[IAUC] CBET 1137: 20071114 : SUPERNOVA 2007qd

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                                                  Electronic Telegram No. 1137
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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SUPERNOVA 2007qd
     B. Bassett, South African Astronomical Observatory and University of
Cape Town (UCT); A. Becker, University of Washington (UW); D. Bizyaev and
H. Brewington, Apache Point Observatory (APO); C. Choi, Seoul National
University (SNU); D. Cinabro, Wayne State University (WSU); C. D'Andrea,
University of Pennsylvania (Penn); J. Dembicky, APO; D. L. DePoy, Ohio State
University (OSU); B. Dilday, University of Chicago (UC); M. Doi, University
of Tokyo (UoT); J. Eastman, OSU; J. Frieman, Fermilab and UC; P. Garnavich,
University of Notre Dame; A. Goobar, Stockholm University; C. Hogan, UW;
J. Holtzman, New Mexico State University; M. Im, SNU; S. Jha, Rutgers
University; R. Kessler, UC; B. Ketzeback, APO; K. Konishi, UoT; J.
Krzesinski, APO; H. Lampeitl, University of Portsmouth (UP); G. Leloudas,
Dark Cosmology Centre, University of Copenhagen; D. Long, O. Malanushenko,
and V. Malanushenko, APO; J. Marriner, Fermilab; R. McMillan, APO; G.
Miknaitis, Fermilab; T. Morokuma, National Astronomical Observatory of Japan;
J. Mosher, Penn; R. Nichol, UP; D. Oravetz and K. Pan, APO; L. Ostman,
Stockholm University; J. L. Prieto, OSU; M. Richmond, Rochester Institute of
Technology; A. Riess, Space Telescope Science Institute; R. Romani, Stanford
University (SU); M. Sako, Penn; D. Schneider, Pennsylvania State University;
A. Simmons, APO; M. Smith, UP; S. Snedden, APO; J. Sollerman and M.
Stritzinger, Dark Cosmology Centre; N. Takanashi and K. Tokita, UoT; M. F.
Taylor, WSU; K. van der Heyden, UCT; S. Watters, APO; N. Yasuda, UoT; C.
Wheeler, University of Texas; and C. Zheng, SU, on behalf of the Sloan
Digital Sky Survey II collaboration, report the discovery of a peculiar,
sub-luminous, type-Ia supernova on g, r, and i images taken with the SDSS
2.5-m telescope at APO by the SDSS observing team on multiple nights.  The
object was first detected with r-band magnitude 20.8 on Oct. 31 UT and
reached maximum light at comparable magnitude around Nov. 2.  SN 2007qd is
located at R.A. = 2h09m33s.56, Decl. = -1o00'02".2 (equinox 2000.0), which
is near the visible end of a spiral arm of a host galaxy centered at R.A. =
2h09m32s.74, Decl.= -0o59'59".6 (redshift z = 0.04313 from the SDSS-I
galaxy redshift survey).
     A. Goobar; R. Nichol; M. Molla, Centro de Investigaciones Energeticas,
Medioambientales y Tecnologicas, Madrid; F. Castander, Institut de Ciencies
de l'Espai, Barcelona; and R. Miquel, Institut de Fisica d'Altes Energies
(IFAE), Barcelona, report that confirming spectroscopy was taken by Miquel,
Molla, and L. Galbany (IFAE) at the 3.58-m Telescopio Nazionale Galileo on
La Palma on the night of Nov. 5.  R. Romani, C. Zheng, M. Sako, C. Wheeler,
D. Schneider, and R. Bender, together with U. Hopp (University of Munich)
and W. Kollatschny (University of Goettingen), report that a second spectrum
was obtained at the Hobby-Eberly Telescope on Nov. 10.  P. Garnavich and S.
Jha report that these spectra show that 2007qd is similar to the peculiar
type-Ia supernovae 2002cx (IAUC 7902, 7903; Li et al. 2003, PASP 115, 453)
and 2005hk (cf. IAUC 8625, 8627; Phillips et al. 2007, PASP 119, 360), but
with more extreme characteristics.  The Si II (rest 635.5 nm) absorption is
very narrow, with an expansion velocity of 2600 km/s, roughly half the
velocity of 2002cx or 2005hk at a similar epoch.  Also, 2007qd at peak is
at least 3 mag fainter than a normal type-Ia supernova, and more than 1 mag
fainter than 2002cx, but does not show an anomalous red color that would be
indicative of heavy dust extinction.  A spectrum obtained by J. Silverman,
A. Filippenko, and R. Foley (University of California, Berkeley) with the
Keck I telescope (+ LRIS) on Nov. 12 confirms the low velocities and the
spectral resemblance to 2005hk and 2002cx.


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                         (C) Copyright 2007 CBAT
2007 November 14                 (CBET 1137)              Daniel W. E. Green