Add Yang+2024 parametric SIDM gravothermal-sequence profile - #556
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Adds YangSIDMSph, the closed-form beta=4 cored-NFW profile of Yang, Nadler, Yu & Zhong (2024, arXiv:2305.16176), whose (rho_s, r_s, r_c) evolve along the universal gravothermal sequence with tau = t / t_c, and YangSIDMMCRLudlowSph, which solves tau per halo from physical inputs (Ludlow+16 concentration, Yang+24 collapse time with C = 0.75, Outmezguine+23 velocity-dependent effective cross section at nu_eff = 0.64 V_max). Includes default priors, exports and unit tests. Requested in PyAutoLens#631; builds on the Kaplinghat profile of #471. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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Summary
Implements the parametric SIDM halo model of Yang, Nadler, Yu & Zhong (2024, arXiv:2305.16176) as a new spherical dark mass profile, spanning the full gravothermal sequence (cored through core-collapsed) via the dimensionless evolution time tau = t / t_c. Requested by @mwiet in PyAutoLabs/PyAutoLens#631; builds on the Kaplinghat cored-NFW profile (#471), which remains fully supported.
YangSIDMSphis the beta = 4 cored-NFW form with the Yang+24 fitting functions for how (rho_s, r_s, r_c) evolve with tau relative to the CDM baseline NFW halo; at tau = 0 it reduces exactly to NFW.YangSIDMMCRLudlowSphconstructs it from physical inputs: Ludlow+16 mass-concentration baseline, the Yang+24 collapse time t_c (C = 0.75), and the Outmezguine+23 effective cross section, supporting a power-law velocity dependence sigma(v) ~ v^(-a) averaged at nu_eff = 0.64 V_max. The density is fully closed-form (no Lane-Emden tables), so the vmapped JAX substructure-batching path works cleanly.API Changes
Two new public mass profiles are added:
YangSIDMSph(kappa_s, scale_radius, tau) andYangSIDMMCRLudlowSph(mass_at_200, sigma_over_m, velocity_exponent, velocity_ref, t_age, redshift_object, redshift_source), with default priors. No existing symbols are removed, renamed or changed.See full details below.
Test Plan
test_autogalaxy/profiles/mass/dark/test_yang24.py— 10 tests: exact NFW reduction at tau = 0, analytic central core density, tau truncation into the fitted [0, 1] range, finite/positive lensing quantities, vmapped-vs-instance deflection parity (jax), MCR NFW reduction at sigma/m = 0, tau linearity in sigma/m, closed-form velocity-dependence checks.test_autogalaxy/suite: 1027 passed.af.Modelcomposition from the new prior configs (5 and 9 free parameters).Full API Changes (for automation & release notes)
Added
autogalaxy.profiles.mass.dark.yang24.YangSIDMSph(centre=, kappa_s=, scale_radius=, tau=)— Yang+2024 parametric SIDM profile; exported asag.mp.YangSIDMSph.autogalaxy.profiles.mass.dark.yang24_mcr.YangSIDMMCRLudlowSph(centre=, mass_at_200=, sigma_over_m=, velocity_exponent=, velocity_ref=, t_age=, redshift_object=, redshift_source=)— physical constructor solving tau = t_age / t_c; exported asag.mp.YangSIDMMCRLudlowSph.autogalaxy/config/priors/mass/dark/yang24.yaml,yang24_mcr.yaml— default priors.Migration
Generated by the PyAutoLabs agent workflow.