Faint M dwarfs and the structure of the galactic disk

We use broadband photometry and low-resolution spectra of a complete sample of late-type K and M dwarfs brighter than I=22 in three fields at high galactic latitude to study issues relating to galactic structure and large-scale abundance gradients in the Galaxy. The observed starcounts in each field are a good match to the predictions of models based on deep starcount data in other intermediate-latitude fields, and these models identify the late-type stars as members of the Galactic disk. Abundances for these late-type stars are estimated via narrow-band indices that measure the strength of the TiO and CaH bands in their spectra. Our results show that the average abundance in the Galactic disk remains close to solar even at heights of more than 2 kpc above the Plane.