BAA Circular - Supernova in M51

[Rick]

BAA electronic circular No. 00191

Guy Hurst reports in The Astronomer E-circular E2124 the discovery by Wolfgang Kloehr, in  Germany of a 14th magnitude supernovae in M51 on June 28.91.
Further CCD images by Richard Miles from Golden Hill Observatory shows a V mag of V=14.53 on 2005 June 30.993 showing the object may well be fading already.

In addition, Maurice Gavin has captured a spectrum which can be viewed at http://home.freeuk.com/m.gavin/2005cs.htm

The TA report is as follows (with thanks to Guy Hurst):-

SUPERNOVA 2005cs IN M51
Wolfgang Kloehr, Schweinfurt, Germany, reports his discovery of a magnitude 14 apparent supernova in Messier 51 (NGC 5194). It was recorded on CCD frames of June 28.91 and 28.93UT using a 0.20-m reflector. It may also have been present on June 27.93UT near magnitude 16.

The discoverer provides the following position:
RA 13h 29m 53.37z DEC +47 10'28.2" (2000), 15" W and 78" S of the host galaxy's centre. Kloehr adds it was not present on May 11 and May 26 and is also absent from the Digitised Sky Survey.

A KAIT image obtained on June 30.25UT confirms the presence of the new object at about magnitude 13.5 with end figures: RA 52.8s DEC 36.3"

Hitoshi Yamaoka, Japan adds:
SN 2005cs is located on the southern arm of "Whirlpool Galaxy" M 51.  On the pre-discovery image, there is a bright star cluster and H II region.  It is possibly a gravitational-collapse of a massive star, but the prompt spectral classification is urgently needed, as well as follow-up photometry.

Editor: Could I please ask all our observers to check any recent images of Messier 51, a popular deep sky object. If the presumed supernova is present please e-mail images with full supporting details. If your images obtained during the last month are negative, please just send date, time and limiting magnitude together with instrumental details.

Roger Pickard
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Director, BAA Variable Star Section,