T-RECS

Role: contributor — HI emission extension. Stack: Fortran executables with Python tooling for catalogue cross-matching. Lead author & maintainer: Anna Bonaldi (SKAO).

T-RECS produces simulated catalogues of radio sources with user-defined frequencies, sky area and depth. The original model covers radio continuum emission for the two main populations of radio galaxies — AGN and star-forming galaxies — including polarisation and clustering. It is now widely used in the radio-cosmology community for survey design and theoretical modelling.

During a research stay at SKAO Headquarters in Manchester I contributed to the second generation of the code, which extends T-RECS to HI line emission. That work builds the HI model on current HI mass function estimates, adds prescriptions to convert HI mass to integrated flux, and models source size, morphology and kinematics including rotational velocity and line width. It also introduces prescriptions that associate an HI mass with the existing continuum SFG and AGN populations, which is what makes it possible to cross-match HI and continuum catalogues and build HI × continuum simulated observations.

T-RECS supplies the radio emission properties in the full-sky mock pipeline described in my research on the galaxy–halo connection, where its populations are assigned to dark-matter haloes via SCAMPy.

The HI extension is presented in Monthly Notices of the Royal Astronomical Society 524, 993 (2023) — see the paper.