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C. C. Hayward, J. A. Irwin, J. N. Bregman (University of Michigan)
We use data collected from the Robotic Optical Transient Search Experiment (ROTSE) Telescope to search for nearby Type Ia supernovae. The nightly sky patrols of ROTSE span a one year period and cover a region of the sky from +65 degrees to -15 degrees declination for all values of right ascension, imaging down to a visual magnitude of 15.5. Such a large area, nightly sky patrol lends itself very well to detecting supernovae that reside in previously undetected low-surface brightness galaxies (LSB) or alternatively free-floating stars not associated with a galaxy out to a maximum distance of 60 Mpc. For each supernovae found that is not obviously associated with a known galaxy, we will use deep optical images to search for an LSB galaxy host for the supernovae. From this we can estimate the space density of LSB galaxies in the local Universe. So far we have searched over 50% of the data, and no supernovae were found. Therefore the results already place cosmological constraints on the mass contribution of LSB galaxies and/or free-floating stars. We will present the results from the entire ROTSE database, and, in the event that no supernovae are found, we will use the volume of sky scanned by ROTSE, the filter detection rate from Monte Carlo simulations, and a typical estimate of the frequency of Ia supernovae in order to place an upper limit on the optical luminosity density due to LSB galaxies in the local Universe and to calculate the ratio of stars in LSB galaxies and free-floating stars to the stars in high surface brightness galaxies.
The author(s) of this abstract have provided an email address for comments about the abstract: cchaywar@umich.edu
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Bulletin of the American Astronomical Society, 34, #4
© 2002. The American Astronomical Soceity.