Changelog

SAGE26 (2026) — Major release

Built on Croton et al. (2016).

New physics

  • Two-regime CGM model (CGMrecipeOn): galaxies are classified as CGM-regime (below the Dekel & Birnboim 2006 shock mass) or hot-halo regime. Each regime uses a dedicated cooling recipe. CGM-regime cooling uses the Voit (2015) precipitation criterion. AGN feedback in the CGM regime uses the same r_heat ratchet as the hot-halo path, additionally capped at R_vir.

  • FIRE stellar feedback (FIREmodeOn): FIRE-calibrated wind mass-loading and ejection efficiencies replace the fixed Croton+2016 values.

  • Feedback-free burst galaxies (FeedbackFreeModeOn): implements the Li+2024 and Boylan-Kolchin+2025 FFB criteria. Multiple sub-modes available (0–7).

  • NFW/beta-profile CGM density (CGMDensityProfile): cooling in CGM-regime halos can use a uniform, NFW, or beta-profile gas distribution.

  • Extended bulge tracking: merger-driven and instability-driven bulge components tracked separately (MergerBulgeMass, InstabilityBulgeMass, MergerBulgeRadius, InstabilityBulgeRadius). Radii follow Tonini+2016 eq. 15.

  • ICS assembly tracking (TrackICSAssembly): records satellite disruption contributions to intracluster stars.

New SF prescriptions (SFprescription)

Value

Prescription

0

Croton et al. (2006) original

1

Blitz & Rosolowsky (2006) H₂

2

Somerville et al. (2025) SFR

3

Somerville et al. (2025) SFR + H₂

4

Krumholz & Dekel (2012)

5

Krumholz, McKee & Tumlinson (2009)

6

Krumholz (2013)

7

Gnedin & Draine (2014)

New tree formats

ConsistentTrees ASCII and HDF5 (consistent_trees_ascii, consistent_trees_hdf5), Genesis HDF5 (genesis_lhalo_hdf5), Gadget-4 HDF5 (gadget4_hdf5).

Infrastructure

  • HDF5 output format (OutputFormat sage_hdf5) with buffered writes.

  • libsage.so shared library for Python bindings and PSO parameter calibration.

  • Full star formation history arrays (SaveFullSFH).

  • Regression baseline test (5444 datasets, bit-identical per dataset).