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Radio Astronomy

Radio Astronomy. Ganesh Sankaranarayanan Graduate Student Electrical Engineering. UW Campus Observatory. Built in 1892 Located on 4 th and University St Moved in 1895 to the current location Second Building on campus next to denny hall. Telescope. 6-inch Brashear objective lens

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Radio Astronomy

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  1. Radio Astronomy Ganesh Sankaranarayanan Graduate Student Electrical Engineering

  2. 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

  3. 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!

  4. Visible World

  5. Electromagnetic spectrum • Electromagnetic radiation • The visible world (We see very little!) • Radio spectrum • X-ray, UV,IR spectrum

  6. History of Radio AstronomySerendipity? Rotating Telescope Karl Jansky –1928

  7. History of Radio Astronomy Grote Reber -1937 9 meter dish antenna Image courtesy NRAO

  8. Radio Sources21-cm Neutral Hydrogen Lines High Energy State Low energy state 21-cm photon

  9. Radio Sources21-cm Neutral Hydrogen linesDiscovery • Emission once in few million years • 80% Hydrogen in Universe • 21-cm emission not obstructed by dust • Used to map galaxies and ISM Harold Irving Ewen 1951

  10. Milky Way in 21cm Image courtesy of NRAO/AUI

  11. M33 Radio and Optical Composite Image courtesy of NRAO/AUI and NOAO/AURA/NSF

  12. Orion Nebula M42 Image courtesy of NRAO/AUI

  13. Radio SourcesPulsars • 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”) Image courtesy Jodrell Bank Pulsar Group

  14. Sounds of Pulsars PSR B1937+21 PSR B0531+21, The Crab Pulsar PSR B0329+54 Image and sound courtesy Jodrell Bank Pulsar Group 47 Tucanae

  15. Pulsar and Supernova Remnant Image courtesy of NRAO/AUI

  16. Crab Nebula Pulsar Image Courtesy J. Hester (ASU), CXC, HST, NRAO, NSF, NASA

  17. 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

  18. Quasar Image courtesy of NRAO/AUI

  19. 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…

  20. Water MASER Image courtesy of NRAO/AUI

  21. Radio SourcesCosmic Microwave Background Radiation Arno Penzias and Robert Wilson1963 Robert Wilson on cosmic noise Image and sound courtesy Lucent Technologies Inc.

  22. Cosmic Microwave Background Radiation The COBE datasets were developed by the NASA Goddard Space Flight Center under the guidance of the COBE Science Working Group and were provided by the NSSDC. COBE

  23. Radio Sources Sun Image courtesy of NRAO/AUI

  24. Radio Sources Planets Saturn Jupiter during impact of comet Shoemaker-Levy 9 Image courtesy of NRAO/AUI

  25. Radio Telescopes Arecibo • Located in Puerto Rico • Operated by Cornell and NSF • 1000 ft (304.8 m) • Used for Astronomy, atmospheric and planetary studies

  26. 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 Image courtesy of NRAO/AUI

  27. Radio TelescopesVLI (Very Large Array) • Located in Socorro, NM • 27 antennas interferometer • Each antenna 25 meters( 82 feet) in diameter Image courtesy of NRAO/AUI

  28. VLBI (Very Large Baseline Array)

  29. ALMA The Atacama Large Millimeter Array • Atacama desert, Chile • 64 radio telescopes • 12 meter (39 feet) wide dish antenna • Expected to operate in 2011 Image courtesy of NRAO/AUI

  30. 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

  31. Radio Astronomy at UW • UAI established in 1999 • 7ft dish • Currently building motion control and receivers for 21cm hydrogen lines (1420 MHz)

  32. 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

  33. The End Questions ? Thank You

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