2005 Aspen Winter Conference The Highest Energies February 17, 2005

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Shedding Light on Dark Energy with the SuperNova/Acceleration Probe (SNAP)

Gregory TarléPhysics DepartmentUniversity of Michigan

2005 Aspen Winter ConferenceThe Highest Energies February 17, 2005

February 17, 2005 Gregory Tarlé ASPEN05 The Highest Energies 2

Welcome to Applied String Theory 501! (Winter 2055)

We will start this course by having you do a simple and straightforward “warm-up” exercise.

Show that the energy contained in the 1 m3

empty box pictured here is 6.3 10-10 J.

1 m

1 m

1 m


M

WMAPDE= 0.7, M= 0.3

for a flat universe

NewStandard Cosmology:

73±4% Dark Energy

27±4% Matter

0.5% Bright Stars

Matter (27%):

22% CDM, 4.4% Baryons,

0.3% s

Golden Age of Cosmology

Weak lensing mass census Large scale structure measurements

M= 0.3

Baryon Density

B= 0.044+/-0.004

Flat universe

total= 1.02+/-0.02

Big Bang Nucleosynthesis

Inflation


A Fish Out of WaterQ: What dominates this picture?A: The Water The discovery of Dark Energy has highlighted our

feeble understanding of the nature of the vacuum. 20th century (Discovery of elementary particles,

QM, SR, QFT, Renormalization… Standard Model) The century of the elementary particle.

21st century (Higgs, Inflation, Dark Energy, String Theory…) The century of the vacuum.

Ph

oto

by

L.

Sa

nd

er


Or alternatively in ten years we could say:

The dark energy is a cosmological constant whose equation of state today is w (z = 0) w0 = -1.07 ± 0.05. The time variation of the EOS is dw/dz w´ = 0.06 ± 0.11. Einstein was not a blunderer when he wrote !μμμμ πGTgRgR 82

1 −=Λ−−

Wouldn’t it be nice if in 10 years we could say, for example:

The dark energy is a dynamical scalar field with an equation of state today of w (z = 0) w0 = -0.82 ± 0.05. The time variation of the EOS is dw/dz w´ = 0.29 ± 0.11 consistent with Supergravity inspired field theories..

What we don’t know Precisely how much mass density (M) and dark energy density (DE) is there? How flat is the universe?

What is the equation of state (w = p/) of the universe and how has it changed in time?

What is the “dark energy?” Theorists have proposed a number of models, each with different properties w(z) that we can measure. Each brings a new understanding as to the nature of the vacuum.

Lots of theories, little data!


QuickTime™ and aDV/DVCPRO - NTSC decompressor

are needed to see this picture.

Type Ia SNe: The Best Tool

Can measure both intensity and spectra as the supernova brightens and fades over many days.

Comparison of SN Ia redshifts and magnitudes provides straightforward measurement of the changing rate of expansion of the universe:

Apparent magnitude measures distance (time back to explosion)

Redshift measures the total relative expansion of the universe since that time

Analysis of the spectra characterizes the details of the explosion and helps to control potential systematic errors.

QuickTime™ and aSorenson Video decompressorare needed to see this picture.

Type Ia supernovae (SNe Ia) provide a bright “standard candle” that can be used to construct a Hubble diagram looking back over both the acceleration and decelleration epochs of the universe.

Accretion sends white dwarf mass near Chandrasekhar limit, leading to C,O detonation (C ~ 109 g/cm3) and complete thermonuclear deflagration of the star.

Each one is a strikingly similar explosion event with nearly the same peak intensity.

Look Here!


The Expansion History of the Universe

Need lots of precisiondata to studythis region


It’s a SNAP!

A large wide-field space telescope with a 0.6 Gpixel visible/NIR imager and a visible/NIR spectrograph will provide: a much larger statistical sample of supernovae (~2000 SNe with ~50 SNe/0.03 z). much better controlled systematic errors (1 – 2%). Precision photometery over a much larger range of redshifts (out to z = 1.7) than can be obtained on the ground.


The SNAP CollaborationLBNL G. Aldering, S. Bailey, C. Bebek, W. Carithers, T. Davis†, K. Dawson, C. Day,

R. DiGennaro, S. Deustua†, D. Groom, M. Hoff, S. Holland, D. Huterer†, A. Karcher, A. Kim, W. Kolbe, W. Kramer, B. Krieger, G. Kushner, N. Kuznetsova, R. Lafever, J. Lamoureux, M. Levi, S. Loken, B. McGinnis, R. Miquel, P. Nugent, H. Oluseyi†, N. Palaio, S. Perlmutter, N. Roe, H. Shukla, A. Spadafora, H. Von Der Lippe, J-P. Walder, G. Wang

Berkeley M. Bester, E. Commins, G. Goldhaber, H. Heetderks, P. Jelinsky, M. Lampton, E. Linder, D. Pankow, M. Sholl, G. Smoot, C. Vale, M. White

Caltech R. Ellis, R. Massey†, A. Refregier†, J. Rhodes, R. Smith, K. Taylor, A. Weintein

Fermi National Laboratory

J. Annis, F. DeJongh, S. Dodelson, T. Diehl, J. Frieman, D. Holz†, L. Hui, S. Kent, P. Limon, J. Marriner, H. Lin, J. Peoples, V. Scarpine, A. Stebbins, C. Stoughton, D. Tucker, W. Wester

Indiana U.

IN2P3-Paris -Marseille

C. Bower, N. Mostek, J. Musser, S. Mufson

P. Astier, E. Barrelet, R. Pain, G. Smadja†, D. VincentA. Bonissent, A. Ealet, D. Fouchez, A. Tilquin

JPL D. Cole, M. Frerking, J. Rhodes, M. Seiffert

LAM (France) S. Basa, R. Malina, A. Mazure, E. Prieto

University of Michigan

B. Bigelow, M. Brown, M. Campbell, D. Gerdes, W. Lorenzon, T. McKay, S. McKee,M. Schubnell, G. Tarlé, A. Tomasch

University of Pennsylvania

G. Bernstein, L. Gladney, B. Jain, D. Rusin

University of Stockholm

R. Amanullah, L. Bergström, A. Goobar, E. Mörtsell

SLAC W. Althouse, R. Blandford, W. Craig, S. Kahn, M. Huffer, P. Marshall

STScI R. Bohlin, D. Figer, A. Fruchter

Yale U. C. Baltay, W. Emmet, J. Snyder, A. Szymkowiak, D. Rabinowitz, N. Morgan†Institutional affiliation


Instrument ConceptBaffled Sun Shade

Solar Array, ‘Sun Side’

3-mirror anastigmat2-meter Telescope

Spacecraft Bus

Solar Array, ‘Dark Side’

Instrument Radiator

Instrument Suite


Instrument ConceptBaffled Sun Shade

Solar Array, ‘Sun Side’

3-mirror anastigmat2-meter Telescope

Spacecraft Bus

Solar Array, ‘Dark Side’

Instrument Radiator

Instrument Suite


Fixed filters atop the sensors

Focal plane Guider

Spectrograph port

VisibleNIRFocus starprojectors

Calibration projectors

D=56.6 cm (13.0 mrad)

0.7 square degrees!

Field beforeslicingPseudo-slitSlicing mirror (S1)SpectrogramPupil mirrors(S2)To spectrographField optics (slit mirrors S3)From telescopeand fore-opticsIntegral Field Spectrograph


Supernova measurementsPhotometry Discover a few thousand SNe from z

= 0.3 to 1.7. Repetitive 4-day scans of a sky field (N or

S ecliptic poles) over many months. Automatic discovery and follow-up Light curves in 9 filter bands from 0.35

μm to 1.7 μm to standardize the SNe.

Spectroscopy Near peak brightness. 0.35 μm to 1.7 μm. ~ 100 for max S/N. Identify spectral features to select type

Ia SNe, and group them according to parameters to reduce systematic errors.

Spectrum of host galaxy desirable.

SII “W”

SiII

Metallicity


SNAP will probe the variability of w, providing an

essential clue to the nature of DE. measure w0 precisely to determine whether it

is a cosmological constant.

Why go to high redshifts? Dark energy has been detected at low

redshift (SCP, High-z). To determine what it is,and not just that it is, requires observations over both the acceleration and deceleration epochs.

This long reach breaks essential degeneracies which low redshift data alone cannot.

zmax=1.7

zmax=0.7

w

w0


Rest frame B and V shift to NIR

Simulated SNAP observations of high redshift SNe

NIRBands Rest frame V

Rest frame B

Z = 0.8 Z = 1.2 Z = 1.6

OpticalBands


OpticalBands

This can’t be done on the ground!

Rest frame B

Rest frame V

Simulated 8m telescope ground based observations of high redshift SNe

Z = 0.8 Z = 1.2 Z = 1.6

NIRBands


SNe IA population evolution– Shifting distribution of

progenitor mass/metallicity/C-O

– Shifting distribution of SN physics parameterss:

• Amount of Nickel fused in explosion

• Distribution of Nickel• Kinetic energy of explosion• Opacity of atmosphere's

inner layers• Metallicity

Gravitational Lensing (de)amplification

Dust/Extinction– Dust that reddens– Evolving gray dust

• Clumpy

• Homogeneous

– Galactic extinction model

Observational biases– Malmquist bias differences– non-SN Ia contamination– K-correction uncertainty– Color zero-point calibration

Confronting Systematic Errors

NIR fixes these

Spectroscopy fixes these


SNAP Deep & Time Domain Survey

Basic SNAP SNe survey: 15 square degrees near ecliptic poles.

~ 6000x as large as ACS deep field, to mAB = 30.4 in nine optical and IR bands.

Provides ≥ 100 epochs over 16 months (each to mAB = 27.8) for time domain studies in all nine bands.

GOODS Survey area

Hubble Deep Field

The Moon


Understanding Dark Energy


Determination of CosmologicalParameters

SNAP will measure(if w= -1) to 0.02 and

M to 0.03.

With prior M measured by

other techniques (e.g. CMB)to 0.03,SNAP will measureM to 0.01 and

w0 to 0.05.


Dark Energy Equation of StateIs w = -1? By measuring the evolution of w to high precision (few

%), SNAP will determine the nature of the Dark Energy.

For a flat universewith prior M

measuredto 0.03,SNAP will measurew0 to 0.05 and

w to 0.27.


SNAP works and plays well with others w0 and w


Dark energy is the dominant fundamental constituent of our Universe, yet we know very little about it.

SNAP will test theories of dark energy and show how the expansion rate has varied over the history of the Universe.

A vigorous R&D program, supported by the DoE is underway, leading to an expected launch early in the next decade.

NASA and DoE have agreed to partner on a Joint Dark Energy Mission (JDEM). SNAP is a prime candidate for JDEM.

Conclusions


THE END

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2005 Aspen Winter Conference The Highest Energies February 17, 2005