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Observational techniques meeting #14

Observational techniques meeting #14. Cosmic microwave background: history + basic instrumentation CMB: recent developments MM/ SubMM instrumentation: SCUBA -> ALMA Sunyaev-Zeldovich effect; detection; implications Light echoes IFU spectrographs Neutrino detectors TEV telescopes

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Observational techniques meeting #14

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  1. Observational techniquesmeeting #14

  2. Cosmic microwave background: history + basic instrumentation • CMB: recent developments • MM/SubMM instrumentation: SCUBA -> ALMA • Sunyaev-Zeldovich effect; detection; implications • Light echoes • IFU spectrographs • Neutrino detectors • TEV telescopes • Cosmic-ray observatories • Gravitational wave detectors • MIR/FIR instrumentation • Future radio arrays: LOFAR, SKA Topics for student talks:

  3. Radio Astronomy

  4. Definitions: • Wavelength λ>0.3 mm (frequency ν<1 THz) • Upper limit set by molecular vibrational opacity (FIR) • Lower limit λ ~ 30m (ν<10 MHz) set by ionospheric reflection; can go lower from space. Radio Astronomy

  5. Some basic features: • The Sun is a weak radio source + little atmospheric scattering: can observe during daytime • The atmosphere is not perfectly transparent; water content a major factor Radio Astronomy

  6. λ > grain size: no dust absorption Dust penetration VLA 1.3cm

  7. Resolution ~ λ/D so very large telescopes required to achieve reasonable resolution • However, can make very fine surfaces (<λ/16) • Can use huge interferometer arrays (D~104 km) • Best resolution achieved in radio Angular resolution VLA: 1-36 km, 0.01-45”, 1.4-43 GHz 100m GBT VLBA; 0.00017” VLA 1.3cm

  8. Discovery: 1932 (Jansky, Bell labs) • Telecom interference: source outside solar system (siderial periodicity) • First map ay 160 MHz by amateur G. Reber (Backyard 10m dish, IL; ApJ 1940) • Final progress after WW2 (radar technology) History VLA: 1-36 km, 0.01-45”, 1.4-43 GHz 100m GBT VLA 1.3cm

  9. Radio sources VLA: 1-36 km, 0.01-45”, 1.4-43 GHz 100m GBT Galactic HI (1.4 GHz; hyperfine transition of H) Galactic diffuse ISM (408 MHz) Cygnus 1: nearby active galactic nucleus VLA 1.3cm M51 in submm: molecular gas (CO) SN remnant Cas A (VLA, 1.4-8.5 GHz) 3C273: the first Quasar

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