Physics 616

  • Prof. Andrew W. Steiner
    (or Andrew or "Dr. Steiner")
  • Office hour: 103 South College, Thursday 11am
  • Email: awsteiner@utk.edu
  • Homework: Electronically as .pdf
  • You may work with each other on the homework, but you must write the solution in your own words
 
 
 
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Outline

Distance Indicators

Distance Indicators I - Tully-Fisher

  • Phenomenological correlation between angular velocity of stars in a galaxy around center and the luminosity of that galaxy
  • Standard correlation includes only stars
  • Slightly different correlations in different bands
  • Found tighter correlation when luminosity includes stars and gas
  • Mass $\propto v^{3-4}$
  • Originally applied to spiral galaxies, applied to ellipticals in "Faber-Jackson" relation
  • Also evidence for dark matter
Tully and Fisher (1977), this figure from Karachentsev et al. (2002)

Distance Indicators II - Type Ia supernova

  • White dwarf always has a mass near the Chandrasekhar limit
  • Luminosity correlated with rise and decline time of the emitted light
  • Emitted light is from the decay of Nickel-56
  • "Phillips relationship"
  • In detail, $$ M_{\mathrm{max}}(B) = -21.7 + 2.7 \Delta m_{15}(B) $$
  • Calibrate correlation with other distance measurements
  • "Standardizable candle"
From Phillips

More General Cosmological Models

More General Cosmological Models II

Cosmic Microwave Background

Cosmic Microwave Background

Recombination

Dipole Anisotropy

Sunayev-Zel'dovich effect

Big Bang Nucleosynthesis

Big Bang Nucleosynthesis II

  • More helium-4 in the universe than can be explained by stellar evolution
  • Deuterium is difficult to create (low binding energy)
  • Observational determinations generally agree with model predictions based on CMB determinations of $\eta$
  • Except lithium 7, "no solution that is either not tuned or requires substantial departures from standard model physics" Cyburt et al. (2016)
  • Stellar depletion of lithium-7 to explain why observed value is smaller than BBN prediction
From NASA

Big Bang Nucleosynthesis III

Cold Dark Matter

  • Cold if (i) non-relativistic, and (at the time of radiation-matter equality) (ii) dissipationless and (iii) collisionless
  • Cold dark matter leads to bottom-up structure formation
  • Bottom-up: small objects clump first, then merge to form larger object
  • What is the opposite of "bottom-up"?
  • WIMPs and axions

WIMP Miracle

Group Work