Astrophysics (Index)About

infrared

(IR, infrared light)
(electromagnetic radiation, wavelength 0.74-300 micrometers)

Infrared (IR or infrared light) is electromagnetic radiation (EMR) with wavelengths in the range of 750 nm to 1 mm. Its frequency is 1 to 400 THz, situated between visible light and radio. Portions of this frequency-span are blocked by Earth atmosphere and astronomical bands tend to be aligned with the intervening atmospheric windows:

near infrared650-1000 nmR band and I band
near infrared1100-1400 nmJ band
near infrared1500-1800 nmH band
near infrared2000-2400 nmK band
near infrared3000-4000 nmL band
near Infrared4600-5000 nmM band
mid infrared7500-14500 nmN band
mid infrared17-25 μmQ band
far infrared28-40 μmZ band
far infrared330-370 μmZ band
far infrared450 μmsubmillimeter

Some near infrared observations are made through optical telescopes, whose mirrors are suitable for adjacent portions of the spectrum. Far infrared telescopes are more like radio telescopes and similar interferometry is often used. IR is often used to detect temperature at a distance, because virtually anything with a temperature less than ~3800 K emits black-body radiation peaking in infrared (thermal IR) and the temperature can be determined (in principle) by Wien's displacement law. IR is also used for sensing "through walls" because some material that is opaque to visible light is transparent to IR. IR sensors are used in the study of planets from space probes: e.g., IR cameras or spectrographs. Infrared luminosity (LIR or LIR), an object's luminosity in the infrared is of interest, often indicating intervening obscuring gas and dust, heated so as to produce an infrared thermal radiation.

Infrared astronomy can view virtually anything producing thermal radiation, but is especially useful for objects whose EMR arrives within the infrared range. Prominent are M-type stars which are dim outside the infrared, and many objects at cosmological distances, whose spectra are redshifted into the infrared, motivating efforts such as the James Webb Space Telescope.


(EMR,spectrum,band)
Further reading:
http://en.wikipedia.org/wiki/Infrared
WaveLFreqPhoton
Energy
  
750nm400THz1.7eVbegininfrared
1mm300GHz1.3meVendinfrared

Referenced by pages:
active galaxy
AFGL Four Color Infrared Sky Survey (AFGL)
active galactic nucleus (AGN)
AKARI
aperture synthesis
ARIEL
Atacama Submillimeter Telescope Experiment (ASTE)
black-body radiation
Cassini
cosmic background radiation (CBR)
CFBDS
Canada-France-Hawaii Telescope (CFHT)
cosmic infrared background (CIB)
Catalog of Infrared Observations (CIO)
circumstellar disk
infrared cirrus
cosmic optical background (COB)
Cosmic Background Explorer (COBE)
cosmic dust
CRIRES
dark nebula
Darwin
Dawn
DENIS
electromagnetic spectrum
electromagnetic radiation (EMR)
extremely red object (ERO)
European Southern Observatory (ESO)
ESO 3.6m Telescope
European Southern Observatory Very Large Telescope (ESO VLT)
Euclid
extreme adaptive optics (ExAO)
far infrared (FIR)
Faint Infrared Grism Survey (FIGS)
filter
FINESSE
Fred Lawrence Whipple Observatory (FLWO)
Fabry-Pérot interferometer (FPI)
Gemini Observatory
Giant Magellan Telescope (GMT)
Gemini Planet Imager (GPI)
grating
greenhouse effect
Gran Telescopio Canarias (GTC)
Hale Telescope
Hubble Deep Field South (HDF-S)
HERMES
Herschel Space Observatory
NEWS
hyperluminous infrared galaxy (HLIRG)
Hubble Space Telescope (HST)
I band
IOTA
IPAC
IRAS
Two Micron Sky Survey (IRC)
infrared dark cloud (IRDC)
IRSA
Infrared Survey Facility (IRSF)
IRTF
infrared excess (IRX)
Infrared Space Observatory (ISO)
Infrared Telescope Maffei (ITM)
Japan Aerospace Exploration Agency (JAXA)
James Clerk Maxwell Telescope (JCMT)
JUICE
Juno
Kuiper Airborne Observatory (KAO)
K band
Keck Observatory
kilonova (KN)
Keck Planet Imager and Characterizer (KPIC)
Large Binocular Telescope (LBT)
luminous infrared galaxy (LIRG)
Large Millimeter Telescope (LMT)
luminous red nova (LRN)
LUVOIR
magnitude
Mars Express
Mars Observer (MO)
maser
microwave
mid infrared (MIR)
Mimir
MMT
Max Planck Institute for Radio Astronomy (MPIR)
Midcourse Space Experiment (MSX)
Munich Near-Infrared Cluster Survey (MUNICS)
near infrared (NIR)
NIRPS
nitrogen (N)
observational astronomy
OH/IR source
OIR
optical interferometer
optics
Origins Space Telescope (OST)
polycyclic aromatic hydrocarbon (PAH)
PAH emissions
passband
photochemistry
photometric system
photomultiplier tube (PMT)
protoplanetary disk (PPD)
Pioneer Venus Orbiter (PVO)
radio
radiometer
Radio Galaxy Zoo (RGZ)
Rosalind Franklin
Rosetta
radial velocity method
Sloan Digital Sky Survey (SDSS)
spectral energy distribution (SED)
Spitzer Extragalactic Representative Volume Survey (SERVS)
star formation rate (SFR)
Shane Telescope
SMART-1
SOAR
SOFIA
SPICA
SPIRITS
SPIRou
Spitzer Space Telescope (SST)
starburst galaxy
STARFIRE
star formation (SF)
submillimeter astronomy
University of Tokyo Atacama Observatory (TAO)
thermal dust emission
Thirty Meter Telescope (TMT)
transient
TripleSpec (TSpec)
UBV photometric system
UKIDSS
United Kingdom Infrared Telescope (UKIRT)
ultraluminous infrared galaxy (ULIRG)
UVOIR
visible light
VISTA
Voyager
vegetation red edge (VRE)
wavelength
James Webb Space Telescope (JWST)
William Herschel Telescope (WHT)
atmospheric window
Wide Field Infrared Explorer (WIRE)
Wide-field Infrared Survey Explorer (WISE)
WIYN 3.5m Telescope
X-ray luminous galaxy cluster

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