Cosmology
Lecture 8
Flux
K-corrections
Wavelength
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Need to allow for redshift of spectrum
Objects both fainter and brighter than implied by F α 1/d2
SN Ia at z>1
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Looks good for the benchmark model
Riess et al. 2007 ApJ 659 98
http://arxiv.org/abs/astro-ph/0611572
Is Λ constant
Riess et al. 2007 ApJ 659 98
Limits for type Ia supernovae
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Hubble Space Telescope cannot see SN Ia
beyond z>2
Need next generation of space telescopes /
instruments
Need more luminous standard candles
Joint Dark Energy Mission
(JDEM)
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Selected as next major NASA mission in
August 2007
3 competing designs
SNAP - Supernova Acceleration
Probe
Field of view 400 times larger than Hubble Space Telescope
Destiny - Dark Energy Space
Telescope
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Similar to SNAP
Very wide field
optical + IR
5 day cadence
Spectroscopy (for
redshifts)
ADEPT - Advanced Dark Energy
Physics Telescope
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Wide field, deep galaxy
survey
Imprint of anisotropy of CMB
on universe at later times
(baryon acoustic
oscillations)
Also, finds ~1000 SN Ia to
z<1.7
Know co-moving size of perturbation: r = a(t) x
Gamma-ray bursts (GRBs)
Brightest
explosions in
universe
Can be 1000+
times brighter
than SN Ia
GRB energies
Gamma-ray
spectrum
corrected
Beaming corrected
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GRBs appear highly non standard, but might be
possible to standardize
GRB
cosmology
Our benchmark universe (ΛCDM)
H0 = 72 km s-1 Mpc-1
Ω0 = 1 - spatially
ΩΛ = 0.73
Ωm = 0.27
Ωm,baryon = 0.04
Ωm,cold-dark-matter = 0.23
What is dark matter?
Ωr = 10-4
Age of universe = 13.7 Gyr
How does structure
form?
What is dark energy?
Does model hold in
very young universe?
Theory is very successful at describing universe
evolution over most of cosmic history
Epochs of the universe