Results 1401-1450 of 2351 (2312 ASCL, 39 submitted)

[ascl:1802.007]
HiGal_SED_Fitter: SED fitting tools for Herschel Hi-Gal data

HiGal SED Fitter fits modified blackbody SEDs to Herschel data, specifically targeted at Herschel Hi-Gal data.

[ascl:2005.008]
HiFLEx: Echelle data reduction pipeline

Errmann, Ronny; Cook, Neil; Anglada-Escudé, Guillem; Sithajan, Sirinrat; Mkrtichian, David; Semenko, Eugene; Martin, William; Tanvir, Tabassum S.; Feng, Fabo; Collett, James L.; Jones, Hugh R. A.

HiFLEx reduces echelle data taken with a single or bifurcated fiber input. It takes a FITS image file (*i.e.*, a CCD image) and runs data reduction steps, extracts out orders from an Echelle spectrograph (regardless of separation and curvature, as long as orders are distinguishable from one-another), applies the wavelength correction, measures the radial velocity, and performs further calibration steps.

[ascl:2007.002]
hierArc: Hierarchical analysis of strong gravitational lenses

hierArc hierarchically infers strong lensing mass density profiles and the cosmological parameters, in particular the Hubble constant. The software supports lenses with imaging data and kinematics, and optionally time delays. The kinematics modeling is performed in conjunction with lenstronomy (ascl:1804.012).

[ascl:1607.019]
HIDE: HI Data Emulator

Akeret, Joel; Seehars, Sebastian; Chang, Chihway; Monstein, Christian; Amara, Adam; Refregier, Alexandre

HIDE (HI Data Emulator) forward-models the process of collecting astronomical radio signals in a single dish radio telescope instrument and outputs pixel-level time-ordered-data. Written in Python, HIDE models the noise and RFI modeling of the data and with its companion code SEEK (ascl:1607.020) provides end-to-end simulation and processing of radio survey data.

[ascl:1606.004]
HIBAYES: Global 21-cm Bayesian Monte-Carlo Model Fitting

HIBAYES implements fully-Bayesian extraction of the sky-averaged (global) 21-cm signal from the Cosmic Dawn and Epoch of Reionization in the presence of foreground emission. User-defined likelihood and prior functions are called by the sampler PyMultiNest (ascl:1606.005) in order to jointly explore the full (signal plus foreground) posterior probability distribution and evaluate the Bayesian evidence for a given model. Implemented models, for simulation and fitting, include gaussians (HI signal) and polynomials (foregrounds). Some simple plotting and analysis tools are supplied. The code can be extended to other models (physical or empirical), to incorporate data from other experiments, or to use alternative Monte-Carlo sampling engines as required.

[ascl:1808.010]
hi_class: Horndeski in the Cosmic Linear Anisotropy Solving System

hi_class implements Horndeski's theory of gravity in the modern Cosmic Linear Anisotropy Solving System (ascl:1106.020). It can be used to compute any cosmological observable at the level of background or linear perturbations, such as cosmological distances, cosmic microwave background, matter power and number count spectra (including relativistic effects). hi_class can be readily interfaced with Monte Python (ascl:1307.002) to test Gravity and Dark Energy models.

[submitted]
HHTpywrapper: Python Wrapper for Hilbert–Huang Transform MATLAB Package

HHTpywrapper is a python interface to call the Hilbert–Huang Transform (HHT) MATLAB package. HHT is a time-frequency analysis method to adaptively decompose a signal, that could be generated by non-stationary and/or nonlinear processes, into basis components at different timescales, and then Hilbert transform these components into instantaneous phases, frequencies and amplitudes as functions of time. HHT has been successfully applied to analyzing X-ray quasi-periodic oscillations (QPOs) from the active galactic nucleus RE J1034+396 (Hu et al. 2014) and two black hole X-ray binaries, XTE J1550–564 (Su et al. 2015) and GX 339-4 (Su et al. 2017). HHTpywrapper provides examples of reproducing HHT analysis results in Su et al. (2015) and Su et al. (2017). This project is originated from the Astro Hack Week 2015.

[ascl:1801.004]
hh0: Hierarchical Hubble Constant Inference

hh0 is a Bayesian hierarchical model (BHM) that describes the full distance ladder, from nearby geometric-distance anchors through Cepheids to SNe in the Hubble flow. It does not rely on any of the underlying distributions being Gaussian, allowing outliers to be modeled and obviating the need for any arbitrary data cuts.

[ascl:1607.011]
HfS: Hyperfine Structure fitting tool

HfS fits the hyperfine structure of spectral lines, with multiple velocity components. The HfS_nh3 procedures included in HfS fit simultaneously the hyperfine structure of the NH_{3} (J,K)= (1,1) and (2,2) inversion transitions, and perform a standard analysis to derive the NH_{3} column density, rotational temperature T_{rot}, and kinetic temperature Tk. HfS uses a Monte Carlo approach for fitting the line parameters, with special attention to the derivation of the parameter uncertainties. HfS includes procedures that make use of parallel computing for fitting spectra from a data cube.

[ascl:1808.005]
hfof: Friends-of-Friends via spatial hashing

hfof is a 3-d friends-of-friends (FoF) cluster finder with Python bindings based on a fast spatial hashing algorithm that identifies connected sets of points where the point-wise connections are determined by a fixed spatial distance. This technique sorts particles into fine cells sufficiently compact to guarantee their cohabitants are linked, and uses locality sensitive hashing to search for neighboring (blocks of) cells. Tests on N-body simulations of up to a billion particles exhibit speed increases of factors up to 20x compared with FOF via trees, and is consistently complete in less than the time of a k-d tree construction, giving it an intrinsic advantage over tree-based methods.

[ascl:1102.016]
HERACLES: 3D Hydrodynamical Code to Simulate Astrophysical Fluid Flows

Audit, Edouard; González, Matthias; Vaytet, Neil; Fromang, Sebastien; Hennebelle, Patrick; Teyssier, Romain; Tremblin, Pascal; Thooris, Bruno

HERACLES is a 3D hydrodynamical code used to simulate astrophysical fluid flows. It uses a finite volume method on fixed grids to solve the equations of hydrodynamics, MHD, radiative transfer and gravity. This software is developed at the Service d'Astrophysique, CEA/Saclay as part of the COAST project and is registered under the CeCILL license. HERACLES simulates astrophysical fluid flows using a grid based Eulerian finite volume Godunov method. It is capable of simulating pure hydrodynamical flows, magneto-hydrodynamic flows, radiation hydrodynamic flows (using either flux limited diffusion or the M1 moment method), self-gravitating flows using a Poisson solver or all of the above. HERACLES uses cartesian, spherical and cylindrical grids.

[ascl:1805.019]
HENDRICS: High ENergy Data Reduction Interface from the Command Shell

HENDRICS, a rewrite and update to MaLTPyNT (ascl:1502.021), contains command-line scripts based on Stingray (ascl:1608.001) to perform a quick-look (spectral-)timing analysis of X-ray data, treating the gaps in the data due, e.g., to occultation from the Earth or passages through the SAA, properly. Despite its original main focus on NuSTAR, HENDRICS can perform standard aperiodic timing analysis on X-ray data from, in principle, any other satellite, and its features include power density and cross spectra, time lags, pulsar searches with the Epoch folding and the Z_n^2 statistics, color-color and color-intensity diagrams. The periodograms produced by HENDRICS (such as a power density spectrum or a cospectrum) can be saved in a format compatible with XSPEC (ascl:9910.005) or ISIS (ascl:1302.002)

[ascl:1807.009]
HELIOS: Radiative transfer code for exoplanetary atmospheres

Malik, Matej; Grosheintz, Luc; Mendonça, João M.; Grimm, Simon L.; Lavie, Baptiste; Kitzmann, Daniel; Tsai, Shang-Min; Burrows, Adam; Kreidberg, Laura; Bedell, Megan; Bean, Jacob L.; Stevenson, Kevin B.; Heng, Kevin

HELIOS, a radiative transfer code, is constructed for studying exoplanetary atmospheres. The model atmospheres of HELIOS are one-dimensional and plane-parallel, and the equation of radiative transfer is solved in the two-stream approximation with non-isotropic scattering. Though HELIOS can be used alone, the opacity calculator HELIOS-K (ascl:1503.004) can be used with it to provide the molecular opacities.

[ascl:1503.004]
HELIOS-K: Opacity Calculator for Radiative Transfer

HELIOS-K is an opacity calculator for exoplanetary atmospheres. It takes a line list as an input and computes the line shapes of an arbitrary number of spectral lines (~millions to billions). HELIOS-K is capable of computing 100,000 spectral lines in 1 second; it is written in CUDA, is optimized for graphics processing units (GPUs), and can be used with the HELIOS radiative transfer code (ascl:1807.009).

[ascl:1903.017]
HelioPy: Heliospheric and planetary physics library

HelioPy provides a set of tools to download and read in data, and carry out other common data processing tasks for heliospheric and planetary physics. It handles a wide variety of solar and satellite data and builds upon the SpiceyPy package (ascl:1903.016) to provide an accessible interface for performing orbital calculations. It has also implemented a framework to perform transformations between some common coordinate systems.

[ascl:1911.008]
HeatingRate: Radioactive heating rate and macronova (kilonova) light curve

HeatingRate calculates the nuclear heating rates [erg/s/g] of beta-decay, alpha-decay, and spontaneous fission of r-process nuclei, taking into account for thermalization of gamma-rays and charged decay products in r-process ejecta. It uses the half-lives and injection energy spectra from an evaluated nuclear data library (ENDF/B-VII.1). Each heating rate is computed for given abundances, ejecta mass, velocity, and density profile. HeatingRate also computes the bolometric light curve and the evolution of the effective temperature for given abundances, ejecta mass, velocity, and density profile assuming opacities independent of the wavelength.

[ascl:1506.009]
HEATCVB: Coronal heating rate approximations

HEATCVB is a stand-alone Fortran 77 subroutine that estimates the local volumetric coronal heating rate with four required inputs: the radial distance r, the wind speed u, the mass density ρ, and the magnetic field strength |B0|. The primary output is the heating rate Qturb at the location defined by the input parameters. HEATCVB also computes the local turbulent dissipation rate of the waves, γ = Qturb/(2UA).

[ascl:1408.004]
HEAsoft: Unified Release of FTOOLS and XANADU

HEASOFT combines XANADU, high-level, multi-mission software for X-ray astronomical spectral, timing, and imaging data analysis tasks, and FTOOLS (ascl:9912.002), general and mission-specific software to manipulate FITS files, into one package. It also contains contains the NuSTAR subpackage of tasks, NuSTAR Data Analysis Software (NuSTARDAS). The source code for the software can be downloaded; precompiled executables for the most widely used computer platforms are also available for download. As an additional service, HEAsoft tasks can be directly from a web browser via WebHera.

[ascl:2006.001]
HEARSAY: Simulations for the probability of alien contact

HEARSAY computes simulations of the causal contacts between emitters in the Galaxy. It implements the Stochastic Constrained Causal Contact Network (SC3Net) model and explores the parameter space of the model for the emergence of communicating nodes through Monte Carlo simulations and analyzes their causal connections. This model for the abundance and duration of civilizations is based on minimal assumptions and three free parameters, with focus on the statistical properties of empirical models instead of an interpretable model with variables to be determined by observation.

[ascl:1907.002]
healvis: Radio interferometric visibility simulator based on HEALpix maps

Healvis simulates radio interferometric visibility off of HEALPix shells. It generates a flat-spectrum and a GSM model and computes visibilities, and can simulates visibilities given an Observation Parameter YAML file. Healvis can perform partial frequency simulations in serial to minimize instantaneous memory loads.

[ascl:2008.022]
healpy: Python wrapper for HEALPix

Zonca, Andrea; Singer, Leo; Lenz, Daniel; Reinecke, Martin; Rosset, Cyrille; Hivon, Eric; Gorski, Krzysztof

healpy handles pixelated data on the sphere. It is based on the Hierarchical Equal Area isoLatitude Pixelization (HEALPix) scheme and bundles the HEALPix (ascl:1107.018) C++ library. healpy provides utilities to convert between sky coordinates and pixel indices in HEALPix nested and ring schemes and find pixels within a disk, a polygon or a strip in the sky. It can apply coordinate transformations between Galactic, Ecliptic and Equatorial reference frames, apply custom rotations either to vectors or full maps, and read and write HEALPix maps to disk in FITS format. healpy also includes utilities to upgrade and downgrade the resolution of existing HEALPix maps and transform maps to Spherical Harmonics space and back using multi-threaded C++ routines, among other utilities.

[ascl:1107.018]
HEALPix: Hierarchical Equal Area isoLatitude Pixelization of a sphere

HEALPix is an acronym for Hierarchical Equal Area isoLatitude Pixelization of a sphere. As suggested in the name, this pixelization produces a subdivision of a spherical surface in which each pixel covers the same surface area as every other pixel. Another property of the HEALPix grid is that the pixel centers occur on a discrete number of rings of constant latitude, the number of constant-latitude rings is dependent on the resolution of the HEALPix grid.

[ascl:1502.009]
HDS: Hierarchical Data System

Pearce, Dave; Walter, Anton; Lupton, W. F.; Warren-Smith, Rodney F.; Lawden, Mike; McIlwrath, Brian; Peden, J. C. M.; Jenness, Tim; Draper, Peter W.

The Hierarchical Data System (HDS) is a file-based hierarchical data system designed for the storage of a wide variety of information. It is particularly suited to the storage of large multi-dimensional arrays (with their ancillary data) where efficient access is needed. It is a key component of the Starlink software collection (ascl:1110.012) and is used by the Starlink N-Dimensional Data Format (NDF) library (ascl:1411.023).

HDS organizes data into hierarchies, broadly similar to the directory structure of a hierarchical filing system, but contained within a single HDS container file. The structures stored in these files are self-describing and flexible; HDS supports modification and extension of structures previously created, as well as functions such as deletion, copying, and renaming. All information stored in HDS files is portable between the machines on which HDS is implemented. Thus, there are no format conversion problems when moving between machines. HDS can write files in a private binary format (version 4), or be layered on top of HDF5 (version 5).

[ascl:1711.023]
HBT+: Subhalo finder and merger tree builder

HBT+ is a hybrid subhalo finder and merger tree builder for cosmological simulations. It comes as an MPI edition that can be run on distributed clusters or shared memory machines and is MPI/OpenMP parallelized, and also as an OpenMP edition that can be run on shared memory machines and is only OpenMP parallelized. This version is more memory efficient than the MPI branch on shared memory machines, and is more suitable for analyzing zoomed-in simulations that are difficult to balance on distributed clusters. Both editions support hydro simulations with gas/stars.

[ascl:1711.022]
HBT: Hierarchical Bound-Tracing

HBT is a Hierarchical Bound-Tracing subhalo finder and merger tree builder, for numerical simulations in cosmology. It tracks haloes from birth and continues to track them after mergers, finding self-bound structures as subhaloes and recording their merger histories as merger trees.

[ascl:1109.004]
HAZEL: HAnle and ZEeman Light

A big challenge in solar and stellar physics in the coming years will be to decipher the magnetism of the solar outer atmosphere (chromosphere and corona) along with its dynamic coupling with the magnetic fields of the underlying photosphere. To this end, it is important to develop rigorous diagnostic tools for the physical interpretation of spectropolarimetric observations in suitably chosen spectral lines. HAZEL is a computer program for the synthesis and inversion of Stokes profiles caused by the joint action of atomic level polarization and the Hanle and Zeeman effects in some spectral lines of diagnostic interest, such as those of the He I 1083.0 nm and 587.6 nm (or D3) multiplets. It is based on the quantum theory of spectral line polarization, which takes into account in a rigorous way all the relevant physical mechanisms and ingredients (optical pumping, atomic level polarization, level crossings and repulsions, Zeeman, Paschen-Back and Hanle effects). The influence of radiative transfer on the emergent spectral line radiation is taken into account through a suitable slab model. The user can either calculate the emergent intensity and polarization for any given magnetic field vector or infer the dynamical and magnetic properties from the observed Stokes profiles via an efficient inversion algorithm based on global optimization methods.

[ascl:1912.014]
HARMPI: 3D massively parallel general relativictic MHD code

HARMPI is a parallel, 3D version of HARM (ascl:1209.005), which solves hyperbolic partial differential equations in conservative form using high-resolution shock-capturing techniques. The code is parallelized using MPI and is fully operational in 3D. HARMPI, like HARM, is capable of using non-uniform grids and solves the relativistic magnetohydrodynamic equations of motion on a stationary black hole spacetime in Kerr-Schild coordinates to evolve an accretion disk model.

[ascl:1306.003]
Harmony: Synchrotron Emission Coefficients

Harmony is a general numerical scheme for evaluating MBS emission and absorption coefficients for both polarized and unpolarized light in a plasma with a general distribution function.

[ascl:2009.022]
Harmonia: Hybrid-basis inference for large-scale galaxy clustering

Harmonia combines clustering statistics decomposed in spherical and Cartesian Fourier bases for large-scale galaxy clustering likelihood analysis. Optimal weighting schemes for spherical Fourier analysis can also be readily implemented using the code.

[ascl:1209.005]
HARM: A Numerical Scheme for General Relativistic Magnetohydrodynamics

HARM uses a conservative, shock-capturing scheme for evolving the equations of general relativistic magnetohydrodynamics. The fluxes are calculated using the Harten, Lax, & van Leer scheme. A variant of constrained transport, proposed earlier by Tóth, is used to maintain a divergence-free magnetic field. Only the covariant form of the metric in a coordinate basis is required to specify the geometry. On smooth flows HARM converges at second order.

[ascl:1905.009]
HAOS-DIPER: HAO Spectral Diagnostic Package For Emitted Radiation

HAOS-DIPER works with and manipulates data for neutral atoms and atomic ions to understand radiation emitted by some space plasmas, notably the solar atmosphere and stellar atmospheres. HAOS-DIPER works with quantum numbers for atomic levels, enabling it to perform tasks otherwise difficult or very tedious, including a variety of data checks, calculations based upon the atomic numbers, and searching and manipulating data based upon these quantum numbers. HAOS-DIPER handles conditions from LTE to coronal-like conditions, in a manner controlled by one system variable !REGIME, and has some capability for estimating data for which no accurate parameters are available and for accounting for the effects of missing atomic levels.

[ascl:1201.014]
Hammurabi: Simulating polarized Galactic synchrotron emission

The Hammurabi code is a publicly available C++ code for generating mock polarized observations of Galactic synchrotron emission with telescopes such as LOFAR, SKA, Planck, and WMAP, based on model inputs for the Galactic magnetic field (GMF), the cosmic-ray density distribution, and the thermal electron density. The Hammurabi code allows one to perform simulations of several different data sets simultaneously, providing a more reliable constraint of the magnetized ISM.

[ascl:1210.022]
HAM2D: 2D Shearing Box Model

HAM solves non-relativistic hyperbolic partial differential equations in conservative form using high-resolution shock-capturing techniques. This version of HAM has been configured to solve the magnetohydrodynamic equations of motion in axisymmetry to evolve a shearing box model.

[ascl:1604.005]
Halotools: Galaxy-Halo connection models

Hearin, Andrew; Tollerud, Erik; Robitaille,Thomas; Droettboom, Michael; Zentner, Andrew; Bray, Erik; Craig, Matt; Bradley, Larry; Barbary, Kyle; Deil, Christoph; Tan, Kevin; Becker, Matthew R.; More, Surhud; Günther, Hans Moritz; Sipocz, Brigitta

Halotools builds and tests models of the galaxy-halo connection and analyzes catalogs of dark matter halos. The core functions of the package include fast generation of synthetic galaxy populations using HODs, abundance matching, and related methods; efficient algorithms for calculating galaxy clustering, lensing, z-space distortions, and other astronomical statistics; a modular, object-oriented framework for designing galaxy evolution models; and end-to-end support for reducing halo catalogs and caching them as hdf5 files.

[ascl:2009.016]
halomod: Flexible interface for the halo model of dark matter halos

halomod calculates cosmological halo model and HOD quantities. It is built on HMF (ascl:1412.006); it retains that code's features and provides extended components for the halo model, including numerous halo bias models, including scale-dependent bias, basic concentration-mass-redshift relations, and several plug-and-play halo-exclusion models. halomod includes built-in HOD parameterizations and halo profiles, support for WDM models, and all basic quantities such as 3D correlations and power spectra, and also several derived quantities such as effective bias and satellite fraction. In addition, it offers a simple routine for populating a halo catalog with galaxies via a HOD. halomod is flexible and modular, making it easily extendable.

[ascl:1407.020]
Halogen: Multimass spherical structure models for N-body simulations

Halogen, written in C, generates multimass spherically symmetric initial conditions for N-body simulations. A large family of radial density profiles is supported. The initial conditions are sampled from the full distribution function.

[ascl:1505.017]
HALOGEN: Approximate synthetic halo catalog generator

HALOGEN generates approximate synthetic halo catalogs. Written in C, it decomposes the problem of generating cosmological tracer distributions (eg. halos) into four steps: generating an approximate density field, generating the required number of tracers from a CDF over mass, placing the tracers on field particles according to a bias scheme dependent on local density, and assigning velocities to the tracers based on velocities of local particles. It also implements a default set of four models for these steps. HALOGEN uses 2LPTic (ascl:1201.005) and CUTE (ascl:1505.016); the software is flexible and can be adapted to varying cosmologies and simulation specifications.

[ascl:1010.053]
Halofitting codes for DGP and Degravitation

We perform N-body simulations of theories with infinite-volume extra dimensions, such as the Dvali-Gabadadze-Porrati (DGP) model and its higher-dimensional generalizations, where 4D gravity is mediated by massive gravitons. The longitudinal mode of these gravitons mediates an extra scalar force, which we model as a density-dependent modification to the Poisson equation. This enhances gravitational clustering, particularly on scales that have undergone mild nonlinear processing. While the standard non-linear fitting algorithm of Smith et al. overestimates this power enhancement on non-linear scales, we present a modified fitting formula that offers a remarkably good fit to our power spectra. Due to the uncertainty in galaxy bias, our results are consistent with precision power spectrum determinations from galaxy redshift surveys, even for graviton Compton wavelengths as small as 300 Mpc. Our model is sufficiently general that we expect it to capture the phenomenology of a wide class of related higher-dimensional gravity scenarios.

[ascl:1402.032]
HALOFIT: Nonlinear distribution of cosmological mass and galaxies

HALOFIT provides an explanatory framework for galaxy bias and clustering and has been incorporated into CMB packages such as CMBFAST (ascl:9909.004) and CAMB (ascl:1102.026). It attains a reasonable level of precision, though the halo model does not match N-body data perfectly. The code is written in Fortran 77. HALOFIT tends to underpredict the power on the smallest scales in standard LCDM universes (although HALOFIT was designed to work for a much wider range of power spectra); its accuracy can be improved by using a supplied correction.

[ascl:2002.014]
HaloAnalysis: Read and analyze halo catalogs and merger trees

HaloAnalysis reads and analyzes halo/galaxy catalogs, generated from Rockstar (ascl:1210.008) or AHF (ascl:1102.009), and merger trees generated from Consistent Trees (ascl:1210.011). Written in Python, it offers the following functionalities: reads halo/galaxy/tree catalogs from multiple file formats; assigns baryonic particles and galaxy properties to dark-matter halos; combines and re-generates halo/galaxy/tree files in hdf5 format; analyzes properties of halos/galaxies; and selects halos to generate zoom-in initial conditions. The code includes a tutorial in the form of a Jupyter notebook.

[ascl:1909.005]
HADES: Hexadecapolar Analysis for Dust Estimation in Simulations (of CMB B-mode thermal dust emission)

HADES analyzse dust levels in simulated CMB galactic dust maps with realistic experimental noise and lensing configurations. It allows detection of dust via its anisotropy properties in CMB B-modes. It also includes techniques for computing null-tests and a rudimentary technique for dedusting.

[ascl:1402.031]
gyrfalcON: N-body code

gyrfalcON (GalaxY simulatoR using falcON) is a full-fledged N-body code using Dehnen’s force algorithm of complexity O(N) (falcON); this algorithm is approximately 10 times faster than an optimally coded tree code. The code features individual adaptive time steps and individual (but fixed) softening lengths. gyrfalcON is included in and requires NEMO to run.

[ascl:1308.010]
GYRE: Stellar oscillation code

GYRE is an oscillation code that solves the stellar pulsation equations (both adiabatic and non-adiabatic) using a novel Magnus Multiple Shooting numerical scheme devised to overcome certain weaknesses of the usual relaxation and shooting schemes. The code is accurate (up to 6th order in the number of grid points), robust, and makes efficient use of multiple processor cores and/or nodes.

[ascl:1203.005]
Gyoto: General relativitY Orbit Tracer of Observatoire de Paris

GYOTO, a general relativistic ray-tracing code, aims at computing images of astronomical bodies in the vicinity of compact objects, as well as trajectories of massive bodies in relativistic environments. This code is capable of integrating the null and timelike geodesic equations not only in the Kerr metric, but also in any metric computed numerically within the 3+1 formalism of general relativity. Simulated images and spectra have been computed for a variety of astronomical targets, such as a moving star or a toroidal accretion structure. The underlying code is open source and freely available. It is user-friendly, quickly handled and very modular so that extensions are easy to integrate. Custom analytical metrics and astronomical targets can be implemented in C++ plug-in extensions independent from the main code.

[ascl:1912.016]
GWpy: Python package for studying data from gravitational-wave detectors

Macleod, Duncan; Urban, Alex L.; Coughlin, Scott; Massinger, Thomas; Pitkin, Matt; Altin, Paul; Areeda, Joseph; Quintero, Eric; Leinweber, Katrin

The Python package GWpy analyzes and characterizes gravitational wave data. It provides a user-friendly, intuitive interface to the common time-domain and frequency-domain data produced by the LIGO and Virgo observatories and their analyses. The core Python infrastructure is influenced by, and extends the functionality of, the Astropy (ascl:1304.002) package, and its methodology has been derived from, and augmented by, the LIGO Algorithm Library Suite (LALSuite), a large collection of primarily C99 routines for analysis and manipulation of data from gravitational-wave detectors. These packages use the SWIG program to produce Python wrappings for all C modules, allowing the GWpy package to leverage both the completeness, and the speed, of these libraries.

[ascl:1701.011]
GWFrames: Manipulate gravitational waveforms

GWFrames eliminates all rotational behavior, thus simplifying the waveform as much as possible and allowing direct generalizations of methods for analyzing nonprecessing systems. In the process, the angular velocity of a waveform is introduced, which also has important uses, such as supplying a partial solution to an important inverse problem.

[ascl:2002.013]
GWecc: Calculator for pulsar timing array signals due to eccentric supermassive binaries

GWecc computes the pulsar timing array (PTA) signals induced by eccentric supermassive binaries. Written in C++, it computes the plus/cross polarizations as well as Earth and pulsar terms of the PTA signal given the binary parameters and the sky locations of the binary and the pulsar. A python wrapper is included through which GWecc can be used to simulate, search for and constrain gravitational wave-emitting eccentric supermassive binaries using packages such as ENTERPRISE (ascl:1912.015) and libstempo (ascl:2002.017).

[ascl:2010.002]
GSpec: Gamma-ray Burst Monitor analyzer

GSpec analyzes the Fermi mission's Gamma-ray Burst Monitor (GBM) data via a user-interactive GUI. The software provides a seamless interface to XSPEC (ascl:9910.005). It allows users to create their own Python scripts using the included libraries, and to define additional data reduction techniques, such as background fitting/estimation and data binning, as Python-based plugins. It is part of a larger effort to produce a set of GBM data tools to allow the broader community to analyze all aspects of GBM data, including the continuous data that GBM produces. GSpec is similar to RMfit (ascl:1409.011), a GUI-based spectral analysis code that specializes in the analysis of GBM trigger data, and is intended to eventually replace that IDL package.

[ascl:1610.005]
GSGS: In-Focus Phase Retrieval Using Non-Redundant Mask Data

GSGS does phase retrieval on images given an estimate of the pupil phase (from a non-redundant mask or other interferometric approach), the pupil geometry, and the in-focus image. The code uses a modified Gerchberg-Saxton algorithm that iterates between pupil plane and image plane to measure the pupil phase.

[ascl:1806.008]
gsf: galactic structure finder

Obreja, Aura; Macciò, Andrea V.; Moster, Benjamin; Dutton, Aaron A.; Buck, Tobias; Stinson, Gregory S.; Wang, Liang

gsf applies Gaussian Mixture Models in the stellar kinematic space of normalized angular momentum and binding energy on NIHAO high resolution galaxies to separate the stars into multiple components. The gsf analysis package assumes that the simulation snapshot has been pre-processed with a halo finder. It is based on pynbody (ascl:1305.002) and the scikit-learnpython package for Machine Learning; after loading, orienting, and transforming a simulation snapshot to physical units, it runs the clustering algorithm and performs the direct N-body gravity force using all the particles in the given halo.

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