[IAUC] CBET 652: 20060928 : SUPERNOVA 2006hb IN MCG -04-12-34

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                                                  Electronic Telegram No. 652
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
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SUPERNOVA 2006hb IN MCG -04-12-34
     S. Blondin, M. Modjaz, R. Kirshner, and P. Challis, Harvard-Smithsonian
Center for Astrophysics, report that a spectrum (range 350-740 nm) of 2006hb
(cf. CBET 649), obtained on Sept. 28.54 UT by M. Calkins with the F. L.
Whipple Observatory 1.5-m telescope (+ FAST), shows it to be a type-Ia
supernova around maximum light.  Cross-correlation with a library of
supernova spectra shows that 2006hb is very similar to the subluminous
supernova 1999by at -3 days from maximum light.  Given the estimated
magnitude of the event (cf. CBET 649), and assuming no peculiar motion, the
absolute visual magnitude is roughly -18.4, thereby confirming the
subluminous nature of this event.  Adopting a recession velocity of 4584
km/s for the host galaxy (from de Vaucouleurs et al. 1991, Third Ref. Cat.
of Bright Galaxies), the maximum absorption in the Si II line (rest 635.5
nm) is blueshifted by roughly 11000 km/s.
     N. Morrell and G. Folatelli, on behalf of the Carnegie Supernova
Project, report that a spectrogram (range 380-920 nm) of SN 2006hb,
obtained on Sept. 28.22 UT with the WFCCD spectrograph attached to the
2.5-m du Pont telescope at Las Campanas Observatory, reveals that it is a
type-Ia supernova, similar to the subluminous supernova 1986G around
maximum light.  Assuming a recesion velocity of 4600 km/s for the host
galaxy from NED (cf. Da Costa et al. 1991, Ap.J. Suppl. 75, 935), an
expansion velocity of 10350 km/s was derived from the absorption
minimum of the Si II 635.5-nm feature.


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                         (C) Copyright 2006 CBAT
2006 September 28                (CBET 652)               Daniel W. E. Green