[IAUC] CBET 1513: 20080924 : SUPERNOVAE 2008fr AND 2008fs

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                                                  Electronic Telegram No. 1513
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
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SUPERNOVAE 2008fr AND 2008fs
     F. Yuan, University of Michigan; R. Quimby, California Institute of
Technology; D. Chamarro and M. D. Sisson, University of Michigan; A. Uecker,
Indiana University of Pennsylvania; C. Akerlof, University of Michigan; and
J. C. Wheeler, University of Texas, on behalf of the ROTSE collaboration,
report the discovery of two supernovae in unfiltered CCD images taken with
the 0.45-m ROTSE-IIIb telescope at McDonald Observatory.  Spectra (range
420-890 nm) of both objects were obtained with the 9.2-m Hobby-Eberly
Telescope (+ Marcario Low-Resolution Spectrograph) by J. Caldwell and A.
Westfall.

 SN       2008 UT       R.A. (2000.0) Decl.      Mag.      Offset
 2008fr   Sep. 14.37   1 11 49.14  +14 38 27.0   17.3      --
 2008fs   Sep. 21.28   1 09 05.75  +14 45 16.9   18.2    3".1 W, 3".9 S

An extended object (magnitude r = 19.26) is seen at the position of 2008fr
in a Sloan Digital Sky Survey (SDSS) image; a ROTSE finding chart for 2008fr
is posted at http://www.rotse.net/rsvp/j011149.1+143827/j011149.1+143827.jpg.
Spectra obtained on Sept. 22.26 UT were compared via SNID (Blondin and Tonry
2007, Ap.J. 666, 1024), showing 2008fr to be a type-Ia supernova around
maximum light at z = 0.039 +/- 0.002; the minimum of the Si II 635.5-nm
feature is blueshifted by 11000 km/s in the restframe.  A ROTSE finding chart
for 2008fs can be found at the following website URL:
http://www.rotse.net/rsvp/j010905.8+144517/j010905.8+144517.jpg.
Spectra obtained on Sept. 22.23 were compared via SNID, showing 2008fs's
spectra to be best matched by that of SN 1999ex at nine days after maximum
at z = 0.049 +/- 0.004.  An average redshift of 0.044 +/- 0.005 was obtained
from matching to type-Ib/c-supernovae spectra templates around ten days
after maximum; this redshift is roughly consistent within uncertainty to that
of the apparent SDSS host galaxy (z = 0.0386 +/- 0.0002, measured by SDSS).


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                         (C) Copyright 2008 CBAT
2008 September 24                (CBET 1513)              Daniel W. E. Green