Radio Astronomy Ganesh Sankaranarayanan

НазваRadio Astronomy Ganesh Sankaranarayanan
Дата конвертації06.06.2013
Розмір453 b.

Radio Astronomy

  • Ganesh Sankaranarayanan

  • Graduate Student

  • Electrical Engineering

UW Campus Observatory

  • Built in 1892

  • Located on 4th and University St

  • Moved in 1895 to the current location

  • Second Building on campus next to denny hall


  • 6-inch Brashear objective lens

  • Warner & Swasey equatorial mount

  • 90-inch focal length

  • Warner & Swasey wooden , rests on 3 civil war era cannon balls!

Visible World

Electromagnetic spectrum

  • Electromagnetic radiation

  • The visible world (We see very little!)

  • Radio spectrum

  • X-ray, UV,IR spectrum

History of Radio Astronomy

Radio Sources 21-cm Neutral Hydrogen Lines

Radio Sources 21-cm Neutral Hydrogen lines Discovery

  • Emission once in few million years

  • 80% Hydrogen in Universe

  • 21-cm emission not obstructed by dust

  • Used to map galaxies and ISM

Milky Way in 21cm

M33 Radio and Optical Composite

Orion Nebula M42

Radio Sources Pulsars

  • Discovered in 1967

  • Rapidly rotating neutron star

  • 10-15 km radius

  • Cosmic clocks in the sky

  • First thought to be a signal from aliens (“little green men”)

Sounds of Pulsars

Pulsar and Supernova Remnant

Crab Nebula Pulsar

Radio Sources Quasars

  • Quasar : Quasi- stellar radio source

  • Most distant object to emit radio waves

  • Contain super massive black holes in the center

  • Radio emission produced by synchrotron radiation

  • Reflect the stage of universe billions of years ago


Radio Sources MASERS

  • Dense molecular clouds with strong emission (T > 106 K)

  • MASER action

  • Microwave Amplification by Stimulated Emission of Radiation

  • OH,H2O,SiO, CH3CH2OH and more…


Radio Sources Cosmic Microwave Background Radiation

Cosmic Microwave Background Radiation

Radio Sources Sun

Radio Sources Planets

Radio Telescopes Arecibo

  • Located in Puerto Rico

  • Operated by Cornell and NSF

  • 1000 ft (304.8 m)

  • Used for Astronomy, atmospheric and planetary studies

Radio Telescopes Green Bank Telescope

  • Located in Green bank, West Virginia

  • 485 feet tall -- taller than the Statue of Liberty!

  • 100 by 110 m width

  • World’s Largest steerable radio telescope

Radio Telescopes VLI (Very Large Array)

  • Located in Socorro, NM

  • 27 antennas interferometer

  • Each antenna 25 meters( 82 feet) in diameter

VLBI (Very Large Baseline Array)

ALMA The Atacama Large Millimeter Array

  • Atacama desert, Chile

  • 64 radio telescopes

  • 12 meter (39 feet) wide dish antenna

  • Expected to operate in 2011

Radio Telescopes around the world

  • Europe

    • Westerbork Synthesis Radio Telescope (WSRT) , Netherlands
    • The Ryle Telescope, United Kingdom
  • Australia

    • Mopra Observatory
  • Asia

    • Giant Meterwave Radio Telescope(GMRT) , India
    • Nobeyama millimeter array ,Japan

Radio Astronomy at UW

  • UAI established in 1999

  • 7ft dish

  • Currently building motion control and receivers for 21cm hydrogen lines (1420 MHz)

Future of Radio Astronomy

  • More cost to build radio telescopes

    • Consortium among countries to build future telescopes
  • Major advancements in telescope technologies

    • Better design to control noise over effective area
      • GMRT,ALMA
    • Better angular resolution
  • Encroachment of radio frequencies by ground and satellite communications

    • More power in deciding frequency allocations
    • Better modulation techniques to prevent spill over

The End


Radio Astronomy Ganesh Sankaranarayanan iconGiant Pulses of Pulsar Radio Emission Giant Pulses of Pulsar Radio Emission

Radio Astronomy Ganesh Sankaranarayanan iconNeutron Star Astronomy Roberto Mignani

Radio Astronomy Ganesh Sankaranarayanan iconRadio Sounding of the Near-Sun Plasma Using Polarized Pulsar Pulses

Radio Astronomy Ganesh Sankaranarayanan iconSterling Park Amateur Radio Club (sparc) Appreciation Hams Everywhere

Radio Astronomy Ganesh Sankaranarayanan iconAstronomy 340 Fall 2007 4 December 2007 Lecture #26 Extrasolar Planets

Radio Astronomy Ganesh Sankaranarayanan iconThe Crab Nebula The Crab Nebula : the standard candle of astronomy

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