The Future: Astrophysical and Cosmological Data

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The Future Astrophysical and Cosmological Data

• PDG 50th Anniversary
• 23 September 2006
• Michael S. Turner
• Kavli Institute for Cosmological Physics

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A Brief History ofCosmological Measurements
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Landau on Cosmologists(not cosmetology)
Often in Error, Never in Doubt!
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Just One NumberH0 550 km/s/Mpc(error bars not
needed)
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Zwicky Dark Matter, Gravitational Lensing,
Supernovae, Jet Propulsion,
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Cosmology The Search for Two Numbers Sandage
1970
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Two Numbers, with error bars
q0 -0.7 0.2
H0 70 7 km/s/Mpc
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Precision Cosmology Science
and large, rich datasets
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A Brief History ofPDG Cosmology
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• August 1968 (29 pages) my first copy
• 1984 (161 pages) astro bound on photon mass
  sneaks in (m lt 3 x 10-33 GeV)
• 1986 (164 pages) Astrophysics arrives
• Astrophysical constants (on page 145 back of
  the bus)
• H0 40 to 100 km/sec/Mpc
• t0 10 to 20 Gyr
• O0 0.05 to 4
• Astrophysical constraints included
• Big Bang Cosmology (Olive Rudaz)
• 1988 (172 pages)
• Astrophysical Constants follow Physical Constants
  (front of bus)
• 1990 (194 pages)
• Dark Matter Review (Flores Olive)
• 1994 (226 pages) CMB arrives
• Astrophysical Constants grow to 2 pages!
• T0 2.726 0.005 K
• H0 40 to 100 km/sec/Mpc
• O0 0.1 to 2
• Oh2 lt 2.4

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• 1998 (255 pages) bad timing
• Cosmic Ray, H0 and BBN Reviews
• H0 60 to 80 km/sec/Mpc
• OM 0.2 to 1
• O? -1 to 2
• T0 2.728 0.002 K
• 2000 (272 pages) The New Cosmology
• Tests of Gravitational Theory Review
• H0 (71 7) x (0.95 to 1.15) km/sec/Mpc
• t0 12 to 18 Gyr
• OM 0.15 to 0.45
• O? 0.6 to 0.8 (!)
• T0 2.725 0.001 K
• 2004 (317 pages) WMAP/SDSS era
• H0 714-3 km/sec/Mpc
• t0 13.7 0.2 Gyr
• OM 0.27 0.04
• OB 0.044 0.004
• O? 0.73 0.04

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Precision Cosmology (and accurate too)
CMB (first to second peak) Obh2
0.0220.001 BBN (Deuterium) Obh2
0.0200.001 Ob 4 to 5!
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Longer Than Physical Constants
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Big Complicated Data Sets The Devil is in the
Details Correlations
Million Correlated Pixels
10 Terabytes
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Spergel et al (WMAP)
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Tegmark et al (SDSS)
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Vive la Difference

• O0 1.003 0.01 to O0 1.05 0.05
• 
  vs 1.02 0.02 (PDG)
• OM 0.238 0.04 to OM 0.266 0.03
• 
  vs 0.27 0.04 (PDG)
• OBh2 0.0225 0.0007 to 0.021 0.001
• 
  vs 0.0223 0.001 (PDG)
• h 0.71 0.03 to 0.53 0.1
• 
  vs 0.73 0.03 (PDG)
• n 0.87 0.05 to 0.97 0.02
• 
  vs 0.95 0.02 (PDG)
• t0 13.76 0.15 to 14 0.2
• 
  vs 13.7 0.2 (PDG)
• t 0.17 0.04 (WMAP1 detection) to 0.09 0.03
  (WMAP3)
• 
  vs 0.17 0.04 (PDG04)
• 
  0.09 0.03 (PDG06)

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We Know More Than We Understand

• Flat Big
• Accelerating
• Old Smooth
• Odd Mix of
• Baryons
• Neutrinos
• CDM
• Dark Energy
• No recent surprises

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Convergence of Frontiers of Particle Physics and
Cosmology

• What is the dark matter particle? (Neutralino?
  Axion?)
• How did the Universe come to be? (Inflation?
  Cause?)
• What are neutrinos telling us about the
  unification of forces and the origin of
  (baryonic) matter? (Leptogenesis?)
• What is the dark energy that is causing the
  Universe to accelerate? (See Next Slide)
• Is there a superworld as envisioned by
  superstring theory?
• How are quantum mechanics and gravity reconciled?
• How many spatial dimensions?
• What are space and time and where did they come
  from?

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Whats the problem? Cosmic Acceleration is caused
by the repulsive gravity of dark energy.
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The Future

• Growing number of cosmological datasets of
  importance and interest to particle physics
• Growing size (mega to tera) and complexity
  (correlations, priors) of data sets (CMB, SDSS,
  )
• Growing importance of computer simulations in
  extracting parameters
• Growing power and importance of correlating
  multiple data sets (SDSS and WMAP)
• Growing number of independent analyses (some
  good, some bad)
• NB same trends in particle physics

weve come a long way since invariant mass plots
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PDG Brings to the Table

• Honest Brokers
• Expert, but not too expert
• Strong, experienced group trusted by the
  community
• Excellent education and outreach
• Strong at simple, objective analyses

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Possible PDG Roles

• Neutral commissioner of reviews (mixed record to
  date in cosmology)
• Stick to the basic parameters (the naughts, etc.)
• Education and Public Outreach!! (getting the word
  out about the exciting discoveries)
• Data Repositories (??)
• In any case change astrophysical to cosmological

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Congratulations on 50 Years of Distinguished and
Valuable Service to the Science and Education
Communities!