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Proceedings Paper

Improving the LSST dithering pattern and cadence for dark energy studies
Author(s): Christopher M. Carroll; Eric Gawiser; Peter L. Kurczynski; Rachel A. Bailey; Rahul Biswas; David Cinabro; Saurabh W. Jha; R. Lynne Jones; K. Simon Krughoff; Aneesa Sonawalla; W. Michael Wood-Vasey
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Paper Abstract

The Large Synoptic Survey Telescope (LSST) will explore the entire southern sky over 10 years starting in 2022 with unprecedented depth and time sampling in six filters, ugrizy. Artificial power on the scale of the 3.5 deg LSST field-of-view will contaminate measurements of baryonic acoustic oscillations (BAO), which fall at the same angular scale at redshift z ~ 1. Using the HEALPix framework, we demonstrate the impact of an “un- dithered” survey, in which 17% of each LSST field-of-view is overlapped by neighboring observations, generating a honeycomb pattern of strongly varying survey depth and significant artificial power on BAO angular scales. We find that adopting large dithers (i.e., telescope pointing o sets) of amplitude close to the LSST field-of-view radius reduces artificial structure in the galaxy distribution by a factor of ~10. We propose an observing strategy utilizing large dithers within the main survey and minimal dithers for the LSST Deep Drilling Fields. We show that applying various magnitude cutos can further increase survey uniformity. We find that a magnitude cut of r < 27:3 removes significant spurious power from the angular power spectrum with a minimal reduction in the total number of observed galaxies over the ten-year LSST run. We also determine the effectiveness of the observing strategy for Type Ia SNe and predict that the main survey will contribute ~100,000 Type Ia SNe. We propose a concentrated survey where LSST observes one-third of its main survey area each year, increasing the number of main survey Type Ia SNe by a factor of ~1.5, while still enabling the successful pursuit of other science drivers.

Paper Details

Date Published: 6 August 2014
PDF: 9 pages
Proc. SPIE 9149, Observatory Operations: Strategies, Processes, and Systems V, 91490C (6 August 2014); doi: 10.1117/12.2057267
Show Author Affiliations
Christopher M. Carroll, Dartmouth College (United States)
Rutgers Univ. (United States)
Eric Gawiser, Rutgers Univ. (United States)
Peter L. Kurczynski, Rutgers Univ. (United States)
Rachel A. Bailey, Rutgers Univ. (United States)
Rahul Biswas, Argonne National Lab. (United States)
David Cinabro, Wayne State Univ. (United States)
Saurabh W. Jha, Rutgers Univ. (United States)
R. Lynne Jones, Univ. of Washington (United States)
K. Simon Krughoff, Univ. of Washington (United States)
Aneesa Sonawalla, The Univ. of Chicago (United States)
W. Michael Wood-Vasey, Univ. of Pittsburgh (United States)


Published in SPIE Proceedings Vol. 9149:
Observatory Operations: Strategies, Processes, and Systems V
Alison B. Peck; Chris R. Benn; Robert L. Seaman, Editor(s)

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