text: 432,46,1287927441852207105,1196266674954985472,Nirmal Raj,"New paper with @DjunaCroon, @davemckeen, & Zihui Wang! ""Subaru through a different lens"": <LINK> . Thread follows. For a flash review of gravitational microlensing see my previous thread on it: <LINK>. <LINK> You'd think a star in the Andromeda Galaxy (10^19 km away) would look like a point from here, but so sharp-eyed is the Subaru Telescope that when it looks for the brief dazzle of starlight bent by a passing object, the star's spatial extent (~10^7 km) actually matters to it! <LINK> If the passing object is a dark matter structure such as a subhalo or a boson star, *its* spatial extent -- and unique mass distribution -- must figure in the lensing signal as well. That gives us a brand new constraint to the hunt for #darkmatter. <LINK>",https://arxiv.org/abs/2007.12697,"We investigate gravitational microlensing signals produced by a spatially extended object transiting in front of a finite-sized source star. The most interesting features arise for lens and source sizes comparable to the Einstein radius of the setup. Using this information, we obtain constraints from the Subaru-HSC survey of M31 on the dark matter populations of NFW subhalos and boson stars of asteroid to Earth masses. These lens profiles capture the qualitative behavior of a wide range of dark matter substructures. We find that deviations from constraints on point-like lenses (e.g. primordial black holes and MACHOs) become visible for lenses of radius 0.1 $R_\odot$ and larger, with the upper bound on lens masses weakening with increasing lens size. ","Subaru through a different lens: microlensing by extended dark matter