| name | flamingo-snapshots |
| description | FLAMINGO SWIFT particle snapshots: virtual HDF5 files, particle types, 78/79 output redshifts, downsampled and reduced variants. Use when reading gas, DM, stars, BHs, or neutrinos from a FLAMINGO run. |
FLAMINGO snapshots
Source of truth: Snapshots
Particle snapshots are SWIFT HDF5 outputs at fixed output redshifts. Each
snapshot is sharded per rank but exposed as one virtual file
flamingo_<NNNN>.hdf5 — always open that file (portal: Reading with swiftsimio).
Layout
<run>/<run>/snapshots/flamingo_<NNNN>/
flamingo_<NNNN>.hdf5 # virtual file (entry point)
flamingo_<NNNN>.<rank>.hdf5 # shards — do not iterate by hand
Sibling directories: snapshots_downsampled/, snapshots_reduced/ (see below).
Output schedule
- L1_m8 and L2p8_m9: 79 snapshot redshifts.
- L1_m9 variations and L1_m10: 78 snapshot redshifts.
SOAP catalogues exist at all listed outputs; full particle data is available
for every output of L1_m9, L1_m9_DMO, L1_m10, and L1_m10_DMO only. For other
runs, check the portal snapshot-redshift table (third column: particle data
available or not).
Snapshot number <NNNN> maps to redshift via the portal tables — do not assume
the same index as power-spectrum files (0000–0122).
Particle types (hydro runs)
| SWIFT group | Content |
|---|
| PartType0 | SPH gas |
| PartType1 | CDM |
| PartType4 | Stars |
| PartType5 | Black holes |
| PartType6 | Massive neutrinos (δf method) |
_DMO runs: PartType1 (+ PartType6); CDM particles carry baryon mass.
Partial snapshots
Downsampled: random 1% of particles per output (not the same 1% each time);
all BHs kept; most masses rescaled ×100 to conserve total mass (BH masses
excepted). Subset of fields — see portal field list.
Reduced: full particle count but only a subset of properties; haloes sampled
in M200c bins (≥200 halos per 0.05 dex bin, else all). Not shipped for
L1_m9, L1_m9_DMO, L1_m10, L1_m10_DMO (full snapshots exist for all outputs).
Same HDF5 format; readable with swiftsimio.
Usage notes
- Coordinates are comoving; use scale factor from snapshot metadata for
physical lengths.
- Neutrino δf: treat masses as weights; see portal particle-properties page.
- Remote/subvolume access: portal documents swiftsimio, hdfstream, and spatial
masks — follow those pages for IO patterns.
Related skills
- flamingo-halo-catalogues — precomputed SOAP / HBT properties
- flamingo-lightcones — on-the-fly lightcone products (not reproducible from
snapshots alone)
- flamingo-power-spectra — precomputed P(k) without loading particles
