Infrared Spectra and Spectral Energy Distributions of Late–M– and L–Dwarfs

We have obtained 1.0—2.5μm spectra at R∼600 of 14 disk dwarfs with spectral types M6 to L7. For four of the dwarfs we have also obtained infrared spectra at R∼3000 in several narrow intervals. In addition, we present new L′ photometry for four of the dwarfs in the sample, which allows improved determinations of their bolometric luminosities. While obtaining the photometry we resolved the L-dwarf Denis-P J 0205-1159 into an identical pair of objects separated by 0. ′′35. The spectra, together with the published energy distribution for one other L5 dwarf, are compared to synthetic spectra generated by upgraded model atmospheres. Good matches are found for 2200≥Teff K≥1900 (spectral types around M9 to L3), but discrepancies exist at Teff ≥2300 K (M8) and for Teff ≤1800 K (L4–L7). At the higher temperatures the mismatches are due to incompleteness in the water vapor opacity linelist. At the lower