We estimate the mass of the compact object in the \gamma -ray binaries LSI+61 ^ { \circ } 303 and MWC 148 , using the latest data for the inclination , orbital motion and assuming that the orbital plane coincides with the equatorial plane of the Be star .
For LSI+61 ^ { \circ } 303 we find the mass of the compact object to be most likely in the range 1.3 M _ { \odot } < M _ { 2 } < 2.0 M _ { \odot } , which means that it is probably a neutron star .
For MWC 148 , we find the mass of the compact object in a higher range , 2.1 M _ { \odot } < M _ { 2 } < 7.3 M _ { \odot } , which increases the chances for this system to host a black hole companion .