Transcript Observing Light from the Early Universe from the Mountains of Chile Extreme Science: Elementary Particles and the Universe Dec 6, 2012

Observing Light from the
Early Universe from the
Mountains of Chile
Extreme Science: Elementary
Particles and the Universe
Dec 6, 2012
We can all measure
the CMB
TCMB=2.725 +\- 0.001 K
400 photons/cc at 0.28 eV/cc
CMB approx 1% of TV noise!
How Big is the Universe?
Really big!
The Sun is 8 light minutes away.
The center of our Galaxy is 25,000 light years away.
The Milky Way in
infrared emission.
COBE/DIRBE satellite image
There are 1011 stars in our galaxy.
From
Hubble
STScI/NASA Field & Levay
1011 Galaxies in Observable Universe
The Universe is Expanding
Hubble observed that the further away a galaxy is
the faster it is moving away.
Us
Galaxy
We are not (that!) special, all observers see the same.
A neighbor
We should think about this as “making space” since the
Big Bang, not as an explosion in a preexisting space. The
Universe appears the same from all vantages.
The Universe is Infinite. We live
in a “Hubble Patch”
Ignore the expansion
and imagine being
able to go anywhere
in the “whole
universe”
instantaneously
Observable
Universe or
Hubble Patch
“Edge” of the
observable universe Diameter set by:
2 (speed of light) x (age of universe)
Because the Speed of Light is Finite,
Telescopes Are Like Time Machines
Still ignoring the expansion
We see distant
objects as they were
when they were
younger.
“Edge” of the
observable universe
Younger
Now Add The Expansion
Light from the “edge”
was emitted when the
universe was much
more compact.
The expansion of
space stretches
wavelengths.
“Edge” of the
observable universe
Younger
Cosmic Evolution
Decoupling
surface
Us
Decoupling at
z=1030
Cosmic Evolution
Mark Subbarao & SDSS Collaboration
The CMB at decoupling as seen through a
Lamdba-dominated spacetime (and through
our galaxy).
WMAP at 61 GHz, 0.5 cm
5º
Angular Power
compression
Spectrum
“Acoustic peaks”
rarefaction
compression
Model
Silk damping tail
Fundamental mode
WMAP
~10X WMAP resolution
The Atacama
Cosmology Telescope
Pontificia Universidad Catόlica de Chile
University of Oxford
Stony Brook University
West Chester University of Pennsylvania
National Aeronautics and Space Administration Goddard Space Flight Center
(NASA GSFC)
University of British ColumbiaInstituto Nacional de Astrofisica, Óptica y
Electrónica (INAOE)
Carnegie Mellon University
University of Pennsylvania
Haverford College
Institute for Advanced Study (IAS)
National Institute of Standards and Technology (NIST)
University of California, Berkeley
Canadian Institute for Theoretical Astrophysics (CITA)
Princeton University
Cardiff University
University of Michigan
University of KwaZulu-Natal
University of Miami
University of Pittsburgh
Academia Sinica
Rutgers, The State University of New Jersey
Cornell University
The Johns Hopkins University
4He
Window
148 GHz
The Millimeter Bolometric
Array Camera
Fridge
Fridge
Pulse Tube
218 GHz
3He
40K Shield
3K Shield
Detectors
1m
277 GHz
Optics
ACT
radio galaxy
SZ cluster
WMAP7
Figure: Amir Hajian
Power spectrum
Power spectrum at ~150 GHz
Statistical errors only
Silk damping
tail
WMAP 7yr
ACT: PRELIMINARY
DSFGs
Das, Nolta et al.
SPT: Shirokoff et al.
Keisler et al.
Lensed CMB
20 80 220 400 650 1000 1500
2250
3000
4000
5000
6000
7500
9000
Cosmic Evolution
Cosmic Evolution
At decoupling
Number of relativistic species, Neff
Dunkley et al., 2011
Silk damping tail
The key to limiting Neff is to identify the increased
damping at small angular scales in the CMB.
Hou et al., 2011
Bashinsky & Seljak, 2004
Neutrino Mass
Compare
today to that at decoupling. Greater
relativistic
means smaller rm/rr, enhanced potential
evolution, and producing less cosmic structure.
e.g., Ichikawa et al., 2005
WMAP+BAO+SN,
sum <0.58 (95%cl)
WMAP
Komatsu et al., 2009
Lensingsmoothes
remaps & out
magnifies/de-magnifies
cmbthe
Lensing
the peaks and alters
patches,
smoothing
out
peaks
statistics of the CMB
˜ n
Θ(
ˆ ) = Θ( n
ˆ + ∇ φ)
Gr avit at ionallensed
l ensing
of t hedeflection
CMB
unlensed
Intervening large-scale potentials
deflect CMB photons and distort
the CMB.
Lens-speak:
Lensing potential:
φ
Deflection field:
d= ∇φ
Convergence:
κ = 12 ∇ · d
The RMS deflection is
about Das
2.7 arcmins,
but(2008)
the
Simulation from
& Bode
deflections are coherent
Sudeep Das, March 2011 7
From Sudeep Das
on degree scales.
Simulations
uK
100 deg2
AAS, Jan 7 2010
Simulations
uK
100 deg2
AAS, Jan 7 2010
Lensing of CMB detected at 4s
Based on Hu &
Okamoto estimator plus
phase randomization.
Shape sensitive to
neutrino mass.
Thank You!
The Standard Model of Cosmology
Surface of last scattering
at “decoupling.”
“Reionization”
Decoupling of the CMB
The universe expands and cools from its fiery beginning.
When the temperature of the Universe is roughly half the
temperature of the Sun, atoms of hydrogen can form.
proton
Universe cools
e-
ee-
eIonized
plasma
CMB
Neutral
atoms
This is called the epoch of decoupling and it occurred
379,000 years after the Big Bang.
How do we get hot and cold
patches?
Colder
Gravitational
landscape--just like
hills and valleys.
W. Hu
Colder
Hotter
1 degree in angle
Spot size = [speed plasma ( ) travels]x[age of universe at decoupling]
Cosmic Paleontology
The “fundamental mode” acts as a fundamental
“footprint” or yardstick at the edge of the
observable universe.
Us
Q=0.595 +/- 0.0015 deg
(12,000 stacked
hot spots.)
This allows us to determine the size of the observable
universe.
From the standard yardstick, we can deduce
the distance to the edge of the universe.
Knowing this distance, and the speed of light,
we deduce that the age of the universe is:
tU=13.75 +/- 0.13 Gyr
Kinematic SZ Effect
Hand et al. 1203.4219