Abstract

We present the results of an archival search for trans-Neptunian objects (TNOs) in an ecliptic field observed with Subaru in 2002. The depth of the search allowed us to find 20 new TNOs with magnitudes between R = 24 and 27. We fit a double power-law model to the data; the most likely values for the bright and faint power-law exponents are alpha(1) = 0.73(-0.09)(+0.08) and alpha(2) = 0.20(-0.14)(+0.12); the differential number density at R = 23 is sigma(23) = 1.46(-0.12)(+0.14) and the break magnitude is R-eq = 25.0(-0.6)(+0.8). This is the most precise measurement of the break in the TNO luminosity function to date. The break in the size distribution corresponds to a diameter of D = 90 +/- 30 km assuming a 4% albedo.