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what good are low frequencies?

what good are low frequencies?. HI, neutral hydrogen, H 0 , atomic hydrogen high redshifts and early times…. USS, GPS, … “enabling technologies” …multi-beaming, all-sky transients,…, the highest energy cosmic rays…. Z = 4. FREQ MHz. 50 100 200 1000.

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what good are low frequencies?

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  1. what good are low frequencies? • HI, neutral hydrogen, H0, atomic hydrogen • high redshifts and early times…. USS, GPS, … • “enabling technologies” …multi-beaming, all-sky transients,…, the highest energy cosmic rays…

  2. Z = 4 FREQ MHz 50 100 200 1000 50 100 200 1000 Gigahertz Peak Sources: young radio sources ??? FREQ. GHz

  3. Big Bang Nucleosynthesis re-ionized re-re-ionized .…. ionized……

  4. 70 MHz ………………..180 MHz HI HI HI HI HI

  5. damped Lyman-a abs-lines 21cm Line Studies (HIPASS)

  6. cosmic density Wg of Neutral Gas extent of metal-rich gaseous halos co-moving number density of bright Quasars Cosmic Star Formation Rate history: the Madau Plot 0 1 2 3 4 5 0 1 2 3 4 5 0 1 2 3 4 5 Cosmic Evolution Indicators Redshift

  7. frequency 1420 500 250 MHz Passive relaxation Violent accretion Cosmic Evolution Indicators Redshift

  8. Cohen et al 3” 3C196-G1 z = 0.437 HST image (Ridgway & Stockton)

  9. Radio spectrum at 988 MHz Westerbork (Briggs, deBruyn, Vermeulen) Double Lobed Radio Source 300 km/s

  10. source centroid as fnct of Frequency SKA map emission ? map absorption ?

  11. new GMRT Kanekar & Chengalur 988 MHz

  12. high redshift radio galaxies TNR J2254+1857 TNR J1402-1510

  13. Radio galaxy spectra No DLA absorption lines No UV continuum

  14. VLBI to resolve source Molonglo Telescope: SKAMP III • frequency coverage • sensitivity • RFI rejection

  15. the Molonglo challenges: • broadband line feeds • 96 station correlator • Defence HQ 3 km away ?!?!

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