The Accelerating Universe

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The Accelerating Universe
Probing Dark Energy with Supernovae
Eric Linder Berkeley Lab
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Evidence for Acceleration
Supernovae Ia ?DE , wp/? , wdw/dz
Observation -- Magnitude-redshift relation
Age of universe Contours of t0 parallel CMB
acoustic peak angle t014.00.5 Gyr Flat
universe, adiabatic perturbations
CMB Acoustic Peaks Substantial dark energy,
e.g. 0.49 lt ??lt 0.74 Small GW contribution,
LSS, H0
Large Scale Structure Power spectrum Pk,
Growth rate, looks simulations
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Supernova Cosmology
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A Dark Energy Universe
Tyson
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Correlation of Age with CMB Peak Angle
Knox et al.
DASI data only
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CMB Power Spectrum and ??
Tegmark
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CMB Power Spectrum
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Matter Power Spectrum
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CMB 2dF (no SN)
Efstathiou et al.
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MAP Sky Coverage
Wright
Jan 02
Nov 01
Wright
Apr 02
Oct 02
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Dark Energy

• Supernova data shows an acceleration of the
  expansion, implying that the universe is
  dominated by a new Dark Energy!
• Remarkable agreement between Supernovae recent
  CMB results.

Credit STScI
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Dark Energy Theory
1970s Why ?M ?k? 1980s Inflation! Not
curvature. 1990s Why ?M ??? 2000s
Quintessence! Not ??
Cosmological constant is an ugly duckling
Dynamic scalar field is a beautiful swan
Lensing ? ?0.70.1-0.2 Chiba
Yoshii Supernovae ? ?0.720.08-0.09 SCP, HiZ Ly?
Forest ? ?0.660.09-0.13 D. Weinberg et al.
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? Ugly Duckling
Field Theorist Vacuum Lorentz invariant Tab
?ab diag -1, 1, 1, 1 ? p
-? Naturally, Evac 1019 GeV E?
meV ?0?

• Astrophysicist
• Einstein equations
• ?gab
• ? p -?
• Naturally, ? const ?PL
• ?? 10120
• Today ????M

• Fine Tuning Puzzle why so small?
• Coincidence Puzzle why now?

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Scalar Field Beautiful Swan
Astrophysicist Friedmann equations
(å/a)2(8?/3)(?m??) ä/a-(4?/3)(?m??3p?
)
Field Theorist Lagrangian L(1/2)?a?
?a?-V(?)?(1/2)?2-V Tab ?a??b? - L gab
.
?KV pK-V wp/? (KV) / (K-V) ? -1, 1
Slow Roll (Inflation) K ltlt V ? p-? ?
w-1 Free Field (kination) V ltlt K ? p?
? w1 Coherent Oscillations (Axions) ltVgtltKgt ?
p0 ? w0 (matter)
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Fundamental Physics
?? (a) ?? (0) e-3?dlna(1w) a-3(1w)
w(z)w0wz
Astrophysics ? Cosmology ? Field
Theory r(z) ? Equation of state w(z) ? V(?) V
( ?( a(t) ) )
SN CMB etc.
Would be number one on my list of things to
figure out - Edward Witten Right now, not
only for cosmology but for elementary particle
theory this is the bone in our throat - Steven
Weinberg
What is the dark energy?
Is ?0 ?
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Type Ia Supernovae

• Characterized by no Hydrogen, but with Silicon
• Progenitor C/O White Dwarf accreting from
  companion
• Just before Chandrasekhar mass, thermonuclear
  runaway
• Standard explosion from nuclear physics

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1 Parameter Family Homogeneity
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Hubble diagram low z
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Hubble diagram - SCP
0.2
0.5
1
0.6
1.0
0.2
0.4
0.8
redshift z
In flat universe ?M0.28 ?.085 stat?.05
syst Prob. of fit to ?0 universe 1
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Supernova Cosmology
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Supernovae Probes - Generations
Original
Current (offset)
Near Term
Proposed
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SNAP The Third Generation
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Dark Energy Equation of State
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Hubble Diagram
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Dark Energy Exploration with SNAP
Current ground based compared with Binned
simulated data and a sample of Dark energy models
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Probing Dark Energy Models
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From Science Goalsto Project Design
Science

• Measure ?M and ?
• Measure w and w (z)

Systematics Requirements
Statistical Requirements

• Identified and proposed systematics
• Measurements to eliminate / bound each one to
  /0.02 mag

• Sufficient (2000) numbers of SNe Ia
• distributed in redshift
• out to z lt 1.7

Data Set Requirements

• Discoveries 3.8 mag before max
• Spectroscopy with S/N10 at 15 Å bins
• Near-IR spectroscopy to 1.7 ?m

Satellite / Instrumentation Requirements

• 2-meter mirror Derived requirements
• 1-square degree imager High Earth orbit
• Spectrograph 50 Mb/sec bandwidth (0.35 ?m
  to 1.7 ?m)

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Mission Design
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SNAP Survey Fields
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GigaCAM

• GigaCAM, a one billion pixel array
• Approximately 1 billion pixels
• 140 Large format CCD detectors required, 30
  HgCdTe Detectors
• Larger than SDSS camera, smaller than H.E.P.
  Vertex Detector (1 m2)
• Approx. 5 times size of FAME (MiDEX)

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Focal Plane Layout with Fixed Filters
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Step and Stare and Rotation
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High-Resistivity CCDs

• New kind of CCD developed at LBNL
• Better overall response than more costly
  thinned devices in use
• High-purity silicon has better radiation
  tolerance for space applications
• The CCDs can be abutted on all four sides
  enabling very large mosaic arrays
• Measured Quantum Efficiency at Lick Observatory
  (R. Stover)

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LBNL CCDs at NOAO
Science studies to date at NOAO using LBNL CCDs

1. Near-earth asteroids
2. Seyfert galaxy black holes
3. LBNL Supernova cosmology

Blue is H-alpha Green is SIII 9532Å Red is HeII
10124Å.
Cover picture taken at WIYN 3.5m with LBNL 2048
x 2048 CCD (Dumbbell Nebula, NGC 6853)
See September 2001 newsletter at
http//www.noao.edu
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Science Goals F21
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Integral Field Unit Spectrograph Design
SNAP Design
Camera
Detector
Prism
Collimator
Slit Plane
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What makes the SN measurement special?Control of
systematic uncertainties
At every moment in the explosion event, each
individual supernova is sending us a rich
stream of information about its internal physical
state.
Lightcurve Peak Brightness
Images
?M and ?L Dark Energy Properties
Redshift SN Properties
Spectra
data
analysis
physics
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Time Series of Spectra SN CAT Scan
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Lightcurves and Spectra from SNAP

• Goddard/Integrated Mission Design
• Center study in June 2001
• no mission tallpoles
• Goddard/Instrument Synthesis and
• Analysis Lab. study in Nov. 2001
• no technology tallpoles

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Supernova Requirements
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Advantages of Space
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Science Reach

• Key Cosmological Studies
• Type II supernova
• Weak lensing
• Strong lensing
• Galaxy clustering
• Structure evolution
• Star formation/reionization

-
-
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SNAP The Third Generation
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Dark Energy Equation of State
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Precision Cosmology
SNAP
Tegmark
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Primary Science Mission Includes
Weak lensing galaxy shear observed from space vs.
ground
Bacon, Ellis, Refregier 2000
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And Beyond
10 band ultradeep imaging survey Feed NGST, CELT
(as Palomar 48 to 200, SDSS to 8-10m) Quasars
to z10 GRB afterglows to z15 Galaxy
populations and morphology to coadd m32 Galaxy
evolution studies, merger rate Stellar
populations, distributions, evolution Epoch of
reionization thru Gunn-Peterson effect Low
surface brightness galaxies in H band,
luminosity function Ultraluminous infrared
galaxies Kuiper belt objects Proper motion,
transient, rare objects
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SNAP Collaboration
12 institutions, 50 researchers
G. Aldering, C. Bebek, W. Carithers, S. Deustua,
W. Edwards, J. Frogel, D. Groom, S. Holland, D.
Huterer, D. Kasen, R. Knop, R. Lafever, M. Levi,
E. Linder, S. Loken, P. Nugent, S. Perlmutter, K.
Robinson (Lawrence Berkeley National
Laboratory) E. Commins, D. Curtis, G. Goldhaber,
J. R. Graham, S. Harris, P. Harvey, H. Heetderks,
A. Kim, M. Lampton, R. Lin, D. Pankow, C.
Pennypacker, A. Spadafora, G. F. Smoot (UC
Berkeley) C. Akerlof, D. Amidei, G. Bernstein, M.
Campbell, D. Levin, T. McKay, S. McKee, M.
Schubnell, G. Tarle , A. Tomasch (U. Michigan)
P. Astier, J.F. Genat, D. Hardin, J.- M. Levy,
R. Pain, K. Schamahneche (IN2P3) A. Baden, J.
Goodman, G. Sullivan (U.Maryland) R. Ellis, A.
Refregier (CalTech) A. Fruchter (STScI) L.
Bergstrom, A. Goobar (U. Stockholm) C. Lidman
(ESO) J. Rich (CEA/DAPNIA) A. Mourao (Inst.
Superior Tecnico,Lisbon)
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SNAP at the American Astronomical Society Jan.
2002 Meeting

• Oral Session 111. Science with Wide Field Imaging
  in Space
• The Astronomical Potential of Wide-field Imaging
  from Space S. Beckwith (Space Telescope Science
  Institute)
• Galaxy Evolution HST ACS Surveys and Beyond to
  SNAP G. Illingworth (UCO/Lick, University of
  California)
• Studying Active Galactic Nuclei with SNAP P.S.
  Osmer (OSU), P.B. Hall (Princeton/Catolica)
• Distant Galaxies with Wide-Field Imagers K. M.
  Lanzetta (State University of NY at Stony Brook)
• Angular Clustering and the Role of Photometric
  Redshifts A. Conti, A. Connolly (University of
  Pittsburgh)
• SNAP and Galactic Structure I. N. Reid (STScI)
• Star Formation and Starburst Galaxies in the
  Infrared D. Calzetti (STScI)
• Wide Field Imagers in Space and the Cluster
  Forbidden Zone M. E. Donahue (STScI)
• An Outer Solar System Survey Using SNAP H.F.
  Levison, J.W. Parker (SwRI), B.G. Marsden (CfA)
• Oral Session 116. Cosmology with SNAP
• Dark Energy or Worse S. Carroll (University of
  Chicago)
• The Primary Science Mission of SNAP S.
  Perlmutter (Lawrence Berkeley National
  Laboratory)
• SNAP mission design and core survey T. A.
  McKay (University of Michigan
• Sensitivities for Future Space- and Ground-based
  Surveys G. M. Bernstein (Univ. of Michigan)
• Constraining the Properties of Dark Energy using
  SNAP D. Huterer (Case Western Reserve University)
• Type Ia Supernovae as Distance Indicators for
  Cosmology D. Branch (U. of Oklahoma)
• Weak Gravitational Lensing with SNAP A.
  Refregier (IoA, Cambridge), Richard Ellis
  (Caltech)

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Resource for the Science Community

• SNAP main survey will be 4000x larger (and as
  deep)
• than the biggest HST deep survey, the ACS
  survey
• Complementary to NGST target selection for rare
  objects
• Can survey 1000 sq. deg. in a year to I29 or
  J28 (AB mag)
• Archive data distributed
• Guest Survey Program
• Whole sky can be observed every few months
• Galaxy populations and morphology to coadded
  m31
• Quasars to redshift 10
• Epoch of reionization through Gunn-Peterson
  effect
• Lensing projects
• Mass selected cluster catalogs
• Evolution of galaxy-mass correlation function