SEDPY performs a variety of tasks for astronomical spectral energy distributions. It can generate synthetic photometry through any filter, provides detailed modeling of extinction curves, and offers basic aperture photometry algorithms. SEDPY can also store and interpolate model SEDs, convolve absolute or apparent fluxes, and calculate rest-frame magnitudes.

Forcepho infers the fluxes and shapes of galaxies from astronomical images. It models the appearance of multiple sources in multiple bands simultaneously and compares to observed data via a likelihood function. Gradients of this likelihood allow for efficient maximization of the posterior probability or sampling of the posterior probability distribution via Hamiltonian Monte Carlo. The model intrinsic galaxy shapes and positions are shared across the different bands, but the fluxes are fit separately for each band. Forcepho does not perform detection; initial locations and (very rough) parameter estimates must be supplied by the user.

Cue interprets nebular emission across a wide range of ionizing conditions of galaxies. The software, based on Cloudy (ascl:9910.001), emulates a neural net. It does not require a specific ionizing spectrum as a source, instead approximating the ionizing spectrum with a 4-part piece-wise power-law. Along with the flexible ionizing spectra, Cue allows freedom in [O/H], [N/O], [C/O], gas density, and total ionizing photon budget.

The dust radiative transfer software Powderday interfaces with galaxy formation simulations to produce spectral energy distributions and images. The code uses fsps (ascl:1010.043) and its Python bindings python-fsps for stellar SEDs, Hyperion (ascl:1207.004) for dust radiative transfer, and works with a variety of packages, including Arepo (ascl:1909.010), Changa (ascl:1105.005), Gasoline (ascl:1710.019), and Gizmo (ascl:1410.003); threaded throughout is yt (ascl:1011.022).

Prospector conducts principled inference of stellar population properties from photometric and/or spectroscopic data. The code combine photometric and spectroscopic data rigorously using a flexible spectroscopic calibration model and infer high-dimensional stellar population properties using parameteric SFHs (with ensemble MCMC sampling). Prospector also constrains the linear combination of stellar population components that are present in a galaxy (e.g. non-parametric SFHs) using spectra and/or photometry, and fits individual stellar spectra using large interpolated grids.