[vsnet-alert 6547] SN 2001ed in NGC 706

[Hitoshi YAMAOKA <yamaoka@rc.kyushu-u.ac.jp>]

Dear SN watchers,

  M. Migliardi discovered a bright SN with 0.5-m CROSS telescope.  The
reported magnitude is far brighter than the expected maximum of SN Ia
from the recession velocity of the host galaxy NGC 706.  It seems the
same case as SN 2001cj, who has a great concern of its distance.  See
also
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Mail/alert5000/msg00954.html . 

  The discovery was made on Sept. 2.96 and 3.01 when SN was mag about
14.9C.  The position is R.A. = 1h51m51s.08, Decl. = +6o17'27".4
(2000.0), which is about 9" east and 20" south of the nucleus of the
face-on spiral (Sbc?) galaxy NGC 706.  It is superposed on the end of
the east-south spical arm, and there are several clumpiness on the DSS
image.  

  Some bright foreground stars are there.  The most neighbouring one
from SN is located about 8" ESE from the SN (17" east and 24" south of
the nucleus of NGC 706) whose rmag is about 15.0.  About 1' north of
the galaxy, there are mag 12 star GSC 36.663 and rmag 15 USNO-A2.0
cataloged star.  

  Like as SN 2001cj, the host galaxy is included the CfA redshift
survey.  With this redshift measurement, Gellar and Huchra, 1983,
ApJS, 52, 61 indicate that NGC 706 is a member of "group 21", as well
as other members (NGC 741 and ), whose mean recession velocity is 5069
km/s.  The expected maximum for this velocity is about mag 15.8, which
is far dimmer than the one for SN 2001ed at discovery.  On the other
hand, there is another group of galaxies in the same literature:
"group 23" including NGC 676, NGC 693 and NGC 718.  The "group 21" and
"group 23" is on the same direction but separated with the resemblance
of the recession velocities.  The RC3 (third reference catalog of
galaxies) notes that NGC 676, NGC 693 and NGC 706 makes a "chain".
The mean velocity of "group 23" is 1443 km/s.  If SN Ia occur in this
"velocity", the expected maximum is mag 13.1, or the gravitational
collapser (type Ib/c or II) expected to reach mag 15.  If NGC 706 is
located the same "velocity" as "group 23", the grouping with redshift
becomes quite doubtful.  The spectroscopic confirmation and type
determination (and follow-up the spectral evolution) is especially
urged.  Multicolor photometry and the magnitude estimate on next 100
days are strongly encouraged.

Sincerely Yours,
Hitoshi Yamaoka, Kyushu Univ., Japan
yamaoka@rc.kyushu-u.ac.jp

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