Testing LSST Dither Strategies for Survey Uniformity and Large-Scale Structure Systematics

Abstract

The Large Synoptic Survey Telescope (LSST) will survey the southern sky from 2022--2032 with unprecedented detail. Since the observing strategy can lead to artifacts in the data, we investigate the effects of telescope-pointing offsets (called dithers) on the $r$-band coadded 5$\sigma$ depth yielded after the 10-year survey. We analyze this survey depth for several geometric patterns of dithers (e.g., random, hexagonal lattice, spiral) with amplitude as large as the radius of the LSST field-of-view, implemented on different timescales (per season, per night, per visit). Our results illustrate that per night and per visit dither assignments are more effective than per season. Also, we find that some dither geometries (e.g., hexagonal lattice) are particularly sensitive to the timescale on which the dithers are implemented, while others like random dithers perform well on all timescales. We then model the propagation of depth variations to artificial fluctuations in galaxy counts, which are a systematic for large-scale structure studies. We calculate the bias in galaxy counts caused by the observing strategy, accounting for photometric calibration uncertainties, dust extinction, and magnitude cuts; uncertainties in this bias limit our ability to account for structure induced by the observing strategy. We find that after 10 years of the LSST survey, the best dither strategies lead to uncertainties in this bias smaller than the minimum statistical floor for a galaxy catalog as deep as $r$$<$27.5. A few of these strategies bring the uncertainties close to the statistical floor for $r$$<$25.7 after only one year of survey.

16 pages, 11 figures, 1 table. Updated to match the version accepted by ApJ

References in corpus (10)

• On the Robustness of the Acoustic Scale in the Low-Redshift Clustering of Matter
• MegaPipe: the MegaCam image stacking pipeline at the Canadian Astronomical Data Centre
• Effects of AGN feedback on LCDM galaxies
• Metal Enrichment of the ICM: a 3-D Picture of Chemical and Dynamical Properties
• Ram pressure stripping in a galaxy formation model. I. A novel numerical approach
• Cosmic tomographies: baryon acoustic oscillations and weak lensing
• Unbiased methods for removing systematics from galaxy clustering measurements
• Properties of Submillimeter Galaxies in a Semi-analytic Model using the "Count Matching" Approach: Application to the ECDF-S
• Multiplicative errors in the galaxy power spectrum: self-calibration of unknown photometric systematics for precision cosmology
• Improving the LSST dithering pattern and cadence for dark energy studies

Cited by in corpus (23)

• Weak lensing for precision cosmology
• Models and Simulations for the Photometric LSST Astronomical Time Series Classification Challenge (PLAsTiCC)
• Optimization of the Observing Cadence for the Rubin Observatory Legacy Survey of Space and Time: a pioneering process of community-focused experimental design
• The LSST DESC DC2 Simulated Sky Survey
• A Framework for Telescope Schedulers: With Applications to the Large Synoptic Survey Telescope
• Mitigating contamination in LSS surveys: a comparison of methods
• Unbiased pseudo-Cl power spectrum estimation with mode projection
• Serendipitous Discoveries of Kilonovae in the LSST Main Survey: Maximising Detections of Sub-Threshold Gravitational Wave Events
• The Impact of Observing Strategy on Cosmological Constraints with LSST
• A Joint Roman Space Telescope and Rubin Observatory Synthetic Wide-Field Imaging Survey
• The LSST DESC Data Challenge 1: Generation and Analysis of Synthetic Images for Next Generation Surveys
• Designing an Optimal LSST Deep Drilling Program for Cosmology with Type Ia Supernovae
• Large-scale retrospective relative spectro-photometric self-calibration in space
• Integrated Sachs-Wolfe map reconstruction in the presence of systematic errors
• A Cohesive Deep Drilling Field Strategy for LSST Cosmology
• Stellar Reddening Based Extinction Maps for Cosmological Applications
• Optimising LSST Observing Strategy for Weak Lensing Systematics
• Impact of photometric redshifts on the galaxy power spectrum and BAO scale in the LSST survey
• ALTSched: Improved Scheduling for Time-Domain Science with LSST
• Spurious correlations between galaxies and multi-epoch image stacks in the DESI Legacy Surveys
• Impact of Large-Scale Structure Systematics on Cosmological Parameter Estimation
• 6x2pt: Forecasting gains from joint weak lensing and galaxy clustering analyses with spectroscopic-photometric galaxy cross-correlations
• Simultaneous Estimation of Large-Scale Structure and Milky Way Dust Extinction from Galaxy Surveys