Probing the local primordial non-Gaussianity with clustering of FRB dispersion measure and galaxies
Abstract
We forecast the sensitivity of a joint fast radio burst (FRB) and galaxy survey to local primordial non-Gaussianity using the full 3×2-point statistic: the angular dispersion-measure (DM) auto-spectrum, the DM-galaxy cross-spectrum, and the galaxy auto-spectrum. Local primordial non-Gaussianity imprints a scale-dependent bias on both the free-electron field probed by FRB dispersion measures and the galaxy field. Hence, all three spectra carry information on the local non-Gaussianity amplitude fNL. Adopting a DESI-like luminous-red-galaxy sample and an FRB population over 35% of the sky, we forecast σ(fNL) ≃ 5 for both NFRB = 104 and 105 at fixed Planck 2018 cosmology, marginalised over three astrophysical bias parameters (be0, zfb, bgamp). The fNL constraint is robust to marginalising over the six ΛCDM parameters (ωb, ωcdm, h, As, ns, τ) with Planck priors. At these sample sizes, the galaxy auto-spectrum sets the constraint, while the DM sector's contribution grows with the burst count and becomes decisive for the larger samples anticipated in the SKA era, reaching σ(fNL) ≃ 2 at 107 bursts.
Related
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BibTeX
@misc{das2026probing,
title = {{Probing the local primordial non-Gaussianity with clustering of FRB dispersion measure and galaxies}},
author = {Indranil Das and Gilbert Holder},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.38735},
eprint = {2610.38735},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.38735},
}
RIS
TY - UNPB
TI - Probing the local primordial non-Gaussianity with clustering of FRB dispersion measure and galaxies
AU - Indranil Das
AU - Gilbert Holder
PY - 2026
DA - 2026/10/28
PB - arXiv
DO - 10.48550/arxiv.2610.38735
UR - https://arxiv.org/abs/2610.38735
AB - We forecast the sensitivity of a joint fast radio burst (FRB) and galaxy survey to local primordial non-Gaussianity using the full 3×2-point statistic: the angular dispersion-measure (DM) auto-spectrum, the DM-galaxy cross-spectrum, and the galaxy auto-spectrum. Local primordial non-Gaussianity imprints a scale-dependent bias on both the free-electron field probed by FRB dispersion measures and the galaxy field. Hence, all three spectra carry information on the local non-Gaussianity amplitude f_NL. Adopting a DESI-like luminous-red-galaxy sample and an FRB population over 35% of the sky, we forecast σ(f_NL) ≃ 5 for both N_FRB = 10^4 and 10^5 at fixed Planck 2018 cosmology, marginalised over three astrophysical bias parameters (b_e^0, z_fb, b_g^amp). The f_NL constraint is robust to marginalising over the six ΛCDM parameters (ω_b, ω_cdm, h, A_s, n_s, τ) with Planck priors. At these sample sizes, the galaxy auto-spectrum sets the constraint, while the DM sector's contribution grows with the burst count and becomes decisive for the larger samples anticipated in the SKA era, reaching σ(f_NL) ≃ 2 at 10^7 bursts.
ER -