Stellar Physics and Stellar Population

Stellar Evolution Code

• MESA - Modules for Experiments in Stellar Astrophysics
  • The most important open 1-D stellar evolution code on the market.
• stars - A Stellar Evolution Code
  • The classic.
• BINSTAR - a detailed binary stellar evolution code

Hydro-simulation

• MAEXTROeX - A C++/F90 low Mach number stellar hydrodynamics code
  • MAESTROeX solves the equations of low Mach number hydrodynamics for stratified atmospheres/stars with a general equation of state.

Isochrones

Softwares

• isochrones - Provides simple interface for interacting with stellar model grids
  • The central goal of isochrones is to standardize model-grid-based stellar parameter inference, and to enable such inference under different sets of stellar models.
  • Online documents is here

Libraries

• MIST - MESA Isochrones & Stellar Tracks
  • Key papers: Choi et al. 2016
• PARSEC: stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code
  • Key papers: Bressan et al. 2012
  • Interpolated PARSEC Stellar Evolution Tracks
• Padova database of stellar evolutionary tracks and isochrones
• YaPSI - Yale-Postdam Stellar Isochrones
• Geneva Grids of Stellar Evolution Models
  • Interactive online tool to generate isochrones
• BaSTI - A Bag of Stellar Tracks and Isocrhones

Stellar Spectra Libraries and SED

Observed

• Pickles et al. 1998 library
  • The spectral range is 1150-25000 Anstroms, sampling 5 Angstroms. 131 stellar spectra.
  • The Pickles library can also be found here
• The Indo-U.S. Library of Coudé Feed Stellar Spectra
  • 1273 stars obtained with the 0.9m Coudé Feed telescope at Kitt Peak National Observatory
  • Original dispersion of 0.44 Angstroms/pixel, at a resolution of ~1 Angstroms FWHM.
  • Cover the entire wavelength range of 3460 Angstroms to 9464 Angstroms
• MILES Stellar Library
  • MILES: ~1000 stars spanning a large range in atmospheric parameters. The spectra were obtained at the 2.5m INT telescope and cover the range 3525-7500 Å at 2.5 Å (FWHM) spectral resolution
  • CaII Triplet Library: 700 stars with spectra around the Ca II triplet region. Cover the spectral range between 8350-9020 Å at 1.5 Å (FWHM)
• The X-Shooter Spectral Library
  • The current release contains more than 200 stars. 3000–25000 Å all stellar spectra observed at a resolving power of R = λ/Δλ ~ 10000 with the medium-resolution spectrograph X-Shooter
• MaStar - MaNGA Stellar Library
  • A stellar spectral library with a very comprehensive stellar parameter coverage, a large sample size, and high quality calibrations, using the same instrument as used by the MaNGA survey
  • Wavelength: 362-1035 nm, resolution R~2000; More than 8000 stars in wide areas of the sky.
• STELIB Stellar Library
  • A stellar Library for stellar population synthesis models
  • An homogeneous library of stellar spectra in the visible range (3200 to 9500A), including stars of all spectral types, luminosity classes and metallicity. The spectral resolution of our Stellar Library is about 3A FWHM.
• ÉLODIE Stellar Library
  • A stellar database of 1959 spectra for 1503 stars, observed with the echelle spectrograph ÉLODIE on the 193 cm telescope at the Observatoire de Haute Provence.
  • Wavelength range is 400-680 nm. For the purpose of population synthesis, the original resolution R=42 000 has been reduced to R=10 000 at lambda=550 nm, or more precisely to a gaussian instrumental profile of FWHM~0.55 A over the whole range of wavelengths.
• INGS Stellar Library
  • INGS is a compendium of 143 stellar-type spectra formed from spectra of stars of similar type from 3 sources: 1) IUE: 1153A to 3201A, 2A/pixel, 2) NGSL v2: 1600A to 11000A; 3) SpeX/IRTF: 8110A to 25000+A, 2.5,3,5A/pixel
• The Gaia FGK Benchmark Stars
  • Library of high resolution and high signal to noise ratio stellar spectra
  • A homogeneous library in the visual range (480-680 nm) of high resolution and signal to noise ratio (S/N) spectra corresponding to the 34 Benchmark Stars and 5 metal-poor candidates.

Near-Mid Infrared

• IRTF Extended Spectral Library
  • A collection of 0.7-2.5 μm (with a subset from 0.8 to 5.2 μm) mostly stellar spectra observed at a resolving power of R ≡ λ/Δλ ~ 2000 with the medium-resolution spectrograph, SpeX. Please see Villaume et al. 2017 for details
  • The original IRTF spectral library is available here
• SpeX Prism Library
  • A repository of low-resolution, near-infrared spectra, primarily of low-temperature dwarf stars and brown dwarfs
  • Resolutions are R~75-200. Wavelength coverage is 0.65-2.55 microns in a single order

Theoretical

• MARCS - a grid of one-dimensional, hydrostatic, plane-parallel and spherical LTE model atmospheres
  • The MARCS site contains about 52,000 stellar atmospheric models of spectral types F, G and K in 3 different formats and also flux sample files indicating rough surface fluxes.
• SYNTHE - synthetic library of stellar spectra
  • Covers the wavelength region from 2500 Å to 1.05 μm at a spectral resolution of σ=6.4 km/s, R=20,000.
• UVBLUE - A High-resolution Theoretical Library of Stellar Spectra
  • A high-resolution library of synthetic spectra of stars covering the ultraviolet wavelength range.
  • Stellar spectra cover the wavelength interval from 850 to 4700 Å, at a spectral resolving power R = λ/Δ λ = 50,000. The grid consists of 1770 SEDs
• Paula Coelho’s Theoretical Spectra of Stars and Stellar Populations
  • A new theoretical library which covers 3000 <= Teff <= 25 000 K, -0.5 <= log g <= 5.5 and 12 chemical mixtures covering 0.0017 <= Z <= 0.049 at both scaled-solar and alpha-enhanced compositions.

Tools for Stellar Physics

• BEAST - Bayesian Extinction and Stellar Tool
  • Fits the ultraviolet to near-infrared photometric SEDs of stars to extract stellar and dust extinction parameters. See Gordon et al. 2016 for details.
  • Online document is here
• ThePayne - Artificial Neural-Net compression and fitting of synthetic spectral grids
  • By Phillip Cargile and Yuan-Sen Ting. Artificial Neural-Net compression and fitting of ab initio synthetic spectral grids.
• TheCannon - a data-driven method for determining stellar parameters and abundances from stellar spectra
  • By Anna Ho. A data-driven method for determining stellar labels (physical parameters and chemical abundances) from stellar spectra in the context of large spectroscopic surveys.
• brutus - Modeling stellar photometry with “brute force” methods
  • By Josh Speagle. A Pure Python package whose core modules involve using “brute force” Bayesian inference to derive distances, reddenings, and stellar properties from photometry using a grid of stellar models.
• Starfish - Tools for Flexible Spectroscopic Inference
  • By Ian Czekala. Starfish is a set of tools used for spectroscopic inference. We designed the package to robustly determine stellar parameters using high resolution spectral models
• MOOG - a code that performs a variety of LTE line analysis and spectrum synthesis tasks
  • Old fashion but classic.
  • If you use Python, try Andy Casey’s Installing MOOG the Easy Way
• StePar - an automatic code used to infer stellar atmospheric parameters using the EW method
  • Please see Tabernero et al. 2019 for more details.
• MINESweeper - MIST Isochrones with NEsted Sampling
  • Isochrone fitting code using latest mass-tracks from the MIST models.
  • Model interpolation and nested-sampling inference of observed stellar SED and/or parameters using the latest MIST stellar evolution models.
  • Based on the work of Cargile et al. 2019

Stellar Population Synthesis or SED Fitting

• This sedfitting.org page is a very good one-stop shopping place for all SED related resources.
  • There is also a review paper

Tools for Generating or Manipulating Stellar Population Model

• FSPS - Flexible Stellar Population Synthesis
  • If you want to see how sausage is made, this is it, including every details of stellar population synthesis. Original code in Frotran. Supports different isochrones and libraries.
  • python-fsps can help you use it in Python
  • cloudyfsps - Python interface between FSPS and Cloudy
• sedpy - Utilities for astronomical spectral energy distributions
  • By Ben Johnson. Modules for storing and operating on astronomical source spectral energy distributions.
  • Has nice function to handle filters and measure SED from spectrum.
• PopStar - generating simple stellar populations from synthetic evolution and atmosphere models
  • PopStar generates single-age, single-metallicity populations (i.e. star clusters). It supports different initial mass functions, multiplicity perscriptions, reddening laws, filter functions, atmosphere models, and evolution models.
  • Support a large variety of theoretical models.

Tools for SED or Spectral Fitting

• prospector - Python code for Stellar Population Inference from Spectra and SEDs
  • By Ben Johnson. Conduct principled inference of stellar population properties from photometric and/or spectroscopic data.
  • Bayesian method, can use emcee, nestle, and dynesty as sampling tool
  • Can fit spectrum and/or SED.
• fastpp - C++ version of the SED fitting code FAST (Kriek et al. 2009);
  • By Corentin Schreiber. “it’s faster, uses less memory, and has more features.”
  • Based on model grid.
  • Can fit spectrum and/or SED.
• STARLIGHT - Spectra decomposition code
  • Written in Fortran, using simulated annealing algorithm with Markov chains.
  • The manual written by Cid Fernandes is a very good introduction of the SSP decomposition business.
  • Mostly used for spectral fitting.
• pPXF - Penalized Pixel-Fitting
  • By Michelle Cappellari. Extract the stellar or gas kinematics and stellar population from galaxy spectra via full spectrum fitting.
  • Available in Python and IDL. Can fit spectrum.
• iSEDfit - IDL routines to fit SED
  • By John Moustakas. Part of the impro suite. Website for downloading library and documents is here
  • Based on model grid, only fit SED.
• Firefly – A Full Spectral Fitting Code
  • FIREFLY is a chi-squared minimisation fitting code for deriving the stellar population properties of stellar systems, be these observed galaxy or star cluster spectra, or model spectra from simulations. Document can be found here
• cigale - Python version of the Code Investigating GALaxy Emission
  • Full document can be found here
• FIT3D - a tool for fitting stellar populations and emission lines in optical spectroscopy
  • FIT3D is a package for fitting optical spectra to deblend the underlying stellar population and the ionized gas, and extract physical information from each component. Focusing on IFU surveys.
  • Fit full spectrum. In Python or Perl
• BEAGLE - BayEsian Analysis of GaLaxy sEds
  • A new-generation tool to model and interpret galaxy spectral energy distributions (SEDs) developed by Jacopo Chevallard (ESA) and Stephane Charlot (IAP).

Stellar Population Models:

• MILES - Population synthesis for the 21st Century
  • The new extended MILES (E-MILES) models covering from 1680Å to 5.0μm
  • Provides useful online tools to use the stellar library and SSP models.
• BPASS - Binary Population and Spectral Synthesis code
  • Best binary population model on the market.
• PEGASE - Projet d’Etude des GAlaxies par Synthese Evolutive