While observations of distant supernovae (SNe) are providing intriguing new information about cosmological parameters, there is still much work to be done on understanding the details of the various types of SNe and the possible systematic uncertainties in their use as precise distance indicators. Such work is best done with studies of relatively nearby SNe (z<0.1) which are bright enough to obtain detailed photometric and spectroscopic follow-up data for.
NGSS (Nearby Galaxies Supernovae Search) is a search for moderate to low redshift SNe using the mosaic camera at the Kitt Peak 0.9-m telescope, in Tucson, AZ. This 8K x 8K mosaic CCD array provides an areal coverage of ~ 1ºx1º and allows us to search for SNe along the celestial equator to a limiting magnitude of R ~ 21.
Due to the limitations in the search methods the NGSS team uses, it is important to investigate how effective we are in finding SNe candidates in residual images. In doing so, we will be able to determine accurate SNe rates from our search sample, and incompleteness in our searches due to our methods.
We added false stars into the images, used Daophot routines to obtain photometry for false stars, and ran NGSS software to combine and substract images. Finally, we used IRAF scripts to search for "false supernovae" to measure detection efficiency and improve detection algorithms. The preliminary results indicate that generating a good PSF is very important. Factors such as stars near the chip edges, bad pixels, or bad seeing must be carefully considered.
Acknowledments
I would like to thank Don Hoard, Lou Strolger and Chris Smith for giving me the opportunity to work in the PIA program and NGSS project. This research was carried out as part of the 2000 Research Experiences for Undergraduates Program at CTIO, funded by the National Science Foundation (NSF).