What are the Big Questions and how can Radio Telescopes help answer them? Roger Blandford KIPAC Stanford Radio Astronomy in 1957 ~100 ~100 ~100 ~100 29 ix 2009 MHz Jy sources arcseconds NRC Scientific Use of Radio Spectrum 2 Radio Astronomy in 2007 ~ ~ ~ ~ 29 ix 2009 10 MHz - ~ 1 THz 10 μJy >106 sources 100 μas NRC Scientific Use of Radio Spectrum 3 Radio Astronomy in 2057? ~ ~ ~ ~ 29 ix 2009 1 MHz - ~ 1 THz 1 pJy 1012 sources 100 pas NRC Scientific Use of Radio Spectrum 4 Radio Telescopes in 2057 ALMA, EVLA + SKA++ • All digital phased array International network of telescopes • Linked by optical fibers with ample bandwidth • Low T amplifiers • Distributed computing will keep up Orbiting antennae • Up to AU baselines • Cheap large (inflatable?) antennas • Radio active and adaptive optics Low frequency lunar array? 29 ix 2009 NRC Scientific Use of Radio Spectrum 5 Organization Physical Cosmology • Cosmography, DE, DM, growth of structure Cosmography • IGM, Galaxy formation Astrophysics • GR, BH, NS, AGN Astronomy • Local galaxies, star formation, SNR Life in the Universe • Astrochemistry, astrobiology, SETI… 29 ix 2009 NRC Scientific Use of Radio Spectrum 6 Physical Cosmology 29 ix 2009 NRC Scientific Use of Radio Spectrum 7 Cosmology Distances • VLBA parallax FΛCDM • a(t) ~ sinh2/3t, w= -1; j=a’’’a2/a’3 =1 Scale invariant fluctuations • CMB Measure d(a), φ(a) • BAO, SZ, WL, SKA-lo 29 ix 2009 NRC Scientific Use of Radio Spectrum 8 Serendipity Inflation Topological defects Phase transitions • CMB • Lens pairs • MSP timing arrays 29 ix 2009 NRC Scientific Use of Radio Spectrum 9 Recombination Measured to limit from irreducible foregrounds~10nK? Accomplishments • Fundamental cosmological parameters - To ~0.01 - Recombination lines • Density fluctuation spectrum to l~104 - Initial conditions • Tensor modes - Inflation? • Non-Gaussianity - Strings monopoles, etc… - Lens searches • Monitor growth of structure - SZ, ISW, lensing… 29 ix 2009 NRC Scientific Use of Radio Spectrum 10 Growth of Structure Statistics phenomenal SZ surveys from South Pole Good working model except • Dwarf dearth • Cluster entropies • Nonlinear phase Galaxy surveys most likely to contribute to understanding of galaxy formation and evolution 29 ix 2009 NRC Scientific Use of Radio Spectrum 11 Cosmoserendipity Gravitational radiation background Neutrino masses CMB, LSS anomalies • Physics of DE, DM Golden gravitational lenses • Rare high order catastrophes • Probes of structure as well as sources 29 ix 2009 NRC Scientific Use of Radio Spectrum 12 Dark Ages H-line Standard model has linear growth of structure • Standard physics, sanity check • Explore the frequency “dimension” • Recombination lines Epoch of reionization • When? 21(1+zreion)cm, 7<zreion<20 • Crucial for telescope design • Intergalactic meteorology? Connect to first stars, galaxies 29 ix 2009 NRC Scientific Use of Radio Spectrum 13 Galaxy Formation and Evolution Re-ionization happens fast through massive stars followed by AGN? Empirical history of assembly of galaxy • Multiwavelength enterprise - ALMA, SKA++ - + JWST, Con-XEUS, GSMT… • CO in hi z quasar hosts 29 ix 2009 NRC Scientific Use of Radio Spectrum 14 Surveys and Monitoring Whole sky surveyed and monitored to limiting flux, that • Ω(S,…,t), N(S,…,t) SKA FOV ~ 0.01 of sky at low frequency • Confusion limit at low frequency High connectivity to multi-wavelength surveys • GLAST whole sky in 3hr • LSST in 3d … Billions of sources in 3D EVLA x 0.1 SKA++ x 0.001 29 ix 2009 NRC Scientific Use of Radio Spectrum 15 Astrophysics Relativity • Radio astronomy has contributed almost all the best quantitative measurements in GR • Much more to come Neutron stars are nuclear/many body physics laboratories • Dynamical and thermal Relativistic outflows • Novel QED, plasma physics… 29 ix 2009 NRC Scientific Use of Radio Spectrum 16 Relativity and Compact Stars Thousands of MSP, binary pulsars • Improved timing • De-dispersion Ter 5 Tests of weak field gravity Spin orbit effects • M[R] Black hole NS systems • Eclipsing • Remote “no hair” tests 29 ix 2009 NRC Scientific Use of Radio Spectrum 17 NS/BH Spacetimes Direct resolution at mm wavelengths • Sgr A* • M87 • Limited by S, λ, b Pulsar timing tests • Double pulsar PK1 PK3 29 ix 2009 NRC Scientific Use of Radio Spectrum PK2 18 Angular limit Terrestrial telescopes connected with optical fibers Angular limit • θ>[10 (b/RE)-1 ν9-1 , 0.5 ν9-2.2]mas, high latitude • θ>ν9-2 as, Galactic Center Baseline limit • b< [1010 ν91.2, 3x1014D91/2 ν9-1/2] cm Linear resolution limit • R>3x1014D91/2 ν9-1/2 cm • M9>D91/2 ν9-1 29 ix 2009 NRC Scientific Use of Radio Spectrum 19 “Engineering” of Relativistic Jets Disk + spinning black hole + magnetic field => Jet • How? High dynamic range mapping of Galactic and extragalactic jets • Radio polarization • Multi-lambda campaigns • Numerical simulations Disk-jet connection • Accretion disks 29 ix 2009 NRC Scientific Use of Radio Spectrum 20 Astroserendipity LIGO, LISA • Locate incipient mergers - LSST, SKA++… Cosmic explosions • GRBs, magnetars… • Flare stars Neutrino bursts • VHE neutrino detection • UHECR radio detection • GW signals 29 ix 2009 NRC Scientific Use of Radio Spectrum 21 Astronomy Study of Galactic structure Molecular clouds as cradles of star formation Galactic ecocycles Stellar evolution 29 ix 2009 NRC Scientific Use of Radio Spectrum 22 ALMA Spectroscopy 29 ix 2009 NRC Scientific Use of Radio Spectrum 23 Life in the Universe Terrestrial planets exist! Astrobiology and chemistry • Prebiotic molecules - entire spectrum • ALMA debris disks, gaps, bloated planets • Search for habitable planets Habitability of nearby planets • Stellar flares SETI program • Checkered history ATA Dedication • Ultimately has strong popular support • Parasitic searches for patterned noise/signals - Great leaps in electronics signal/information processing 29 ix 2009 NRC Scientific Use of Radio Spectrum 24
© Copyright 2026 Paperzz