Single Stellar Spectra

This section describes how to generate spectra of individual stars using the spec1d.SingleStar module in GEHONG.

Template Library

Single stellar templates are precomputed from high-resolution spectral libraries. Currently supported:

  • Munari2005 (default): Theoretical grid with wide parameter coverage

  • XSL: Observed empirical spectra (limited grid)

Use the SingleStarTemplate class to load the template grid:

from gehong import spec1d
starlib = spec1d.SingleStarTemplate(config, template="Munari2005")

Main Parameters:

  • config: Simulation configuration

  • template: Template type, “Munari2005” or “XSL”

Generating Stellar Spectrum

Use the SingleStar class to generate a single stellar spectrum from atmospheric parameters.

Input Parameters:

  • mag: Apparent SDSS r-band magnitude (default: 15.0)

  • teff: Effective temperature in Kelvin

  • logg: Surface gravity (log10 cm/s²)

  • feh: Metallicity [Fe/H] in dex

  • vel: Radial velocity in km/s (default: 100)

  • ebv: Dust extinction E(B-V) in mag (default: 0.0)

star = spec1d.SingleStar(config, starlib,
                         mag=14.2, teff=5800, logg=4.4, feh=0.0,
                         vel=150, ebv=0.1)

Output Attributes:

  • star.wave: Wavelength array in Ångströms

  • star.flux: Flux array in units of \(10^{-17}\\ \\mathrm{erg~s^{-1}~cm^{-2}~\mathring{A}^{-1}}\)

Notes

  • The input stellar parameters will be clipped if outside the template grid.

  • Spectra are velocity-shifted, extincted, and calibrated to the input magnitude.

  • For XSL templates, the resolution varies with wavelength; this is accounted for internally.

SingleStar provides a straightforward way to model stellar sources in realistic simulations.