Results 1751-1800 of 2074 (2041 ASCL, 33 submitted)

[ascl:1505.010]
COBS: COnstrained B-Splines

COBS (COnstrained B-Splines), written in R, creates constrained regression smoothing splines via linear programming and sparse matrices. The method has two important features: the number and location of knots for the spline fit are established using the likelihood-based Akaike Information Criterion (rather than a heuristic procedure); and fits can be made for quantiles (e.g. 25% and 75% as well as the usual 50%) in the response variable, which is valuable when the scatter is asymmetrical or non-Gaussian. This code is useful for, for example, estimating cluster ages when there is a wide spread in stellar ages at a chosen absorption, as a standard regression line does not give an effective measure of this relationship.

[ascl:1011.014]
CO5BOLD: COnservative COde for the COmputation of COmpressible COnvection in a BOx of L Dimensions with l=2,3

The code was supplemented with an (optional) MHD version [Schaffenberger et al. (2005)] that can treat magnetic fields. There are also modules for the formation and advection of dust available. The current version now contains the treatment of chemical reaction networks, mostly used for the formation of molecules [Wedemeyer-Böhm et al. (2005)], and hydrogen ionization [Leenaarts & Wedemeyer-Böhm (2005)], too.

Freytag, Bernd; Steffen, Matthias; Wedemeyer-Böhm, Sven; Ludwig, Hans-Günter; Leenaarts, Jorrit; Schaffenberger, Werner; Allard, France; Chiavassa, Andrea; Höfner, Susanne; Kamp, Inga; Steiner, Oskar

CO5BOLD - nickname COBOLD - is the short form of "COnservative COde for the COmputation of COmpressible COnvection in a BOx of L Dimensions with l=2,3''.

It is used to model solar and stellar surface convection. For solar-type stars only a small fraction of the stellar surface layers are included in the computational domain. In the case of red supergiants the computational box contains the entire star. Recently, the model range has been extended to sub-stellar objects (brown dwarfs).

CO5BOLD solves the coupled non-linear equations of compressible hydrodynamics in an external gravity field together with non-local frequency-dependent radiation transport. Operator splitting is applied to solve the equations of hydrodynamics (including gravity), the radiative energy transfer (with a long-characteristics or a short-characteristics ray scheme), and possibly additional 3D (turbulent) diffusion in individual sub steps. The 3D hydrodynamics step is further simplified with directional splitting (usually). The 1D sub steps are performed with a Roe solver, accounting for an external gravity field and an arbitrary equation of state from a table.

The radiation transport is computed with either one of three modules:

- MSrad module: It uses long characteristics. The lateral boundaries have to be periodic. Top and bottom can be closed or open ("solar module'').

- LHDrad module: It uses long characteristics and is restricted to an equidistant grid and open boundaries at all surfaces (old "supergiant module'').

- SHORTrad module: It uses short characteristics and is restricted to an equidistant grid and open boundaries at all surfaces (new "supergiant module'').

The code was supplemented with an (optional) MHD version [Schaffenberger et al. (2005)] that can treat magnetic fields. There are also modules for the formation and advection of dust available. The current version now contains the treatment of chemical reaction networks, mostly used for the formation of molecules [Wedemeyer-Böhm et al. (2005)], and hydrogen ionization [Leenaarts & Wedemeyer-Böhm (2005)], too.

CO5BOLD is written in Fortran90. The parallelization is done with OpenMP directives.

[ascl:1101.005]
CMHOG: Code for Ideal Compressible Hydrodynamics

CMHOG (Connection Machine Higher Order Godunov) is a code for ideal compressible hydrodynamics based on the Lagrange-plus-remap version of the piecewise parabolic method (PPM) of Colella & Woodward (1984, J. Comp. Phys., 74, 1). It works in one-, two- or three-dimensional Cartesian coordinates with either an adiabatic or isothermal equation of state. A limited amount of extra physics has been added using operator splitting, including optically-thin radiative cooling, and chemistry for combustion simulations.

[ascl:1109.020]
CMFGEN: Probing the Universe through Spectroscopy

A radiative transfer code designed to solve the radiative transfer and statistical equilibrium equations in spherical geometry. It has been designed for application to W-R stars, O stars, and Luminous Blue-Variables. CMFGEN allows fundamental parameters such as effective temperatures, stellar radii and stellar luminosities to be determined. It can provide constraints on mass-loss rates, and allow abundance determinations for a wide range of atomic species. Further it can provide accurate energy distributions, and hence ionizing fluxes, which can be used as input for codes which model the spectra of HII regions and ring nebular.

[ascl:1907.022]
CMDPT: Color Magnitude Diagrams Plot Tool

CMD Plot Tool calculates and plots Color Magnitude Diagrams (CMDs) from astronomical photometric data, *e.g.* of a star cluster observed in two filter bandpasses. It handles multiple file formats (plain text, DAOPHOT .mag files, ACS Survey of Galactic Globular Clusters .zpt files) to generate professional and customized plots without a steep learning curve. It works “out of the box” and does not require any installation of development environments, additional libraries, or resetting of system paths. The tool is available as a single application/executable file with the source code. Sample data is also bundled for demonstration. CMD Plot Tool can also convert DAOPHOT magnitude files to CSV format.

[ascl:1611.020]
CMCIRSED: Far-infrared spectral energy distribution fitting for galaxies near and far

The Caitlin M. Casey Infra Red Spectral Energy Distribution model (CMCIRSED) provides a simple SED fitting technique suitable for a wide range of IR data, from sources which have only three IR photometric points to sources with >10 photometric points. These SED fits produce accurate estimates to a source's integrated IR luminosity, dust temperature and dust mass. CMCIRSED is based on a single dust temperature greybody fit linked to a MIR power law, fitted simultaneously to data across ∼5–2000 μm.

[ascl:1112.011]
CMBview: A Mac OS X program for viewing HEALPix-format sky map data on a sphere

CMBview is a viewer for FITS files containing HEALPix sky maps. Sky maps are projected onto a 3d sphere which can be rotated and zoomed interactively with the mouse. Features include:

- rendering of the field of Stokes vectors

- ray-tracing mode in which each screen pixel is projected onto the sphere for high quality rendering

- control over sphere lighting

- export an arbitrarily large rendered texture

- variety of preset colormaps

[ascl:1109.009]
CMBquick: Spectrum and Bispectrum of Cosmic Microwave Background (CMB)

CMBquick is a package for Mathematica in which tools are provided to compute the spectrum and bispectrum of Cosmic Microwave Background (CMB). It is unavoidably slow, but the main goal is not to design a tool which can be used for systematic exploration of parameters in cosmology, but rather a toy CMB code which is transparent and easily modified. Considering this, the name chosen is nothing but a joke which refers to the widely spread and used softwares CMBFAST, CAMB or CMBeasy (ascl:1007.004), which should be used for serious and heavy first order CMB computations, and which are indeed very fast.

The package CMBquick is unavoidably slow when it comes to compute the multipoles Cls, and most of it is due to the access time for variables which in Mathematica is approximately ten times slower than in C or Fortran. CMBquick is thus approximately 10 times slower than CAMB and cannot be used for the same reasons. It uses the same method as CAMB for computing the CMB spectrum, which is based on the line of sight approach. However the integration is performed in a different gauge with different time steps and k-spacing. It benefits from the power of Mathematica on numerical resolution of stiff differential systems, and the transfer functions can be obtained with exquisite accuracy.

The purpose of CMBquick is thus twofold. First, CMBquick is a slow but precise and pedagogical, tool which can be used to explore and modify the physical content of the linear and non-linear dynamics. Second, it is a tool which can help developing templates for nonlinear computations, which could then be hard coded once their correctness is checked. The number of equations for non-linear dynamics is quite sizable and CMBquick makes it easy (but slow) to manipulate the non-linear equations, to solve them precisely, and to plot them.

[ascl:9909.004]
CMBFAST: A microwave anisotropy code

CMBFAST is the most extensively used code for computing cosmic microwave background anisotropy, polarization and matter power spectra. This package contains cosmological linear perturbation theory code to compute the evolution of various cosmological matter and radiation components, both today and at high redshift. The code has been tested over a wide range of cosmological parameters.

This code is no longer supported; please investigate using CAMB (ascl:1102.026) instead.

[ascl:1007.004]
CMBEASY: An object-oriented code for the cosmic microwave background

CMBEASY is a software package for calculating the evolution of density fluctuations in the universe. Most notably, the Cosmic Microwave Background temperature anisotropies. It features a Markov Chain Monte Carlo driver and many routines to compute likelihoods of any given model. It is based on the CMBFAST package by Uros Seljak and Matias Zaldarriaga.

[ascl:1106.023]
CMBACT: CMB from ACTive sources

This code is based on the cosmic string model described in this paper by Pogosian and Vachaspati, as well as on the CMBFAST code created by Uros Seljak and Matias Zaldarriaga. It contains an integrator for the vector contribution to the CMB temperature and polarization. The code is reconfigured to make it easier to use with or without active sources. To produce inflationary CMB spectra one simply sets the string tension to zero (gmu=0.0d0). For a non-zero value of tension only the string contribution is calculated.

An option is added to randomize the directions of velocities of consolidated segments as they evolve in time. In the original segment model, which is still the default version (irandomv=0), each segment is given a random velocity initially, but then continues to move in a straight line for the rest of its life. The new option (irandomv=1) allows to additionally randomize velocities of each segment at roughly each Hubble time. However, the merits of this new option are still under investigation. The default version (irandomv=0) is strongly recommended, since it actually gives reasonable unequal time correlators. For each Fourier mode, k, the string stress-energy components are now evaluated on a time grid sufficiently fine for that k.

[ascl:1106.018]
CMB B-modes from Faraday Rotation

This code is a quick and exact calculator of B-mode angular spectrum due to Faraday rotation by stochastic magnetic fields. Faraday rotation induced B-modes can provide a distinctive signature of primordial magnetic fields because of their characteristic frequency dependence and because they are only weakly damped on small scales, allowing them to dominate B-modes from other sources. By numerically solving the full CMB radiative transport equations, we study the B-mode power spectrum induced by stochastic magnetic fields that have significant power on scales smaller than the thickness of the last scattering surface. Constraints on the magnetic field energy density and inertial scale are derived from WMAP 7-year data, and are stronger than the big bang nucleosynthesis (BBN) bound for a range of parameters. Observations of the CMB polarization at smaller angular scales are crucial to provide tighter constraints or a detection.

[ascl:1802.003]
CMacIonize: Monte Carlo photoionisation and moving-mesh radiation hydrodynamics

CMacIonize simulates the self-consistent evolution of HII regions surrounding young O and B stars, or other sources of ionizing radiation. The code combines a Monte Carlo photoionization algorithm that uses a complex mix of hydrogen, helium and several coolants in order to self-consistently solve for the ionization and temperature balance at any given time, with a standard first order hydrodynamics scheme. The code can be run as a post-processing tool to get the line emission from an existing simulation snapshot, but can also be used to run full radiation hydrodynamical simulations. Both the radiation transfer and the hydrodynamics are implemented in a general way that is independent of the grid structure that is used to discretize the system, allowing it to be run both as a standard fixed grid code and also as a moving-mesh code.

[ascl:1905.022]
ClusterPyXT: Galaxy cluster pipeline for X-ray temperature maps

ClusterPyXT (Cluster Pypeline for X-ray Temperature maps) creates X-ray temperature maps, pressure maps, surface brightness maps, and density maps from X-ray observations of galaxy clusters to show turbulence, shock fronts, nonthermal phenomena, and the overall dynamics of cluster mergers. It requires CIAO (ascl:1311.006) and CALDB. The code analyzes archival data and provides capability for integrating additional observations into the analysis. The ClusterPyXT code is general enough to analyze data from other sources, such as galaxies, active galactic nuclei, and supernovae, though minor modifications may be necessary.

[ascl:1605.002]
cluster-lensing: Tools for calculating properties and weak lensing profiles of galaxy clusters

The cluster-lensing package calculates properties and weak lensing profiles of galaxy clusters. Implemented in Python, it includes cluster mass-richness and mass-concentration scaling relations, and NFW halo profiles for weak lensing shear, the differential surface mass density ΔΣ(r), and for magnification, Σ(r). Optionally the calculation will include the effects of cluster miscentering offsets.

[ascl:1610.008]
cluster-in-a-box: Statistical model of sub-millimeter emission from embedded protostellar clusters

Cluster-in-a-box provides a statistical model of sub-millimeter emission from embedded protostellar clusters and consists of three modules grouped in two scripts. The first (cluster_distribution) generates the cluster based on the number of stars, input initial mass function, spatial distribution and age distribution. The second (cluster_emission) takes an input file of observations, determines the mass-intensity correlation and generates outflow emission for all low-mass Class 0 and I sources. The output is stored as a FITS image where the flux density is determined by the desired resolution, pixel scale and cluster distance.

[ascl:1711.008]
clustep: Initial conditions for galaxy cluster halo simulations

clustep generates a snapshot in GADGET-2 (ascl:0003.001) format containing a galaxy cluster halo in equilibrium; this snapshot can also be read in RAMSES (ascl:1011.007) using the DICE patch. The halo is made of a dark matter component and a gas component, with the latter representing the ICM. Each of these components follows a Dehnen density profile, with gamma=0 or gamma=1. If gamma=1, then the profile corresponds to a Hernquist profile.

[ascl:1201.012]
CLUMPY: A code for gamma-ray signals from dark matter structures

CLUMPY is a public code for semi-analytical calculation of the gamma-ray flux astrophysical J-factor from dark matter annihilation/decay in the Galaxy, including dark matter substructures. The core of the code is the calculation of the line of sight integral of the dark matter density squared (for annihilations) or density (for decaying dark matter). The code can be used in three modes: i) to draw skymaps from the Galactic smooth component and/or the substructure contributions, ii) to calculate the flux from a specific halo (that is not the Galactic halo, e.g. dwarf spheroidal galaxies) or iii) to perform simple statistical operations from a list of allowed DM profiles for a given object. Extragalactic contributions and other tracers of DM annihilation (e.g. positrons, antiprotons) will be included in a second release.

[ascl:1107.014]
Clumpfind: Determining Structure in Molecular Clouds

We describe an automatic, objective routine for analyzing the clumpy structure in a spectral line position-position-velocity data cube. The algorithm works by first contouring the data at a multiple of the rms noise of the observations, then searches for peaks of emission which locate the clumps, and then follows them down to lower intensities. No a proiri clump profile is assumed. By creating simulated data, we test the performance of the algorithm and show that a contour map most accurately depicts internal structure at a contouring interval equal to twice the rms noise of the map. Blending of clump emission leads to small errors in mass and size determinations and in severe cases can result in a number of clumps being misidentified as a single unit, flattening the measured clump mass spectrum. The algorithm is applied to two real data sets as an example of its use. The Rosette molecular cloud is a 'typical' star-forming cloud, but in the Maddalena molecular cloud high-mass star formation is completely absent. Comparison of the two clump lists generated by the algorithm show that on a one-to-one basis the clumps in the star-forming cloud have higher peak temperatures, higher average densities, and are more gravitationally bound than in the non-star-forming cloud. Collective properties of the clumps, such as temperature-size-line-width-mass relations appear very similar, however. Contrary to the initial results reported in a previous paper (Williams & Blitz 1993), we find that the current, more thoroughly tested analysis finds no significant difference in the clump mass spectrum of the two clouds.

[ascl:1909.009]
CLOVER: Convolutional neural network spectra identifier and kinematics predictor

CLOVER (Convnet Line-fitting Of Velocities in Emission-line Regions) is a convolutional neural network (ConvNet) trained to identify spectra with two velocity components along the line of sight and predict their kinematics. It works with Gaussian emission lines (e.g., CO) and lines with hyperfine structure (e.g., NH3). CLOVER has two prediction steps, classification and parameter prediction. For the first step, CLOVER segments the pixels in an input data cube into one of three classes: noise (i.e., no emission), one-component (emission line with single velocity component), and two-component (emission line with two velocity components). For the pixels identified as two-components in the first step, a second regression ConvNet is used to predict centroid velocity, velocity dispersion, and peak intensity for each velocity component.

[ascl:9910.001]
Cloudy: Numerical simulation of plasmas and their spectra

Ferland, Gary; van Hoof, Peter; Verner, Dima; Verner, Katya; Ferguson, Jason; Hamann, Fred; Kingdon, Jim; Korista, Kirk; Shields, Joe

Cloudy is a large-scale spectral synthesis code designed to simulate fully physical conditions within an astronomical plasma and then predict the emitted spectrum. The code is freely available and is widely used in the analysis and interpretation of emission-line spectra.

[ascl:1103.015]
Cloudy_3D: Quick Pseudo-3D Photoionization Code

We developed a new quick pseudo-3D photoionization code based on Cloudy (G. Ferland) and IDL (RSI) tools. The code is running the 1D photoionization code Cloudy various times, changing at each run the input parameters (e.g. inner radius, density law) according to an angular law describing the morphology of the object. Then a cube is generated by interpolating the outputs of Cloudy. In each cell of the cube, the physical conditions (electron temperature and density, ionic fractions) and the emissivities of lines are determined. Associated tools (VISNEB and VELNEB_3D) are used to rotate the nebula and to compute surface brightness maps and emission line profiles, given a velocity law and taking into account the effect of the thermal broadening and eventually the turbulence. Integrated emission line profiles are computed, given aperture shapes and positions (seeing and instrumental width effects are included). The main advantage of this tool is the short time needed to compute a model (a few tens minutes).

[ascl:1602.019]
CLOC: Cluster Luminosity Order-Statistic Code

CLOC computes cluster order statistics, *i.e.* the luminosity distribution of the Nth most luminous cluster in a population. It is flexible and requires few assumptions, allowing for parametrized variations in the initial cluster mass function and its upper and lower cutoffs, variations in the cluster age distribution, stellar evolution and dust extinction, as well as observational uncertainties in both the properties of star clusters and their underlying host galaxies. It uses Markov chain Monte Carlo methods to search parameter space to find best-fitting values for the parameters describing cluster formation and disruption, and to obtain rigorous confidence intervals on the inferred values.

[ascl:1904.010]
CLEAR: CANDELS Ly-alpha Emission at Reionization processing pipeline and library

Simons, Raymond; Estrada-Carpenter, Vicente; Gosmeyer, Catherine; Papovich, Casey; Momcheva, Ivelina

The CLEAR pipeline and library performs various tasks for the CANDELS Ly-alpha Emission at Reionization (CLEAR) experiment of deep Hubble grism observations of high-z galaxies. It interlaces images, models contamination of overlapping grism spectra, extracts source spectra, stacks the extracted source spectra, and estimates fits for sources redshifts and emission lines.

[ascl:1407.010]
CLE: Coronal line synthesis

CLE, written in Fortran 77, synthesizes Stokes profiles of forbidden lines such as Fe XIII 1074.7nm, formed in magnetic dipole transitions under coronal conditions. The lines are assumed to be optically thin, excited by (anisotropic) photospheric radiation and thermal particle collisions.

[ascl:1807.013]
CLASSgal: Relativistic cosmological large scale structure code

CLASSgal computes large scale structure observables; it includes all relativistic corrections and computes both the power spectrum *C _{l}*(

[ascl:1106.020]
CLASS: Cosmic Linear Anisotropy Solving System

Boltzmann codes are used extensively by several groups for constraining cosmological parameters with Cosmic Microwave Background and Large Scale Structure data. This activity is computationally expensive, since a typical project requires from 10'000 to 100'000 Boltzmann code executions. The code CLASS (Cosmic Linear Anisotropy Solving System) incorporates improved approximation schemes leading to a simultaneous gain in speed and precision. We describe here the three approximations used by CLASS for basic LambdaCDM models, namely: a baryon-photon tight-coupling approximation which can be set to first order, second order or to a compromise between the two; an ultra-relativistic fluid approximation which had not been implemented in public distributions before; and finally a radiation streaming approximation taking reionisation into account.

[ascl:1312.013]
CJAM: First and second velocity moments calculations

CJAM calculates first and second velocity moments using the Jeans Anisotropic MGE (JAM) models of Cappellari (2008) and Cappellari (2012). These models have been extended to calculate all three (x, y, z) first moments and all six (xx, yy, zz, xy, xz, yz) second moments. CJAM, written in C, is based on the IDL implementation of the line-of-sight calculations by Michele Cappellari.

[ascl:1202.001]
CISM_DX: Visualization and analysis tool

CISM_DX is a community-developed suite of integrated data, models, and data and model explorers, for research and education. The data and model explorers are based on code written for OpenDX and Octave; OpenDX provides the visualization infrastructures as well as the process for creating user interfaces to the model and data, and Octave allows for extensive data manipulation and reduction operations. The CISM-DX package extends the capabilities of the core software programs to meet the needs of space physics researchers.

[ascl:1708.002]
CINE: Comet INfrared Excitation

CINE calculates infrared pumping efficiencies that can be applied to the most common molecules found in cometary comae such as water, hydrogen cyanide or methanol. One of the main mechanisms for molecular excitation in comets is the fluorescence by the solar radiation followed by radiative decay to the ground vibrational state. This command-line tool calculates the effective pumping rates for rotational levels in the ground vibrational state scaled by the heliocentric distance of the comet. Fluorescence coefficients are useful for modeling rotational emission lines observed in cometary spectra at sub-millimeter wavelengths. Combined with computational methods to solve the radiative transfer equations based, e.g., on the Monte Carlo algorithm, this model can retrieve production rates and rotational temperatures from the observed emission spectrum.

[ascl:1111.004]
CIGALE: Code Investigating GALaxy Emission

The CIGALE code has been developed to study the evolution of galaxies by comparing modelled galaxy spectral energy distributions (SEDs) to observed ones from the far ultraviolet to the far infrared. It extends the SED fitting algorithm written by Burgarella et al. (2005, MNRAS 360, 1411). While the previous code was designed to fit SEDs in the optical and near infrared, CIGALE is able to fit SEDs up to the far infrared using Dale & Helou (2002, ApJ 576, 159). CIGALE Bayesian and CIGALE Monte Carlo Markov Chain are available.

[ascl:1803.002]
CIFOG: Cosmological Ionization Fields frOm Galaxies

CIFOG is a versatile MPI-parallelised semi-numerical tool to perform simulations of the Epoch of Reionization. From a set of evolving cosmological gas density and ionizing emissivity fields, it computes the time and spatially dependent ionization of neutral hydrogen (HI), neutral (HeI) and singly ionized helium (HeII) in the intergalactic medium (IGM). The code accounts for HII, HeII, HeIII recombinations, and provides different descriptions for the photoionization rate that are used to calculate the residual HI fraction in ionized regions. This tool has been designed to be coupled to semi-analytic galaxy formation models or hydrodynamical simulations. The modular fashion of the code allows the user to easily introduce new descriptions for recombinations and the photoionization rate.

[ascl:1311.006]
CIAO: Chandra Interactive Analysis of Observations

CIAO is a data analysis system written for the needs of users of the Chandra X-ray Observatory. Because Chandra data is 4-dimensional (2 spatial, time, energy) and each dimension has many independent elements, CIAO was built to handle N-dimensional data without concern about which particular axes were being analyzed. Apart from a few Chandra instrument tools, CIAO is mission independent. CIAO tools read and write several formats, including FITS images and tables (which includes event files) and IRAF imh files. CIAO is a powerful system for the analysis of many types of data.

[ascl:1804.007]
chroma: Chromatic effects for LSST weak lensing

Chroma investigates biases originating from two chromatic effects in the atmosphere: differential chromatic refraction (DCR), and wavelength dependence of seeing. These biases arise when using the point spread function (PSF) measured with stars to estimate the shapes of galaxies with different spectral energy distributions (SEDs) than the stars.

[ascl:1209.004]
CHORIZOS: CHi-square cOde for parameterRized modeling and characterIZation of phOtometry and Spectrophotmetry

CHORIZOS is a multi-purpose Bayesian code developed in IDL to compare photometric data with model spectral energy distributions (SEDs). The user can select the SED family (e.g. Kurucz) and choose the behavior of each parameter (e.g. Teff) to be fixed, constrained to a given range, or unconstrained. The code calculates the likelihood for the full specified parameter ranges, thus allowing for the identification of multiple solutions and the evaluation of the full correlation matrix for the derived parameters of a single solution.

[ascl:1202.008]
Chombo: Adaptive Solutions of Partial Differential Equations

Chombo provides a set of tools for implementing finite difference methods for the solution of partial differential equations on block-structured adaptively refined rectangular grids. Both elliptic and time-dependent modules are included. Chombo supports calculations in complex geometries with both embedded boundaries and mapped grids, and also supports particle methods. Most parallel platforms are supported, and cross-platform self-describing file formats are included.

The Chombo package is a product of the community of Collaborators working with the Applied Numerical Algorithms Group (ANAG), part of the Computational Research Division at LBNL.

[ascl:1607.006]
Cholla: 3D GPU-based hydrodynamics code for astrophysical simulation

Cholla (Computational Hydrodynamics On ParaLLel Architectures) models the Euler equations on a static mesh and evolves the fluid properties of thousands of cells simultaneously using GPUs. It can update over ten million cells per GPU-second while using an exact Riemann solver and PPM reconstruction, allowing computation of astrophysical simulations with physically interesting grid resolutions (>256^3) on a single device; calculations can be extended onto multiple devices with nearly ideal scaling beyond 64 GPUs.

[ascl:1409.008]
CHLOE: A tool for automatic detection of peculiar galaxies

CHLOE is an image analysis unsupervised learning algorithm that detects peculiar galaxies in datasets of galaxy images. The algorithm first computes a large set of numerical descriptors reflecting different aspects of the visual content, and then weighs them based on the standard deviation of the values computed from the galaxy images. The weighted Euclidean distance of each galaxy image from the median is measured, and the peculiarity of each galaxy is determined based on that distance.

[ascl:1104.012]
CHIWEI: A Code of Goodness of Fit Tests for Weighted and Unweighed Histograms

A self-contained Fortran-77 program for goodness of fit tests for histograms with weighted entries as well as with unweighted entries is presented. The code calculates test statistic for case of histogram with normalized weights of events and for case of unnormalized weights of events.

[ascl:1602.017]
CHIP: Caltech High-res IRS Pipeline

CHIP (Caltech High-res IRS Pipeline) reduces high signal-to-noise short-high and long-high Spitzer-IRS spectra, especially that taken with dedicated background exposures. Written in IDL, it is independent of other Spitzer reduction tools except IRSFRINGE (ascl:1602.016).

[ascl:1403.006]
CHIMERA: Core-collapse supernovae simulation code

Mezzacappa, Anthony; Hix, Raph; Messor, Bronson; Lentz, Eric; Chertkow, Merek Austin; Parete-Koon, Suzanne; Lingerfelt, Eric

CHIMERA simulates core collapse supernovas; it is three-dimensional and accounts for the differing energies of neutrinos. This massively parallel multiphysics code conserves total energy (gravitational, internal, kinetic, and neutrino) to within 0.5 B, given a conservative gravitational potential. CHIMERA has three main components: a hydro component, a neutrino transport component, and a nuclear reaction network component. It also includes a Poisson solver for the gravitational potential and a sophisticated equation of state.

[ascl:1504.005]
chimenea: Multi-epoch radio-synthesis data imaging

Chimenea implements an heuristic algorithm for automated imaging of multi-epoch radio-synthesis data. It generates a deep image via an iterative Clean subroutine performed on the concatenated visibility set and locates steady sources in the field of view. The code then uses this information to apply constrained and then unconstrained (*i.e.*, masked/open-box) Cleans to the single-epoch observations. This obtains better results than if the single-epoch data had been processed independently without prior knowledge of the sky-model. The chimenea pipeline is built upon CASA (ascl:1107.013) subroutines, interacting with the CASA environment via the drive-casa (ascl:1504.006) interface layer.

[ascl:1308.017]
ChiantiPy: Python package for the CHIANTI atomic database

ChiantiPy is an object-orient Python package for calculating astrophysical spectra using the CHIANTI atomic database for astrophysical spectroscopy. It provides access to the database and the ability to calculate various physical quantities for the interpretation of astrophysical spectra.

[ascl:9911.004]
CHIANTI: A database for astrophysical emission line spectroscopy

CHIANTI consists of a critically evaluated set of atomic data necessary to calculate the emission line spectrum of astrophysical plasmas. The data consists of atomic energy levels, atomic radiative data such as wavelengths, weighted oscillator strengths and A values, and electron collisional excitation rates. A set of programs that use these data to calculate the spectrum in a desired wavelength range as a function of temperature and density are also provided. These programs have been written in Interactive Data Language (IDL) and descriptions of these various programs are provided on the website.

[ascl:1909.006]
ChempyMulti: Multi-star Bayesian inference with Chempy

ChempyMulti is an update to Chempy (ascl:1702.011) and provides yield table scoring and multi-star Bayesian inference. This replaces the ChempyScoring package in Chempy. Chempy is a flexible one-zone open-box chemical evolution model, incorporating abundance fitting and stellar feedback calculations. It includes routines for parameter optimization for simulations and observational data and yield table scoring.

[ascl:1702.011]
Chempy: A flexible chemical evolution model for abundance fitting

Chempy models Galactic chemical evolution (GCE); it is a parametrized open one-zone model within a Bayesian framework. A Chempy model is specified by a set of 5-10 parameters that describe the effective galaxy evolution along with the stellar and star-formation physics: e.g. the star-formation history (SFH), the feedback efficiency, the stellar initial mass function (IMF) and the incidence of supernova of type Ia (SN Ia). Chempy can sample the posterior probability distribution in the full model parameter space and test data-model matches for different nucleosynthetic yield sets, performing essentially as a chemical evolution fitting tool. Chempy can be used to confront predictions from stellar nucleosynthesis with complex abundance data sets and to refine the physical processes governing the chemical evolution of stellar systems.

ChempyMulti (ascl:1909.006) is available as an update to the ChempyScoring package.

[ascl:1412.002]
Cheetah: Starspot modeling code

Cheetah models starspots in photometric data (lightcurves) by calculating the modulation of a light curve due to starspots. The main parameters of the program are the linear and quadratic limb darkening coefficients, stellar inclination, spot locations and sizes, and the intensity ratio of the spots to the stellar photosphere. Cheetah uses uniform spot contrast and the minimum number of spots needed to produce a good fit and ignores bright regions for the sake of simplicity.

[ascl:1703.015]
Charm: Cosmic history agnostic reconstruction method

Charm (cosmic history agnostic reconstruction method) reconstructs the cosmic expansion history in the framework of Information Field Theory. The reconstruction is performed via the iterative Wiener filter from an agnostic or from an informative prior. The charm code allows one to test the compatibility of several different data sets with the LambdaCDM model in a non-parametric way.

[ascl:1105.005]
ChaNGa: Charm N-body GrAvity solver

ChaNGa (Charm N-body GrAvity solver) performs collisionless N-body simulations. It can perform cosmological simulations with periodic boundary conditions in comoving coordinates or simulations of isolated stellar systems. It also can include hydrodynamics using the Smooth Particle Hydrodynamics (SPH) technique. It uses a Barnes-Hut tree to calculate gravity, with hexadecapole expansion of nodes and Ewald summation for periodic forces. Timestepping is done with a leapfrog integrator with individual timesteps for each particle.

[ascl:1406.013]
CGS4DR: Automated reduction of data from CGS4

CGS4DR is data reduction software for the CGS4 instrument at UKIRT. The software can be used offline to reprocess CGS4 data. CGS4DR allows a wide variety of data reduction configurations, and can interlace oversampled data frames; reduce known bias, dark, flat, arc, object and sky frames; remove the sky, residual sky OH-lines (λ < 2.3 μm) and thermal emission (λ ≥ 2.3 μm) from data; and add data into groups for improved signal-to-noise. It can also extract and de-ripple a spectrum and offers a variety of ways to plot data, in addition to other useful features. CGS4DR is distributed as part of the Starlink software collection (ascl:1110.012).

Would you like to view a random code?