Electronic Telegram No. 1789
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 2009dp, 2009dq, 2009ds, AND 2009dt
     J. Anderson, N. Morrell, G. Folatelli, and M. Stritzinger, on behalf of
the Millennium Center for Supernova Science and the Carnegie Supernova
Project, report that they obtained spectra (range 388-942 nm) of 2009dp (cf.
CBET 1779), 2009dq (cf. CBET 1781), 2009ds (cf. CBET 1784, 1788), and 2009dt
(cf. CBET 1785) on Apr. 30.1-30.4 UT with the Magellan II Clay 6.5-m telescope
(+ LDSS3) at Las Campanas Observatory.
     SN 2009dp is a type-Ic supernova around maximum light.  Cross-correlation
with a library of supernova spectra using the "Supernova Identification" code
(SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) provides matches to spectra
of SN 1994I and SN 1990aa at maximum light, although the prominent absorption
at 750 nm due to O I is absent in the spectrum of SN 2009dp.
     SN 2009dq is a type-IIb supernova around maximum light.  SNID provides
matches with spectra of SN 1996cb at -2 and +1 days.  H-alpha appears
prominently with a P-Cyg profile; from its absorption minimum, and adopting a
recession velocity of 1397 km/s for the host galaxy (cf. H I Parkes All Sky
Survey Final Catalogue, 2006), an expansion velocity of about 14000 km/s is
derived.  H-beta is not detected.
     SN 2009ds is a type-Ia supernova around a week or more before maximum
light.  The best SNID matches correspond to spectra of SN 2003du at -10 and
-7 days and of SN 1990N at -6 days.  The supernova presents a very weak Si II
597.2-nm line.  Adopting a recession velocity of 5774 km/s for the host
galaxy (cf. de Vaucouleurs et al. 1991, Third Reference Catalogue of Bright
Galaxies, ver. 3.9), expansion velocities of 14200 and 15500 km/s are derived
from the absorption minima of the Si II 635.5-nm and 587.2-nm lines,
respectively.  Although its continuum is quite blue, the spectrum shows
interstellar Na I D in absorption with an equivalent width of 0.13 nm,
suggesting that 2009ds may suffer from significant reddening.
     SN 2009dt is a type-Ic supernova near maximum light.  According to SNID,
its spectrum is most similar to those of SN 2004aw between -2 and +2 days.


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2009 CBAT
2009 May 1                       (CBET 1789)              Daniel W. E. Green