Astrophysics Source Code Library

Making codes discoverable since 1999

Welcome to the ASCL

The Astrophysics Source Code Library (ASCL) is a free online registry for source codes of interest to astronomers and astrophysicists, including solar system astronomers, and lists codes that have been used in research that has appeared in, or been submitted to, peer-reviewed publications. The ASCL is indexed by the SAO/NASA Astrophysics Data System (ADS) and Web of Science and is citable by using the unique ascl ID assigned to each code. The ascl ID can be used to link to the code entry by prefacing the number with (i.e.,

Most Recently Added Codes

2021 Dec 06

[submitted] pycelp: a python package for Coronal Emission Line Polarization

pyCELP (aka "pi-KELP") is a python package for Coronal Emission Line Polarization calculations. It is used to forward synthesize the polarized emission of ionized atoms formed in the solar corona. It calculates the atomic density matrix elements for a single ion under coronal equilibrium conditions and excited by a prescribed radiation field and thermal collisions. In its initial release, pyCELP solves a set of statistical equilibrium equations in the spherical statistical tensor representation for a multi-level atom for the no-coherence case. This approximation is useful in the case of forbidden line emission by visible and infrared lines, such as Fe XIII 1074.7 nm and Si X 3934 nm.

2021 Dec 03

[submitted] forecaster-plus

An internally overhauled but fundamentally similar version of Forecaster by Jingjing Chen and David Kipping, originally presented in arXiv:1603.08614 and hosted at

The model itself has not changed- no new data was included and the hyperparameter file was not regenerated. All functions were rewritten to take advantage of Numpy vectorization and some additional user features were added. Now able to be installed via pip.

2021 Dec 01

[submitted] Caustic Mass Estimator for Galaxy Clusters

The caustic technique is a powerful method to infer cluster mass profiles to clustrocentric distances well beyond the virial radius. It relies in the measure of the escape velocity of the sistem using only galaxy redshift information. This method was introduced by Diaferio & Geller (1997) and Diaferio (1999). This code allows the caustic mass estimation for galaxy clusters, as well as outlier identification as a side effect. However, a pre-cleaning of interlopers is recommended, using e.g., the shifting-gapper technique.

2021 Nov 30

[ascl:2111.018] GWToolbox: Gravitational wave observation simulator

GWToolbox simulates gravitational wave observations for various detectors. The package is composed of three modules, namely the ground-based detectors (and their targets), the space-borne detectors (and their targets) and pulsar timing arrays (PTA). These three modules work independently and have different dependencies on other packages and libraries; failed dependencies met in one module will not influence the usage of another module. GWToolbox can accessed with a web interface ( or as a python package (

[ascl:2111.017] pySYD: Measuring global asteroseismic parameters

pySYD detects solar-like oscillations and measures global asteroseismic parameters. The code is a python-based implementation of the IDL-based SYD pipeline by Huber et al. (2009), which was extensively used to measure asteroseismic parameters for Kepler stars, and adapts the well-tested methodology from SYD and also improves these existing analyses. It also provides additional capabilities, including an automated best-fit background model selection, parallel processing, the ability to samples for further analyses, and an accessible and command-line friendly interface. PySYD provides best-fit values and uncertainties for the granulation background, frequency of maximum power, large frequency separation, and mean oscillation amplitudes.

[ascl:2111.016] SteParSyn: Stellar atmospheric parameters using the spectral synthesis method

SteParSyn infers stellar atmospheric parameters (Teff, log g, [Fe/H], and Vbroad) of FGKM-type stars using the spectral synthesis method. The code uses the MCMC sampler emcee (ascl:1303.002) in conjunction with an spectral emulator that can interpolate spectra down to a precision < 1%. A grid of synthetic spectra that allow the user to characterize the spectra of FGKM-type stars with parameters in the range of 3500 to 7000 K in Teff, 0.0 to 5.5 dex in log g, and −2.0 to 1.0 dex in [Fe/H] is also provided.

[ascl:2111.015] gCMCRT: 3D Monte Carlo Radiative Transfer for exoplanet atmospheres using GPUs

gCMCRT globally processes 3D atmospheric data, and as a fully 3D model, it avoids the biases and assumptions present when using 1D models to process 3D structures. It is well suited to performing the post-processing of large parameter GCM model grids, and provides simple pipelines that convert the 3D GCM structures from many well used GCMs in the community to the gCMCRT format, interpolating chemical abundances (if needed) and performing the required spectra calculation. The high-resolution spectra modes of gCMCRT provide an additional highly useful capability for 3D modellers to directly compare output to high-resolution spectral data.

[ascl:2111.014] UniMAP: Unicorn Multi-window Anomaly Detection Pipeline

The data analysis UniMAP (Unicorn Multi-window Anomaly Detection Pipeline) leverages the Temporal Outlier Factor (TOF) method to find anomalies in LVC data. The pipeline requires a target detector and a start and stop GPS time describing a time interval to analyze, and has three outputs: 1.) an array of GPS times corresponding to TOF detections; 2.) a long q-transform of the entire data interval with visualizations of the TOF detections in the time series; and 3.) q-transforms of the data windows that triggered TOF detections.

[ascl:2111.013] Astrosat: Satellite transit calculator

Astrosat calculates which satellites can be seen by a given observer in a given field of view at a given observation time and observation duration. This includes the geometry of the satellite and observer but also estimates the expected apparent brightness of the satellite to aid astronomers in assessing the impact on their observations.

[ascl:2111.012] flatstar: Make 2d intensity maps of limb-darkened stars

flatstar is an open-source Python tool for drawing stellar disks as numpy.ndarray objects with scientifically-rigorous limb darkening. Each pixel has an accurate fractional intensity in relation to the total stellar intensity of 1.0. It is ideal for ray-tracing simulations of stars and planetary transits. The code is fast, has the most well-known limb-darkening laws, including linear, quadratic, square-root, logarithmic, and exponential, and allows the user to implement custom limb-darkening laws. flatstar also offers supersampling for situations where both coarse arrays and precision in stellar disk intensity (i.e., no hard pixel boundaries) is desired, and upscaling to save on computation time when high-resolution intensity maps are needed, though there is some precision loss in intensities.