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Radio AstronomyJin KodaRadio astronomyAtmospheric WindowCentimeter radio astronomyEffelsberg 100m telescope (Germany)Green Bank 100m telescope(National Radio Astronomy Observatory; West Virginia)Centimeterradio astronomyHI 21cm line emission traces the distribution of atomic hydrogen.Dust: far-Infrared (60-240micron) mapNASA/GSFCAtomic hydrogen (HI): 21cm emission-line Dickey & Lockman 1990Ionized hydrogen (HII): Ha emission-line Douglas Finkbeiner (Harvard CfA)Molecular hydrogen (H2): CO mapDame, Hartmann, Thaddeus, 2001Centimeter radio astronomyThermal Bremsstrahlung emission from HII regionsCentimeter radio astronomyRadio (20cm obs. with the Very Large Array)OpticalM87 -- galaxy at center of Virgo cluster of galaxies)Synchrotron radiationMillimeter radio astronomyMillimeter wavelengthIRAM 30m telescope (Spain)Nobeyama 45m telescope (Japan)Large Millimeter Telescope(Mexico, UMASS)Millimeterradio astronomyDust: far-Infrared (60-240micron) mapNASA/GSFCAtomic hydrogen (HI): 21cm emission-line Dickey & Lockman 1990Ionized hydrogen (HII): Ha emission-line Douglas Finkbeiner (Harvard CfA)Molecular hydrogen (H2): CO mapDame, Hartmann, Thaddeus, 2001Molecular line emissions(CO, HCN, CS, NH3, many mores) trace dense molecular gas where stars form.Submillimeter radio astronomySub-Millimeter wavelengthJames Clerk Maxwell telescope - 15m(Hawaii, UK)Caltech Submillimeter Observatory - 10m(Hawaii)Atacama Submillimeter Telescope Experiment-10m (Chile, Japan)Atacama PathfinderExperiment-10m (Chile, Europe)Submillimeter radio astronomySize of telescopeSnow sweepat Nobeyama 45m telescopeAntennasAntenna response function•Resolution•Main beam & sidelobes•depends on surface accuracy -- sidelobes could be very high λDDetectors/ReceiversBolometerBolocamCalibrationat CARMAInterferometerOld Green Bank 100m telescopeAngular resolution: λ/D ~ 60” in 3cmArecibo 300m telescopeRadio interferometerRadio interferometerVery Large Array (VLA)(New Mexico)Westerbork Synthesis Radio telescope(Netherlands)Centimeter wavelengthCARMA Interferometer (California)Radio interferometerAngular resolution: λ/B ~1” for 1km baseline in 3mmPlateau de Bure interferometer (France)Submillimeter Array (Hawaii)Millimeter wavelengthSub-Millimeter wavelengthRadio interferometerCase of 2 elementsInterferometerlll sin(2πνt) sin(2πν(t −τ))DlA Fourier component F = sin(2πνt)sin(2πν(t −τ)) ≈ cos(2πντ) = cos(2πDlλ)lInterferometerlll sin(2πνt) sin(2πν(t −τ))Dl F = sin(2πνt)sin(2πν(t −τ)) ≈ cos(2πντ) = cos(2πDlλ) Image = ADcos(2πDlλ)D∑lUV-coveragelll sin(2πνt) sin(2πν(t −τ))Dl F = sin(2πνt)sin(2πν(t −τ)) ≈ cos(2πντ) = cos(2πDlλ) Image = ADcos(2πDlλ)D∑Synthesis imaging (2 antennas)Earth (rotating)Look down the earthfrom your favorite targetData coverage in Fourier spaceSynthesis imaging (6 antennas)Earth (rotating)Data coverage in Fourier space# of ant pairs = N(N+1)/2 N=6 15 pairsSynthesis imaging (15 antennas)Earth (rotating)Data coverage in Fourier spaceCARMA array# of ant pairs = N(N+1)/2 N=15 105 pairs!Configuration ChangeB-configurationE-configurationFourier CoverageData coverage in Fourier spaceCARMA arrayHole!CARMA + NobeyamaSynthesis imaging + Single Dish CARMA arrayData coverage in Fourier spaceNobeyama 45m telescoperesolution ~20”Single Dish Map of Molecular GasXCO=2x1020resolution ~20”resolution ~4”Interferometer + Single-Dish CombinedNon-redundant masking in opticalNear FutureStony Brook radio interferometerFuture: Space VLBIFuture: ALMAAltitude ~5000mEarly operation


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SBU AST 443 - Radio Astronomy

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