Evidence of Lensing of the Cosmic Microwave Background by Dark Matter   Halos
  We present evidence of the gravitational lensing of the cosmic microwave background by $10^{13}$ solar mass dark matter halos. Lensing convergence maps from the Atacama Cosmology Telescope Polarimeter (ACTPol) are stacked at the positions of around 12,000 optically-selected CMASS galaxies from the SDSS-III/BOSS survey. The mean lensing signal is consistent with simulated dark matter halo profiles, and is favored over a null signal at 3.2 sigma significance. This result demonstrates the potential of microwave background lensing to probe the dark matter distribution in galaxy group and galaxy cluster halos. 
Mathew Madhavacheril, Neelima Sehgal, Rupert Allison, Nick Battaglia,   J Richard Bond, Erminia Calabrese, Jerod Caligiuri, ...
astro-ph.CO