Evidence for the kinematic Sunyaev-Zeľdovich effect with ACTPol and velocity reconstruction from BOSS

21 Oct 2015  ·  Emmanuel Schaan, Simone Ferraro, Mariana Vargas-Magaña, Kendrick M. Smith, Shirley Ho, Simone Aiola, Nicholas Battaglia, J. Richard Bond, Francesco De Bernardis, Erminia Calabrese, Hsiao-Mei Cho, Mark J. Devlin, Joanna Dunkley, Patricio A. Gallardo, Matthew Hasselfield, Shawn Henderson, J. Colin Hill, Adam D. Hincks, Renée Hlozek, Johannes Hubmayr, John P. Hughes, Kent D. Irwin, Brian Koopman, Arthur Kosowsky, Dale Li, Thibaut Louis, Marius Lungu, Mathew Madhavacheril, Loïc Maurin, Jeffrey John McMahon, Kavilan Moodley, Sigurd Naess, Federico Nati, Laura Newburgh, Michael D. Niemack, Lyman A. Page, Christine G. Pappas, Bruce Partridge, Benjamin L. Schmitt, Neelima Sehgal, Blake D. Sherwin, Jonathan L. Sievers, David N. Spergel, Suzanne T. Staggs, Alexander van Engelen, Edward J. Wollack ·

We use microwave temperature maps from two seasons of data from the Atacama Cosmology Telescope (ACTPol) at 146 GHz, together with the Constant Mass CMASS galaxy sample from the Baryon Oscillation Spectroscopic Survey to measure the kinematic Sunyaev-Ze\v{l}dovich (kSZ) effect over the redshift range z = 0.4 - 0.7. We use galaxy positions and the continuity equation to obtain a reconstruction of the line-of-sight velocity field. We stack the cosmic microwave background temperature at the location of each halo, weighted by the corresponding reconstructed velocity. The resulting best fit kSZ model is preferred over the no-kSZ hypothesis at 3.3sigma and 2.9sigma for two independent velocity reconstruction methods, using 25,537 galaxies over 660 square degrees. The effect of foregrounds that are uncorrelated with the galaxy velocities is expected to be well below our signal, and residual thermal Sunyaev-Ze\v{l}dovich contamination is controlled by masking the most massive clusters. Finally, we discuss the systematics involved in converting our measurement of the kSZ amplitude into the mean free electron fraction of the halos in our sample.

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Cosmology and Nongalactic Astrophysics