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Thijs de Graauw

Thijs de Graauw. Instrument Top Level Requirements and Resulting Concept. Heterodyne spectroscopy single pixel on the sky very high spectral resolution 7 dual-pol mixer bands 480-1250 GHz (625-240 m m) 5x2 SIS mixers, IF 4-8 GHz 1410-1910 GHz(212-157 m m; 2x2 HEB mixers,

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Thijs de Graauw

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  1. Thijs de Graauw

  2. Instrument Top Level Requirements and Resulting Concept • Heterodyne spectroscopy • single pixel on the sky • very high spectral resolution • 7 dual-pol mixer bands • 480-1250 GHz (625-240 mm) 5x2 SIS mixers, IF 4-8 GHz • 1410-1910 GHz(212-157 mm; 2x2 HEB mixers, IF 2.4-4.8 GHz • 14 LO sub-bands • LO source unit in common • LO multiplier chains • 2 spectrometer systems; • for each polarisation - auto-correlator spectrometer - acousto-optical spectrometer Angular Resolution (with Herschel): 12”- 40” • HIFI designed for: • - Spectral Scans and Spectral line surveys • - Very high spectral resolution • - Widest possible coverage in the unexplored FIR/Submm range • Frequency coverage: • 480 – 1250 GHz (625-240 m) • 1410 – 1910 GHz (212-157 m) • 2. Sensitivity • Near-quantum noise limit sensitivity • IF bandwidth/Resolution: • - 4 GHz (in 2 polarisations) • - 140 – 280 kHz –0.5 and 1 MHz • 3. Calibration Accuracy: • 10% baseline; 3% goal HIFI SVR 20/21-04-2006

  3. ISM in Galaxies: • Normal galaxies • Physical properties of star-forming ISM • ISM in the Milky Way: • Structure • Dynamics (pressure) • Composition(gradients) • Dense cores and star-formation: • Temperature, density structure • Dust properties • Stellar IMF • Late stages of stellar evolution: • Winds • Shells • Asymmetries • Composition • Solar System: • Water in GiantPlanets • Atmospheric chemistry • Water activity and composition of comets HIFI Science ObjectivesLife Cycle of Gas and Dust HIFI SVR 20/21-04-2006

  4. HIFI Unique Science: Molecular Universe,Spectral Line Surveys CSO Spectrum of Orion: 8 nights For HIFI: < 1 hr; Total HIFI range in 12 hours Spectral survey of Orion-KL showing hundreds of molecular lines with atmospheric transmission overlaid. HIFI will be able to survey outside of the atmospheric windows and at frequencies never probed before, allowing for searches of new molecules. JCMT Spectral Survey IRAS16293 HIFI SVR 20/21-04-2006

  5. HIFI water line observations Observations by ISO and SWAS/Odin have shown: Water is present in a variety of objects, all over the Galaxy. The high resolving power, high sensitivity and large frequency coverage of HIFI, combined with Herschel’s smaller beam ‘will extend our knowledge by orders of magnitude’ HIFI SVR 20/21-04-2006

  6. 1.9E-16 1.8E-16 1.7E-16 1.6E-16 1.5E-16 TA* (K) W cm-2 m-1 ntensity o-H2O 221-110 -100 0 100 Velocity (km/s) VLSR (km/s) HIFI Unique Science: Water abundant from SWAS, ODIN, ISO, Spitzer, etc ISO- LWS SWAS ISO-SWS relative warm H2O HIFI SVR 20/21-04-2006

  7. SURD: Conclusions of the individual instrument requirements • Frequency coverage: Closure of the frequency-gaps between bands 5 and 6 would provide contiguous coverage of the high frequency range for spectral surveys. • Sensitivity drivers are observations of isotopic water lines and isotopic fine-structure lines at the higher frequencies, and the [CII] line detection at high redshift. • High spectral resolution is required for several water studies and [NII] and [CII] studies of the diffuse ISM, for dense cores, for absorption lines, for comet emission lines, and for planetary absorption lines. • Wide instantaneous bandwidth is needed for efficient line surveys and for Extra-Galactic lines especially the [CII] line at high red shift. HIFI SVR 20/21-04-2006

  8. Drivers for Frequency Coverage HIFI SVR 20/21-04-2006

  9. HIFIScience and Instrument Requirements HIFI SVR 20/21-04-2006

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