Papers › Fitting the nonlinear matter bispectrum by the Halofit approach
Fitting the nonlinear matter bispectrum by the Halofit approach
Ryuichi Takahashi, Takahiro Nishimichi, Toshiya Namikawa, Atsushi Taruya, Issha Kayo, Ken Osato, Yosuke Kobayashi, Masato Shirasaki
The archive published only this paper's code-link row. Authors, date and abstract are from arXiv's metadata (CC0), read from the Kaggle arXiv metadata snapshot of 2026-09-12 where its title matched the archive's; the title is the archive's.
We provide a new fitting formula of the matter bispectrum in the nonlinear regime calibrated by high-resolution cosmological N-body simulations of 41 cold dark matter (wCDM, w= constant) models around the Planck 2015 best-fit parameters. As the parameterization in our fitting function is similar to that in Halofit, our fitting is named BiHalofit. The simulation volume is sufficiently large (> 10 Gpc³) to cover almost all measurable triangle bispectrum configurations in the universe. The function is also calibrated using one-loop perturbation theory at large scales (k<0.3 h Mpc⁻¹). Our formula reproduced the matter bispectrum to within 10 (15) % accuracy in the Planck 2015 model at wavenumber k< 3 (10) h Mpc⁻¹ and redshifts z=0-3. The other 40 wCDM models obtained poorer fits, with accuracy approximating 20 % at k<3 h Mpc⁻¹ and z=0-1.5 (the deviation includes the 10 %-level sample variance of the simulations). We also provide a fitting formula that corrects the baryonic effects such as radiative cooling and active galactic nucleus feedback, using the latest hydrodynamical simulation IllustrisTNG. We demonstrate that our new formula more accurately predicts the weak-lensing bispectrum than the existing fitting formulas. This formula will assist current and future weak-lensing surveys and cosmic microwave background lensing experiments. Numerical codes of the formula are available, written in Python, C and Fortran.
Code
Repository list and official/mentioned flags are the archive's, frozen 2025-07-28. Reachability, where shown, is from one Syntology probe window (2026-09-16 to 2026-09-18); repositories not probed show nothing. GitHub stars are not tracked.
Code Syntology ran Syntology
Not run by Syntology. Nothing on this page verifies that the listed code works.
Results from the paper archive 2025-07-28
No leaderboard rows for this paper in the archive.
Report a problem or propose a change · a person checks every report against the paper or source before anything changes; decisions are listed on /corrections