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Neutrino Ocillations and Astroparticle Physics (3)
Introduction to Cosmology and High Energy Astronomy
John Carr Centre de Physique des Particules de Marseille (IN2P3/CNRS)
Pisa, 8 May 2002
- expansion of the universe- some astronomy - some cosmology- big bang nucleosynthesis - cosmic microwave background radiation- SuperNova Type 1a- Energy composition of universe
Expansion of Universe
Edwin Hubble
Mt. Wilson100 InchTelescope
Velocity of galaxyproportional to distance:
v= H r
H ~ 70 km/sec / Mpc
Astronomy Scales
4.5 pc 450 kpc 150 Mpc
Nearest Stars Nearest Galaxies Nearest Galaxy Clusters
1 pc = 3 light years = 3 1016 km
GalaxiesSpiral (Milky Way)
Solar Mass: M = 2 1033g
Typical stars mass 1-10 M
Typical Galaxies 106 - 1012 M
~ 10% mass
~ 90% mass
1kpc1kpc
100kpc
Milky Way Galaxy
Magnetic field few G
Cosmic Accelerators: Hillas Plot
E Z B L Z: Charge of particleB: Magnetic fieldL: Size of object: Lorentz factor of shock wave
L
B
GRB (artist)
Crab Pulsar
Vela SNR
3C47
M87, AGN
Centurus A
M87
Radio Images
Visible light
Active Galactic Nuclei
QUASAR MICROQUASAR QUASAR MICROQUASAR
Central black hole
108- 109 102- 105
distant galaxies local galaxy
QUASARS & MICROQUASARS
QUASARS & MICROQUASARS
Gamma-Ray Burst StoryGamma-Ray Burst StoryGamma Ray Burst were first detected by the Vela satellites that were developed in the sixties to monitor nuclear test ban treaties.
1st GRB
Gamma Ray Bursts : present knowledge ~1-2 / day, duration 10ms - 100s, isotropic distribution in sky, at extra galactic distances.
secNow evidenceof GRB associationwith supernova
Cou
nt r
ate
in u
nit o
f 100
0 co
unts
s-1
ANTARES will dump all data in 100 secs of gamma ray burst warning signal
Multi-Messengers to see Whole Universe
Distant universeinvisible in high energy photons
need neutrinos
Quasarformation period
Evolution of the Universe
: mass density in universeConsider a particle on surface of sphere which expands with universe: r : radius of sphereMass inside sphere is: (4/3) r3 Potential energy of particle: -(4/3)r3 G/rKinetic energy: r2/2so total energy: r2/2 -(4/3)r3 G/r = E
..
Sphere evolves with time, write r(t) = a(t) xremember H = v/r = a/a
.
Then get Freidmann equation: H2 = (8/3) G - K/a2
where K = -2EEvolution of universe depends on value of K if K < 0, energy E > 0 expansion continues for ever if K > 0, energy E < 0 eventually universe contracts K = 0 critical value
Matter Density and Curvature of the Universe
With K = 0 Freidmann equation: H2 = (8/3) G define critical density: c = (3/8)H2/G
define density fraction: = / c
Same K comes into the spatial line element in General Relativity:
Freidmann eqn: H2 = (8/3) G - K/a2
If K = 0, geometry is Euclidean - flat, if K = 0, geometry curved
equivalently if = 0 universe is flat > 0 curvature positive, universe is closed < 0 curvature negative, universe is open
Cosmological Constant
Freidmann equation becomes: H2 = (8/3) G - K/a2 + /3
where is cosmological constant
Einstein did not know about the expansion of the universe andadd a ad-hoc term to make universe static
Theory no longer needs it, but experiment seems to indicate its presence
Conventional to treat it as another contribution to the density fraction (t) = matter(t) +
= matter +
Future of Universe
Origin of Elements
formed in:
Big Bang Nucleo-synthesis
Hot Stars
Supernova Explosions
Cosmic Ray Interactions
Big Bang
time after big bang
tem
pera
ture
of
univ
erse
3000 K
1010 K
3 105 y 100 s
Neutral hydrogen formsuniverse transparent to lightfossil photon radiation frozen
T (K) ~ 1010/t½ (s)Equilibrium n/p endsNucleosynthesis begins
nuclei atoms
Particle Physics after Big Bang
time since Big Bang
First Minute after Big Bang
Production rates = Annihilation rates equilibrium of particles and no nuclei formed
N (neutron)N (proton) = e m/kT
When temperature falls below 1010 K (1 MeV) reactions cease
(m = 1.3 MeV)In equilibrium:
Nucleosynthesis starts
Deuterium necessary to start nucleosynthesis
Helium formed from deuterium
( Difficult to continue because no stable mass 5, 8 nuclei)
Nucleosynthesis development
tritium
deuterium
helium-4
helium-3
(free neutrons decay)
Be, Li low levels
Element Production in StarsPP cycle : cold stars CNO cycle : hot stars
Heavy Element Production in Supernova
neutrons
protons
CNO cycle : hot stars rp process : supernova explosions
Nuclear cross-sections not well known: need accelerator measurements
stable nuclei
rp process
Nucleosynthesis rate gives baryon density
Measured abundance of He, D Fraction of baryons < 5%
Must have non-baryonic particle dark matter
= Nb/N , baryon number fraction
End of Opaque Universe
After recombination universe becomes transparent.See photons as Cosmic Microwave Background Radiation redshifted by 1000 to 2.7K
Penzas and Wilson Discovery of Cosmic Microwave Background
Cosmic Microwave Background Radiation
Cosmic Microwave Background Radiation
(degrees)
(d
egre
es)
30 45 60 75 90 105 120 135
-30
-35
-40
-45
-50
-55
-60
temperature variation
Analyse angular distribution to see typical variation scale
Measure Scale of CMBR Fluctuations
CMBR Data Analysis
location of first peak: total~ 1 amplitude of other peaks sensitive to baryon
Supernova Type 1aI mplosiondu noyaud ’étoile
Explosion d ’étoile
Expansion du matière onde de choc accélération
Supernova Restes du Supernova
Implosion of core ofred giant
Expansion of mattershock wave 0.5 c
Explosion of star
Supernova
Supernova Remnant
SNIa occurs at Chandrasekar mass, 1.4 Msun ‘Standard Candle’ measure brightness distance: B = L / 4d2
measure host galaxy redshift get recession velocity
test Hubble’s Law: v = H d, at large distances
SuperNovae observed in our galaxy
Date Remnant Observed
352 BC Chinese 185 AD SNR 185 Chinese 369 ? Chinese 386 Chinese 393 SNR 393 Chinese 437 ? 827 ? 902 ? 1006 SN1006 Arabic, ... 1054 Crab Chinese,.. 1181 3C58 Chinese,.. 1203 ? 1230 ? 1572 Tycho Tycho Brahe 1604 Kepler Johannes Kepler 1667 Cas A not seen ?
SuperNovae Remnants
Vela Cas ATycho
Crab
Cygnus Loop
Soleil
Tycho
Crab
Cas A
Vela
Kepler
Cygnus
SN1006
SN1006SN1006SN1054 (Crab)SN1680 (CasA)
Supernova in Large Magellenic Cloud
Distant Supernova
Life of big star ( > 1,4 M)
End in Supernovae of type Ib, Ic et II
Life of big star ( < 1,4 M)
La nébuleuse de la Lyre
Type Ia supernovae SNe Ia sont which accrete matter from neighbour star in binary system When the mass achieves the Chandrasekhar mass (~1.4 M) star collapses to neutron star in supernova explosion.
Always same mass so always same luminosity Standard Candle for measuring universe expansion
Flow of matter
Red Giant
White Dwarf
Reference Image
Subtraction
Expansion with Supernova Ia
Acceleration ofuniverse expansion
effe
ctiv
e m
agni
tude
b
righ
tnes
s
dis
tanc
e
non-linear v = H(t) d
redshift recession velocity
In 1998, two teams: High-Z Supernovae and Supernovae Cosmology Project simultaneously annouce non-zero cosmological constant:
= 0,72 ± 0,23
M = 0,28 ± 0,09
So what does it mean?
( due to E. Copeland, a theorist)
Supernova at z1.7
• 2500 SNe Ia per year with z < 1.7• Study Equation of state w=pw/w
Future Project: SNAP
-
-
Understanding Nature of Dark Energy
Evidence for Matter DensityCombined Data
Cosmic Microwave Background Radiation, Supernova 1a, Galaxy clusters and BBN
tot = total critical
critical density for flat universecritical= 3H2/8GN
H = h . 100 km/s/Mpc
M = matter critical
Matter/Energy in the Universe
baryons neutrinos cold dark matter
b +CDM
total
matter dark energy
Baryonic matter : b stars, gas, brown dwarfs, white
dwarfs
Matter:
Cold Dark Matter :CDM 0.3
WIMPS/neutralinos, axions
Neutrinos: if eV as from oscillations