ScalPy: A Python Package For Late Time Scalar Field Cosmology

TL;DR

ScalPy is a Python package that models late-time scalar field cosmologies, computes key observables, and integrates with MCMC tools for data-driven model constraints.

Contribution

It introduces a versatile Python toolkit for analyzing various scalar field dark energy models and their observational signatures, with easy extensibility and data fitting capabilities.

Findings

Provides calculations for background and perturbation observables.

Enables model constraints using current observational data.

Supports multiple scalar field and dark energy parameterizations.

Abstract

We present a python package "ScalPy" for studying the late time scalar field cosmology for a wide variety of scalar field models, namely the quintessence, tachyon and Galileon model. The package solves the autonomous system of equations for power law and exponential potential. But it can be easily generalized to add more complicated potential. For completeness, we also include the standard parameterization for dark energy models, e.g. the $\Lambda$CDM, $w$CDM, $w_{0}w_{a}$CDM as well as the GCG parameterization. The package also solves the linear growth equation for matter perturbations on sub-horizon scales. All the important observables related to background universe as well as to the perturbed universe, e.g. luminosity distance ($D_{L}(z)$), angular diameter distance ($D_{A}(z)$), normalized Hubble parameter ($h(z)$), lookback time ($t_{L}$), equation of state for the dark energy ($w(z)$), growth rate ($f=\frac{d \ln\delta}{d \ln a}$), linear matter power spectra ($P(k)$), and its normalization $\sigma_{8}$ can be obtained from this package. The code is further integrated with the publicly available MCMC hammer "emcee" to constrain the different models using the presently available observational data. The code is available online at \url{https://github.com/sum33it/scalpy}