Skymodels

Skymodels

This page describes ALMASim’s source-model layer.

Location

Skymodel implementations live in src/almasim/skymodels.

Supported Source Types

ALMASim currently supports:

  • point

  • gaussian

  • extended

  • diffuse

  • galaxy-zoo

  • molecular

  • hubble-100

Common Structure

All skymodels are built on the base class in base.py.

They receive:

  • a datacube object

  • continuum flux array

  • line fluxes

  • spectral line positions and widths

  • spatial parameters when needed

Point and Gaussian Models

For compact-source tests:

  • PointlikeSkyModel inserts a point source into the cube

  • GaussianSkyModel inserts an extended 2D Gaussian source

These are useful for:

  • debugging

  • PSF and CLEAN validation

  • controlled synthetic datasets

Physically Richer Models

extended

Uses TNG-backed source content for more realistic extended systems.

galaxy-zoo

Uses Galaxy Zoo image assets as spatial morphology priors.

hubble-100

Uses Hubble-derived image assets.

molecular

Generates molecular-cloud-like structured emission.

diffuse

Builds diffuse emission fields.

Source Placement

The science target is now:

  • centered at the phase center by default

  • optionally shifted by explicit source_offset_x_arcsec and source_offset_y_arcsec

Random source placement is no longer the default.

Serendipitous Sources

ALMASim can optionally inject additional serendipitous sources with the existing serendipitous-source utilities.

That is separate from the new background-sky feature:

  • serendipitous sources are discrete extra sources

  • background sky is an additive field-level background component