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We compared the number of faint stars detected in deep survey fields with thecurrent stellar distribution model of the Galaxy and found that the detectednumber in the H band is significantly smaller than the predicted number. Thisindicates that M-dwarfs, the major component, are fewer in the halo and thethick disk. We used archived data of several surveys in both the north andsouth field of GOODS (Great Observatories Origins Deep Survey), MODS inGOODS-N, and ERS and CANDELS in GOODS-S. The number density of M-dwarfs in thehalo has to be 20+/-13% relative to that in the solar vicinity, in order forthe detected number of stars fainter than 20.5 mag in the H band to match withthe predicted value from the model. In the thick disk, the number density ofM-dwarfs must be reduced (52+/-13%) or the scale height must be decreased (~600pc). Alternatively, overall fractions of the halo and thick disks can besignificantly reduced to achieve the same effect, because our sample mainlyconsists of faint M-dwarfs. Our results imply that the M-dwarf population inregions distant from the Galactic plane is significantly smaller thanpreviously thought. We then discussed the implications this has on thesuitability of the model predictions for the prediction of non-companion faintstars in direct imaging extrasolar planet surveys by using the best-fit numberdensities.

Indications of M-dwarf Deficits in the Halo and Thick Disk of the Galaxy