Scalar fields with masses in the range 1e-33 eV to 1e-10 eV might compose all of, or a fraction of, the dark matter (DM) in the Universe. Due to the astrophysically (or even cosmologically large) wavelength, this type of DM has distinctive effects on observables. I will discuss a zoo of constraints, present and future, on the fraction of DM allowed across this entire range. Constraints include: cosmic microwave background temperature, polarisation and lensing anisotropies, galaxy clustering, weak lensing galaxy shear, hydrogen intensity mapping, "velocity acoustic oscillations", heating of stellar structures, lyman alpha forest, pulsar timing, and black hole spins. Together, these probes can give percent level constraints on the DM composition across 23 orders of magnitude in particle mass, and may test predictions of the string theory landscape using purely gravitational physics.
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Meeting ID: 921 1801 0804
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