redback.transient_models.afterglow_models.vegas_models.vegas_step_powerlaw

redback.transient_models.afterglow_models.vegas_models.vegas_step_powerlaw(time, redshift, thv, loge0, thc, lognism, loga, p, logepse, logepsb, g0, loge0_w, g0_w, ke, kg, **kwargs)[source]

VegasAfterglow step power-law jet with unified medium (ISM/Wind/Hybrid)

Jet with uniform core (theta < theta_c) transitioning to power-law wings (theta > theta_c). Core: E(theta) = E_iso, Gamma(theta) = Gamma0 Wings: E(theta) = E_iso_w * (theta/theta_c)^(-ke)

Gamma(theta) = Gamma0_w * (theta/theta_c)^(-kg)

Combines the benefits of both tophat and power-law structures, allowing for a bright core with extended wings.

Parameters:

  • time – time in days in observer frame

  • redshift – source redshift

  • thv – viewing angle in radians

  • loge0 – log10 core isotropic energy [erg]

  • thc – core opening angle in radians

  • lognism – log10 ISM number density [cm^-3] (use small number e.g., -20) for pure wind)

  • loga – log10 wind parameter A_* [g/cm] (use small number e.g., -20 for pure ISM)

  • p – electron power-law index

  • logepse – log10 electron energy fraction

  • logepsb – log10 magnetic field energy fraction

  • g0 – core initial Lorentz factor

  • loge0_w – log10 wing normalization energy [erg]

  • g0_w – wing normalization Lorentz factor

  • ke – energy power-law index for wings (typically 2-8)

  • kg – Lorentz factor power-law index for wings (typically 2-8)

  • kwargs – Same optional parameters as vegas_tophat (see vegas_tophat docstring)

Returns:

flux density [mJy] or AB magnitude

Examples:

Pure ISM: lognism=0.0, loga=-20 Pure Wind: lognism=-20, loga=11.0 Hybrid: lognism=0.0, loga=11.0 (wind with ISM floor)