Astrophysics (index)about

Frequency

(number of cycles per unit of time, such as waves per second)

Frequency is number of cycles per unit time, e.g., per second. Typical measurement is in Hertz, number of cycles per second. In astrophysics, frequency is used for Electromagnetic Radiation, in which the Wavelength times the frequency is the speed of Electromagnetic waves. The energy of a Photon is directly related to the frequency of the electromagnetic radiation:

E = h × f

Wavelength is often used to characterize electromagnetic radiation, perhaps frequency often being most used for the longest wavelengths (e.g., Radio) and photon energy most often used for the shortest (e.g., Gamma Rays).

Other astronomical phenomena such as regularly pulsing radiation (Pulsar, spinning Neutron Star) can have a frequency, i.e., number of cycles per some unit of time.


(EMR,measure,waves)
http://en.wikipedia.org/wiki/Frequency

Referenced by:
Absorption Line
AB System
Atacama Cosmology Telescope (ACT)
Anisotropy
Antenna Temperature
Allen Telescope Array (ATA)
Bandwidth
Black Hole Merger
Black-Body Radiation
Bohr Model
Bolometer
Cambridge Catalog of Radio Sources
Canadian Hydrogen Intensity Mapping Experiment (CHIME)
Chirp
Chirp Mass (Mc)
Carbon Monoxide (CO)
Coherent Light
Compton Scattering
Cosmic Explorer
Corotation Resonance (CR)
Cyclotron Radiation
de Broglie Wavelength
Degeneracy
Velocity Dispersion (σ)
Doppler Shift
Effelsberg 100-m Radio Telescope
Eigenmode
Einstein Telescope
Electromagnetic Spectrum
Electron Orbital
Extremely Low Frequency (ELF)
Epicyclic Frequency
Frequency Modulation (FM)
Fourier Space
Fourier Transform
Fast Radio Burst (FRB)
Galactic Electron Density
Galaxy Power Spectrum
Gamma Rays
Green Bank Telescope (GBT)
Gravitational Wave (GW)
Gravitational Wave Strain (h)
Habitable Zone (HZ)
Hadley Cell
Hellings and Downs Curve
Infrared (IR)
Interference
International Pulsar Timing Array (IPTA)
Infrared Survey Facility (IRSF)
Jansky (Jy)
Low Frequency Radio Astronomy
LIGO
Lunar Reconnaissance Orbiter (LRO)
Crab Nebula (M1)
Next Generation Very Large Array (ngVLA)
Nanohertz Gravitational Waves
Nançay Radio Telescope (NRT)
Passband
Phased Array
Photoionization
Photon
Parkes Catalog (PKS)
Planck
Planck Constant (h)
Plasma Frequency
Power Law
Pulsar Timing Array (PTA)
Pulsar (PSR)
Radiance
Radiant Flux
Radio
Radio Astronomy
Radiometer Equation
Red Noise
Radio Frequency Interference (RFI)
RMS Astronomy
Rossby Number (Ro)
Equation of Radiative Transfer (RTE)
Spectral Energy Distribution (SED)
Sensitivity Function (S)
Square Kilometre Array (SKA)
Super Low Frequency (SLF)
Solar and Heliospheric Observatory (SOHO)
Spectral Power Distribution (SPD)
Spectral Density
Spectral Index (α)
Spiral Galaxy
South Pole Telescope (SPT)
Sardinia Radio Telescope (SRT)
Synchrotron Self-Compton (SSC)
Subradio
Sunspot
Superradiance
Synchrotron Radiation
Sunyaev-Zel'dovich Effect (SZ Effect)
Telegrapher's Equations
Thomson Scattering
Time Series Analysis
Tremendously Low Frequency (TLF)
Ultra Low Frequency (ULF)
Virgo
Very Low Frequency (VLF)
Wavelength
Wave-particle Duality
Atmospheric Window
X-ray

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