while the
overall continuum remains relatively blue.  In the LDSS3 spectrum, He II
(rest 541.1 nm) is clearly present.  Adopting a host-galaxy recession
velocity of 2883 km/s (H I Parkes All-Sky Survey Final Catalog; Wong et al.
2006, MNRAS 371, 1855) for the host galaxy (ESO 221-18), H_beta is measured
from the IMACS and LDSS3 spectra to be blue-shifted by roughly 3000 km/s.
In addition, from an acquisition image obtained prior to the du Pont
spectrum, they derive an absolute B-band magnitude of -17.4 +/- 0.5.
     Spectra (range 402.7-1011 nm) of 2009ao (cf. CBET 1711) and 2009au
(cf. CBET 1719) also were obtained on Mar. 16.1-16.2 UT with the Magellan I
BAADE telescope (+ IMACS).  SN 2009ao is a young type-IIP supernova around
a week past explosion; adopting a host-galaxy recession velocity of 3339
km/s (Chengalur et al. 1993, Ap.J. 419, 30) for the host galaxy (NGC 2939),
H_beta is measured to be blue-shifted by roughly 8000 km/s.  SN 2009au
appears to be a young type-IIn event soon after explosion; the spectrum
consists of a strong blue continuum with prominent H_alpha and H_beta
emission features.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2009 CBAT
2009 March 17                    (CBET 1725)              Daniel W. E. Green