The Lick Observatory Supernova Search with the Katzman Automatic Imaging Telescope

Abstract

The Katzman Automatic Imaging Telescope (KAIT) at Lick Observatory is a fully robotic 0.76-m reflector equipped with a CCD imaging camera. Its telescope control system checks the weather, opens the dome, points to the desired objects, finds and acquires guide stars, exposes, stores the data, and manipulates the data without human intervention. There is a 20-slot filter wheel, including UBV RI . Five-minute guided exposures yield detections of stars at R ≈ 20 mag when the seeing is good (≤2″). One of our main goals is to discover nearby supernovae (SNe; redshifts generally less than 5000 km s −1 ), to be used for a variety of studies. Special emphasis is placed on finding them well before maximum brightness. A limit of ~ 19 mag is reached in the 25-sec unfiltered, unguided exposures of our Lick Observatory Supernova Search (LOSS). We can observe over 1200 galaxies in a long night, and we try to cycle back to the same galaxies after 3 to 4 nights. Our software automatically subtracts template images from new observations and identifies supernova candidates that are subsequently examined by student research assistants. LOSS found 20 SNe in 1998, 40 in 1999, and 36 in 2000, making KAIT the world’s most successful search engine for nearby SNe. We also find novae in the Local Group, comets, asteroids, and cataclysmic variables. Multifilter follow-up photometry is conducted of the most important SNe, and all objects are monitored in unfiltered mode. A Web page describing LOSS is at http://astro.berkeley.edu/~bait/kait.html .