Demonstrating the Use of the Spherical Fourier Bessel Basis for Large Scale Clustering Systematics Discovery and Mitigation with eBOSS
Abstract
The spherical Fourier-Bessel (SFB) basis, in separating the angular and radial modes of the power spectrum, permits a targeted identification and mitigation of systematics in clustering surveys while retaining more cosmological signal than traditional bases. We demonstrate this principle on the eBOSS DR16 luminous red galaxy (LRG) and quasistellar object (QSO) samples, identifying modes which may be contaminated by systematics. Our initial inference on the LRG sample yields an fNL value consistent with zero, while the QSO value is in slight tension with zero. Using the SFB basis, we vary the selection of angular and radial modes to search for inconsistencies in the inferred value of fNL, an indicator of underlying systematics. In the QSO sample, we find evidence (p ≲ 0.002 compared to the same cuts on EZMocks) of a systematic afflicting large physical scales, which is consistent with residual stellar contamination; we also find evidence for an unknown systematic in the QSO sample (p=0.01), with consistent but less significant evidence in the LRGs (p≈0.06), at the approximate angular plate and imaging scale of eBOSS.
Related
- Dark Energy Survey Year 6 Results: improved mitigation of spatially varying observational systematics with masking for the MagLim++ lens sample
- Indirect Dark Matter Detection in the Multi-Messenger Era: Experiments, Systematics, Anomalies, and Prospects for Discovery
- Hidden in Pixels. I. Discovery of dual “little red dots” indicates excess clustering on kilo-parsec scales
- Mitigating scanning-induced systematics in Hipparcos andimplications for Gaia astrometry
- Demonstrating the integration of a photonic lantern with an all-fiber-based nulling interferometer
BibTeX
@misc{bruton2026demonstrating,
title = {{Demonstrating the Use of the Spherical Fourier Bessel Basis for Large Scale Clustering Systematics Discovery and Mitigation with eBOSS}},
author = {Sean Bruton and James R. Cheshire IV and Olivier Doré and Henry S. Grasshorn Gebhardt and Robin Y. Wen},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2605.10935},
eprint = {2605.10935},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2605.10935},
}
RIS
TY - UNPB
TI - Demonstrating the Use of the Spherical Fourier Bessel Basis for Large Scale Clustering Systematics Discovery and Mitigation with eBOSS
AU - Sean Bruton
AU - James R. Cheshire IV
AU - Olivier Doré
AU - Henry S. Grasshorn Gebhardt
AU - Robin Y. Wen
PY - 2026
DA - 2026/09/25
PB - arXiv
DO - 10.48550/arxiv.2605.10935
UR - https://arxiv.org/abs/2605.10935
AB - The spherical Fourier-Bessel (SFB) basis, in separating the angular and radial modes of the power spectrum, permits a targeted identification and mitigation of systematics in clustering surveys while retaining more cosmological signal than traditional bases. We demonstrate this principle on the eBOSS DR16 luminous red galaxy (LRG) and quasistellar object (QSO) samples, identifying modes which may be contaminated by systematics. Our initial inference on the LRG sample yields an fNL value consistent with zero, while the QSO value is in slight tension with zero. Using the SFB basis, we vary the selection of angular and radial modes to search for inconsistencies in the inferred value of fNL, an indicator of underlying systematics. In the QSO sample, we find evidence (p ≲ 0.002 compared to the same cuts on EZMocks) of a systematic afflicting large physical scales, which is consistent with residual stellar contamination; we also find evidence for an unknown systematic in the QSO sample (p=0.01), with consistent but less significant evidence in the LRGs (p≈0.06), at the approximate angular plate and imaging scale of eBOSS.
ER -