[IAUC] CBET 1101: 20071015 : SUPERNOVAE 2007iq, 2007ir, 2007ke, AND 2007le

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                                                  Electronic Telegram No. 1101
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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SUPERNOVAE 2007iq, 2007ir, 2007ke, AND 2007le
     A. V. Filippenko, J. M. Silverman, R. J. Foley, and M. Modjaz,
University of California, Berkeley; and C. Papovich and C. N. A. Willmer,
Steward Observatory, report that inspection of a CCD spectrum (range 320-870
nm), obtained on Oct. 14 UT with the Keck I 10-m telescope (+ LRIS), shows
that 2007ir (CBET 1067, 1077) is a type-Ia supernova, roughly 1 to 1.5
months past maximum brightness.

     Filippenko, Modjaz, Silverman, and Foley add that inspection of a CCD
spectrum (range 320-920 nm), obtained as above on Oct. 15 UT, shows that
2007iq (CBET 1064) is a type-Ic supernova roughly two months past maximum
brightness.  The spectrum resembles that of SN 1987M at a comparable phase
(Filippenko et al. 1990, A.J. 100, 1575).

     Silverman, Filippenko, Foley, and Modjaz also report that inspection of
a preliminary calibration of CCD spectra (range 310-910 nm), obtained as
above on Oct. 15 UT, shows that 2007le (CBET 1100) is a type-Ia supernova
about 1-2 weeks before maximum brightness and 2007ke (CBET 1084) is a
type-Ib supernova, about 1 month after maximum.  Removing the host-galaxy
recession velocity of 2015 km/s (Koribalski et al. 2004, A.J. 128, 16) from
the spectrum of 2007le, the minimum of the Si II 635.5-nm absorption feature
is found to be blueshifted by about 16000 km/s.  Despite probably having a
rising light curve (CBET 1100) and fast-moving ejecta, 2007le has a
relatively red spectral-energy distribution for an object this young.
Although this may be the result of host-galaxy reddening, Na I D absorption
is detected at the host-galaxy redshift with an equivalent width of only 0.1
nm.  SN 2007ke has a strong [Ca II] line, reminiscent of "calcium-rich"
type-Ib/c supernovae such as 2001co and 2003H (IAUC 8159), but bluer and
possibly at an earlier phase.  If true, the [Ca II] line should become very
strong as the object transitions into the nebular phase.

     S. Blondin, Harvard-Smithsonian Center for Astrophysics (CfA), on
behalf of the CfA Supernova Group, reports that a spectrogram (range
350-740 nm) of 2007le (cf. CBET 1100), obtained by W. Brown on Oct. 15.28
UT with the F. L. Whipple Observatory 1.5-m telescope (+ FAST), shows it to
be a type-Ia supernova around one week before maximum light.  The Si II line
(rest 635.5 nm) presents an asymmetric absorption profile, suggestive of a
high-velocity component.  Cross-correlation with a library of supernova
spectra using the "Supernova Identification" code (SNID; Blondin and Tonry
2007, Ap.J. 666, 1024) indicates that 2007le is most similar to the type-Ia
supernova 2005cf at 9 days before maximum, which also displayed high-
velocity features (Garavini et al. 2007, A.Ap. 471, 527).  Adopting a
recession velocity of 2039 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 16000 km/s.  Also,
interstellar Na I D absorption at the redshift of the host galaxy is visible
in the spectrum with an equivalent width of roughly 0.2 nm.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
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                         (C) Copyright 2007 CBAT
2007 October 15                  (CBET 1101)              Daniel W. E. Green