ATRONOMY – RADIO ATRONOMY & IGNAL (30) CALCULATOR
Free Free Emission
A precise tool.
What is the Free Free Emission & How does it work?
Free‑free (bremsstrahlung) emission arises when free electrons are accelerated in the Coulomb fields of ions. The resulting radiation spans a broad range of radio frequencies and is a dominant continuum source in ionised nebulae, H II regions, and the interstellar medium.
The emissivity per unit frequency, (epsilon_{nu}), depends on the electron temperature (T), the densities of electrons (n_{e}) and ions (n_{i}), the ionic charge (Z), the observing frequency (nu), and the quantum‑mechanical Gaunt factor (bar{g}_{ff}). Higher temperatures increase the kinetic energy of electrons, while higher densities raise the probability of encounters that produce radiation.
In radio astronomy the free‑free spectrum is often approximated as a power law because the exponential term (e^{-hnu/kT}) is close to unity at centimetre wavelengths. Accurate modelling, however, requires the full expression to capture the slight turnover at higher frequencies.
epsilon_{nu} = 6.8 times 10^{-38}, Z^{2}, n_{e}, n_{i}, T^{-1/2}, e^{-hnu/(kT)}, bar{g}_{ff}
epsilon_{nu} = emissivity per unit frequency (erg s⁻¹ cm⁻³ Hz⁻¹)
Parameters
Result
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Frequently Asked Questions
What is free-free emission in astronomy?
Free-free emission occurs when electrons are accelerated by ions, producing broad radio frequency radiation.
How does electron temperature affect free-free emission?
Higher electron temperatures increase the energy of emitted photons, shifting the peak emission to higher frequencies.
What is the significance of ionic charge in free-free emission?
The ionic charge affects the strength of the Coulomb field, influencing the rate and intensity of radiation.
How does electron density impact free-free emission?
Higher electron densities lead to more frequent collisions and thus higher overall emission rates.
What is the role of observing frequency in free-free emission calculations?
The observing frequency determines which part of the spectrum is being observed, affecting the detected intensity.
Can you explain the quantum aspect in free-free emission?
Quantum mechanics governs the transition probabilities and energy levels involved in electron acceleration.
Where does free-free emission occur in space?
It is a dominant feature in ionized nebulae, HII regions, and the interstellar medium.
Results are for informational purposes only and do not constitute professional advice.