Astrophysical Tests of Gravity

Jeremy Sakstein


Screened theories of modified gravity such as chameleon models have attracted a lot of attention over the last few years. They give rise to order one fifth-forces on large scales whilst masquerading as General Relativity in our own solar system. This leaves us with the problem of searching for them observationally. In this talk, I will describe some recent work over the past few years at using astrophysical tests to constrain these theories. Unscreened stars situated in Dwarf galaxies in voids can show novel effects compared with General Relativity. They are brighter, hotter and they pulsate faster. By exploiting these new features, we have been able to place the strongest constraints to date and there is little room left for these theories to hide..