Lightcone outputs

When we observe the real Universe, the light from distant objects takes time to reach us. This means we see these objects as they were when the light was emitted. More distant objects are seen as they were at earlier times.

The FLAMINGO simulations attempt to replicate this effect for easier comparison with observations. We place several virtual observers in the simulated volume of space at the present day, and as the simulation evolves we identify and store particles which cross each observer’s lightcone. A particle crosses the lightcone when it passes exactly the distance at which light emitted from it would arrive at the observer today.

The FLAMINGO lightcone outputs include particle data, HEALPix maps, and halo catalogues. These are described in the following sections:

• Observer positions
  • Positions in the 1Gpc boxes
  • Positions in the 2.8Gpc boxes
  • Positions in the 5.6Gpc box
  • Positions in the 11.2Gpc box
• Particle lightcones
  • Directory layout
  • File format
  • Redshift ranges
  • Particle properties
  • Reading the particles
• HEALPix maps
  • Directory layout
  • File format
  • Shell redshifts
  • Map descriptions
  • Reading the maps
  • Integrated lightcones
• Halo lightcones
  • Construction
  • Directory layout
  • File format
  • Reading the halos