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Interstellar Matter

Interstellar Matter. Emily Linden & Fiona Ward. Question. Specify the radio techniques used to probe the nature of interstellar matter. Book example. Optical Spectral Analysis Requires -Background source of radiation

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Interstellar Matter

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  1. Interstellar Matter Emily Linden & Fiona Ward

  2. Question • Specify the radio • techniques used to • probe the nature • of interstellar matter.

  3. Book example • Optical Spectral Analysis Requires • -Background source of radiation • -Stars viewed through clouds to be relatively close to earth (w/in a few thousand pcs) • Low-energy Radio Emissions produced by the gas of the nebula itself is more versatile • Astronomers examine hydrogen spin-rates to determine radio spectral lines • Hydrogen 21-Centimeter Radiation

  4. Book Example • Hydrogen ground state spin patterns: parallel or antiparallel • Antiparallel has slightly less energy than parallel • All matter tends to achieve lowest possible energy state. • When hydrogen atom drops down to antiparallel spin, a photon is emitted. • High energy  low energy: Emitted photon is equal to energy lost • Energy difference is very low, so energy of photon is very low • Wavelength= 21.1 cm (radio portion) • 21-centimeter radiation: the spectral line that results from this hydrogen-spin-flip process

  5. Book Example • Requires no visible light • Can be used on any interstellar region that contains enough hydrogen gas to produce a detectable signal • This includes low-density regions between dark clouds • Wavelength much larger than typical interstellar dust particles • Radio radiation reaches Earth unscatteredby interstellar debris • Can reach well beyond a few thousand parsecs • Can reach in directions lacking background stars

  6. http://hubblesite.org/newscenter/archive/releases/2003/30/image/a/http://hubblesite.org/newscenter/archive/releases/2003/30/image/a/ Ultraviolet, Visible, and infrared • Hubble's Wide Field Planetary Camera 2 in 1994, 1995, and 2001 • Color filters were used to isolate light emitted by hydrogen, oxygen, nitrogen, and sulfur atoms • This nebula is an emission • NGC 604 (Nicolas-Claude Fabri de Peiresc.) • First noted by the English astronomer William Herschel

  7. http://spectrevision.net/2013/05/31/interstellar-radio/ Gravitational Lens • Radio signals will be sent out • Usually up to five satellites in space • Higher the frequency the father the distance

  8. http://www.nasa.gov/multimedia/imagegallery/image_feature_701.htmlhttp://www.nasa.gov/multimedia/imagegallery/image_feature_701.html Reflection Nebula • Gives off a blue color • The star Rigel supplying the light • Retains light from other source

  9. Answer • Book Example: Astronomers use Hydrogen 21-Centimeter Radiation to probe the nature of interstellar matter. • Web Example: Astronomers use cameras from telescopes such as Hubble equipped with color filters and radio emissions to probe the nature of interstellar matter.

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