Twinkle calculates and plots the stellar spectral energy distribution (SED) using empirical photometric data and stellar model grids. The code was originally created to help calculate the excess infrared (IR) flux from a star; the presence of an IR excess indicates dust orbiting the star. This dust likely results from the grinding and collisions of asteroids, influenced by a larger planetary object—pointing to the potential for finding planets. Twinkle quickly calculates the temperature and location of the dust to first order by fitting the assumed blackbody or modified blackbody function to the broadband excess emission.

Stimela2 develops data reduction workflows and is a significant update of Stimela (ascl:2305.007). Though designed for radio astronomy data, it can be adapted for other data processing applications. Stimela2 represents workflows by linear, concise and intuitive YAML-format "recipes". Atomic data reduction tasks (binary executables, Python functions and code, and CASA tasks) are described by YAML-format "cab definitions" detailing each task's "schema" (inputs and outputs). Stimela2 provides a rich syntax for chaining tasks together, and encourages a high degree of modularity: recipes may be nested into other recipes, and configuration is cleanly separated from recipe logic. Tasks can be executed natively or in isolated environments using containerization technologies such as Apptainer. Stimela2 facilitates the deployment of scalable, distributed workflows by interfacing with the Slurm scheduler and the Kubernetes API, the latter allowing workflows to be readily deployed in the cloud.

dask-ms constructs xarray datasets from CASA tables, thus providing a data access layer for Measurement Set v2.0 data. It supports the CASA Data Table System, Zarr and Apache Arrow formats, but abstracts them away from the developer at the xarray dataset level. It therefore serves as a basis for writing distributed PyData Radio Astronomy applications and supports writing variables back to the respective column in the Table. The intention behind dask-ms is to support the Measurement Set as a data source and sink for the purposes of writing parallel, distributed radio astronomy algorithms.

BADASS (Bayesian AGN Decomposition Analysis for SDSS Spectra) decomposes Sloan Digital Sky Survey (SDSS) spectra and fits Type 1 ("broad line") Active Galactic Nuclei (AGN) in the optical. The fitting process uses the Bayesian affine-invariant Markov-Chain Monte Carlo sampler emcee (ascl:1303.002) for robust parameter and uncertainty estimation, as well as autocorrelation analysis to access parameter chain convergence. Out of the box, BADASS fits SDSS spectra, and MANGA IFU cube data; the code can be modified to fit user-input spectra of any instrument.

pmwd simulates and models cosmological evolutionary history. The code includes reverse time integration in addition to traditional forward simulation, enabling symmetrical dynamics analysis using the adjoint method. The pmwd particle-mesh model supports fully-differentiable analytic, semi-analytics, and deep learning components in parallel. Based on JAX (ascl:2111.002), pmwd is optimized for PU computation.

Coport computes covariant polarized radiation transfer in any spacetime. It is particularly useful for imaging black hole accretion systems. Written in Julia, it contains functions for handling the computation of all rays and a single ray, and deriving initial ray directions. Coport also has functions for interpolating GRMHD data, obtaining covariant emission, absorption, and Faraday rotation coefficients, and projecting the polarization tensor at the observer's screen, among other tasks.

FINUFFT (Flatiron Institute Nonuniform Fast Fourier Transform) computes the three standard types of nonuniform FFT to a specified precision, in one, two, or three dimensions. It can be run on a multi-core shared-memory machine or on a GPU. It is extremely fast and has very simple interfaces to most major numerical languages (such as C/C++, Fortran, MATLAB, octave, Python, and Julia). FINUFFT also provides more advanced (vectorized and “guru”) interfaces that allow multiple strength vectors and the reuse of FFT plans.

nifty-ls evaluates the Lomb-Scargle periodogram very quickly and accurately. The Lomb-Scargle periodogram, used for identifying periodicity in irregularly-spaced observations, is useful but computationally expensive. However, when it is phrased mathematically as a pair of non-uniform FFTs (NUFFTs), FINUFFT (ascl:2412.007), which is really fast, can be leveraged to improve performance. It also enables GPU (CUDA) support and is several orders of magnitude more accurate than Astropy's (ascl:1304.002) Lomb Scargle with default settings.

Codex Africanus presents radio astronomy algorithms to the user as modular functions accepting NumPy inputs and producing NumPy outputs. Internally, it uses Numba to accelerate these codes and Dask to parallelize and distribute them. The library contains functions for plotting convolution filters and tapers associated with convolution filters and can compute the discretised direct Fourier transform (DFT) for an ideal interferometer. Codex Africanus has routines for gridding or degridding complex visibilities onto or from an image, includes deconvolution algorithms and coordinate transforms, and many other functions.

exoTEDRF (Exoplanet Transit and Eclipse Data Reduction Framework) reduces and analyzes JWST exoplanet time series observations. The code is modular and tunable, which makes it easy to run multiple reductions of a given dataset, and therefore ascertain whether the spectral features driving atmosphere inferences are robust or are sensitive to the peculiarities of a given reduction. exoTEDRF has full support for TSOs with NIRISS/SOSS and can run the ATOCA extraction algorithm to explicitly model the SOSS order overlap.

DIES calculates equilibrium dust temperatures and the resulting dust emission spectra. It handles spherical models (cells are spherical shells), computes dust temperatures (equilibrium temperatures only), and returns spectra for different impact parameters. The code uses the immediate re-emission method; it is not suitable for problems where the stochastic heating of the grains is important. DIES can assume constant dust properties throughout the model, and also offers an alternative script that allows dust properties to be set cell by cell. The program uses OpenCL libraries and is recommended to be run on GPUs.

CosmoFlow automatically computes cosmological correlators. The Cosmological Flow approach is based on computing cosmological correlators by solving differential equations in time governing their time evolution through the entirety of the spacetime during inflation, from their origin as quantum fluctuations in the deep past to the end of inflation. This method takes into account all physical effects at tree-level without approximation. Specifically, CosmoFlow computes the two- and three-point correlators of fields and/or conjugate momenta X a in Fourier space that includes an arbitrary number of degrees of freedom with any propagation speeds, couplings, and time-dependencies.

Spectuner identifies spectral lines of interstellar molecules automatically. The code uses XCLASS (ascl:1810.016) for the spectral line model and SciPy for the peak finder. Spectral fitting is performed using article swarm optimization and the peak matching loss function. From frequency in a unit of MHz and temperature in a unit of K, Spectuner returns the combined spectrum, identification of the combined spectrum, and the identification of all candidates.

Siril reduces reduction and improves the signal/noise ratio of an image from multiple captures. It can can align automatically or manually, and stack and enhance pictures from various file formats, even image sequence files (films and SER files). Its Graphical User Interface (GUI) allows manual processing of images in addition to scripts or typing commands. Siril provides astrometry and photometry options and performs geometric transformations in addition to many other tools.

The Payne precisely and simultaneously determines numerous stellar labels from observed spectra based on fitting physical spectral models. It fits all all labels (stellar parameters and element abundances) simultaneously, and uses spectral models where the atmosphere structure and the radiative transport are consistently calculated to reflect the stellar labels. The Payne leads to both precise and accurate estimates of stellar labels, based on physical models and without re-calibration.

WD_models transforms white dwarf (WD) photometry to physical parameters (i.e., mass, cooling age, and Teff) and vice versa, based on interpolation of existing WD atmosphere grid and cooling models. The code converts the coordinates of Gaia (and other passbands) H--R diagram into WD parameters and plots contours of WD parameters on the Gaia (and other passbands) H--R diagram. WD_models also provides tools to transform any desired WD parameters and compare the results of different WD models. In addition, the user may customize many parameters, such as the choice of cooling models and setting details of plotting.

Particle_spray models the position and velocity distributions of newly-escaped stream particles that emerge from globular clusters (GCs). Rather than computing the detailed internal cluster dynamics, which is computationally expensive, the code directly draws tracer particles from these distributions. This algorithm is fast and accurate, and is implemented in a series of notebooks for several galactic dynamics codes, including AGAMA (ascl:1805.008) and galpy (ascl:1411.008).

gwforge generates mock gravitational wave detector data using user-defined population and arbitrary detector sensitivity. The code can, for example, simulate a wide range of binary source populations by specifying parameters such as the local merger rate, distribution functions, and additional keyword arguments, and simulate coloured Gaussian or zero noise using a provided or default power spectrum to represent the detector noise. gwforge can also inject gravitational wave signal(s) into the generated detector data using the previously generated population and a chosen waveform model.

FitTeD solves time-dependent general relativistic disc equations to fit multi-band light curves and spectra. It includes relativistic optics effects such as Doppler and gravitational energy shifting, and gravitational lensing, and can include non-disc light curve and spectral components to, for example, model the early time rise and decay of tidal disruption event light curves in optical-to-UV bands. FitTeD also provides Monte Carlo Markov Chain fitting procedures that return posterior distributions of black hole and disc parameters.

Combustion Toolbox (CT) models thermodynamic properties of the gaseous species with the ideal gas equation of state (EoS). Written in MATLAB, this thermochemical code is modular and has three main modules: CT-EQUIL, CT-SD, and CT-ROCKET. CT-EQUIL computes the composition at the equilibrium of multi-component gas mixtures that undergo canonical thermochemical transformations from an initial state (reactants). CT-SD solves steady-state shock and detonation waves in either normal or oblique incidence, and CT-ROCKET computes the theoretical performance of rocket engines under highly idealized conditions. Modules can be accessed through user-friendly GUI or from MATLAB’s command line in plain code mode.

BlendingToolKit (BTK) generates images of blended objects and evaluate performance metrics on various detection, deblending and measurement algorithms. The toolkit is a convenient way to produce multi-band postage stamp images of blend scenes and evaluate the performance of deblending algorithms, as well as train samples for machine learning algorithms.

ForestFlow emulates the linear biases and small-scale deviation parameters of the 3D flux power spectrum of the Lyman-alpha forest. The parameters are modeled as a function of cosmology – the small-scale amplitude and slope of the linear power spectrum – and the physics of the intergalactic medium.

cogsworth merges rapid population synthesis and galactic dynamics together; the code can evolve a population of stars using population synthesis while self-consistently integrating their orbits with a chosen galactic potential. This enables exploration of the full evolutionary history (both stellar and orbital) of a population of stars and the ability to make predictions for present day kinematics and other distributions. cogsworth also provides tools for transforming the intrinsic populations into observables and for classifying the nature of each system.

CLOWN (CLOud Watcher at Night) detects and monitors clouds in real time. The software can be used with any type of all-sky camera even without knowing its parameters; parameters are stored instead in a configuration file. CLOWN correctly traces cloud positions in the sky and provides accurate pointing information to the observation planning of the optical telescope to avoid cloudy areas.

squishyplanet produces realistic lightcurves and phase curves of non-spherical exoplanets. The code generates models of triaxial planets; fitting for the triaxial shape can provide additional constraints on the planet’s interior properties and evolution. squishyplanet also handles complex limb darkening profiles while also accounting for the planet’s non-circular, potentially time-varying, projected shape.

The euclidlib python package is an unofficial tool designed to read products from the Euclid Consortium Science Ground Segment. Euclidlib offers user-friendly reading and writing routines, and effectively enables to work overall with Large-Scale Structure cosmological products.

The visualization tool MARDIGRAS (Mass-Radius DIaGRAm with Sliders) enables simple and intuitive manipulation of mass-radius relationships (also known as iso-composition curves) using interactive sliders. It infers composition based on mass and radius (and other parameters). As a result, it requires use of actual measurements of mass and radius; values that are upper/lower limits, derived from empirical mass-radius relations, or are somewhat controversial should not be used. MARDIGRAS screen captures can be used for general scientific communication but are not of suitable quality for article publication.

Mister plotter (mr-plotter) creates paper-quality mass-radius diagrams based on a wide range of state-of-the-art models of planetary interiors and atmospheres. It can be used to contextualize planets and infer their possible internal structures. It can also be used to search for correlations at a population level with its color-coding option based on any property collected in the NASA Exoplanet Archive, PlanetS, and Exoplanet.eu catalogs. mr-plotter can also produce article-ready two-column plots.

POSEIDON models and retrieves 1D, 2D, and 3D exoplanet transmission spectra. Given a set of observed exoplanet spectra from space-based or ground-based telescopes, the code uses Bayesian techniques to infer the atmospheric properties of the planet. POSEIDON also includes disk-integrated thermal emission and reflection spectra modeling and retrievals for both secondary eclipses and directly-imaged substellar objects.

lintsampler performs linear interpolant sampling to create a set of sample points from a density function. The code uses the evaluation of the density at the two endpoints of 1D interval, or the four corners of a 2D rectangle, or generally the 2^k vertices of a dimensional hyperbox (or a series of such hyperboxes, e.g., the cells of a k-dimensional grid) to draw random samples within the hyperbox. lintsampler works by evaluating a given PDF on the nodes of a grid (or grid-like structure, such as a tree); the number of evaluations (and memory occupancy) grows exponentially with the number of dimensions.

γ-Cascade (also called GCascade) uses a semi-analytic approach to model gamma-ray propagation through cosmological distances accounting for attenuation, the formation of electromagnetic cascades,and cosmological redshifting. V4 implements an assortment of the most widely used EBL models, significantly improves computational precision, and provides new core functionality. Additionally, GCascadeV4 uses a new method to estimate the uncertainty due to the EBL model.

easyspec is a tool designed to streamline long-slit spectroscopy, offering an intuitive framework for reducing, extracting, and analyzing astrophysical spectra.