The Accelerating Universe Probing Dark Energy with Supernovae Eric Linder Berkeley Lab.
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The Accelerating Universe
Probing Dark Energy with Supernovae
Eric Linder
Berkeley Lab
Evidence for AccelerationEvidence for AccelerationSupernovae Ia:
DE , w=p/ , w´=dw/dz
Observation -- Magnitude-redshift relation
Age of universe:
Contours of t0 parallel CMB acoustic peak angle: t0=14.0±0.5 Gyr
[Flat universe, adiabatic perturbations]
CMB Acoustic Peaks:
Substantial dark energy, e.g. 0.49 < < 0.74
[Small GW contribution, LSS, H0]
Large Scale Structure:
Power spectrum Pk, Growth rate, “looks”
[simulations]
Supernova CosmologySupernova Cosmology
A Dark Energy UniverseA Dark Energy Universe
Tyson
Correlation of Age with CMB Peak Angle
Knox et al.DASI data only
CMB Power Spectrum and
Tegmark
CMB Power CMB Power SpectrumSpectrum
Matter Power SpectrumMatter Power Spectrum
CMB + 2dF (no SN)
Efstathiou et al.
MAP Sky CoverageMAP Sky Coverage Wright
Nov ‘01 Jan ‘02
Apr ‘02 Oct ‘02 Wright
• 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.
Dark EnergyDark Energy
Credit STScI
Dark Energy TheoryDark 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 =0.7+0.1-0.2 Chiba & Yoshii
Supernovae =0.72+0.08-0.09 SCP, HiZ
Ly Forest =0.66+0.09-0.13 D. Weinberg et al.
: Ugly Duckling: Ugly Duckling
Astrophysicist:
Einstein equations –
gab
p = -
Naturally, =const= PL
= 10120
Today M
Field Theorist:
Vacuum – Lorentz invariant
Tab ~ab = diag { -1, 1, 1, 1}
p = -
Naturally, Evac ~ 1019 GeV
E ~ meV
=0?
• Fine Tuning Puzzle – why so small?
• Coincidence Puzzle – why now?
Scalar Field: Beautiful SwanScalar 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= ab - L gab
=K+V p=K-V w=p/ = (K+V) / (K-V) [-1, +1]
Slow Roll (Inflation)
K << V p=- w=-1
Free Field (kination)
V << K p=+ w=+1
Coherent Oscillations (Axions)
<V>=<K> p=0 w=0 (matter)
.
Fundamental PhysicsFundamental Physics
(a) = (0) e-3dlna(1+w) ~ a-3(1+w) w(z)=w0+w’z
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
Is =0 ? What is the dark energy?
Type Ia SupernovaeType 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
1 Parameter Family Homogeneity1 Parameter Family Homogeneity
Hubble diagram – low zHubble diagram – low z
Hubble diagram - SCPHubble diagram - SCP
0.2 0.5 1
In flat universe: M=0.28 [.085 stat][.05 syst]
Prob. of fit to =0 universe: 1%
redshift z
0.2 0.4 0.6 0.8 1.0
Supernova CosmologySupernova Cosmology
Original Current (offset) Near Term Proposed
Supernovae Probes - GenerationsSupernovae Probes - Generations
SNAP: The Third GenerationSNAP: The Third Generation
Dark Energy Equation of StateDark Energy Equation of State
Hubble DiagramHubble Diagram
Dark Energy Exploration with SNAPDark Energy Exploration with SNAP
Current ground based compared with
Binned simulated data and a sample of
Dark energy models
Probing Dark Energy ModelsProbing Dark Energy Models
From Science GoalsFrom Science Goalsto Project Designto Project Design
Science• Measure M and
• Measure w and w (z)
Data Set Requirements• Discoveries 3.8 mag before max
• Spectroscopy with S/N=10 at 15 Å bins
• Near-IR spectroscopy to 1.7 m
Statistical Requirements• Sufficient (~2000) numbers of SNe Ia
• …distributed in redshift
• …out to z < 1.7
Systematics RequirementsIdentified and proposed systematics:
• Measurements to eliminate / bound each one to +/–0.02 mag
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) •••
•••
Mission DesignMission Design
SNAP Survey FieldsSNAP Survey Fields
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)
GigaCAMGigaCAM
Focal Plane Layout with Fixed FiltersFocal Plane Layout with Fixed Filters
Q1
Q2
Q3
Q4
Step and Stare and RotationStep and Stare and Rotation
High-Resistivity CCD’sHigh-Resistivity CCD’s• 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 CCD’s can be abutted on all four sides enabling very large mosaic arrays• Measured Quantum Efficiency at Lick Observatory (R. Stover):
LBNL CCD’s at NOAOLBNL CCD’s at NOAO
See September 2001 newsletter at http://www.noao.edu
1) Near-earth asteroids2) Seyfert galaxy black holes3) LBNL Supernova cosmology
Cover picture taken at WIYN 3.5m with LBNL 2048 x 2048 CCD(Dumbbell Nebula, NGC 6853)
Science studies to date at NOAO usingLBNL CCD’s:
Blue is H-alphaGreen is SIII 9532ÅRed is HeII 10124Å.
Science Goals – F21Science Goals – F21
Slit Plane
DetectorCamera
Prism
Collimator
Integral Field Unit Spectrograph DesignIntegral Field Unit Spectrograph Design
F o re -o p tic s(a n a m o rp h o s is )
T e le s c o p e e x it p u p il
S L IC E R M IR R O R
P U P IL M IR R O R S
S L IT M IR R O R S
Im a g e d th e re
In th e te le s c o p efo c a l p la n e
T e le s c o p e fo c a l p la n e im a g e d b y th efo re -o p tic s o n th e s l ic e r m ir ro r
S lic e s im a g e d b y th e p u p ilm ir ro rs o n th e s l i t m ir ro rs
E n tra n c e o f th es p e c tro g ra p h
S q u a re f ie ld
1 x 2 p ro p o r tio n e dim a g e
SNAP Design:
Images
Spectra
Redshift & SN Properties
Lightcurve & Peak Brightness
data analysis physics
M and
Dark Energy Properties
At every moment in the explosion event, each individual supernova is “sending” us a rich stream of information about its internal physical state.
What makes the SN measurement special?What makes the SN measurement special?Control of systematic uncertaintiesControl of systematic uncertainties
Time Series of Spectra = SN “CAT Scan”
Lightcurves and Spectra from SNAPLightcurves 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
Supernova RequirementsSupernova Requirements
Advantages of SpaceAdvantages of Space
Science ReachScience Reach
Key Cosmological Studies• Type II supernova • Weak lensing• Strong lensing • Galaxy clustering• Structure evolution• Star formation/reionization
-
-
SNAP: The Third GenerationSNAP: The Third Generation
Dark Energy Equation of StateDark Energy Equation of State
Precision CosmologyPrecision Cosmology
Tegmark
NOWSNAP
Primary Science Mission Includes…Primary Science Mission Includes…
Weak lensing galaxy shear
observed from space vs. ground
Bacon, Ellis, Refregier 2000
……And BeyondAnd Beyond
10 band ultradeep imaging survey
Feed NGST, CELT (as Palomar 48” to 200”, SDSS to 8-10m)
Quasars to z=10
GRB afterglows to z=15
Galaxy populations and morphology to coadd m=32
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
SNAP CollaborationSNAP Collaboration
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)
12 institutions, ~50 researchers
SNAP at the American Astronomical Society SNAP at the American Astronomical Society Jan. 2002 MeetingJan. 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)Strong Gravitational Lensing with SNAP R. D. Blandford, L. V. E. Koopmans, (Caltech)Strong lensing of supernovae D.E. Holz (ITP, UCSB)
Poster Session 64. Overview of The Supernova/Acceleration Probe:Supernova / Acceleration Probe: An Overview M. Levi (LBNL)The SNAP Telescope M. Lampton (UCB)SNAP: An Integral Field Spectrograph for SN Identification R. Malina (LAMarseille,INSU), A. Ealet (CPPM)SNAP: GigaCAM - A Billion Pixel Imager C. Bebek (LBNL)SNAP: Cosmology with Type Ia Supernovae A. Kim (LBNL)SNAP: Science with Wide Deep Fields E. Linder (LBNL)
Resource for the Science CommunityResource 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 I=29 or J=28 (AB mag)
• Archive data distributed
• Guest Survey Program
Whole sky can be observed every few months
• Galaxy populations and morphology to coadded m=31 • Quasars to redshift 10• Epoch of reionization through Gunn-Peterson effect• Lensing projects: Mass selected cluster catalogs Evolution of galaxy-mass correlation function Maps of mass in filaments
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