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Designing an inflation galaxy survey: How to measure σ(f_(NL))∼1 using scale-dependent galaxy bias

de Putter, Roland and Doré, Olivier (2017) Designing an inflation galaxy survey: How to measure σ(f_(NL))∼1 using scale-dependent galaxy bias. Physical Review D, 95 (12). Art. No. 123513. ISSN 2470-0010. doi:10.1103/PhysRevD.95.123513.

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The most promising method for measuring primordial non-Gaussianity in the post-Planck era is to detect large-scale, scale-dependent galaxy bias. Considering the information in the galaxy power spectrum, we here derive the properties of a galaxy clustering survey that would optimize constraints on primordial non-Gaussianity using this technique. Specifically, we ask the question of what survey design is needed to reach a precision σ(f^(loc)_(NL))≈1. To answer this question, we calculate the sensitivity to f^(loc)_(NL) as a function of galaxy number density, redshift accuracy and sky coverage. We include the multitracer technique, which helps minimize cosmic variance noise, by considering the possibility of dividing the galaxy sample into stellar mass bins. We show that the ideal survey for f^(loc)_(NL) looks very different than most galaxy redshift surveys scheduled for the near future. Since those are more or less optimized for measuring the baryon acoustic oscillation scale, they typically require spectroscopic redshifts. On the contrary, to optimize the f^(loc)_(NL) measurement, a deep, wide, multiband imaging survey is preferred. An uncertainty σ(f^(loc)_(NL))=1 can be reached with a full-sky survey that is complete to an i-band AB magnitude i≈23 and has a number density ∼8  arcmin^(-2). Requirements on the multiband photometry are set by a modest photo-z accuracy σ(z)/(1+z)<0.1 and the ability to measure stellar mass with a precision ∼0.2 dex or better (or another proxy for halo mass with equivalent scatter). Finally, we estimate that for the idealized case of a survey measuring all halos down to a mass 10^(10)h^(-1)  M⊙ on the full sky out to high redshift, in principle a precision of order σ(f_(NL))∼0.1 can be achieved.

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URLURL TypeDescription Paper
Doré, Olivier0000-0002-5009-7563
Additional Information:© 2017 American Physical Society. Received 6 January 2017; published 12 June 2017. We thank Alexie Leauthaud and Peter Capak for sharing their expertise on the observational properties of galaxies. In addition, we thank Alexie Leauthaud for providing the COSMOS catalog used in our Sec. IV. Part of the research described in this paper was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. This work is supported by NASA ATP grant 11-ATP-090.
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Issue or Number:12
Record Number:CaltechAUTHORS:20170612-101050606
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:78096
Deposited By: Tony Diaz
Deposited On:12 Jun 2017 18:24
Last Modified:15 Nov 2021 17:36

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