Mediaspace scheduled maintenance: Aug 25, 2026 07:00 - 12:00 AM. During this time, videos will be temporarily unavailable. Check status updates.

Lecture

Continuum Emissions: Thermal vs Non-thermal

Description

This lecture explores the concepts of thermal and non-thermal continuum emissions in astrophysics, covering topics such as free-free emission, Bremsstrahlung, and synchrotron radiation. It delves into the differences between Maxwell-Boltzmann, electrostatic, and magnetic forces in the context of the radio universe.

In MOOC

The Radio Sky I: Science and Observations

Official source

Related concepts (32)

Bremsstrahlung

In particle physics, bremsstrahlung ˈbrɛmʃtrɑːləŋ (ˈbʁɛms.ʃtʁaːlʊŋ; ) is electromagnetic radiation produced by the deceleration of a charged particle when deflected by another charged particle, typically an electron by an atomic nucleus. The moving particle loses kinetic energy, which is converted into radiation (i.e., photons), thus satisfying the law of conservation of energy. The term is also used to refer to the process of producing the radiation.

Synchrotron radiation

Synchrotron radiation (also known as magnetobremsstrahlung radiation) is the electromagnetic radiation emitted when relativistic charged particles are subject to an acceleration perpendicular to their velocity (a ⊥ v). It is produced artificially in some types of particle accelerators or naturally by fast electrons moving through magnetic fields. The radiation produced in this way has a characteristic polarization, and the frequencies generated can range over a large portion of the electromagnetic spectrum.

Free-electron laser

A free-electron laser (FEL) is a (fourth generation) light source producing extremely brilliant and short pulses of radiation. An FEL functions and behaves in many ways like a laser, but instead of using stimulated emission from atomic or molecular excitations, it employs relativistic electrons as a gain medium. Radiation is generated by a bunch of electrons passing through a magnetic structure (called undulator or wiggler).

Chronology of the universe

The chronology of the universe describes the history and future of the universe according to Big Bang cosmology. Research published in 2015 estimates the earliest stages of the universe's existence as taking place 13.8 billion years ago, with an uncertainty of around 21 million years at the 68% confidence level. For the purposes of this summary, it is convenient to divide the chronology of the universe since it originated, into five parts.

Observable universe

The observable universe is a ball-shaped region of the universe comprising all matter that can be observed from Earth or its space-based telescopes and exploratory probes at the present time; the electromagnetic radiation from these objects has had time to reach the Solar System and Earth since the beginning of the cosmological expansion. Initially, it was estimated that there may be 2 trillion galaxies in the observable universe, although that number was reduced in 2021 to only several hundred billion based on data from New Horizons.

Related lectures (33)

Synchrotron Emissions: Basics & Applications MOOC: The Radio Sky I: Science and Observations

Explores synchrotron emissions, electron energy, magnetic fields, and their impact on the Radio Universe.

Continuum Emissions: Magnetobremsstrahlung and Synchrotron Radiation MOOC: The Radio Sky I: Science and Observations

Explores magnetobremsstrahlung emission and synchrotron radiation in continuum emissions in the Radio Universe.

Photons: Energy Transport MOOC: Introduction to Astrophysics

Covers the role of photons in energy transport, energy measurement in astrophysics, photon energy distribution, and various radiation phenomena.

Calorimeter Model and Milky Way MOOC: The Radio Sky I: Science and Observations

Covers the Calorimeter model of the interstellar medium and explores the spectrum of a normal galaxy and Milky Way emission.

Blackbody Emission and Radiation Transport MOOC: The Radio Sky I: Science and Observations