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[ascl:2309.020] PlanetSlicer: Orange-slice algorithm for fitting brightness maps to phase curves

PlanetSlicer fits brightness maps to phase curves using the "orange-slice" method and works both for self-luminous objects and those that diffuse reflected light assuming Lambertian reflectance. In both cases, the model supposes that a spherical object can be divided into slices of constant brightness (or albedo) which may be integrated to yield the total flux observed, given the angles of observation. The package contains two key functions: toPhaseCurve and fromPhaseCurve; the former integrates the brightness for each slice to calculate the observed total flux from the object, given the longitude of observation. The latter does the opposite, estimating the brightness of the slices from a set of observed total flux (the phase curve).

[ascl:2309.019] FRISBHEE: FRIedmann Solver for Black Hole Evaporation in the Early-universe

FRISBHEE (FRIedmann Solver for Black Hole Evaporation in the Early-universe solves the Friedmann - Boltzmann equations for Primordial Black Holes + SM radiation + BSM Models. Considering the collapse of density fluctuations as the PBH formation mechanism, the code handles monochromatic and extended mass and spin distributions. FRISBHEE can return the full evolution of the PBH, SM and Dark Radiation comoving energy densities, together with the evolution of the PBH mass and spin as a function of the log10 at scale factor, and can determine the relic abundance in the case of Dark Matter produced from BH evaporation for monochromatic and extended distributions.

[ascl:2309.018] Sprout: Moving mesh finite volume hydro code

The finite volume hydro code Sprout uses a simple expanding Cartesian grid to track outflows for several orders of magnitudes in expansion. It captures shocks whether they are aligned or misaligned with the grid, and provides second-order convergence for smooth flows. The code's expanding mesh capability reduces numerical diffusion drastically for outflows, especially when the analytic nature of the bulk flow is known beforehand. Sprout can be used to study fluid instabilities in expanding flows, such as in SN explosions and jets; it resolves fine fluid structures at small length scales and expand the mesh gradually as the structures grow.

[ascl:2309.017] ChEAP: Chemical Evolution Analytic Package

ChEAP (Chemical Evolution Analytic Package) implements an analytic solution for the chemical evolution model of the Galaxy that extends the instantaneous recycling approximation with the contribution of Type Ia SNe. The code works for different prescriptions of the delay time distributions (DTDs), including the single and double degenerate scenarios, and allows the inclusion of an arbitrary number of pristine gas infalls. The required functions are contained in the CheapTools.py file, which is imported as a Python library. ChEAP also includes code to illustrate, with a random-parameter chemical evolution model, the accuracy of this analytic solution compared to one using numerical integration.

[ascl:2309.016] PEREGRINE: Gravitational wave parameter inference with neural ration estimation

PEREGRINE performs full parameter estimation on gravitational wave signals. Using an internal Truncated Marginal Neural Ratio Estimation (TMNRE) algorithm and building upon the swyft (ascl:2302.016) code to efficiently access marginal posteriors, PEREGRINE conducts a sequential simulation-based inference approach to support the analysis of both transient and continuous gravitational wave sources. The code can fully reconstruct the posterior distributions for all parameters of spinning, precessing compact binary mergers using waveform approximants.

[ascl:2309.015] bskit: Bispectra from cosmological simulation snapshots

bskit, built upon the nbodykit (ascl:1904.027) simulation analysis package, measures density bispectra from snapshots of cosmological N-body or hydrodynamical simulations. It can measure auto or cross bispectra in a user-specified set of triangle bins (that is, triplets of 3-vector wavenumbers). Several common sets of bins are also implemented, including all triangle bins for specified k_min and k_max, equilateral triangles between specified k_min and k_max, isosceles triangles, and squeezed isosceles triangles.

[ascl:2309.014] fitScalingRelation: Fit galaxy cluster scaling relations using MCMC

fitScalingRelation fits galaxy cluster scaling relations using orthogonal or bisector regression and MCMC. It takes into account errors on both variables and intrinsic scatter. Although it geared for fitting galaxy cluster scaling relations of all kinds, it can be used for any kind of regression problem with errors on both variables and intrinsic scatter.

[ascl:2309.013] maszcal: Mass calibrations for thermal-SZ clusters

maszcal calibrates the observable-mass relation for galaxy clusters, with a focus on the thermal Sunyaev-Zeldovich signal's relation to mass. maszcal explicitly models baryonic matter density profiles, differing from most previous approaches that treat galaxy clusters as purely dark matter. To do this, it uses a generalized Nararro-Frenk-White (GNFW) density to represent the baryons, while using the more typical NFW profile to represent dark matter.

[ascl:2309.012] StarbugII: JWST PSF photometry for crowded fields

The python photometry suite StarbugII provides accurate photometry on point-like sources embedded in complex diffuse emissions. The tool has a simple modular interface with a wide range of photometric routines including embedded source detection, aperture and PSF photometry, diffuse background emission estimation, catalog matching and artificial star testing. The core is built around Photutils (ascl:1609.011).

[ascl:2309.011] PCOSTPD: Periodogram Comparison for Optimizing Small Transiting Planet Detection

The Periodogram Comparison for Optimizing Small Transiting Planet Detection R code compares two periodogram algorithms for detecting transiting exoplanets: the Box-fitting Least Squares (BLS) and the Transit Comb Filter (TCF). It calculates the False Alarm Probability (FAP) based on extreme value theory and signal-to-noise ratio (SNR) metrics to quantify periodogram peak significance. The comparison approach is aimed at optimizing the detection of small transiting planets in future transiting exoplanet surveys. The code can be extended for comparing any set of periodograms.

[ascl:2309.010] pymccorrelation: Correlation coefficients with uncertainties

pymccorrelation calculates correlation coefficients for data, using bootstrapping and/or perturbation to estimate the uncertainties on the correlation coefficient and p-value. The code supports Pearson's r, Spearman's rho, and Kendall's tau. Calculations of Kendall's tau additionally support censored data. This code supercedes and expands the deprecated code pymcspearman (ascl:2309.009).

[ascl:2309.009] pymcspearman: Monte carlo calculation of Spearman's rank correlation coefficient with uncertainties

pymcspearman is a python implementation of MCSpearman (ascl:1504.008) and calculates Spearman's rank correlation coefficient for data, using bootstrapping and/or perturbation to estimate the uncertainties on the correlation coefficient. This software project has migrated (and expanded) to pymccorrelation (ascl:2309.010).

[submitted] INSPECTA: INtegrated SDHDF Processing Engine in C for Telescope data Analysis

INSPECTA (formerly sdhdfProc) is a software package to read, manipulate and process radio astronomy data in Spectral-Domain Hierarchical Data Format (SDHDF). It is available as part of the 'sdhdf_tools' repository.

[submitted] A pseudo GUI with pyplot

Working with a GUI, or adding interaction in plotting, will help a lot in data analysis. However, the common GUI of Python is OS-dependent, while manually adding interactive codes is too complex. A pseudo-GUI tool is introduced in this work. It will help to add buttons/checkers in the graph and assign callback functions to them. The remaining problem is that the documents in this package are in Chinese and will be in English in the next version. This program is published to the PyPI, and can be installed by 'pip install pltgui'.

[submitted] qmatch: Some astronomical image matching programs

Matching stars in astronomical images is an essential step in data reduction. This work includes some matching programs implemented by Python: simple matching, fast matching, and triangle matching. For two catalogs with m and n objects, the simple method has a time and space complexity of O(m*n) but is fast for fewer n or m. The time complexity of the fast method is O(mlogm+nlogn). The triangle method will work between rotated and scaled images. All methods are applied in pipelines and work well. This package is published to the PyPI with the name 'qmatch'.

[submitted] LOFAR H5plot

Calibration solutions for the LOFAR radio telescope are stored in a 5-dimensional (time, frequency, station, polarisation and direction in the sky) HDF5 table. H5plot is a GUI application focussing on interactive visual inspection of these calibration solutions.

[ascl:2309.008] PI: Plages Identification

Plages Identification identifies solar plages from Ca II K photographic observations irrespective of noise level, brightness, and other image properties. The code provides an efficient, reliable method for identifying solar plages. The output of the algorithm is an image highlighting the plages and the calculated plage index. Plages Identification is also deployed as a webapp, allowing users to experiment with different hyperparameters and visualize their impact on the output image in real time.

[ascl:2309.007] MATRIX: Multi-phAse Transits Recovery from Injected eXoplanets toolkit

The injection-recovery MATRIX (Multi-phAse Transits Recovery from Injected eXoplanets) Toolkit creates grids of scenarios with a set of periods, radii, and epochs of synthetic transiting exoplanet signals in a provided light curve. Typical injection-recovery executions consist of 2-dimensional scenarios, where only one epoch (random or hardcoded) was used for each period and radius, which may reduce accuracy. MATRIX performs multi-phase analyses needing only a few parameters in a configuration file and running one line of code.

[ascl:2309.006] CoLFI: Cosmological Likelihood-Free Inference

CoLFI (Cosmological Likelihood-Free Inference) estimates parameters directly from the observational data sets using neural density estimators (NDEs); it is a fully ANN-based framework that differs from the Bayesian inference. The package contains three NDEs that are used to estimate parameters: an artificial neural network (ANN), a mixture density network (MDN), and a mixture neural network (MNN). CoLFI can learn the conditional probability density using samples generated by models, and the posterior distribution can be obtained for given observational data.

[ascl:2309.005] DeepGlow: Neural network emulator for BOXFIT

The feed-forward neural network DeepGlow emulates BOXFIT (ascl:2306.059) simulation data of gamma-ray burst (GRB) afterglows. The package provides an easy interface to generate GRB afterglow spectra and light curves mimicking those generated through BOXFIT with high accuracy. The code used to generate the training data and to train the neural networks is also included.

[ascl:2309.004] GWSim: Mock gravitational waves event generator

GWSim generates mock gravitational waves (GW) events corresponding to different binary black holes (BBHs) population models. It can incorporate scenarios of GW mass models, GW spin distributions, the merger rate, and the cosmological parameters. GWSim generates samples of binary compact objects for a fixed amount of observation time, duty cycle, and configurations of the detector network; the universe created by the code is uniform in comobile volume.

[ascl:2309.003] Swiftbat: Utilities for handing BAT instrument data from the Neil Gehrels Swift Observatory

Swiftbat retrieves, analyzes, and displays data from NASA's Swift spacecraft, especially data from the Swift Burst Alert Telescope (BAT). All BAT data are available from the Swift data archive; however, a few routines in this library use data access methods not available to the general public and thus are useful only to Swift team members. The package also installs a command-line program 'swinfo' that provides Swift Information such as what the MET (onboard-clock) time is, where Swift was pointing, and whether a specific source was above the horizon and/or in the field of view.

[ascl:2309.002] UBHM: Uncertainty quantification of black hole mass estimation

Uncertain_blackholemass predicts virial black hole masses using a neural network model and quantifies their uncertainties. The scripts retrieve data and run feature extraction and uncertainty quantification for regression. They can be used separately or deployed to existing machine learning methods to generate prediction intervals for the black hole mass predictions.

[ascl:2309.001] TRES: TRiple Evolution Simulation package

TRES simulates hierarchical triple systems with stellar and planetary components, including stellar evolution, stellar winds, tides, general relativistic effects, mass transfer, and three-body dynamics. It combines stellar evolution and interactions with three-body dynamics in a self-consistent way. The code includes the effects of common-envelope evolution, circularized stable mass transfer, tides, gravitational wave emission and up-to-date stellar evolution through SeBa (ascl:1201.003). Other stellar evolution codes, such as SSE (ascl:1303.015), can also be used. TRES is written in the AMUSE (ascl:1107.007) software framework.

[ascl:2308.015] FishLSS: Fisher forecasting for Large Scale Structure surveys

FishLSS computes the Fisher information matrix for a set of observables and model parameters. It can model the redshift-space power spectrum of any biased tracer of the CDM+baryon field and the post-reconstruction galaxy power spectrum. The code also models the projected cross-correlation of galaxies with the CMB lensing convergence, the projected galaxy power spectrum, and the CMB lensing convergence power spectrum. FishLSS requires pyFFTW (ascl:2109.009), velocileptors (ascl:2308.014), and CLASS (ascl:1106.020).

[ascl:2308.014] velocileptors: Velocity-based Lagrangian and Eulerian PT expansions of redshift-space distortions

velocileptors computes the real- and redshift-space power spectra and correlation functions of biased tracers using 1-loop perturbation theory (with effective field theory counter terms and up to cubic biasing) as well as the real-space pairwise velocity moments. It provides simple computation of the power spectrum wedges or multipoles, and uses a reduced set of parameters for computing the most common case of the redshift-space power spectrum. In addition, velocileptors offers two "direct expansion" modules available in LPT and EPT.

[ascl:2308.013] Driftscan: Drift scan telescope analysis

Driftscan simulates and analyzes transit radio interferometers, with a particular focus on 21cm cosmology. Given a design of a telescope, it generates a set of products used to analyze data from it and simulate timestreams. Driftscan also constructs a filter to extract cosmological 21 cm emission from astrophysical foregrounds, such as our galaxy and radio point sources, and estimates the 21cm power spectrum using an optimal quadratic estimator.

[ascl:2308.012] KeplerFit: Keplerian velocity distribution model fitter

KeplerFit fits a Keplerian velocity distribution model to position-velocity (PV) data to obtain an estimate of the enclosed mass. The code extracts the scales of the pixels in both directions, spatial and spectral, then extracts the most extreme velocity at each position; this returns two arrays of positions and velocities. KeplerFit then models the extracted PV data and returns a set of the best-fit parameters, the standard deviations in each of the parameters, and the total residual of the fit.

[ascl:2308.011] glmnet: Lasso and elastic-net regularized generalized linear models

glmnet efficiently fits the entire lasso or elastic-net regularization path for linear regression (gaussian), multi-task gaussian, logistic and multinomial regression models (grouped or not), Poisson regression and the Cox model. The algorithm uses cyclical coordinate descent in a path-wise fashion.

[ascl:2308.010] BCemu: Model baryonic effects in cosmological simulations

BCMemu provides emulators to model the suppression in the power spectrum due to baryonic feedback processes. These emulators are based on the baryonification model, where gravity-only N-body simulation results are manipulated to include the impact of baryonic feedback processes. The package also has a three parameter barynification model; the first assumes all the three parameters to be independent of redshift while the second assumes the parameters to be redshift dependent.

[ascl:2308.009] caput: Utilities for building radio astronomy data analysis pipelines

Caput (Cluster Astronomical Python Utilities) contains utilities for handling large datasets on computer clusters. Written with radio astronomy in mind, the package provides an infrastructure for building, managing and configuring pipelines for data processing. It includes modules for dynamically importing and utilizing mpi4py, in-memory mock-ups of h5py objects, and infrastructure for running data analysis pipelines on computer clusters. Caput features a generic container for holding self-documenting datasets in memory with straightforward syncing to h5py files, and offers specialization for holding time stream data. Caput also includes tools for MPI-parallel analysis and routines for converting between different time representations, dealing with leap seconds, and calculating celestial times.

[ascl:2308.008] Rapster: Rapid population synthesis for binary black hole mergers in dynamical environments

Rapster (RAPid cluSTER evolution) models binary black hole population synthesis and the evolution of star clusters based on simple, yet realistic prescriptions. The code can generate large populations of dynamically formed binary black holes. Rapster uses SEVN (ascl:2206.019) to model the initial black hole mass spectrum and PRECESSION (ascl:1611.004) to model the mass, spin, and gravitational recoil of merger remnants.

[ascl:2308.007] DiskMINT: Disk Model For INdividual Targets

DiskMINT (Disk Model for INdividual Targets) models individual disks and derives robust disk mass estimates. Built on RADMC-3D (ascl:1202.015) for continuum (and gas line) radiative transfer, the code includes a reduced chemical network to determine the C18O emission. DiskMINT has a Python3 module that generates a self-consistent 2D disk structure to satisfy VHSE (Vertical Hydrostatic Equilibrium). It also contains a Fortran code of the reduced chemical network that contains the main chemical processes necessary for C18O modeling: the isotopologue-selective photodissociation, and the grain-surface chemistry where the CO converting to CO2 ice is the main reaction.

[ascl:2308.006] Nemo: Millimeter-wave map filtering and Sunyaev-Zel'dovich galaxy cluster and source detection

Nemo detects millimeter-wave Sunyaev-Zel'dovich galaxy clusters and compact sources. Originally developed for the Atacama Cosmology Telescope project, the code is capable of analyzing the next generation of deep, wide multifrequency millimeter-wave maps that will be produced by experiments such as the Simons Observatory. Nemo provides several modules for analyzing ACT/SO data in addition to the command-line programs provided in the package.

[ascl:2308.005] FastSpecFit: Fast spectral synthesis and emission-line fitting of DESI spectra

FastSpecFit models the observed-frame optical spectroscopy and broadband photometry of extragalactic targets using physically grounded stellar continuum and emission-line templates. The code handles data from the Dark Energy Spectroscopic Instrument (DESI) Survey, which is amassing spectrophotometry for an unprecedented 40 million extragalactic targets, although the algorithms are general enough to accommodate other upcoming, massively multiplexed spectroscopic surveys. FastSpecFit extracts nearly 800 observed- and rest-frame quantities from each target, including light-weighted ages and stellar velocity dispersions based on the underlying stellar continuum; line-widths, velocity shifts, integrated fluxes, and equivalent widths for nearly 40 rest-frame ultraviolet, optical, and near-infrared emission lines arising from both star formation and active galactic nuclear activity; and K-corrections and rest-frame absolute magnitudes and colors. Moreover, FastSpecFit is designed with speed and parallelism in mind, enabling it to deliver robust model fits to tens of millions of targets.

[ascl:2308.004] AstroPhot: Fitting everything everywhere all at once in astronomical images

AstroPhot quickly extracts detailed information from complex astronomical data for individual images or large survey programs. It fits models for sky, stars, galaxies, PSFs, and more in a principled chi^2 forward optimization, recovering Bayesian posterior information and covariance of all parameters. The code optimizes forward models on CPU or GPU, across images that are large, multi-band, multi-epoch, rotated, dithered, and more. Models are optimized together, thus handling overlapping objects and including the covariance between parameters (including PSF and galaxy parameters). AstroPhot includes several optimization algorithms, including Levenberg-Marquardt, Gradient descent, and No-U-Turn MCMC sampling.

[ascl:2308.003] SIMBI: 3D relativistic gas dynamics code

SIMBI simulates heterogeneous relativistic gas dynamics up to 3d for special relativistic hydrodynamics and up to 2D Newtonian hydrodynamics. It supports user-defined mesh expansion and contraction, density, momentum, and energy density terms outside of grid; the code also supports source terms in the Euler equations and source terms at the boundaries. Boundary conditions, which include periodic, reflecting, outflow, and inflow boundaries, are given as an array of strings. If an inflow boundary condition is set but no inflow boundary source terms are given, SIMBI switches to outflow boundary conditions to prevent crashes. The code can track a single passive scalar, insert an immersed boundary, and is impermeable by default. SIMBI USES the Cython framework to blend together C++, CUDA, HIP, and Python.

[ascl:2308.002] FLATW'RM: Finding flares in Kepler data using machine-learning tools

FLATW'RM (FLAre deTection With Ransac Method) detects stellar flares in light curves using a classical machine-learning method. The code tries to find a rotation period in the light curve and splits the data to detection windows. The light curve sections are fit with the robust fitting algorithm RANSAC (Random sample consensus); outlier points (flare candidates) above the pre-set detection level are marked for each section. For the given detection window, only those flare candidates that have at least a given number of consecutive points (three by default) are kept and marked as flares. When using FLATW’RM, the code's output should be checked to determine whether changes to the default settings are needed to account for light curve noise, data sampling frequency, and scientific needs.

[ascl:2308.001] MOOG_SCAT: Scattering version of the MOOG Line Transfer Code

MOOG_SCAT, a redevelopment of the LTE radiative transfer code MOOG (ascl:1202.009), contains modifications that allow for the treatment of isotropic, coherent scattering in stars. MOOG_SCAT employs a modified form of the source function and solves radiative transfer with a short charactersitics approach and an acclerated lambda iteration scheme.

[ascl:2307.062] FABADA: Non-parametric noise reduction using Bayesian inference

FABADA (Fully Adaptive Bayesian Algorithm for Data Analysis) performs non-parametric noise reduction using Bayesian inference. It iteratively evaluates possible smoothed models of the data to estimate the underlying signal that is statistically compatible with the noisy measurements. Iterations stop based on the evidence E and the χ2 statistic of the last smooth model, and the expected value of the signal is computed as a weighted average of the smooth models. Though FABADA was written for astronomical data, such as spectra (1D) or images (2D), it can be used as a general noise reduction algorithm for any one- or two-dimensional data; the only requisite of the input data is an estimation of its associated variance.

[ascl:2307.061] connect: COsmological Neural Network Emulator of CLASS using TensorFlow

connect (COsmological Neural Network Emulator of CLASS using TensorFlow) emulates cosmological parameters using neural networks. This includes both sampling of training data and training of the actual networks using the TensorFlow library. connect aids in cosmological parameter inference by immensely speeding up the process, which is achieved by substituting the cosmological Einstein-Boltzmann solver codes, needed for every evaluation of the likelihood, with a neural network with a 102 to 103 times faster evaluation time. The code requires CLASS (ascl:1106.020) and Monte Python (ascl:1307.002) if iterative sampling is used.

[ascl:2307.060] MBASC: Multi-Band AGN-SFG Classifier

MBASC (Multi-Band AGN-SFG Classifier) classifies sources as Active Galactic Nuclei (AGNs) and Star Forming Galaxies (SFGs). The algorithm is based on the light gradient-boosting machine ML technique. MBASC can use a wide range of multi-wavelength data and redshifts to predict a classification for sources.

[ascl:2307.059] orbitN: Symplectic integrator for near-Keplerian planetary systems

orbitN generates accurate and reproducible long-term orbital solutions for near-Keplerian planetary systems with a dominant mass M0. The code focuses on hierarchical systems without close encounters but can be extended to include additional features. Among other features, the package includes M0's quadrupole moment, a lunar contribution, and post-Newtonian corrections (1PN) due to M0 (fast symplectic implementation). To reduce numerical roundoff errors, orbitN features Kahan compensated summation.

[ascl:2307.058] APOLLO: Radiative transfer and atmosphere spectroscopic retrieval for exoplanets

APOLLO forward models the radiative transfer of light through a planetary (or brown dwarf) atmosphere; it also forward models transit and emission spectra and retrieves atmospheric properties of extrasolar planets. The code has two operational modes: one to compute a planetary spectrum given a set of parameters, and one to retrieve those parameters based on an observed spectrum. The package uses emcee (ascl:1303.002) to find the best fit to a spectrum for a given parameter set. APOLLO is modular and offers many options that may be turned on and off, including the type of observations, a flexible molecular composition, multiple cloud prescriptions, multiple temperature-pressure profile prescriptions, multiple priors, and continuum normalization.

[ascl:2307.057] species: Atmospheric characterization of directly imaged exoplanets

species (spectral characterization and inference for exoplanet science) provides a coherent framework for spectral and photometric analysis of directly imaged exoplanets and brown dwarfs which builds on publicly-available data and models from various resources. species contains tools for grid and free retrievals using Bayesian inference, synthetic photometry, interpolating a variety atmospheric and evolutionary model grids (including the possibility to add a custom grid), color-magnitude and color-color diagrams, empirical spectral analysis, spectral and photometric calibration, and analysis of emission lines.

[ascl:2307.056] HELA: Random Forest retrieval for exoplanet atmospheres

HELA performs atmospheric retrieval on exoplanet atmospheres using a Random Forest algorithm. The code has two stages: training (which includes testing), and predicting. It requires a training set that matches the format of the data to be analyzed, with the same number of points and a sample spectrum for each parameter. The number of trees used and the number of jobs are editable. The HELA package includes a training set and data as examples.

[ascl:2307.055] plan-net: Bayesian neural networks for exoplanetary atmospheric retrieval

plan-net uses machine learning with an ensemble of Bayesian neural networks for atmospheric retrieval; this approach yields greater accuracy and more robust uncertainties than a single model. A new loss function for BNNs learns correlations between the model outputs. Performance is improved by incorporating domain-specific knowledge into the machine learning models and provides additional insight by inferring the covariance of the retrieved atmospheric parameters.

[ascl:2307.054] LEFTfield: Forward modeling of cosmological density fields

LEFTfield forward models cosmological matter density fields and biased tracers of large-scale structure. The model, written in C++ code, is centered around classes encapsulating scalar, vector, and tensor grids. It includes the complete bias expansion at any order in perturbations and captures general expansion histories without relying on the EdS approximation; however, the latter is also implemented and results in substantially smaller computational demands. LEFTfield includes a subset of the nonlinear higher-derivative terms in the bias expansion of general tracers.

[submitted] backtrack: fit relative motion of candidate direct imaging sources with background proper motion and parallax

Directly imaged planet candidates (high contrast point sources near bright stars) are often validated, among other supporting lines of evidence, by comparing their observed motion against the projected motion of a background source due to the proper motion of the bright star and the parallax motion due to the Earth's orbit. Often, the "background track" is constructed assuming an interloping point source is at infinity and has no proper motion itself, but this assumption can fail, producing false positive results, for crowded fields or insufficient observing time-baselines (e.g. Nielsen et al. 2017). `backtrack` is a tool for constructing background proper motion and parallax tracks for validation of high contrast candidates. It can produce classical infinite distance, stationary background tracks, but was constructed in order to fit finite distance, non-stationary tracks using nested sampling (and can be used on clusters). The code sets priors on parallax based on the relations in Bailer-Jones et al. 2021 that are fit to Gaia eDR3 data, and are therefore representative of the galactic stellar density. The public example currently reproduces the results of Nielsen et al. 2017 and Wagner et al. 2022, demonstrating that the motion of HD 131399A "b" is fit by a finite distance, non-stationary background star, but the code has been tested and validated on proprietary datasets. The code is open source, available on github, and additional contributions are welcome.

[ascl:2307.053] EVolve: Growth and evolution of volcanically-derived atmospheres

EVolve calculates the chemical composition and surface pressure of a ID atmosphere on a rocky planet that is being produced by volcanic activity, as it grows over time. Once the initial volatile content of the planet's mantle and the composition and resultant surface pressure of any pre-existing atmosphere is set, the volcanic degassing model EVo (ascl:2307.052) calculates the amount and speciation of any volcanic gases released into the atmosphere over each time step. Atmospheric processing is calculated using FastChem (ascl:1804.025); thermochemical equilibrium is assumed so the final chemical composition of the atmosphere is calculated according to the pre-set surface temperature.

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