[ascl:1407.008]
Exopop: Exoplanet population inference

Exopop is a general hierarchical probabilistic framework for making justified inferences about the population of exoplanets. Written in python, it requires that the occurrence rate density be a smooth function of period and radius (employing a Gaussian process) and takes survey completeness and observational uncertainties into account. Exopop produces more accurate estimates of the whole population than standard procedures based on weighting by inverse detection efficiency.

[ascl:1603.010]
ExoPriors: Accounting for observational bias of transiting exoplanets

ExoPriors calculates a log-likelihood penalty for an input set of transit parameters to account for observational bias (geometric and signal-to-noise ratio detection bias) of transiting exoplanets. Written in Python, the code calculates this log-likelihood penalty in one of seven user-specified cases specified with Boolean input parameters for geometric and/or SNR bias, grazing or non-grazing events, and occultation events.

[ascl:1501.012]
Exorings: Exoring modelling software

Exorings, written in Python, contains tools for displaying and fitting giant extrasolar planet ring systems; it uses FITS formatted data for input.

[ascl:1703.008]
exorings: Exoring Transit Properties

Exorings is suitable for surveying entire catalogs of transiting planet candidates for exoring candidates, providing a subset of objects worthy of more detailed light curve analysis. Moreover, it is highly suited for uncovering evidence of a population of ringed planets by comparing the radius anomaly and PR-effects in ensemble studies.

[ascl:1212.013]
EXSdetect: Extended X-ray Source Detection

Liu, Teng; Tozzi, Paolo; Tundo, Elena; Moretti, A.; Wang, Jun-Xian; Rosati, Piero; Guglielmetti, Fabrizia

EXSdetect is a python implementation of an X-ray source detection algorithm which is optimally designed to detected faint extended sources and makes use of Voronoi tessellation and Friend-of-Friend technique. It is a flexible tool capable of detecting extended sources down to the lowest flux levels attainable within instrumental limitations while maintaining robust photometry, high completeness, and low contamination, regardless of source morphology. EXSdetect was developed mainly to exploit the ever-increasing wealth of archival X-ray data, but is also ideally suited to explore the scientific capabilities of future X-ray facilities, with a strong focus on investigations of distant groups and clusters of galaxies.

[ascl:9906.002]
EXTINCT: A computerized model of large-scale visual interstellar extinction

The program EXTINCT.FOR is a FORTRAN subroutine summarizing a three-dimensional visual Galactic extinction model, based on a number of published studies. INPUTS: Galactic latitude (degrees), Galactic longitude (degrees), and source distance (kpc). OUTPUTS (magnitudes): Extinction, extinction error, a statistical correction term, and an array containing extinction and extinction error from each subroutine. The model is useful for correcting visual magnitudes of Galactic sources (particularly in statistical models), and has been used to find Galactic extinction of extragalactic sources. The model's limited angular resolution (subroutine-dependent, but with a minimum resolution of roughly 2 degrees) is necessitated by its ability to describe three-dimensional structure.

[ascl:1010.032]
Extreme Deconvolution: Density Estimation using Gaussian Mixtures in the Presence of Noisy, Heterogeneous and Incomplete Data

Extreme-deconvolution is a general algorithm to infer a d-dimensional distribution function from a set of heterogeneous, noisy observations or samples. It is fast, flexible, and treats the data's individual uncertainties properly, to get the best description possible for the underlying distribution. It performs well over the full range of density estimation, from small data sets with only tens of samples per dimension, to large data sets with hundreds of thousands of data points.

[ascl:1010.061]
EyE: Enhance Your Extraction

In EyE (Enhance Your Extraction) an artificial neural network connected to pixels of a moving window (retina) is trained to associate these input stimuli to the corresponding response in one or several output image(s). The resulting filter can be loaded in SExtractor to operate complex, wildly non-linear filters on astronomical images. Typical applications of EyE include adaptive filtering, feature detection and cosmetic corrections.

[ascl:1407.019]
EZ_Ages: Stellar population age calculator

EZ_Ages is an IDL code package that computes the mean, light-weighted stellar population age, [Fe/H], and abundance enhancements [Mg/Fe], [C/Fe], [N/Fe], and [Ca/Fe] for unresolved stellar populations. This is accomplished by comparing Lick index line strengths between the data and the stellar population models of Schiavon (2007), using a method described in Graves & Schiavon (2008). The algorithm uses the inversion of index-index model grids to determine ages and abundances, and exploits the sensitivities of the various Lick indices to measure Mg, C, N, and Ca enhancements over their solar abundances with respect to Fe.

[ascl:1210.004]
EZ: A Tool For Automatic Redshift Measurement

EZ (Easy-Z) estimates redshifts for extragalactic objects. It compares the observed spectrum with a set of (user given) spectral templates to find out the best value for the redshift. To accomplish this task, it uses a highly configurable set of algorithms. EZ is easily extendible with new algorithms. It is implemented as a set of C programs and a number of python classes. It can be used as a standalone program, or the python classes can be directly imported by other applications.

[ascl:1208.021]
EzGal: A Flexible Interface for Stellar Population Synthesis Models

EzGal is a flexible Python program which generates observable parameters (magnitudes, colors, and mass-to-light ratios) for arbitrary input stellar population synthesis (SPS) models; it enables simple, direct comparison of different model sets so that the uncertainty introduced by choice of model set can be quantified. EzGal is also capable of generating composite stellar population models (CSPs) for arbitrary input star-formation histories and reddening laws, and can be used to interpolate between metallicities for a given model set.

[ascl:1509.004]
FalconIC: Initial conditions generator for cosmological N-body simulations in Newtonian, Relativistic and Modified theories

FalconIC generates discrete particle positions, velocities, masses and pressures based on linear Boltzmann solutions that are computed by libraries such as CLASS and CAMB. FalconIC generates these initial conditions for any species included in the selection, including Baryons, Cold Dark Matter and Dark Energy fluids. Any species can be set in Eulerian (on a fixed grid) or Lagrangian (particle motion) representation, depending on the gauge and reality chosen. That is, for relativistic initial conditions in the synchronous comoving gauge, Dark Matter can only be described in an Eulerian representation. For all other choices (Relativistic in Longitudinal gauge, Newtonian with relativistic expansion rates, Newtonian without any notion of radiation), all species can be treated in all representations. The code also computes spectra. FalconIC is useful for comparative studies on initial conditions.

[ascl:1402.016]
FAMA: Fast Automatic MOOG Analysis

Magrini, Laura; Randich, Sofia; Friel, Eileen; Spina, Lorenzo; Jacobson, Heather; Cantat-Gaudin, Tristan; Donati, Paolo; Baglioni, Roberto; Maiorca, Enrico; Bragaglia, Angela; Sordo, Rosanna; Vallenari, Antonella

FAMA (Fast Automatic MOOG Analysis), written in Perl, computes the atmospheric parameters and abundances of a large number of stars using measurements of equivalent widths (EWs) automatically and independently of any subjective approach. Based on the widely-used MOOG code, it simultaneously searches for three equilibria, excitation equilibrium, ionization balance, and the relationship between logn(FeI) and the reduced EWs. FAMA also evaluates the statistical errors on individual element abundances and errors due to the uncertainties in the stellar parameters. Convergence criteria are not fixed "a priori" but instead are based on the quality of the spectra.

[ascl:1209.014]
FAMIAS: Frequency Analysis and Mode Identification for AsteroSeismology

FAMIAS (Frequency Analysis and Mode Identification for Asteroseismology) is a package of software tools programmed in C++ for the analysis of photometric and spectroscopic time-series data. FAMIAS provides analysis tools that are required for the steps between the data reduction and the seismic modeling. Two main sets of tools are incorporated in FAMIAS. The first set permits to search for periodicities in the data using Fourier and non-linear least-squares fitting techniques. The other set permits to carry out a mode identification for the detected pulsation frequencies to determine their harmonic degree l, and azimuthal order m. FAMIAS is applicable to main-sequence pulsators hotter than the Sun. This includes Gamma Dor, Delta Sct stars, slowly pulsating B (SPB)-stars and Beta Cep stars - basically all stars for which empirical mode identification is required to successfully carry out asteroseismology.

[ascl:1102.017]
FARGO: Fast Advection in Rotating Gaseous Objects

FARGO is an efficient and simple modification of the standard transport algorithm used in explicit eulerian fixed polar grid codes, aimed at getting rid of the average azimuthal velocity when applying the Courant condition. This results in a much larger timestep than the usual procedure, and it is particularly well-suited to the description of a Keplerian disk where one is traditionally limited by the very demanding Courant condition on the fast orbital motion at the inner boundary. In this modified algorithm, the timestep is limited by the perturbed velocity and by the shear arising from the differential rotation. The speed-up resulting from the use of the FARGO algorithm is problem dependent. In the example presented in the code paper below, which shows the evolution of a Jupiter sized protoplanet embedded in a minimum mass protoplanetary nebula, the FARGO algorithm is about an order of magnitude faster than a traditional transport scheme, with a much smaller numerical diffusivity.

[ascl:1509.006]
FARGO3D: Hydrodynamics/magnetohydrodynamics code

A successor of FARGO (ascl:1102.017), FARGO3D is a versatile HD/MHD code that runs on clusters of CPUs or GPUs, with special emphasis on protoplanetary disks. FARGO3D offers Cartesian, cylindrical or spherical geometry; 1-, 2- or 3-dimensional calculations; and orbital advection (aka FARGO) for HD and MHD calculations. As in FARGO, a simple Runge-Kutta N-body solver may be used to describe the orbital evolution of embedded point-like objects. There is no need to know CUDA; users can develop new functions in C and have them translated to CUDA automatically to run on GPUs.

[submitted]
Fast Template Periodogram

The Fast Template Periodogram extends the Generalised Lomb Scargle periodogram (Zechmeister and Kurster 2009) for arbitrary (periodic) signal shapes. A template is first approximated by a truncated Fourier series of length H. The Nonequispaced Fast Fourier Transform NFFT is used to efficiently compute frequency-dependent sums. Template fitting can now be done in NlogN time, improving existing algorithms by an order of magnitude for even small datasets. The FTP can be used in conjunction with gradient descent to accelerate a non-linear model fit, or be used in place of the multi-harmonic periodogram for non-sinusoidal signals with a priori known shapes.

[ascl:1010.010]
Fast WMAP Likelihood Code and GSR PC Functions

We place functional constraints on the shape of the inflaton potential from the cosmic microwave background through a variant of the generalized slow roll approximation that allows large amplitude, rapidly changing deviations from scale-free conditions. Employing a principal component decomposition of the source function G'~3(V'/V)^2 - 2V''/V and keeping only those measured to better than 10% results in 5 nearly independent Gaussian constraints that maybe used to test any single-field inflationary model where such deviations are expected. The first component implies < 3% variations at the 100 Mpc scale. One component shows a 95% CL preference for deviations around the 300 Mpc scale at the ~10% level but the global significance is reduced considering the 5 components examined. This deviation also requires a change in the cold dark matter density which in a flat LCDM model is disfavored by current supernova and Hubble constant data and can be tested with future polarization or high multipole temperature data. Its impact resembles a local running of the tilt from multipoles 30-800 but is only marginally consistent with a constant running beyond this range. For this analysis, we have implemented a ~40x faster WMAP7 likelihood method which we have made publicly available.

[ascl:1603.006]
FAST-PT: Convolution integrals in cosmological perturbation theory calculator

FAST-PT calculates 1-loop corrections to the matter power spectrum in cosmology. The code utilizes Fourier methods combined with analytic expressions to reduce the computation time down to scale as N log N, where N is the number of grid point in the input linear power spectrum. FAST-PT is extremely fast, enabling mode-coupling integral computations fast enough to embed in Monte Carlo Markov Chain parameter estimation.

[ascl:1010.037]
FastChi: A Fast Chi-squared Technique For Period Search of Irregularly Sampled Data

The Fast Chi-Squared Algorithm is a fast, powerful technique for detecting periodicity. It was developed for analyzing variable stars, but is applicable to many of the other applications where the Fast Fourier Transforms (FFTs) or other periodograms (such as Lomb-Scargle) are currently used. The Fast Chi-squared technique takes a data set (e.g. the brightness of a star measured at many different times during a series of observations) and finds the periodic function that has the best frequency and shape (to an arbitrary number of harmonics) to fit the data. Among its advantages are:

- Statistical efficiency: all of the data are used, weighted by their individual error bars, giving a result with a significance calibrated in well-understood Chi-squared statistics.
- Sensitivity to harmonic content: many conventional techniques look only at the significance (or the amplitude) of the fundamental sinusoid and discard the power of the higher harmonics.
- Insensitivity to the sample timing: you won't find a period of 24 hours just because you take your observations at night. You do not need to window your data.
- The frequency search is gridded more tightly than the traditional "integer number of cycles over the span of observations", eliminating power loss from peaks that fall between the grid points.
- Computational speed: The complexity of the algorithm is O(NlogN), where N is the number of frequencies searched, due to its use of the FFT.

[ascl:9910.003]
FASTELL: Fast calculation of a family of elliptical mass gravitational lens models

Because of their simplicity, axisymmetric mass distributions are often used to model gravitational lenses. Since galaxies are usually observed to have elliptical light distributions, mass distributions with elliptical density contours offer more general and realistic lens models. They are difficult to use, however, since previous studies have shown that the deflection angle (and magnification) in this case can only be obtained by rather expensive numerical integrations. We present a family of lens models for which the deflection can be calculated to high relative accuracy (10-5) with a greatly reduced numerical effort, for small and large ellipticity alike. This makes it easier to use these distributions for modeling individual lenses as well as for applications requiring larger computing times, such as statistical lensing studies. FASTELL is a code to calculate quickly and accurately the lensing deflection and magnification matrix for the softened power-law elliptical mass distribution (SPEMD) lens galaxy model. The SPEMD consists of a softened power-law radial distribution with elliptical isodensity contours.

[ascl:1010.041]
FASTLens (FAst STatistics for weak Lensing): Fast Method for Weak Lensing Statistics and Map Making

The analysis of weak lensing data requires to account for missing data such as masking out of bright stars. To date, the majority of lensing analyses uses the two point-statistics of the cosmic shear field. These can either be studied directly using the two-point correlation function, or in Fourier space, using the power spectrum. The two-point correlation function is unbiased by missing data but its direct calculation will soon become a burden with the exponential growth of astronomical data sets. The power spectrum is fast to estimate but a mask correction should be estimated. Other statistics can be used but these are strongly sensitive to missing data. The solution that is proposed by FASTLens is to properly fill-in the gaps with only NlogN operations, leading to a complete weak lensing mass map from which one can compute straight forwardly and with a very good accuracy any kind of statistics like power spectrum or bispectrum.

[ascl:1302.008]
FASTPHOT: A simple and quick IDL PSF-fitting routine

PSF fitting photometry allows a simultaneously fit of a PSF profile on the sources. Many routines use PSF fitting photometry, including IRAF/allstar, Strarfinder, and Convphot. These routines are in general complex to use and slow. FASTPHOT is optimized for prior extraction (the position of the sources is known) and is very fast and simple.

[ascl:1507.011]
FAT: Fully Automated TiRiFiC

Kamphuis, P.; Józsa, G. I. G.; Oh, S-. H.; Spekkens, K.; Urbancic, N.; Serra, P.; Koribalski, B. S.; Dettmar, R.-J.

FAT (Fully Automated TiRiFiC) is an automated procedure that fits tilted-ring models to Hi data cubes of individual, well-resolved galaxies. The method builds on the 3D Tilted Ring Fitting Code (TiRiFiC, ascl:1208.008). FAT accurately models the kinematics and the morphologies of galaxies with an extent of eight beams across the major axis in the inclination range 20°-90° without the need for priors such as disc inclination. FAT's performance allows us to model the gas kinematics of many thousands of well-resolved galaxies, which is essential for future HI surveys, with the Square Kilometre Array and its pathfinders.

[ascl:1505.014]
FCLC: Featureless Classification of Light Curves

FCLC (Featureless Classification of Light Curves) software describes the static behavior of a light curve in a probabilistic way. Individual data points are converted to densities and consequently probability density are compared instead of features. This gives rise to an independent classification which can corroborate the usefulness of the selected features.

[ascl:1606.011]
FDIPS: Finite Difference Iterative Potential-field Solver

FDIPS is a finite difference iterative potential-field solver that can generate the 3D potential magnetic field solution based on a magnetogram. It is offered as an alternative to the spherical harmonics approach, as when the number of spherical harmonics is increased, using the raw magnetogram data given on a grid that is uniform in the sine of the latitude coordinate can result in inaccurate and unreliable results, especially in the polar regions close to the Sun. FDIPS is written in Fortran 90 and uses the MPI library for parallel execution.

[ascl:1604.011]
FDPS: Framework for Developing Particle Simulators

Iwasawa, Masaki; Tanikawa, Ataru; Hosono, Natsuki; Nitadori, Keigo; Muranushi, Takayuki; Makino, Junichiro

FDPS provides the necessary functions for efficient parallel execution of particle-based simulations as templates independent of the data structure of particles and the functional form of the interaction. It is used to develop particle-based simulation programs for large-scale distributed-memory parallel supercomputers. FDPS includes templates for domain decomposition, redistribution of particles, and gathering of particle information for interaction calculation. It uses algorithms such as Barnes-Hut tree method for long-range interactions; methods to limit the calculation to neighbor particles are used for short-range interactions. FDPS reduces the time and effort necessary to write a simple, sequential and unoptimized program of O(N^2) calculation cost, and produces compiled programs that will run efficiently on large-scale parallel supercomputers.

[ascl:1203.004]
FERENGI: Full and Efficient Redshifting of Ensembles of Nearby Galaxy Images

Bandpass shifting and the (1+z)5 surface brightness dimming (for a fixed width filter) make standard tools for the extraction of structural parameters of galaxies wavelength dependent. If only few (or one) observed high-res bands exist, this dependence has to be corrected to make unbiased statements on the evolution of structural parameters or on galaxy subsamples defined by morphology. FERENGI artificially redshifts low-redshift galaxy images to different redshifts by applying the correct cosmological corrections for size, surface brightness and bandpass shifting. A set of artificially redshifted galaxies in the range 0.1<z<1.1 using a set of ~100 SDSS low-redshift (v<7000 km s-1) images as input has been created to use as a training set of realistic images of galaxies of diverse morphologies and a large range of redshifts for the GEMS and COSMOS galaxy evolution projects. This training set allows other studies to investigate and quantify the effects of cosmological redshift on the determination of galaxy morphologies, distortions, and other galaxy properties that are potentially sensitive to resolution, surface brightness, and bandpass issues. The data sets are also available for download from the FERENGI website.

[ascl:1208.011]
Fewbody: Numerical toolkit for simulating small-N gravitational dynamics

Fewbody is a numerical toolkit for simulating small-N gravitational dynamics. It is a general N-body dynamics code, although it was written for the purpose of performing scattering experiments, and therefore has several features that make it well-suited for this purpose. Fewbody uses the 8th-order Runge-Kutta Prince-Dormand integration method with 9th-order error estimate and adaptive timestep to advance the N-body system forward in time. It integrates the usual formulation of the N-body equations in configuration space, but allows for the option of global pairwise Kustaanheimo-Stiefel (K-S) regularization (Heggie 1974; Mikkola 1985). The code uses a binary tree algorithm to classify the N-body system into a set of independently bound hierarchies, and performs collisions between stars in the “sticky star” approximation. Fewbody contains a collection of command line utilities that can be used to perform individual scattering and N-body interactions, but is more generally a library of functions that can be used from within other codes.

[ascl:1512.017]
FFTLog: Fast Fourier or Hankel transform

FFTLog is a set of Fortran subroutines that compute the fast Fourier or Hankel (= Fourier-Bessel) transform of a periodic sequence of logarithmically spaced points. FFTLog can be regarded as a natural analogue to the standard Fast Fourier Transform (FFT), in the sense that, just as the normal FFT gives the exact (to machine precision) Fourier transform of a linearly spaced periodic sequence, so also FFTLog gives the exact Fourier or Hankel transform, of arbitrary order m, of a logarithmically spaced periodic sequence.

[ascl:1201.015]
FFTW: Fastest Fourier Transform in the West

FFTW is a C subroutine library for computing the discrete Fourier transform (DFT) in one or more dimensions, of arbitrary input size, and of both real and complex data (as well as of even/odd data, i.e. the discrete cosine/sine transforms or DCT/DST).

Benchmarks performed on a variety of platforms show that FFTW's performance is typically superior to that of other publicly available FFT software, and is even competitive with vendor-tuned codes. In contrast to vendor-tuned codes, however, FFTW's performance is portable: the same program will perform well on most architectures without modification.

The FFTW library is required by other codes such as StarCrash and Hammurabi.

[ascl:1603.014]
fibmeasure: Python/Cython module to find the center of back-illuminated optical fibers in metrology images

fibmeasure finds the precise locations of the centers of back-illuminated optical fibers in images. It was developed for astronomical fiber positioning feedback via machine vision cameras and is optimized for high-magnification images where fibers appear as resolvable circles. It was originally written during the design of the WEAVE pick-and-place fiber positioner for the William Herschel Telescope.

[ascl:1111.013]
FIBRE-pac: FMOS Image-based Reduction Package

Iwamuro, F.; Moritani, Y.; Yabe, K.; Sumiyoshi, M.; Kawate, K.; Tamura, N.; Akiyama, M.; Kimura, M.; Takato, N.; Tait, P.; Ohta, K.; Totani, T.; Suzuki, Y.; Tonegawa, M.

The FIBRE-pac (FMOS image-based reduction package) is an IRAF-based reduction tool for the fiber multiple-object spectrograph (FMOS) of the Subaru telescope. To reduce FMOS images, a number of special techniques are necessary because each image contains about 200 separate spectra with airglow emission lines variable in spatial and time domains, and with complicated throughput patterns for the airglow masks. In spite of these features, almost all of the reduction processes except for a few steps are carried out automatically by scripts in text format making it easy to check the commands step by step. Wavelength- and flux-calibrated images together with their noise maps are obtained using this reduction package.

[ascl:1307.004]
FieldInf: Field Inflation exact integration routines

FieldInf is a collection of fast modern Fortran routines for computing exactly the background evolution and primordial power spectra of any single field inflationary models. It implements reheating without any assumptions through the "reheating parameter" R allowing robust inflationary parameter estimations and inference on the reheating energy scale. The underlying perturbation code actually deals with N fields minimally-coupled and/or non-minimally coupled to gravity and works for flat FLRW only.

[ascl:1203.013]
Figaro: Data Reduction Software

Figaro is a data reduction system that originated at Caltech and whose development continued at the Anglo-Australian Observatory. Although it is intended to be able to deal with any sort of data, almost all its applications to date are geared towards processing optical and infrared data. Figaro uses hierarchical data structures to provide flexibility in its data file formats. Figaro was originally written to run under DEC's VMS operating system, but is now available both for VMS and for various flavours of UNIX.

[ascl:1608.009]
FilFinder: Filamentary structure in molecular clouds

FilFinder extracts and analyzes filamentary structure in molecular clouds. In particular, it is capable of uniformly extracting structure over a large dynamical range in intensity. It returns the main filament properties: local amplitude and background, width, length, orientation and curvature. FilFinder offers additional tools to, for example, create a filament-only image based on the properties of the radial fits. The resulting mask and skeletons may be saved in FITS format, and property tables may be saved as a CSV, FITS or LaTeX table.

[ascl:1602.007]
FilTER: Filament Trait-Evaluated Reconstruction

FilTER (Filament Trait-Evaluated Reconstruction) post-processes output from DisPerSE (ascl:1302.015

[ascl:1202.014]
FISA: Fast Integrated Spectra Analyzer

FISA (Fast Integrated Spectra Analyzer) permits fast and reasonably accurate age and reddening determinations for small angular diameter open clusters by using their integrated spectra in the (3600-7400) AA range and currently available template spectrum libraries. This algorithm and its implementation help to achieve astrophysical results in shorter times than from other methods. FISA has successfully been applied to integrated spectroscopy of open clusters, both in the Galaxy and in the Magellanic Clouds, to determine ages and reddenings.

[ascl:1010.070]
Fisher.py: Fisher Matrix Manipulation and Confidence Contour Plotting

Fisher.py allows you to combine constraints from multiple experiments (e.g., weak lensing + supernovae) and add priors (e.g., a flat universe) simply and easily. Calculate parameter uncertainties and plot confidence ellipses. Fisher matrix expectations for several experiments are included as calculated by myself (time delays) and the Dark Energy Task Force (WL/SN/BAO/CL/CMB), or provide your own.

[ascl:1201.007]
Fisher4Cast: Fisher Matrix Toolbox

The Fisher4Cast suite, which requires MatLab, provides a standard, tested tool set for general Fisher Information matrix prediction and forecasting for use in both research and education. The toolbox design is robust and modular, allowing for easy additions and adaptation while keeping the user interface intuitive and easy to use. Fisher4Cast is completely general but the default is coded for cosmology. It provides parameter error forecasts for cosmological surveys providing distance, Hubble expansion and growth measurements in a general, curved FLRW background.

[ascl:1609.004]
FISHPACK: Efficient FORTRAN Subprograms for the Solution of Separable Elliptic Partial Differential Equations

The FISHPACK collection of Fortran77 subroutines solves second- and fourth-order finite difference approximations to separable elliptic Partial Differential Equations (PDEs). These include Helmholtz equations in cartesian, polar, cylindrical, and spherical coordinates, as well as more general separable elliptic equations. The solvers use the cyclic reduction algorithm. When the problem is singular, a least-squares solution is computed. Singularities induced by the coordinate system are handled, including at the origin r=0 in cylindrical coordinates, and at the poles in spherical coordinates.

[ascl:1609.005]
FISHPACK90: Efficient FORTRAN Subprograms for the Solution of Separable Elliptic Partial Differential Equations

FISHPACK90 is a modernization of the original FISHPACK (ascl:1609.004), employing Fortran90 to slightly simplify and standardize the interface to some of the routines. This collection of Fortran programs and subroutines solves second- and fourth-order finite difference approximations to separable elliptic Partial Differential Equations (PDEs). These include Helmholtz equations in cartesian, polar, cylindrical, and spherical coordinates, as well as more general separable elliptic equations. The solvers use the cyclic reduction algorithm. When the problem is singular, a least-squares solution is computed. Singularities induced by the coordinate system are handled, including at the origin r=0 in cylindrical coordinates, and at the poles in spherical coordinates. Test programs are provided for the 19 solvers. Each serves two purposes: as a template to guide you in writing your own codes utilizing the FISHPACK90 solvers, and as a demonstration on your computer that you can correctly produce FISHPACK90 executables.

[ascl:1601.016]
Fit Kinematic PA: Fit the global kinematic position-angle of galaxies

Fit kinematic PA measures the global kinematic position-angle (PA) from integral field observations of a galaxy stellar or gas kinematics; the code is available in IDL and Python.

[ascl:1609.015]
FIT3D: Fitting optical spectra

Sánchez, S. F.; Pérez, E.; Sánchez-Blázquez, P.; González, J. J.; Rosales-Ortega, F. F.; Cano-Díaz, M.; López-Cobá, C.; Marino, R. A.; Gil de Paz, A.; Mollá, M.; López-Sánchez, A. R.; Ascasibar, Y.; Barrera-Ballesteros, J.

FIT3D fits optical spectra to deblend the underlying stellar population and the ionized gas, and extract physical information from each component. FIT3D is focused on the analysis of Integral Field Spectroscopy data, but is not restricted to it, and is the basis of Pipe3D, a pipeline used in the analysis of datasets like CALIFA, MaNGA, and SAMI. It can run iteratively or in an automatic way to derive the parameters of a large set of spectra.

[ascl:1305.011]
FITDisk: Cataclysmic Variable Accretion Disk Demonstration Tool

FITDisk models accretion disk phenomena using a fully three-dimensional hydrodynamics calculation, and data can either be visualized as they are computed or stored to hard drive for later playback at a fast frame rate. Simulations are visualized using OpenGL graphics and the viewing angle can be changed interactively. Pseudo light curves of simulated systems can be plotted along with the associated Fourier amplitude spectrum. It provides an easy to use graphical user interface as well as 3-D interactive graphics. The code computes the evolution of a CV accretion disk, visualizes results in real time, records and plays back simulations, and generates and plots pseudo light curves and associated power spectra.

[ascl:1206.002]
FITS Liberator: Image processing software

Lindberg Christensen, Lars; Nielsen, Lars Holm; Nielsen, Kaspar K.; Johansen, Teis; Hurt, Robert; de Martin, David

The ESA/ESO/NASA FITS Liberator makes it possible to process and edit astronomical science data in the FITS format to produce stunning images of the universe. Formerly a plugin for Adobe Photoshop, the current version of FITS Liberator is a stand-alone application and no longer requires Photoshop. This image processing software makes it possible to create color images using raw observations from a range of telescopes; the FITS Liberator continues to support the FITS and PDS formats, preferred by astronomers and planetary scientists respectively, which enables data to be processed from a wide range of telescopes and planetary probes, including ESO’s Very Large Telescope, the NASA/ESA Hubble Space Telescope, NASA’s Spitzer Space Telescope, ESA’s XMM–Newton Telescope and Cassini–Huygens or Mars Reconnaissance Orbiter.

[ascl:1505.029]
fits2hdf: FITS to HDFITS conversion

fits2hdf ports FITS files to Hierarchical Data Format (HDF5) files in the HDFITS format. HDFITS allows faster reading of data, higher compression ratios, and higher throughput. HDFITS formatted data can be presented transparently as an in-memory FITS equivalent by changing the import lines in Python-based FITS utilities. fits2hdf includes a utility to port MeasurementSets (MS) to HDF5 files.

[ascl:1111.014]
FITSH: Software Package for Image Processing

FITSH provides a standalone environment for analysis of data acquired by imaging astronomical detectors. The package provides utilities both for the full pipeline of subsequent related data processing steps (including image calibration, astrometry, source identification, photometry, differential analysis, low-level arithmetic operations, multiple image combinations, spatial transformations and interpolations, etc.) and for aiding the interpretation of the (mainly photometric and/or astrometric) results. The package also features a consistent implementation of photometry based on image subtraction, point spread function fitting and aperture photometry and provides easy-to-use interfaces for comparisons and for picking the most suitable method for a particular problem. The utilities in the package are built on the top of the commonly used UNIX/POSIX shells (hence the name of the package), therefore both frequently used and well-documented tools for such environments can be exploited and managing massive amount of data is rather convenient.

[ascl:1107.003]
FITSManager: Management of Personal Astronomical Data

Cui, Chenzhou; Fan, Dongwei; Zhao, Yongheng; Kembhavi, Ajit; He, Boliang; Cao, Zihuang; Li, Jian; Nandrekar, Deoyani

With the increase of personal storage capacity, it is easy to find hundreds to thousands of FITS files in the personal computer of an astrophysicist. Because Flexible Image Transport System (FITS) is a professional data format initiated by astronomers and used mainly in the small community, data management toolkits for FITS files are very few. Astronomers need a powerful tool to help them manage their local astronomical data. Although Virtual Observatory (VO) is a network oriented astronomical research environment, its applications and related technologies provide useful solutions to enhance the management and utilization of astronomical data hosted in an astronomer's personal computer. FITSManager is such a tool to provide astronomers an efficient management and utilization of their local data, bringing VO to astronomers in a seamless and transparent way. FITSManager provides fruitful functions for FITS file management, like thumbnail, preview, type dependent icons, header keyword indexing and search, collaborated working with other tools and online services, and so on. The development of the FITSManager is an effort to fill the gap between management and analysis of astronomical data.

[ascl:1112.007]
FLAGCAL: FLAGging and CALlibration Pipeline for GMRT Data

FLAGging and CALlibration (FLAGCAL) is a software pipeline developed for automatic flagging and calibration of the GMRT data. This pipeline can be used for preprocessing (before importing the data in AIPS) any other interferromteric data also (given that the data file is in FITS format and contains multiple channels & scans).There are also a few GUI based tools which can be used for quick visualization of the data.

[ascl:1010.082]
FLASH: Adaptive Mesh Hydrodynamics Code for Modeling Astrophysical Thermonuclear Flashes

Fryxell, B.; Olson, K.; Ricker, P.; Timmes, F. X.; Zingale, M.; Lamb, D. Q.; MacNeice, P.; Rosner, R.; Truran, J. W.; Tufo, H.

The FLASH code, currently in its 4th version, is a publicly available high performance application code which has evolved into a modular, extensible software system from a collection of unconnected legacy codes. FLASH consists of inter-operable modules that can be combined to generate different applications. The FLASH architecture allows arbitrarily many alternative implementations of its components to co-exist and interchange with each other. A simple and elegant mechanism exists for customization of code functionality without the need to modify the core implementation of the source. A built-in unit test framework combined with regression tests that run nightly on multiple platforms verify the code.

[ascl:1606.015]
FLASK: Full-sky Lognormal Astro-fields Simulation Kit

FLASK (Full-sky Lognormal Astro-fields Simulation Kit) makes tomographic realizations on the sphere of an arbitrary number of correlated lognormal or Gaussian random fields; it can create joint simulations of clustering and lensing with sub-per-cent accuracy over relevant angular scales and redshift ranges. It is C++ code parallelized with OpenMP; FLASK generates fast full-sky simulations of cosmological large-scale structure observables such as multiple matter density tracers (galaxies, quasars, dark matter haloes), CMB temperature anisotropies and weak lensing convergence and shear fields. The mutiple fields can be generated tomographically in an arbitrary number of redshift slices and all their statistical properties (including cross-correlations) are determined by the angular power spectra supplied as input and the multivariate lognormal (or Gaussian) distribution assumed for the fields. Effects like redshift space distortions, doppler distortions, magnification biases, evolution and intrinsic aligments can be introduced in the simulations via the input power spectra which must be supplied by the user.

[ascl:1612.006]
flexCE: Flexible one-zone chemical evolution code

flexCE (flexible Chemical Evolution) computes the evolution of a one-zone chemical evolution model with inflow and outflow in which gas is instantaneously and completely mixed. It can be used to demonstrate the sensitivity of chemical evolution models to parameter variations, show the effect of CCSN yields on chemical evolution models, and reproduce the 2D distribution in [O/Fe]{[Fe/H] by mixing models with a range of inflow and outflow histories. It can also post-process cosmological simulations to predict element distributions.

[ascl:1107.004]
Flexible DM-NRG

This code combines the spectral sum-conserving methods of Weichselbaum and von Delft and of Peters, Pruschke and Anders (both relying upon the complete basis set construction of Anders and Schiller) with the use of non-Abelian symmetries in a flexible manner: Essentially any non-Abelian symmetry can be taught to the code, and any number of such symmetries can be used throughout the computation for any density of states, and to compute any local operators' correlation function's real and imaginary parts or any thermodynamical expectation value. The code works both at zero and finite temperatures.

[ascl:1205.006]
Flexion: IDL code for calculating gravitational flexion

Gravitational flexion is a technique for measuring 2nd order gravitational lensing signals in background galaxies and radio lobes. Unlike shear, flexion directly probes variations of the potential field. Moreover, the information contained in flexion is orthogonal to what is found in the shear. Thus, we get the information "for free."

[ascl:1411.016]
Flicker: Mean stellar densities from flicker

Flicker calculates the mean stellar density of a star by inputting the flicker observed in a photometric time series. Written in Fortran90, its output may be used as an informative prior on stellar density when fitting transit light curves.

[ascl:1210.007]
FLUKA: Fully integrated particle physics Monte Carlo simulation package

Fassò, Alberto; Ferrari, Alfredo; Ranft, Johannes; Sala, Paola; Mairani, Andrea; Empl, Anton; Sommerer, Florian; Cerutti, Francesco; Battistoni, Giuseppe; Roesler, Stefan; Vlachoudis, Vasilis; Patera, Vincenzo; Aarnio, P.; Möhring, J.-H.; Stevenson, G. R.; Zazula, J. M.

FLUKA (FLUktuierende KAskade) is a general-purpose tool for calculations of particle transport and interactions with matter. FLUKA can simulate with high accuracy the interaction and propagation in matter of about 60 different particles, including photons and electrons from 1 keV to thousands of TeV, neutrinos, muons of any energy, hadrons of energies up to 20 TeV (up to 10 PeV by linking FLUKA with the DPMJET code) and all the corresponding antiparticles, neutrons down to thermal energies and heavy ions. The program, written in Fortran, can also transport polarised photons (e.g., synchrotron radiation) and optical photons. Time evolution and tracking of emitted radiation from unstable residual nuclei can be performed online.

[ascl:1105.008]
Flux Tube Model

This Fortran code computes magnetohydrostatic flux tubes and sheets according to the method of Steiner, Pneuman, & Stenflo (1986) A&A 170, 126-137. The code has many parameters contained in one input file that are easily modified. Extensive documentation is provided in README files.

[ascl:1405.010]
FLUXES: Position and flux density of planets

Jenness, Tim; Privett, Grant; Matthews, Henry; Hohenkerk, Catherine; Barnard, Vicki; Tilanus, Remo; Watt, Graeme; Emerson, Jim

FLUXES calculates approximate topocentric positions of the planets and also integrated flux densities of five of them at several wavelengths. These provide calibration information at the effective frequencies and beam-sizes employed by the UKT14, SCUBA and SCUBA-2 receivers on the JCMT telescope based on Mauna Kea, Hawaii. FLUXES is part of the bundle that comprises the Starlink multi-purpose astronomy software package (ascl:1110.012).

[ascl:1011.019]
FLY: MPI-2 High Resolution code for LSS Cosmological Simulations

Cosmological simulations of structures and galaxies formations have played a fundamental role in the study of the origin, formation and evolution of the Universe. These studies improved enormously with the use of supercomputers and parallel systems and, recently, grid based systems and Linux clusters. Now we present the new version of the tree N-body parallel code FLY that runs on a PC Linux Cluster using the one side communication paradigm MPI-2 and we show the performances obtained. FLY is included in the Computer Physics Communication Program Library. This new version was developed using the Linux Cluster of CINECA, an IBM Cluster with 1024 Intel Xeon Pentium IV 3.0 Ghz. The results show that it is possible to run a 64 Million particle simulation in less than 15 minutes for each timestep, and the code scalability with the number of processors is achieved. This lead us to propose FLY as a code to run very large N-Body simulations with more than $10^{9}$ particles with the higher resolution of a pure tree code.

[ascl:1701.007]
Forecaster: Mass and radii of planets predictor

Forecaster predicts the mass (or radius) from the radius (or mass) for objects covering nine orders-of-magnitude in mass. It is an unbiased forecasting model built upon a probabilistic mass-radius relation conditioned on a sample of 316 well-constrained objects. It accounts for observational errors, hyper-parameter uncertainties and the intrinsic dispersions observed in the calibration sample.

[ascl:1405.007]
FORWARD: Forward modeling of coronal observables

Gibson, Sarah E.; Kucera, Therese A.; Casini, Roberto; Dove, James; Forland, Blake; Judge, Philip; Rachmeler, Laurel

FORWARD forward models various coronal observables and can access and compare existing data. Given a coronal model, it can produce many different synthetic observables (including Stokes polarimetry), as well as plots of model plasma properties (density, magnetic field, etc.). It uses the CHIANTI database (ascl:9911.004) and CLE polarimetry synthesis code, works with numerical model datacubes, interfaces with the PFSS module of SolarSoft (ascl:1208.013), includes several analytic models, and connects to the Virtual Solar Observatory for downloading data in a format directly comparable to model predictions.

[ascl:1204.004]
Fosite: 2D advection problem solver

Fosite implements a method for the solution of hyperbolic conservation laws in curvilinear orthogonal coordinates. It is written in Fortran 90/95 integrating object-oriented (OO) design patterns, incorporating the flexibility of OO-programming into Fortran 90/95 while preserving the efficiency of the numerical computation. Although mainly intended for CFD simulations, Fosite's modular design allows its application to other advection problems as well. Unlike other two-dimensional implementations of finite volume methods, it accounts for local conservation of specific angular momentum. This feature turns the program into a perfect tool for astrophysical simulations where angular momentum transport is crucial. Angular momentum transport is not only implemented for standard coordinate systems with rotational symmetry (i.e. cylindrical, spherical) but also for a general set of orthogonal coordinate systems allowing the use of exotic curvilinear meshes (e.g. oblate-spheroidal). As in the case of the advection problem, this part of the software is also kept modular, therefore new geometries may be incorporated into the framework in a straightforward manner.

[ascl:1610.012]
Fourierdimredn: Fourier dimensionality reduction model for interferometric imaging

Fourierdimredn (Fourier dimensionality reduction) implements Fourier-based dimensionality reduction of interferometric data. Written in Matlab, it derives the theoretically optimal dimensionality reduction operator from a singular value decomposition perspective of the measurement operator. Fourierdimredn ensures a fast implementation of the full measurement operator and also preserves the i.i.d. Gaussian properties of the original measurement noise.

[ascl:1010.002]
fpack: FITS Image Compression Program

fpack is a utility program for optimally compressing images in the FITS data format. The associated funpack program will restore the compressed file back to its original state. These programs may be run from the host operating system command line and are analogous to the gzip and gunzip utility programs, except that they are specifically optimized for FITS format images and offer a wider choice of compression options.

fpack uses the tiled image compression convention for storing the compressed images. This convention can in principle support any number of of different compression algorithms; currently GZIP, Rice, Hcompress, and the IRAF pixel list compression algorithms have been implemented.

The main advantages of fpack compared to the commonly used technique of externally compressing the whole FITS file with gzip are:

- It is generally faster and offers better compression than gzip.
- The FITS header keywords remain uncompressed for fast access.
- Each HDU of a multi-extension FITS file is compressed separately, so it is not necessary to uncompress the entire file to read a single image in a multi-extension file.
- Dividing the image into tiles before compression enables faster access to small subsections of the image.
- The compressed image is itself a valid FITS file and can be manipulated by other general FITS utility software.
- Lossy compression can be used for much higher compression in cases where it is not necessary to exactly preserve the original image.
- The CHECKSUM keywords are automatically updated to help verify the integrity of the files.
- Software that supports the tiled image compression technique can directly read and write the FITS images in their compressed form.

[ascl:1610.014]
Freddi: Fast Rise Exponential Decay accretion Disk model Implementation

Freddi (Fast Rise Exponential Decay: accretion Disk model Implementation) solves 1-D evolution equations of the Shakura-Sunyaev accretion disk. It simulates fast rise exponential decay (FRED) light curves of low mass X-ray binaries (LMXBs). The basic equation of the viscous evolution relates the surface density and viscous stresses and is of diffusion type; evolution of the accretion rate can be found on solving the equation. The distribution of viscous stresses defines the emission from the source. The standard model for the accretion disk is implied; the inner boundary of the disk is at the ISCO or can be explicitely set. The boundary conditions in the disk are the zero stress at the inner boundary and the zero accretion rate at the outer boundary. The conditions are suitable during the outbursts in X-ray binary transients with black holes. In a binary system, the accretion disk is radially confined. In Freddi, the outer radius of the disk can be set explicitely or calculated as the position of the tidal truncation radius.

[ascl:1211.002]
FreeEOS: Equation of State for stellar interiors calculations

FreeEOS is a Fortran library for rapidly calculating the equation of state using an efficient free-energy minimization technique that is suitable for physical conditions in stellar interiors. Converged FreeEOS solutions can be reliably determined for the first time for physical conditions occurring in stellar models with masses between 0.1 M_{☉} and the hydrogen-burning limit near 0.07 M_{☉} and hot brown-dwarf models just below that limit. However, an initial survey of results for those conditions showed EOS discontinuities (plasma phase transitions) and other problems which will need to be addressed in future work by adjusting the interaction radii characterizing the pressure ionization used for the FreeEOS calculations.

[ascl:1508.004]
FRELLED: FITS Realtime Explorer of Low Latency in Every Dimension

FRELLED (FITS Realtime Explorer of Low Latency in Every Dimension) creates 3D images in real time from 3D FITS files and is written in Python for the 3D graphics suite Blender. Users can interactively generate masks around regions of arbitrary geometry and use them to catalog sources, hide regions, and perform basic analysis (*e.g.*, image statistics within the selected region, generate contour plots, query NED and the SDSS). World coordinates are supported and multi-volume rendering is possible. FRELLED is designed for viewing HI data cubes and provides a number of tasks to commonly-used MIRIAD (ascl:1106.007) tasks (e.g. mbspect); however, many of its features are suitable for any type of data set. It also includes an n-body particle viewer with the ability to display 3D vector information as well as the ability to render time series movies of multiple FITS files and setup simple turntable rotation movies for single files.

[ascl:1406.006]
FROG: Time-series analysis

FROG performs time series analysis and display. It provides a simple user interface for astronomers wanting to do time-domain astrophysics but still offers the powerful features found in packages such as PERIOD (ascl:1406.005). FROG includes a number of tools for manipulation of time series. Among other things, the user can combine individual time series, detrend series (multiple methods) and perform basic arithmetic functions. The data can also be exported directly into the TOPCAT (ascl:1101.010) application for further manipulation if needed.

[ascl:1506.006]
fsclean: Faraday Synthesis CLEAN imager

Fsclean produces 3D Faraday spectra using the Faraday synthesis method, transforming directly from multi-frequency visibility data to the Faraday depth-sky plane space. Deconvolution is accomplished using the CLEAN algorithm, and the package includes Clark and Högbom style CLEAN algorithms. Fsclean reads in MeasurementSet visibility data and produces HDF5 formatted images; it handles images and data of arbitrary size, using scratch HDF5 files as buffers for data that is not being immediately processed, and is limited only by available disk space.

[ascl:1010.043]
FSPS: Flexible Stellar Population Synthesis

FSPS is a flexible SPS package that allows the user to compute simple stellar populations (SSPs) for a range of IMFs and metallicities, and for a variety of assumptions regarding the morphology of the horizontal branch, the blue straggler population, the post--AGB phase, and the location in the HR diagram of the TP-AGB phase. From these SSPs the user may then generate composite stellar populations (CSPs) for a variety of star formation histories (SFHs) and dust attenuation prescriptions. Outputs include the "observed" spectra and magnitudes of the SSPs and CSPs at arbitrary redshift. In addition to these fortran routines, several IDL routines are provided that allow easy manipulation of the output. FSPS was designed with the intention that the user would make full use of the provided fortran routines. However, the full FSPS package is quite large, and requires some time for the user to become familiar with all of the options and syntax. Some users may only need SSPs for a range of metallicities and IMFs. For such users, standard SSP sets for several IMFs, evolutionary tracks, and spectral libraries are available here.

[ascl:9912.002]
FTOOLS: A general package of software to manipulate FITS files

FTOOLS, a highly modular collection of utilities for processing and analyzing data in the FITS (Flexible Image Transport System) format, has been developed in support of the HEASARC (High Energy Astrophysics Research Archive Center) at NASA's Goddard Space Flight Center. The FTOOLS package contains many utility programs which perform modular tasks on any FITS image or table, as well as higher-level analysis programs designed specifically for data from current and past high energy astrophysics missions. The utility programs for FITS tables are especially rich and powerful, and provide functions for presentation of file contents, extraction of specific rows or columns, appending or merging tables, binning values in a column or selecting subsets of rows based on a boolean expression. Individual FTOOLS programs can easily be chained together in scripts to achieve more complex operations such as the generation and displaying of spectra or light curves. FTOOLS development began in 1991 and has produced the main set of data analysis software for the current ASCA and RXTE space missions and for other archival sets of X-ray and gamma-ray data. The FTOOLS software package is supported on most UNIX platforms and on Windows machines. The user interface is controlled by standard parameter files that are very similar to those used by IRAF. The package is self documenting through a stand alone help task called fhelp. Software is written in ANSI C and FORTRAN to provide portability across most computer systems. The data format dependencies between hardware platforms are isolated through the FITSIO library package.

[ascl:1112.002]
Funtools: FITS Users Need Tools

Funtools is a "minimal buy-in" FITS library and utility package developed at the the High Energy Astrophysics Division of SAO. The Funtools library provides simplified access to a wide array of file types: standard astronomical FITS images and binary tables, raw arrays and binary event lists, and even tables of ASCII column data. A sophisticated region filtering library (compatible with ds9) filters images and tables using boolean operations between geometric shapes, support world coordinates, etc. Funtools also supports advanced capabilities such as optimized data searching using index files.

Because Funtools consists of a library and a set of user programs, it is most appropriately built from source. Funtools has been ported to Solaris, Linux, LinuxPPC, SGI, Alpha OSF1, Mac OSX (darwin) and Windows 98/NT/2000/XP. Once the source code tar file is retrieved, Funtools can be built and installed easily using standard commands.

[ascl:1205.005]
Fv: Interactive FITS file editor

[ascl:1010.015]
Fyris Alpha: Computational Fluid Dynamics Code

Fyris Alpha is a high resolution, shock capturing, multi-phase, up-wind Godunov method hydrodynamics code that includes a variable equation of state and optional microphysics such as cooling, gravity and multiple tracer variables. The code has been designed and developed for use primarily in astrophysical applications, such as galactic and interstellar bubbles, hypersonic shocks, and a range of jet phenomena. Fyris Alpha boasts both higher performance and more detailed microphysics than its predecessors, with the aim of producing output that is closer to the observational domain, such as emission line fluxes, and eventually, detailed spectral synthesis. Fyris Alpha is approximately 75,000 lines of C code; it encapsulates the split sweep semi-lagrangian remap PPM method used by ppmlr (in turn developed from VH1, Blondin et al. 1998) but with an improved Riemann solver, which is derived from the exact solver of Gottlieb and Groth (1988), a significantly faster solution than previous solvers. It has a number of optimisations that have improved the speed so that additional calculations neeed for multi-phase simulations become practical.

[ascl:0003.001]
GADGET-2: A Code for Cosmological Simulations of Structure Formation

The cosmological simulation code GADGET-2, a new massively parallel TreeSPH code, is capable of following a collisionless fluid with the N-body method, and an ideal gas by means of smoothed particle hydrodynamics (SPH). The implementation of SPH manifestly conserves energy and entropy in regions free of dissipation, while allowing for fully adaptive smoothing lengths. Gravitational forces are computed with a hierarchical multipole expansion, which can optionally be applied in the form of a TreePM algorithm, where only short-range forces are computed with the `tree'-method while long-range forces are determined with Fourier techniques. Time integration is based on a quasi-symplectic scheme where long-range and short-range forces can be integrated with different timesteps. Individual and adaptive short-range timesteps may also be employed. The domain decomposition used in the parallelisation algorithm is based on a space-filling curve, resulting in high flexibility and tree force errors that do not depend on the way the domains are cut. The code is efficient in terms of memory consumption and required communication bandwidth. It has been used to compute the first cosmological N-body simulation with more than 10^10 dark matter particles, reaching a homogeneous spatial dynamic range of 10^5 per dimension in a 3D box. It has also been used to carry out very large cosmological SPH simulations that account for radiative cooling and star formation, reaching total particle numbers of more than 250 million. GADGET-2 is publicly released to the research community.

[ascl:1108.005]
Gaepsi: Gadget Visualization Toolkit

Feng, Yu; Croft, Rupert A. C.; Di Matteo, Tiziana; Khandai, Nishikanta; Sargent, Randy; Nourbakhsh, Illah; Dille, Paul; Bartley, Chris; Springel, Volker; Jana, Anirban; Gardner, Jeffrey

Gaepsi is a PYTHON extension for visualizing cosmology simulations produced by Gadget. Visualization is the most important facet of Gaepsi, but it also allows data analysis on GADGET simulations with its growing number of physics related subroutines and constants. Unlike mesh based scheme, SPH simulations are directly visible in the sense that a splatting process is required to produce raster images from the simulations. Gaepsi produces images of 2-dimensional line-of-sight projections of the simulation. Scalar fields and vector fields are both supported.

Besides the traditional way of slicing a simulation, Gaepsi also has built-in support of 'Survey-like' domain transformation proposed by Carlson & White. An improved implementation is used in Gaepsi. Gaepsi both implements an interactive shell for plotting and exposes its API for batch processing. When complied with OpenMP, Gaepsi automatically takes the advantage of the multi-core computers. In interactive mode, Gaepsi is capable of producing images of size up to 32000 x 32000 pixels. The user can zoom, pan and rotate the field with a command in on the finger tip. The interactive mode takes full advantages of matplotlib's rich annotating, labeling and image composition facilities. There are also built-in commands to add objects that are commonly used in cosmology simulations to the figures.

[ascl:1403.024]
GAIA: Graphical Astronomy and Image Analysis Tool

GAIA is an image and data-cube display and analysis tool for astronomy. It provides the usual facilities of image display tools, plus more astronomically useful ones such as aperture and optimal photometry, contouring, source detection, surface photometry, arbitrary region analysis, celestial coordinate readout, calibration and modification, grid overlays, blink comparison, defect patching and the ability to query on-line catalogues and image servers. It can also display slices from data-cubes, extract and visualize spectra as well as perform full 3D rendering. GAIA uses the Starlink software environment (ascl:1110.012) and is derived from the ESO SkyCat tool (ascl:1109.019).

[submitted]
Gala: Galactic astronomy and gravitational dynamics

Gala is a Python package (and Astropy affiliated package) for Galactic astronomy and gravitational dynamics. The bulk of the package centers around implementations of gravitational potentials, numerical integration, nonlinear dynamics, and astronomical velocity transformations (i.e. proper motions). Gala uses the Astropy units and coordinates subpackages extensively to provide a clean, pythonic interface to these features but does any heavy-lifting in C and Cython for speed.

[ascl:1302.011]
GALA: Stellar atmospheric parameters and chemical abundances

GALA is a freely distributed Fortran code to derive the atmospheric parameters (temperature, gravity, microturbulent velocity and overall metallicity) and abundances for individual species of stellar spectra using the classical method based on the equivalent widths of metallic lines. The abundances of individual spectral lines are derived by using the WIDTH9 code developed by R. L. Kurucz. GALA is designed to obtain the best model atmosphere, by optimizing temperature, surface gravity, microturbulent velocity and metallicity, after rejecting the discrepant lines. Finally, it computes accurate internal errors for each atmospheric parameter and abundance. The code obtains chemical abundances and atmospheric parameters for large stellar samples quickly, thus making GALA an useful tool in the epoch of the multi-object spectrographs and large surveys.

[ascl:1109.011]
GalactICS: Galaxy Model Building Package

GalactICS generates N-body realizations of axisymmetric galaxy models consisting of disk, bulge and halo. Some of the code is in Fortran 77, using lines longer than 72 characters in some cases. The -e flag in the makefile allow for this for a Solaris f77 compiler. Other programs are written in C. Again, the linking between these routines works on Solaris systems, but may need to be adjusted for other architectures. We have found that linking using f77 instead of ld will often automatically load the appropriate libraries.

The graphics output by some of the programs (dbh, plotforce, diskdf, plothalo) uses the PGPLOT library. Alternatively, remove all calls to routines with names starting with "PG", as well as the -lpgplot flag in the Makefile, and the programs should still run fine.

[ascl:1108.004]
Galacticus: A Semi-Analytic Model of Galaxy Formation

Galacticus is designed to solve the physics involved in the formation of galaxies within the current standard cosmological framework. It is of a type of model known as “semi-analytic” in which the numerous complex non-linear physics involved are solved using a combination of analytic approximations and empirical calibrations from more detailed, numerical solutions. Models of this type aim to begin with the initial state of the Universe (specified shortly after the Big Bang) and apply physical principles to determine the properties of galaxies in the Universe at later times, including the present day. Typical properties computed include the mass of stars and gas in each galaxy, broad structural properties (e.g. radii, rotation speeds, geometrical shape etc.), dark matter and black hole contents, and observable quantities such as luminosities, chemical composition etc.

[ascl:1303.018]
Galactus: Modeling and fitting of galaxies from neutral hydrogen (HI) cubes

Galactus, written in python, is an astronomical software tool for the modeling and fitting of galaxies from neutral hydrogen (HI) cubes. Galactus uses a uniform medium to generate a cube. Galactus can perform the full-radiative transfer for the HI, so can model self-absorption in the galaxy.

[ascl:1408.011]
GALAPAGOS-C: Galaxy Analysis over Large Areas

GALAPAGOS-C is a C implementation of the IDL code GALAPAGOS (ascl:1203.002). It processes a complete set of survey images through automation of source detection via SExtractor (ascl:1010.064), postage stamp cutting, object mask preparation, sky background estimation and complex two-dimensional light profile Sérsic modelling via GALFIT (ascl:1104.010). GALAPAGOS-C uses MPI-parallelization, thus allowing quick processing of large data sets. The code can fit multiple Sérsic profiles to each galaxy, each representing distinct galaxy components (e.g. bulge, disc, bar), and optionally can fit asymmetric Fourier mode distortions.

[ascl:1203.002]
GALAPAGOS: Galaxy Analysis over Large Areas: Parameter Assessment by GALFITting Objects from SExtractor

GALAPAGOS, Galaxy Analysis over Large Areas: Parameter Assessment by GALFITting Objects from SExtractor (ascl:1010.064), automates source detection, two-dimensional light-profile Sersic modelling and catalogue compilation in large survey applications. Based on a single setup, GALAPAGOS can process a complete set of survey images. It detects sources in the data, estimates a local sky background, cuts postage stamp images for all sources, prepares object masks, performs Sersic fitting including neighbours and compiles all objects in a final output catalogue. For the initial source detection GALAPAGOS applies SExtractor, while GALFIT (ascl:1104.010) is incorporated for modelling Sersic profiles. It measures the background sky involved in the Sersic fitting by means of a flux growth curve. GALAPAGOS determines postage stamp sizes based on SExtractor shape parameters. In order to obtain precise model parameters GALAPAGOS incorporates a complex sorting mechanism and makes use of multiplexing capabilities. It combines SExtractor and GALFIT data in a single output table. When incorporating information from overlapping tiles, GALAPAGOS automatically removes multiple entries from identical sources. GALAPAGOS is programmed in the Interactive Data Language, IDL. A C implementation of the software, GALAPAGOS-C (ascl:1408.011), is available.

[ascl:1503.002]
Galax2d: 2D isothermal Euler equations solver

Galax2d computes the 2D stationary solution of the isothermal Euler equations of gas dynamics in a rotating galaxy with a weak bar. The gravitational potential represents a weak bar and controls the flow. A damped Newton method solves the second-order upwind discretization of the equations for a steady-state solution, using a consistent linearization and a direct solver. The code can be applied as a tool for generating flow models if used on not too fine meshes, up to 256 by 256 cells for half a disk in polar coordinates.

[ascl:1104.005]
GALAXEV: Evolutionary Stellar Population Synthesis Models

GALAXEV is a library of evolutionary stellar population synthesis models computed using the new isochrone synthesis code of Bruzual & Charlot (2003). This code allows one to computes the spectral evolution of stellar populations in wide ranges of ages and metallicities at a resolution of 3 Å across the whole wavelength range from 3200 Å to 9500 Å, and at lower resolution outside this range.

[ascl:1101.007]
Galaxia: A Code to Generate a Synthetic Survey of the Milky Way

We present here a fast code for creating a synthetic survey of the Milky Way. Given one or more color-magnitude bounds, a survey size and geometry, the code returns a catalog of stars in accordance with a given model of the Milky Way. The model can be specified by a set of density distributions or as an N-body realization. We provide fast and efficient algorithms for sampling both types of models. As compared to earlier sampling schemes which generate stars at specified locations along a line of sight, our scheme can generate a continuous and smooth distribution of stars over any given volume. The code is quite general and flexible and can accept input in the form of a star formation rate, age metallicity relation, age velocity dispersion relation and analytic density distribution functions. Theoretical isochrones are then used to generate a catalog of stars and support is available for a wide range of photometric bands. As a concrete example we implement the Besancon Milky Way model for the disc. For the stellar halo we employ the simulated stellar halo N-body models of Bullock & Johnston (2005). In order to sample N-body models, we present a scheme that disperses the stars spawned by an N-body particle, in such a way that the phase space density of the spawned stars is consistent with that of the N-body particles. The code is ideally suited to generating synthetic data sets that mimic near future wide area surveys such as GAIA, LSST and HERMES. As an application we study the prospect of identifying structures in the stellar halo with a simulated GAIA survey.

[ascl:1312.010]
GalaxyCount: Galaxy counts and variance calculator

GalaxyCount calculates the number and standard deviation of galaxies in a magnitude limited observation of a given area. The methods to calculate both the number and standard deviation may be selected from different options. Variances may be computed for circular, elliptical and rectangular window functions.

[ascl:1702.006]
GalaxyGAN: Generative Adversarial Networks for recovery of galaxy features

GalaxyGAN uses Generative Adversarial Networks to reliably recover features in images of galaxies. The package uses machine learning to train on higher quality data and learns to recover detailed features such as galaxy morphology by effectively building priors. This method opens up the possibility of recovering more information from existing and future imaging data.

[ascl:1010.033]
GALEV Evolutionary Synthesis Models

GALEV evolutionary synthesis models describe the evolution of stellar populations in general, of star clusters as well as of galaxies, both in terms of resolved stellar populations and of integrated light properties over cosmological timescales of > 13 Gyr from the onset of star formation shortly after the Big Bang until today.

For galaxies, GALEV includes a simultaneous treatment of the chemical evolution of the gas and the spectral evolution of the stellar content, allowing for a chemically consistent treatment using input physics (stellar evolutionary tracks, stellar yields and model atmospheres) for a large range of metallicities and consistently account for the increasing initial abundances of successive stellar generations.

[ascl:1104.010]
GALFIT: Detailed Structural Decomposition of Galaxy Images

GALFIT is a two-dimensional (2-D) fitting algorithm designed to extract structural components from galaxy images, with emphasis on closely modeling light profiles of spatially well-resolved, nearby galaxies observed with the Hubble Space Telescope. The algorithm improves on previous techniques in two areas: 1.) by being able to simultaneously fit a galaxy with an arbitrary number of components, and 2.) with optimization in computation speed, suited for working on large galaxy images. 2-D models such as the "Nuker'' law, the Sersic (de Vaucouleurs) profile, an exponential disk, and Gaussian or Moffat functions are used. The azimuthal shapes are generalized ellipses that can fit disky and boxy components. Many galaxies with complex isophotes, ellipticity changes, and position-angle twists can be modeled accurately in 2-D. When examined in detail, even simple-looking galaxies generally require at least three components to be modeled accurately rather than the one or two components more often employed. This is illustrated by way of seven case studies, which include regular and barred spiral galaxies, highly disky lenticular galaxies, and elliptical galaxies displaying various levels of complexities. A useful extension of this algorithm is to accurately extract nuclear point sources in galaxies.

[ascl:1510.005]
GALFORM: Galactic modeling

GALFORM is a semi-analytic model for calculating the formation and evolution of galaxies in hierarchical clustering cosmologies. Using a Monte Carlo algorithm to follow the merging evolution of dark matter haloes with arbitrary mass resolution, it incorporates realistic descriptions of the density profiles of dark matter haloes and the gas they contain. It follows the chemical evolution of gas and stars, and the associated production of dust and includes a detailed calculation of the sizes of discs and spheroids.

[ascl:1408.008]
GALIC: Galaxy initial conditions construction

GalIC (GALaxy Initial Conditions) is an implementation of an iterative method to construct steady state composite halo-disk-bulge galaxy models with prescribed density distribution and velocity anisotropy that can be used as initial conditions for N-body simulations. The code is parallelized for distributed memory based on MPI. While running, GalIC produces "snapshot files" that can be used as initial conditions files. GalIC supports the three file formats ('type1' format, the slightly improved 'type2' format, and an HDF5 format) of the GADGET (ascl:0003.001) code for its output snapshot files.

[ascl:1511.010]
Galileon-Solver: N-body code

Galileon-Solver adds an extra force to PMCode (ascl:9909.001) using a modified Poisson equation to provide a non-linearly transformed density field, with the operations all performed in real space. The code's implicit spherical top-hat assumption only works over fairly long distance averaging scales, where the coarse-grained picture it relies on is a good approximation of reality; it uses discrete Fourier transforms and cyclic reduction in the usual way.

[ascl:1501.014]
GalPaK 3D: Galaxy parameters and kinematics extraction from 3D data

GalPaK 3D extracts the intrinsic (i.e. deconvolved) galaxy parameters and kinematics from any 3-dimensional data. The algorithm uses a disk parametric model with 10 free parameters (which can also be fixed independently) and a MCMC approach with non-traditional sampling laws in order to efficiently probe the parameter space. More importantly, it uses the knowledge of the 3-dimensional spread-function to return the intrinsic galaxy properties and the intrinsic data-cube. The 3D spread-function class is flexible enough to handle any instrument.

GalPaK 3D can simultaneously constrain the kinematics and morphological parameters of (non-merging, i.e. regular) galaxies observed in non-optimal seeing conditions and can also be used on AO data or on high-quality, high-SNR data to look for non-axisymmetric structures in the residuals.

[ascl:1611.006]
GalPot: Galaxy potential code

GalPot finds the gravitational potential associated with axisymmetric density profiles. The package includes code that performs transformations between commonly used coordinate systems for both positions and velocities (the class OmniCoords), and that integrates orbits in the potentials. GalPot is a stand-alone version of Walter Dehnen's GalaxyPotential C++ code taken from the falcON code in the NEMO Stellar Dynamics Toolbox (ascl:1010.051).

[ascl:1010.028]
GALPROP: Code for Cosmic-ray Transport and Diffuse Emission Production

GALPROP is a numerical code for calculating the propagation of relativistic charged particles and the diffuse emissions produced during their propagation. The GALPROP code incorporates as much realistic astrophysical input as possible together with latest theoretical developments. The code calculates the propagation of cosmic-ray nuclei, antiprotons, electrons and positrons, and computes diffuse γ-rays and synchrotron emission in the same framework. Each run of the code is governed by a configuration file allowing the user to specify and control many details of the calculation. Thus, each run of the code corresponds to a potentially different "model." The code continues to be developed and is available to the scientific community.

[ascl:1411.008]
galpy: Galactic dynamics package

galpy is a python package for galactic dynamics. It supports orbit integration in a variety of potentials, evaluating and sampling various distribution functions, and the calculation of action-angle coordinates for all static potentials.

[ascl:1402.009]
GalSim: Modular galaxy image simulation toolkit

GalSim is a fast, modular software package for simulation of astronomical images. Though its primary purpose is for tests of weak lensing analysis methods, it can be used for other purposes. GalSim allows galaxies and PSFs to be represented in a variety of ways, and can apply shear, magnification, dilation, or rotation to a galaxy profile including lensing-based models from a power spectrum or NFW halo profile. It can write images in regular FITS files, FITS data cubes, or multi-extension FITS files. It can also compress the output files using various compressions including gzip, bzip2, and rice. The user interface is in python or via configuration scripts, and the computations are done in C++ for speed.

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