TheHaloMod: an Online Calculator for the Halo Model.

The halo model is a successful framework for describing the distribution of matter in the Universe - from weak lensing observables to galaxy n-point correlation functions. We review the basic formulation of the halo model and several of its components in the context of galaxy 2-point statistics, developing a coherent framework for its application. We use this framework to motivate the presentation of a new PYTHON tool for simple and efficient calculation of halo model quantities, and their extension to galaxy statistics via a halo occupation distribution, called HALOMOD. This tool is efficient, simple to use, comprehensive and importantly provides a great deal of flexibility in terms of custom extensions. This PYTHON tool is complemented by a new web-application at https://thehalomod.app that supports the generation of many halo model quantities directly from the browser - useful for educators, students, theorists and observers. (C) 2021 Elsevier B.V. All rights reserved.