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THE ASTRONOMER Electronic Circular No 3003      2014 May 22 16.08UT
Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise,  Basingstoke,
Hants, RG22 4PP,England.Telephone/FAX(01256)471074Int:+441256471074
INTERNET: GUY@TAHQ.DEMON.CO.UK      Backup: gmh@wdcc1.bnsc.rl.ac.uk
WORLD WIDE WEB                         http://www.theastronomer.org
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PROBABLE SUPERNOVA IN MESSIER 106 (=NGC 4258)
S. J. Smartt et. al. University of Belfast and others report on The
Astronomer's telegram 6156 that the Pan-STARRS 1 telescope  has recorded a
suspected supernova near the core of Messier 106 as part of the 3pi survey.
The transient was observed at coordinates: RA 12:18:57.71 DEC +47:18:11.3
(2000) by PS1 on 2014 May 19.25 and had a magnitude of z=14.77 (in the PS1
z-band system as defined by Tonry et al. It is detected in 4 separate 30 sec
z-band images, taken over a 7 minute interval. PS1 does not have a useful
constraint on the epoch of explosion before this date, with the last image
of this field taken 2014 March 24.

At a distance of 7.6 Mpc, the absolute magnitude of M_z = -14.6 suggests it
is either a young supernova, heavily reddened or intrinsically faint.
Confirmation images are required and spectroscopic classification is
required as soon as possible. 

A further report on The Astronomers' Telegram 6159 relays a prediscovery
detection by KAIT. It was observed with the 0.76-m Katzman Automatic Imaging
Telescope (KAIT) as part of the Lick Observatory Supernova Search, with an
average cadence of 3 days. The object was detected in KAIT unfiltered
(roughly R) images obtained on Apr. 09.35, Apr 12.35, Apr. 14.35 UT and
thereafter, but there was no detection in KAIT images obtained on Apr 06.35
with a limiting mag of about 18.0. Preliminary analysis shows that the
target had a rising light curve since the detection on Apr. 09, with an
increase of about 2 mag in the first two weeks. The brightness thereafter is
roughly constant at 15 mag. Owing to the high background and the very small
projected distance from the host nucleus, it is difficult to make a precise
measurement of the brightness, but the light curve is consistent with that
of a Type II-P supernova.

For further information see:
http://star.pst.qub.ac.uk/ps1threepi/psdb/candidate/1121857711471811300/

Guy M Hurst