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arXiv · 1207.4543

The Atacama Cosmology Telescope: Cross-Correlation of CMB Lensing and Quasars

Blake D. Sherwin·Sudeep Das·Amir Hajian·Graeme Addison·J. Richard Bond·Devin Crichton·Mark J. Devlin·Joanna Dunkley·Megan B. Gralla·Mark Halpern·J. Colin Hill·Adam D. Hincks·John P. Hughes·Kevin Huffenberger·Renee Hlozek·Arthur Kosowsky·Thibaut Louis·Tobias A. Marriage·Danica Marsden·Felipe Menanteau·Kavilan Moodley·Michael D. Niemack·Lyman A. Page·Erik D. Reese·Neelima Sehgal·Jon Sievers·Cristobal Sifon·David N. Spergel·Suzanne T. Staggs·Eric R. Switzer·Ed Wollack
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Abstract

We measure the cross-correlation of Atacama Cosmology Telescope CMB lensing convergence maps with quasar maps made from the Sloan Digital Sky Survey DR8 SDSS-XDQSO photometric catalog. The CMB lensing-quasar cross-power spectrum is detected for the first time at a significance of 3.8 sigma, which directly confirms that the quasar distribution traces the mass distribution at high redshifts z>1. Our detection passes a number of null tests and systematic checks. Using this cross-power spectrum, we measure the amplitude of the linear quasar bias assuming a template for its redshift dependence, and find the amplitude to be consistent with an earlier measurement from clustering; at redshift z ~ 1.4, the peak of the distribution of quasars in our maps, our measurement corresponds to a bias of b = 2.5 +/- 0.6. With the signal-to-noise ratio on CMB lensing measurements likely to improve by an order of magnitude over the next few years, our results demonstrate the potential of CMB lensing cross-correlations to probe astrophysics at high redshifts.

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Blake D. Sherwin, Sudeep Das, Amir Hajian, Graeme Addison, J. Richard Bond, Devin Crichton, Mark J. Devlin, Joanna Dunkley, Megan B. Gralla, Mark Halpern, J. Colin Hill, Adam D. Hincks, John P. Hughes, Kevin Huffenberger, Renee Hlozek, Arthur Kosowsky, Thibaut Louis, Tobias A. Marriage, Danica Marsden, Felipe Menanteau, Kavilan Moodley, Michael D. Niemack, Lyman A. Page, Erik D. Reese, Neelima Sehgal, Jon Sievers, Cristobal Sifon, David N. Spergel, Suzanne T. Staggs, Eric R. Switzer, Ed Wollack. 2012-11-17. The Atacama Cosmology Telescope: Cross-Correlation of CMB Lensing and Quasars. https://doi.org/10.1103/physrevd.86.083006

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