PowerPoint Presentation Globular Cluster Ages and Dark Energy

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Projects
First come first served..

• A new neutral majorana fermion, k, that interacts
  only with neutrinos (all species with equal
  strength) via exchange of a new U(1) gauge boson
  of mass 350 GeV is rumored to have been observed
  in accelerator expts. It is apparently stable,
  but its mass and coupling strength are not yet
  known. How can cosmology help?
• A new axion-like particle with mass 10-3 eV and
  fAMpl is posited, but its cosmological and
  astrophysical implications need to be explored.
• A new unstable heavy fermion of mass 500 GeV, but
  with gravitational coupling strength to all light
  particles is claimed to exist. Is this
  consistent with existing cosmological
  constraints?
• New observations are made that suggest that Fermi
  constant, and the gravitational constant are both
  changing with time, as t-.005. Discuss the
  implications for Big Bang Nucleosynthesis.
• A supernova located 10 kpc away from us goes off,
  and 3,000 events are observed in
  Super-Kamiokande. The burst lasts 20 seconds,
  and 1300 electron neutrino events are observed,
  100 muon neutrino events, and 600 tau neutrino
  events.. Give the implications for neutrino
  physics and cosmology.
• A remarkable new laboratory experiment measures
  dark energy, and just to embarrass Lawrence
  Krauss, they find w -1.2. Give the implications
  for cosmology, life, stellar evolution, particle
  theory, or whatever..

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Cosmology 566 Class 4Density of the Universe
Equation of State, and Dark Matter
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How Much Dark Matter is out there?

• Local mass estimates i.e. clusters
• global mass estimates
• Large scale structure
• Distance-redshift relation
• Direct measures of geometry

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Weighing Clusters of Galaxies
X-Ray Clusters Top of the Cosmic Food Chain
Large Clusters of Galaxies, containing 100s of
galaxies. -The largest bound clumps in the
Universe. Tens of millions of light years across.
- anything that can fall into them, will -good
probes of total matter density?
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Largest clusters galaxies a small contamination,
most of the mass of these systems is in HOT GAS!
T107K
X-Rays!
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Assume in Hydrostatic Equilibrium (uniform,
spherical)
Pressure lt-gtGrav
(T,R) -gt (Mgas,Mtot)
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(SZE indep estimate of Mgas
)
If Mgas MB (a reasonable assumption) then
DARK MATTER IS NON-BARYONIC!
Note ?m lt 1 !!!!!!!!!!!
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Gravitational Lensing
Invert!
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Mtot comparable with X-Ray data
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Large Scale Structure Formation A Primer

• Primordial Fluctuations

Scale independent
Scale invariant n1 (isotropy and BHs)
But observed fluctuations Gravity Plus equation
of state
Large k -gt small wavelength
rad
Comes inside causal horizon sooner i.e. during
radiation domination..
matter
?
aeq
Damped
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keq
k
Problem calculate zeq if Wm0.3 and Wrad10-4
today
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Generally Define Shape Factor, G Naively, G
Wh However, considering effect of baryons on
overall density, and allowing for effects of
curvature, or other, Non-clustered forms of
energy G W0h exp -WB(12h1/2/W) (Peacock
and Dodds 94 sugiyama 95) Allowing for
primordial density perturbations with n?1 G W0h
exp -WB(12h1/2/W) 0.28 (1/n -1) (Liddle
et al, 96)
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.25lt?mhlt.35
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Liddle et al, 96 found
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Update Shape Function
SDSS 3D power spectrum Angular power
spectrum
Dodelson et al, astroph 0107421
Szalay et al, astroph 0107419
2DF
Assignment FIND NEWER NUMBERS
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Late time Evolution of Large Scale Structure
In a flat, matter dominated universe, ?? a(t)
for all scales inside the horizon.
Hence, large scale structure does not stop
forming. (NOTE in open or dark energy dominated
universe, ?? lta(t), so structure formation cannot
keep up with expansion).
Hence there should be many more large scale
galaxy clusters today than there were at higher
redshift
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?mlt. 5 ?
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Results

• Dark Matter dominates all large scale structure
• It is probably non-baryonic
• THERE IS NOT ENOUGH DARK MATTER TO MAKE THE
  UNIVERSE FLAT

QUESTIONS?

• What IS the Dark Matter?
• What about a flat universe?

Stay tuned
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The most important equation in Cosmology?
Distance -redshift relation This provides
dynamical information on the matter content and
equation of state of the Universe.. (cf-age
redshift relationdescribed earlier)
Problem 5
Define comoving distance interval R0dr (where
dr is the coordinate distance interval and R0 is
the scale factor today). Show
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Operational Distances
Luminosity Distance (Hubble Constant, SN..)
Angular Diameter Distance (Angular Size, Grav.
Lensing)
Proper Distance (Grav Lensing)
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Probes of Eq. Of State
Gravitational Lensing Statistics.. Integrate
Probabilities over Some Distance.. Galaxy
Number vs. redshift dN/dz sensitive to distance
redshift relation (Peebles) more
on both of these later
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Luminosity Distance-redshift Relation
(i.e. see Riess 0005229)
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(2) Dark Energy
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(2) Dark Energy
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WHAT GIVES??????
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Magnitude-redshift relation for various eq. of
state
(subtracting off empty universe prediction)
0.15
z
1.5
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Mag. differences
Go to higher redshift?
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Problem Observational uncertainty increases with
Redshift!
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Problem Observational uncertainty increases with
Redshift!
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Hence optimal redshift 0.8? (LMK,CD,EL) Also,
limits depend upon questions asked, ie, is w
constant, is w?-1? Best limit 20-30
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Distance to CMB Surface! w lt 0.78
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Cluster Redshift Distribution (Mohr0105396)
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Cluster Redshift Distribution (Mohr0112512)
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Cluster Redshift Distribution (Mohr0112512)
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Cluster Redshift Distribution (Mohr0112512)
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Cluster Redshift Distribution (Mohr0112512)
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Fresh off the pressSNAP vs Clusters
To determine distance redshift relation must
determine redshift as well as distance but what
about redshift uncertainty? (DH, AK, LMK, TB,
astroph 0402002)
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Supernovae
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Clusters
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Why isnt the Universe flat?
1929-1999
Expansion Rate Density Curvature
?
R
8
G
2
p
r ( ?)

2
R
3
2000 A NEW WAY! MEASURE THE GEOMETRY
DIRECTLY!
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Q How could you measure curvature of the Earth
if (a) no recourse to outside space? (b) not
able to go around it?
GEOMETRY
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Last Scattering Surface
dct J 10
t105 yrs T 3000 K
t109 yrs T 10 K
t1010 yrs T 2.735 K
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First Scale to Collapse after Recombination
(sound speeddistance spanned by light ray
horizon size)
OPEN CLOSED FLAT