The Size Distribution of Near-Earth Objects Larger Than 10 m

We analyzed data from the first year of a survey for Near-Earth Objects (NEOs) that we are carrying out with the Dark Energy Camera (DECam) on the 4 m Blanco telescope at the Cerro Tololo Inter-American Observatory. We implanted synthetic NEOs into the data stream to derive our nightly detection efficiency as a function of magnitude and rate of motion. Using these measured efficiencies and the solar system absolute magnitudes derived by the Minor Planet Center for the 1377 measurements of 235 unique NEOs detected, we directly derive, for the first time from a single observational data set, the NEO size distribution from 1 km down to 10 m. We find that there are {10}^6.6 NEOs larger than 10 m. This result implies a factor of 10 fewer small NEOs than some previous results, though our derived size distribution is in good agreement with several other estimates.