Not so Fast: Revised Calibration of SIDM Core Collapse

Abstract

Self-interacting dark matter (SIDM) haloes undergo gravothermal evolution whose late-time behaviour is central to predictions for dense substructure and black-hole seed formation. We revisit the calibration of this evolution using a new spherical Direct Simulation Monte Carlo code, SphDSMC, which follows spherically symmetric SIDM systems without force softening and to substantially higher central densities than standard N-body simulations. We compare SphDSMC, calculations with conventional N-body simulations and with one-dimensional gravothermal fluid models. We show that N-body results converge to SphDSMC, only for softening lengths significantly smaller than those normally adopted for collisionless simulations, and that allowing multiple scatterings per particle per time step does not introduce significant errors when implemented appropriately. Calibrating the gravothermal fluid equations against SphDSMC, we find that the commonly used harmonic interpolation between the long- and short-mean-free-path conductivities is inaccurate. A gentler transition, however, yields excellent agreement for NFW haloes over a range of concentrations and truncation radii, with a single long-mean-free-path conductivity parameter. The revised calibration gives a long-mean-free-path collapse time that is somewhat shorter than previous estimates, but we show that collapse slows dramatically once the core becomes optically thick. We provide fitting functions for the late-time evolution and argue that black-hole seed formation by SIDM gravothermal collapse has generally been underestimated in duration, making it unlikely to explain the massive high-redshift black holes inferred from JWST observations without additional physics.

Feeding the Void: Co-evolution of the SIDM-seeded Black Hole and the dark halo after core-collapse
Zhichao Carton Zeng, Annika H. G. Peter, Louis E. Strigari +3
arXiv19 Sep 2026PreprintCC BY 4.0Full textCosmology GalaxiesarXiv
Baryon-Accelerated Core Collapse in SIDM Halos and its Imprint on Galactic Disks
Zeineb Mezghanni, Elliot Y. Davies, Adriana Dropulic +3
arXiv4 Sep 2026PreprintarXiv licenceFull textGalaxies High-energy & particle physicsarXiv
A three-dimensional exploration of magnetic fields, rotation, and shock revival in a 39 M⊙ core-collapse supernova progenitor
Liubov Kovalenko, Evan O'Connor, Haakon Andresen +1
Astronomy & Astrophysics8 Oct 2026Peer-reviewedPublisher termsHigh-energy astrophysicsCrossref
Neutron star-companion interaction in core-collapse supernovae. Population synthesis based on detailed binary evolution models
Andrea Ercolino, Norbert Langer, Avishay Gal-Yam +6
Astronomy & Astrophysics6 Nov 2026Peer-reviewedPublisher termsSolar & stellar physicsCrossref
Neutrino Flavor Conversion Shapes the Rate of Failed Core-collapse Supernovae
Mariam Gogilashvili, Irene Tamborra
arXiv18 Aug 2026PreprintCC BY 4.0Full textHigh-energy astrophysics Solar & stellar physicsarXiv

Cite

BibTeX RIS

BibTeX

@article{bosch2026fast,
  title = {{Not so Fast: Revised Calibration of SIDM Core Collapse}},
  author = {Frank C van den Bosch and Yarone M Tokayer},
  journal = {Monthly Notices of the Royal Astronomical Society},
  year = {2026},
  month = oct,
  doi = {10.1093/mnras/stag2015},
  url = {https://academic.oup.com/mnras/advance-article/doi/10.1093/mnras/stag2015/8979794},
  note = {CC BY 4.0},
}

RIS

TY  - JOUR
TI  - Not so Fast: Revised Calibration of SIDM Core Collapse
AU  - Frank C van den Bosch
AU  - Yarone M Tokayer
PY  - 2026
DA  - 2026/10/22
JO  - Monthly Notices of the Royal Astronomical Society
DO  - 10.1093/mnras/stag2015
UR  - https://academic.oup.com/mnras/advance-article/doi/10.1093/mnras/stag2015/8979794
AB  - Self-interacting dark matter (SIDM) haloes undergo gravothermal evolution whose late-time behaviour is central to predictions for dense substructure and black-hole seed formation. We revisit the calibration of this evolution using a new spherical Direct Simulation Monte Carlo code, SphDSMC, which follows spherically symmetric SIDM systems without force softening and to substantially higher central densities than standard N-body simulations. We compare SphDSMC, calculations with conventional N-body simulations and with one-dimensional gravothermal fluid models. We show that N-body results converge to SphDSMC, only for softening lengths significantly smaller than those normally adopted for collisionless simulations, and that allowing multiple scatterings per particle per time step does not introduce significant errors when implemented appropriately. Calibrating the gravothermal fluid equations against SphDSMC, we find that the commonly used harmonic interpolation between the long- and short-mean-free-path conductivities is inaccurate. A gentler transition, however, yields excellent agreement for NFW haloes over a range of concentrations and truncation radii, with a single long-mean-free-path conductivity parameter. The revised calibration gives a long-mean-free-path collapse time that is somewhat shorter than previous estimates, but we show that collapse slows dramatically once the core becomes optically thick. We provide fitting functions for the late-time evolution and argue that black-hole seed formation by SIDM gravothermal collapse has generally been underestimated in duration, making it unlikely to explain the massive high-redshift black holes inferred from JWST observations without additional physics.
SN  - 0035-8711
SN  - 1365-2966
ER  -

Abstract

Related

Cite