Leuschner Observatory Supernova Search (LOSS)
Session 29 -- Novae and Supernovae
Display presentation, Tuesday, 9:30-6:30, Pauley Room

## [29.11] Leuschner Observatory Supernova Search (LOSS)

R.R. Treffers, B. Leibundgut, A.V. Filippenko (UC Berkeley), M.W. Richmond (Princeton University)

We describe a newly commissioned search for supernovae in nearby galaxies of the northern hemisphere. The search uses the automated 0.76m telescope at the Leuschner Observatory near Berkeley and is aimed at finding and studying supernovae early in their evolution. The galaxy sample is derived from the catalog of 2810 nearby galaxies (Kraan-Korteweg, 1986, A\&AS, 66, 255) with the following selection criteria: (1) luminosity class not later than III-IV, (2) not more distant than 5 times the Virgo distance. We search the 566 galaxies from this list that are brighter than 12.5 mag and north of $0^{\circ}$ declination on a three day interval. In addition we observe the 309 galaxies with magnitudes 12.6-12.8 and north of $-10^{\circ}$ once per week. We use $R$ band images with an integration time of 120 seconds taken with a CCD camera (field of view $\sim 6^\prime \times 6^\prime$) owned by the Lawrence Berkeley Laboratory. The current detection threshold varies depending on the presence of bright stars, galactic nuclei and weather conditions, but is on the order of 17th magnitude.

We use the software developed for the Berkeley Automated Imaging Telescope (Richmond, Treffers, and Filippenko, PASP, submitted) to schedule the observations. Our image analysis software performs a subtraction of a reference image from the search frame after scaling, shifting, and rotating according to brightness and location of fiducial stars in the field. The analysis software is an X-windows version of PCVISTA (Treffers and Richmond, 1990, PASP, 101, 725) running on UNIX. The search runs as a background project on the telescope which serves requests for a variety of other scientific and educational projects. We have acquired approximately 3000 galaxy images between January 1 and April 5, 1993, corresponding to a total control time of $\sim$90 galaxy years. On March 5, 1993, we discovered the type II SN 1993G in NGC3690 at $R=16.6 \pm 0.2$ mag. Preliminary results on the analysis of this object will be presented.