Title: Unbiased clustering estimates with the DESI fibre assignment

Abstract

The Emission Line Galaxy survey made by the Dark Energy Spectroscopic Instrument (DESI) survey will be created from five passes of the instrument on the sky. On each pass, the constrained mobility of the ends of the fibres in the DESI focal plane means that the angular distribution of targets that can be observed is limited. Thus, the clustering of samples constructed using a limited number of passes will be strongly affected by missing targets. In two recent papers, we showed how the effect of missing galaxies can be corrected when calculating the correlation function using a weighting scheme for pairs. Using mock galaxy catalogues we now show that this method provides an unbiased estimator of the true correlation function for the DESI survey after any number of passes. We use multiple mocks to determine the expected errors given one to four passes, compared to an idealized survey observing an equivalent number of randomly selected targets. On BAO scales, we find that the error is a factor of 2 worse after one pass, but that after three or more passes, the errors are very similar. Thus, we find that the fibre assignment strategy enforced by the design of DESI willmore » not affect the cosmological measurements to be made by the survey, and can be removed as a potential risk for this experiment.« less

Authors:

Bianchi, Davide ^[1]; Burden, Angela ^[2]; Percival, Will J. ^[3]; Brooks, David ^[4]; Cahn, Robert N. ^[5]; Forero-Romero, Jaime E. ^[6]; Levi, Michael ^[5]; Ross, Ashley J.  ^[7];

• Search DOE PAGES for author "Ross, Ashley J."
• Search DOE PAGES for ORCID "0000-0002-7522-9083"

Tarle, Gregory ^[8]

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+ Show Author Affiliations

1. Institute of Cosmology & Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth PO1 3FX, UK
2. Department of Physics, Yale University, New Haven, CT 06511, USA
3. Institute of Cosmology & Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth PO1 3FX, UK, Department of Physics and Astronomy, University of Waterloo, 200 University Ave W, Waterloo ON N2L 3G1, Canada, Perimeter Institute for Theoretical Physics, 31 Caroline St. North, Waterloo, ON N2L 2Y5, Canada
4. Department of Physics & Astronomy, University College London, Gower Street, London WC1E 6BT, UK
5. Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
6. Departamento de Física, Universidad de los Andes, Cra. 1 No. 18A-10, Edificio Ip, Bogotá, Colombia
7. Center for Cosmology and AstroParticle Physics, The Ohio State University, 191 West Woodruff Avenue, Columbus, OH 43210, USA, Department of Astronomy, The Ohio State University, 4055 McPherson Laboratory, 140 W 18th Avenue, Columbus, OH 43210, USA
8. Physics Department, University of Michigan Ann Arbor, MI 48109, USA

Publication Date:

Fri Aug 31 00:00:00 EDT 2018

Research Org.:

Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)

Sponsoring Org.:

USDOE

OSTI Identifier:

1471256

Alternate Identifier(s):

OSTI ID: 1543969

Grant/Contract Number:  

AC02-05CH1123

Resource Type:

Published Article

Journal Name:

Monthly Notices of the Royal Astronomical Society

Additional Journal Information:

Journal Name: Monthly Notices of the Royal Astronomical Society Journal Volume: 481 Journal Issue: 2; Journal ID: ISSN 0035-8711

Publisher:

Oxford University Press

Country of Publication:

United Kingdom

Language:

English

Subject:

79 ASTRONOMY AND ASTROPHYSICS; Astronomy & Astrophysics