Radio Astronomy Ganesh Sankaranarayanan


НазваRadio Astronomy Ganesh Sankaranarayanan
Дата конвертації06.06.2013
Розмір453 b.
ТипПрезентации


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



Telescope

  • 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



Quasar



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…



Water MASER



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



Схожі:

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


Додайте кнопку на своєму сайті:
dok.znaimo.com.ua


База даних захищена авторським правом ©dok.znaimo.com.ua 2013
звернутися до адміністрації
dok.znaimo.com.ua
Головна сторінка