Revealing S0 galaxies' formation histories using the stellar kinematics of the faint outer disks

Lenticular galaxies display the prominent disks that are characteristic of late-type galaxies, but contain no gas, dust or star formation like early-type systems. So are they more closely related to spiral or ellipticals? One important clue to their origin is recorded in the kinematics. If they are simply quenched spiral galaxies then their stellar motions should be identical to those in spirals, whereas if their origins are closer to an elliptical, produced through merging, then this history should be reflected in more random stellar motions ([1]). We performed a maximum likelihood analysis in order to recover rotation velocity and random motions in the spheroidal and disk component of the galaxy NGC 1023. Its kinematics are consistent with the one of a stripped spiral, somehow complicated by an ongoing minor merger.