Results 201-250 of 2546 (2498 ASCL, 48 submitted)
TM (Torus Mapper) produces models for orbits in action-angle coordinates in axisymmetric potentials using torus mapping, a non-perturbative technique for creating orbital tori for specified values of the action integrals. It can compute a star's position at any time given an orbital torus and a star’s position at a reference time, and also provides a way to choose initial conditions for N-body simulations of realistic disc galaxies that start in perfect equilibrium. TM provides some advantages over use of a standard time-stepper to create orbits.
TLUSTY is a user-oriented package written in FORTRAN77 for modeling stellar atmospheres and accretion disks and wide range of spectroscopic diagnostics. In the program's maximum configuration, the user may start from scratch and calculate a model atmosphere of a chosen degree of complexity, and end with a synthetic spectrum in a wavelength region of interest for an arbitrary stellar rotation and an arbitrary instrumental profile. The user may also model the vertical structure of annuli of an accretion disk.
TLS is an optimized transit-fitting algorithm to search for periodic transits of small planets. In contrast to BLS: Box Least Squares (ascl:1607.008), which searches for rectangular signals in stellar light curves, TLS searches for transit-like features with stellar limb-darkening and including the effects of planetary ingress and egress. TLS also analyses the entire, unbinned data of the phase-folded light curve. TLS yields a ~10% higher detection efficiency (and similar false alarm rates) compared to BLS though has a higher computational load. This load is partly compensated for by applying an optimized period sampling and transit duration sampling constrained to the physically plausible range.
tlpipe processes the drift scan survey data from the Tianlai experiment; the Tainlai project is a 21cm intensity mapping experiment aimed at detecting dark energy by measuring the baryon acoustic oscillation (BAO) features in the large scale structure power spectrum. tlpipe performs offline data processing tasks such as radio frequency interference (RFI) flagging, array calibration, binning, and map-making, in addition to other tasks. It includes utility functions needed for the data analysis, such as data selection, transformation, visualization and others. tlpipe implements a number of new algorithms are implemented, including the eigenvector decomposition method for array calibration and the Tikhnov regularization for m-mode analysis.
Tidally Locked Coordinates converts global climate model (GCM) output from standard/Earth-like coordinates into a tidally locked coordinate system. The transformations in Tidally Locked Coordinates are useful for plotting and analyzing GCM simulations of slowly rotating tidally locked planets such as Earth-like planets inside the habitable zone of small stars. They can be used to leverage the fact that a slowly rotating planet's climate will start to look approximately symmetric about the axis of insolation.
TITAN is a general-purpose radiation hydrodynamics code developed at the Laboratory for Computational Astrophysics (NCSA, University of Illinois at Urbana-Champaign). TITAN solves the coupled sets of radiation transfer and fluid dynamics equations on an adaptive mesh in one spatial dimension.
Tilted Ring Fitting Code (TiRiFiC) is a prototype computer program to construct simulated (high-resolution) astronomical spectroscopic 3d-observations (data cubes) of simple kinematical and morphological models of rotating (galactic) disks. It is possible to automatically optimize the parameterizations of constructed model disks to fit spectroscopic (3d-) observations via a χ2 minimization. TiRiFiC is currently implemented as an add-on to the Groningen Image Processing System (GIPSY) software package and attempts to provide a method to automatically fit an extended tilted-ring model directly to a data cube.
The development of TIPSY was motivated by the need to quickly display and analyze the results of N-body simulations. Most data visualization packages are designed for the display of gridded data, and hence are unsuitable for use with particle data. Therefore, a special package was built that could easily perform the following functions:
1.) Display particle positions (as points), and velocities (as line segments) from an arbitrary viewpoint;
2.) Zoom in to a chosen position. Due to their extremely clustered nature, structure of interest in an N-body simulation is often so small that it cannot be seen when looking at the simulation as a whole;
3.) Color particles to display scalar fields. Examples of such fields are potential energy, or for SPH particles, density and temperature;
4.) Selection of a subset of the particles for display and analysis. Regions of interest are generally small subsets of the simulation;
5.) Following selected particles from one timestep to another; and,
6.) Finding cumulative properties of a collection of particles. This usually involves just a sum over the particles.
The basic data structure is an array of particle structures. Since TIPSY was built for use with cosmological N-body simulations, there are actually three separate arrays for each of the types of particle used in such simulations: collisionless particles, SPH particles, and star particles. A single timestep is read into these arrays from a disk file. Display is done by finding the x and y coordinates of the particles in the rotated coordinate system, and storing them in arrays. Screen coordinates are calculated from these arrays according to the current zoom factor. Also, a software Z-buffer is maintained to save time if many particles project to the same screen pixel. There are several types of display. An "all plot" displays all particles colored according to their type. A "radial plot" will color particles according to the projection of the velocity along the line-of-sight. A "gas plot" will color gas according to SPH quantities such as density, temperature, neutral hydrogen fraction, etc. Subsets of particles are maintained using boxes." A box structure contains a bounding box, and an array of pointers to particles within the box. All display and analysis functions are performed on the "active box." By default all particles are loaded into box 0, which becomes the active box. If a new timestep is read from disk, all boxes are destroyed. A selection of particles can be followed between timesteps via a "mark" array. Marked particles are displayed in a different color, and the analysis functions can be told to only operate on the marked particles.
Tiny Tim generates simulated Hubble Space Telescope point spread functions (PSFs). It is written in C and distributed as source code and runs on a wide variety of UNIX and VMS systems. Tiny Tim includes mirror zonal errors, time dependent aberrations (for the pre-repair instruments), field dependent obscuration patterns (for WF/PC-1 and WFPC2), and filter passband effects. It can produce a normally sampled or subsampled PSF. Output is a FITS image file.
Time-domain astronomy sandbox consists in a series of classes to simulate and process time-domain astronomy data products in Python. The code was originally developed to model Fast Radio Burst (FRB) and Radio Frequency Interference (RFI), and evaluate different RFI mitigation methods and their effect on FRB search.
Time Utilities are software tools that, in principal, allow one to calculate BJD to a precision of 1 μs for any target from anywhere on Earth or from any spacecraft. As the quality and quantity of astrophysical data continue to improve, the precision with which certain astrophysical events can be timed becomes limited not by the data themselves, but by the manner, standard, and uniformity with which time itself is referenced. While some areas of astronomy (most notably pulsar studies) have required absolute time stamps with precisions of considerably better than 1 minute for many decades, recently new areas have crossed into this regime. In particular, in the exoplanet community, we have found that the (typically unspecified) time standards adopted by various groups can differ by as much as a minute. Left uncorrected, this ambiguity may be mistaken for transit timing variations and bias eccentricity measurements. We recommend using BJD_TDB, the Barycentric Julian Date in the Barycentric Dynamical Time standard for any astrophysical event. The BJD_TDB is the most practical absolute time stamp for extraterrestrial phenomena, and is ultimately limited by the properties of the target system. We compile a general summary of factors that must be considered in order to achieve timing precisions ranging from 15 minutes to 1 μs, and provide software for download and online webapps for use.
TIDEV (Tidal Evolution package) calculates the evolution of rotation for tidally interacting bodies using Efroimsky-Makarov-Williams (EMW) formalism. The package integrates tidal evolution equations and computes the rotational and dynamical evolution of a planet under tidal and triaxial torques. TIDEV accounts for the perturbative effects due to the presence of the other planets in the system, especially the secular variations of the eccentricity. Bulk parameters include the mass and radius of the planet (and those of the other planets involved in the integration), the size and mass of the host star, the Maxwell time and Andrade's parameter. TIDEV also calculates the time scale that a planet takes to be tidally locked as well as the periods of rotation reached at the end of the spin-orbit evolution.
ThumbStack produces stacked maps and profiles, given catalogs of object positions and maps. It is designed for thermal and kinematic Sunyaev-Zel'dovich measurements. Based on Pixell (ascl:2102.003), it outputs 2D stacked maps and radial profiles for different filters (e.g., aperture photometry filters), as well as their covariances, estimated through several methods including bootstrap.
Thrust is a parallel algorithms library which resembles the C++ Standard Template Library (STL). Thrust's high-level interface greatly enhances programmer productivity while enabling performance portability between GPUs and multicore CPUs. Interoperability with established technologies (such as CUDA, TBB, and OpenMP) facilitates integration with existing software.
THOR solves the three-dimensional nonhydrostatic Euler equations. The code implements an icosahedral grid for the poles where converging meridians lead to increasingly smaller time steps; irregularities in the grid are smoothed using spring dynamics. THOR is designed to run on graphics processing units (GPUs) and is part of the open-source Exoclimes Simulation Platform.
Thindisk computes the line emission from a geometrically thin protoplanetary disk. It creates a datacube in FITS format that can be processed with a data reduction package (such as GILDAS, ascl:1305.010) to produce synthetic images and visibilities. These synthetic data can be compared with observations to determine the properties (e.g. central mass or inclination) of an observed disk. The disk is assumed to be in Keplerian rotation at a radius lower than the centrifugal radius (which can be set to a large value, for a purely Keplerian disk), and in infall with rotation beyond the centrifugal radius.
THERMINATOR is a Monte Carlo event generator dedicated to studies of the statistical production of particles in relativistic heavy-ion collisions. The increased functionality of the code contains the following features: The input of any shape of the freeze-out hypersurface and the expansion velocity field, including the 3+1 dimensional profiles, in particular those generated externally with various hydrodynamic codes. The hypersufraces may have variable thermal parameters, which allows for studies departing significantly from the mid-rapidity region, where the baryon chemical potential becomes large. We include a library of standard sets of hypersurfaces and velocity profiles describing the RHIC Au+Au data at sqrt(s_(NN)) = 200 GeV for various centralities, as well as those anticipated for the LHC Pb+Pb collisions at sqrt(s_(NN)) = 5.5 TeV. A separate code, FEMTO-THERMINATOR, is provided to carry out the analysis of femtoscopic correlations which are an important source of information concerning the size and expansion of the system. We also include several useful scripts that carry out auxiliary tasks, such as obtaining an estimate of the number of elastic collisions after the freeze-out, counting of particles flowing back into the fireball and violating causality (typically very few), or visualizing various results: the particle p_T-spectra, the elliptic flow coefficients, and the HBT correlation radii. We also investigate the problem of the back-flow of particles into the hydrodynamic region, as well as estimate the elastic rescattering in terms of trajectory crossings. The package is written in C++ and uses the CERN ROOT environment.
THELI is an easy-to-use, end-to-end pipeline for the reduction of any optical, near-IR and mid-IR imaging data. It combines a variety of processing algorithms and third party software into a single, homogeneous tool. Over 90 optical and infrared instruments at observatories world-wide are pre-configured; more can be added by the user. The code's online appendix contains three walk-through examples using public data (optical, near-IR and mid-IR) and additional online documentation is available for training and troubleshooting.
the-wizz clusters redshift estimates for any photometric unknown sample in a survey. The software is composed of two main parts: a pair finder and a pdf maker. The pair finder finds spatial pairs and stores the indices of all closer pairs around target reference objects in an output HDF5 data file. Users then query this data file using the indices of their unknown sample to produce an output clustering-z.
The Tractor optimizes or samples from models of astronomical objects. The approach is generative: given astronomical sources and a description of the image properties, the code produces pixel-space estimates or predictions of what will be observed in the images. This estimate can be used to produce a likelihood for the observed data given the model: assuming the model space actually includes the truth (it doesn’t, in detail), then if we had the optimal model parameters, the predicted image would differ from the actually observed image only by noise. Given a noise model of the instrument and assuming pixelwise independent noise, the log-likelihood is the negative chi-squared difference: (image - model) / noise.
The Starfish Diagram is a statistical visualization tool that simultaneously displays the properties of an individual and its parent sample through a series of histograms. The code is useful for large datasets for which one needs to understand the standing or significance of a single entry.
The Sequencer reveals the main sequence in a dataset if one exists. To do so, it reorders objects within a set to produce the most elongated manifold describing their similarities which are measured in a multi-scale manner and using a collection of metrics. To be generic, it combines information from four different metrics: the Euclidean Distance, the Kullback-Leibler Divergence, the Monge-Wasserstein or Earth Mover Distance, and the Energy Distance. It considers different scales of the data by dividing each object in the input data into separate parts (chunks), and estimating pair-wise similarities between the chunks. It then aggregates the information in each of the chunks into a single estimator for each metric+scale.
The Exoplanet Modeling and Analysis Center (EMAC) is a website which serves as a catalog, repository and integration platform for modeling and analysis resources focused on the study of exoplanet characteristics and environments. EMAC hosts user-submitted software ranging in category from planetary interior models to data visualization tools. Other features of EMAC include integrated web tools developed by the EMAC team in collaboration with the tools' original authors and video demonstrations of a growing number of hosted tools. EMAC aims to be a comprehensive repository for researchers to access a variety of exoplanet resources that can assist them in their work, and currently hosts a growing number of code bases, models, and tools. EMAC is a key project of the NASA GSFC Sellers Exoplanet Environments Collaboration (SEEC).
Given sparse or low-quality radial-velocity measurements of a star, there are often many qualitatively different stellar or exoplanet companion orbit models that are consistent with the data. The consequent multimodality of the likelihood function leads to extremely challenging search, optimization, and MCMC posterior sampling over the orbital parameters. The Joker is a custom-built Monte Carlo sampler that can produce a posterior sampling for orbital parameters given sparse or noisy radial-velocity measurements, even when the likelihood function is poorly behaved. The method produces correct samplings in orbital parameters for data that include as few as three epochs. The Joker can therefore be used to produce proper samplings of multimodal pdfs, which are still highly informative and can be used in hierarchical (population) modeling.
The Hammer can classify spectra in a variety of formats with targets spanning the MK spectral sequence. It processes a list of input spectra by automatically estimating each object's spectral type and measuring activity and metallicity tracers in late type stars. Once automatic processing is complete, an interactive interface allows the user to manually tweak the final assigned spectral type through visual comparison with a set of templates.
The Exo-Striker analyzes exoplanet orbitals, performs N-body simulations, and models the RV stellar reflex motion caused by dynamically interacting planets in multi-planetary systems. It offers a broad range of tools for detailed analysis of transit and Doppler data, including power spectrum analysis for Doppler and transit data; Keplerian and dynamical modeling of multi-planet systems; MCMC and nested sampling; Gaussian Processes modeling; and a long-term stability check of multi-planet systems. The Exo-Striker can also analyze Mean Motion Resonance (MMR) analysis, create fast fully interactive plots, and export ready-to-use LaTeX tables with best-fit parameters, errors, and statistics. It combines Fortran efficiency and Python flexibility and is cross-platform compatible (MAC OS, Linux, Windows). The tool relies on a number of open-source packages, including RVmod engine, emcee (ascl:1303.002), batman (ascl:1510.002), celerite (ascl:1709.008), and dynesty (ascl:1809.013).
We present the DTFE public software, a code for reconstructing fields from a discrete set of samples/measurements using the maximum of information contained in the point distribution. The code is written in C++ using the CGAL library and is parallelized using OpenMP. The software was designed for the analysis of cosmological data but can be used in other fields where one must interpolate quantities given at a discrete point set. The software comes with a wide suite of options to facilitate the analysis of 2- and 3-dimensional data and of both numerical simulations and galaxy redshift surveys. For comparison purposes, the code also implements the TSC and SPH grid interpolation methods. The code comes with an extensive user guide detailing the program options, examples and the inner workings of the code.
The Cannon is a data-driven method for determining stellar labels (physical parameters and chemical abundances) from stellar spectra in the context of vast spectroscopic surveys. It fits for the spectral model given training spectra and labels, with the polynomial order for the spectral model decided by the user, infers labels for the test spectra, and provides diagnostic output for monitoring and evaluating the process. It offers SNR-independent continuum normalization, performs well at lower signal-to-noise, and is very accurate.
THALASSA (Tool for High-Accuracy, Long-term Analyses for SSA) propagates orbits for bodies in the Earth-Moon-Sun system. Written in Fortran, it integrates either Newtonian equations in Cartesian coordinates or regularized equations of motion with the LSODAR (Livermore Solver for Ordinary Differential equations with Automatic Root-finding). THALASSA is a command-line tool; the repository also includes some Python3 scripts to perform batch propagations.
The Tsyganenko models are semi-empirical best-fit representations for the magnetic field, based on a large number of satellite observations (IMP, HEOS, ISEE, POLAR, Geotail, GOES, etc). The models include the contributions from major external magnetospheric sources: ring current, magnetotail current system, magnetopause currents, and large-scale system of field-aligned currents.
TGCat is an archive of Chandra transmission grating spectra and a suite of software for processing such data. Users can browse and categorize Chandra gratings observations quickly and easily, generate custom plots of resulting response corrected spectra on-line without the need for special software and download analysis ready products from multiple observations in one convenient operation. Data processing for the catalog is done with a suite of ISIS/S-Lang scripts; the software is available for download. These ISIS scripts wrap and call CIAO tools for reprocessing from "Level 1" (acis_process_events or hrc_process_events) through "Level 2" (binned spectra, via tg_resolve_events and tgextract), compute responses (grating "RMFs" and "ARFs", via mkgrmf and mkgarf), and make summary plots.
TFIT measures galaxy photometry using prior knowledge of sources in a deep, high‐resolution image (HRI) to improve photometric measurements of objects in a corresponding low‐resolution image (LRI) of the same field, usually at a different wavelength. For background‐limited data, this technique produces optimally weighted photometry that maximizes signal‐to‐noise ratio (S/N). For objects not significantly detected in the low‐resolution image, it provides useful and quantitative information for setting upper limits.
This code is no longer updated and has been superseded by T-PHOT (ascl:1609.001).
TFF derives the Fourier decomposition of period-folded RR Lyrae light curves with gaps. The method can be used for the same purpose on any other types of variables, assuming that the the template database is changed to the proper type of variables.
tf_unet mitigates radio frequency interference (RFI) signals in radio data using a special type of Convolutional Neural Network, the U-Net, that enables the classification of clean signal and RFI signatures in 2D time-ordered data acquired from a radio telescope. The code is not tied to a specific segmentation and can be used, for example, to detect radio frequency interference (RFI) in radio astronomy or galaxies and stars in widefield imaging data. This U-Net implementation can outperform classical RFI mitigation algorithms.
TesseRACt computes concentrations of simulated dark matter halos from volume information for particles generated using Voronoi tesselation. This technique is advantageous as it is non-parametric, does not assume spherical symmetry, and allows for the presence of substructure. TesseRACt accepts data in a number of formats, including Gadget-2 (ascl:0003.001), Gasoline (ascl:1710.019), and ASCII, and computes concentrations using particles volumes, traditional fitting to an NFW profile, and non-parametric techniques that assume spherical symmetry.
TESS-Point converts astronomical target coordinates given in right ascension and declination to detector pixel coordinates for the MIT-led NASA Transiting Exoplanet Survey Satellite (TESS) spacecraft. The program can also provide detector pixel coordinates for a star by TESS input catalog identifier number and common astronomical name. Tess-point outputs the observing sector number, camera number, detector number, and pixel column and row.
TES models the evolution of exoplanet systems. This n-body integration package comes in two parts, the C++ TES source code, and the Python-based experiment manager for running experiments and plotting the results. The experiment manager, used as the interface to TES, handles temporary data storage and allows for experiment results to be saved and then loaded later on for plotting. The experiment manager can automatically use multiple threads to run independent experiments in parallel using the mpi4py package. The experiment manager is specifically designed to enable HPC to be performed as easily as possible.
Tempo2 is a pulsar timing package developed to be used both for general pulsar timing applications and also for pulsar timing array research in which data-sets from multiple pulsars need to be processed simultaneously. It was initially developed by George Hobbs and Russell Edwards as part of the Parkes Pulsar Timing Array project. Tempo2 is based on the original Tempo (ascl:1509.002) code and can be used (from the command-line) in a similar fashion. It is very versatile and can be extended by plugins.
Tempo analyzes pulsar timing data. Pulse times of arrival (TOAs), pulsar model parameters, and coded instructions are read from one or more input files. The TOAs are fitted by a pulse timing model incorporating transformation to the solar-system barycenter, pulsar rotation and spin-down and, where necessary, one of several binary models. Program output includes parameter values and uncertainties, residual pulse arrival times, chi-squared statistics, and the covariance matrix of the model. In prediction mode, ephemerides of pulse phase behavior (in the form of polynomial expansions) are calculated from input timing models. Tempo is the basis for the Tempo2 (ascl:1210.015) code.
TelFit calculates the best-fit telluric absorption spectrum in high-resolution optical and near-IR spectra. The best-fit model can then be divided out to remove the telluric contamination. Written in Python, TelFit is essentially a wrapper to LBLRTM, the Line-By-Line Radiative Transfer Model, and simplifies the process of generating a telluric model.
TEA (Thermal Equilibrium Abundances) calculates gaseous molecular abundances under thermochemical equilibrium conditions. Given a single T,P point or a list of T,P pairs (the thermal profile of an atmosphere) and elemental abundances, TEA calculates mole fractions of the desired molecular species. TEA uses 84 elemental species and thermodynamical data for more then 600 gaseous molecular species, and can adopt any initial elemental abundances.
TDEmass interprets Tidal Disruption Event (TDE) observations. In TDEs, a supermassive black hole at the center of a galaxy tears apart an ordinary star; the debris is placed on highly eccentric orbits and ultimately produces a very bright flare. Using this TDEmass, one can infer the mass of the black hole (mbh) and the mass of the star (mstar) involved in a TDE.
Three-Body Integration performs numerical n-body simulations for mapping conditions for close approaches for the relevant parameter space of configurations and mass values of two white dwarfs and a third star. Low tertiary masses of 0.1M⊙ can be studied, and the collision probability can be estimated with good confidence for the case of nearly equal mass white dwarfs.
TAU is a 1D line-by-line radiative transfer code for modeling transmission spectra of close-in extrasolar planets. The code calculates the optical path through the planetary atmosphere of the radiation from the host star and quantifies the absorption due to the modeled composition in a transmission spectrum of transit depth as a function of wavelength. The code is written in C++ and is parallelized using OpenMP.
TATTER (Two-sAmple TesT EstimatoR) performs two-sample hypothesis test. The two-sample hypothesis test is concerned with whether distributions p(x) and q(x) are different on the basis of finite samples drawn from each of them. This ubiquitous problem appears in a legion of applications, ranging from data mining to data analysis and inference. This implementation can perform the Kolmogorov-Smirnov test (for one-dimensional data only), Kullback-Leibler divergence, and Maximum Mean Discrepancy (MMD) test. The module performs a bootstrap algorithm to estimate the null distribution and compute p-value.
TATOO (Tidal-chronology Age TOOl) estimates the age of massive close-in planetary systems, even those subject to tidal spin-up, using the systems' observed properties: the mass of the planet and the star, stellar rotational, and planetary orbital periods. It can also be used as a classical gyrochronological tool and offers first order correction of the impact of tidal interaction on gyrochronology.
TARDIS creates synthetic spectra for supernova ejecta and is sufficiently fast to allow exploration of the complex parameter spaces of models for SN ejecta. TARDIS uses Monte Carlo methods to obtain a self-consistent description of the plasma state and to compute a synthetic spectrum. It is written in Python with a modular design that facilitates the implementation of a range of physical approximations that can be compared to assess both accuracy and computational expediency; this allows users to choose a level of sophistication appropriate for their application.
Tapir is a set of tools, written in Perl, that provides a web interface for showing the observability of periodic astronomical events, such as exoplanet transits or eclipsing binaries. The package provides tools for creating finding charts for each target and airmass plots for each event. The code can access target lists that are stored on-line in a Google spreadsheet or in a local text file.
Tangra performs scientific grade data reduction of GPS time-tagged video observations, including reduction of stellar occultation light curves and astrometry of close flybys of Near Earth Objects. It offers Dark and Flat frame image correction, PSF and aperture photometry, multiple methods for deriving a background as well as extensibility via add-ins. Tangra is actively developed for Windows and the current version of the software supports UCAC2, UCAC3, UCAC4, NOMAD, PPMXL and Gaia DR2 star catalogues for astrometry. The software can perform motion-fitting for fast objects and derive a mini-normal astrometric positions. The supported video file formats are AVI, SER, ADV and AAV. Tangra can be also used with observations recorded as a sequence of FITS files. There are also versions for Linux and OS-X with more limited functionality.
Tangos builds databases (along the lines of Eagle or MultiDark) for cosmological and zoom simulations. Its
modular system generates and queries databases. It is designed to store and manage results from a user's own analysis code, provides web and python interfaces, and allows users to construct science-focused queries, including across entire merger trees, without requiring knowledge of SQL. Tangos manages the process of populating the database with science data, including auto-parallelizing the analysis. It can be customized to work with multiple python modules such as pynbody (ascl:1305.002) or yt (ascl:1011.022) to process raw simulation data; it defaults to using SQLite, but allows use of other databases as the underlying store through the use of SQLAlchemy.
Would you like to view a random code?