astrosylva

Carry merger trees from the forest to Galacticus.

A Python library and CLI that converts halo merger-tree catalogues into the Galacticus HDF5 input format.

Supports:

• Consistent-Trees (Rockstar pipeline; forests.list + locations.dat + tree_*.dat)
• LHaloTree (Millennium-style binary)
• SubLink (IllustrisTNG-style HDF5)
• AHF (Amiga Halo Finder MergerTree output)

This package is a Python port of the original C utility rockstar2galacticus. The legacy C sources are preserved at galacticusorg/rockstar2galacticus for reference; new development happens here in src/astrosylva/.

Install

pip install astrosylva

Or, from a checkout:

pip install -e ".[dev]"

Quickstart

astrosylva convert config.yaml

A minimal config:

reader:
  name: consistent_trees
  source:
    input_path: ./Illustris-3/tree/trees/
    forests_path: ./Illustris-3/tree/forests.list
    locations_path: ./Illustris-3/tree/locations.dat
  options:
    host_source: pid           # or "upid"
    scale_radius_source: rs    # or "rs_klypin"

writer:
  output_path: galacticus_illustris3.hdf5

metadata:
  cosmology:
    HubbleParam: 0.704
    Omega0: 0.2726
    OmegaLambda: 0.7274
    OmegaBaryon: 0.0456
    sigma_8: 0.809
  simulation:
    boxSize: 75000.0
    simulationCode: AREPO
    startRedshift: 127.0
  groupFinder:
    groupFinderCode: rockstar
    minimumParticleNumber: 10
  haloTrees:
    haloMassesIncludeSubhalos: 1
    forestsAreSelfContained: 1
    treesHaveSubhalos: 1
    velocitiesIncludeHubbleFlow: 0

Values that the reader can introspect from the input data (e.g. cosmological parameters from a Consistent-Trees header) override the metadata block; conflicts emit a MetadataConflictWarning showing both values.

CLI

Implementation status

The Galacticus writer emits formatVersion = 2, matching the legacy C tool's output layout byte-for-byte (group structure, dataset names, attribute names).

License

MIT — see LICENSE.

Contributing

Bug reports, feature requests, and pull requests welcome. See CONTRIBUTING.md for the dev-loop guide and CONTRIBUTORS.md for credits.