2005 Aspen Winter Conference The Highest Energies February 17, 2005

1. 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

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 Gregory Tarlé ASPEN05 The Highest Energies

3. Big Bang Nucleosynthesis Inflation Flat universe total= 1.02+/-0.02 Baryon Density B= 0.044+/-0.004  DE= 0.7, M= 0.3 for a flat universe WMAP M Golden Age of Cosmology • Weak lensing mass census • Large scale structure measurements M= 0.3 New Standard Cosmology: 73±4% Dark Energy 27±4% Matter 0.5% Bright Stars Matter (27%): 22% CDM, 4.4% Baryons, 0.3% s Gregory Tarlé ASPEN05 The Highest Energies

4. A Fish Out of Water • Q: 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. Photo by L. Sander Gregory Tarlé ASPEN05 The Highest Energies

5. 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 ! 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/r) 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! 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.. Gregory Tarlé ASPEN05 The Highest Energies

6. Look Here! Type Ia SNe: The Best Tool • 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 thesame peak intensity. 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 measuresthe total relativeexpansionof the universe since that time • Analysis of the spectra characterizes the details of the explosion and helps to control potential systematic errors. Can measure both intensity and spectra as the supernova brightens and fades over many days. Gregory Tarlé ASPEN05 The Highest Energies

7. The Expansion History of the Universe Need lots of precision data to study this region Gregory Tarlé ASPEN05 The Highest Energies

8. 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. Gregory Tarlé ASPEN05 The Highest Energies

9. The SNAP Collaboration Gregory Tarlé ASPEN05 The Highest Energies

10. Instrument Concept Baffled Sun Shade Solar Array, ‘Sun Side’ Instrument Suite 3-mirror anastigmat 2-meter Telescope Solar Array, ‘Dark Side’ Instrument Radiator Spacecraft Bus Gregory Tarlé ASPEN05 The Highest Energies

11. Instrument Concept Baffled Sun Shade Solar Array, ‘Sun Side’ Instrument Suite 3-mirror anastigmat 2-meter Telescope Solar Array, ‘Dark Side’ Instrument Radiator Spacecraft Bus Gregory Tarlé ASPEN05 The Highest Energies

12. D=56.6 cm (13.0 mrad) 0.7 square degrees! Fixed filters atop the sensors Focus star projectors Guider NIR Visible Integral Field Spectrograph Spectrograph port Calibration projectors Focal plane Gregory Tarlé ASPEN05 The Highest Energies

13. Supernova measurements Metallicity SII “W” SiII 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. Photometry • 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. Gregory Tarlé ASPEN05 The Highest Energies

14. w w0 Why go to high redshifts? • 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. • Dark energy has been detected at low redshift (SCP, High-z). Todeterminewhat it is,and not justthatit is, requires observations over both the acceleration and deceleration epochs. • This long reach breaks essential degeneracies which low redshift data alone cannot. zmax=0.7 zmax=1.7 Gregory Tarlé ASPEN05 The Highest Energies

15. Rest frame B and V shift to NIR Z = 0.8 Z = 1.2 Z = 1.6 Optical Bands Rest frame B NIR Bands Rest frame V Simulated SNAP observations of high redshift SNe Gregory Tarlé ASPEN05 The Highest Energies

16. Rest frame B Rest frame V This can’t be done on the ground! Z = 0.8 Z = 1.2 Z = 1.6 Optical Bands NIR Bands Simulated 8m telescope ground based observations of high redshift SNe Gregory Tarlé ASPEN05 The Highest Energies

17. 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 Spectroscopy fixes these NIR fixes these Gregory Tarlé ASPEN05 The Highest Energies

18. SNAP Deep & Time Domain Survey Hubble Deep Field • 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. The Moon GOODS Survey area Gregory Tarlé ASPEN05 The Highest Energies

19. Understanding Dark Energy Gregory Tarlé ASPEN05 The Highest Energies

20. Determination of CosmologicalParameters • SNAPwill 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,SNAPwill measureM to  0.01 andw0 to  0.05. Gregory Tarlé ASPEN05 The Highest Energies

21. Dark Energy Equation of State Is 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 Mmeasuredto  0.03,SNAP will measurew0 to  0.05 andw to  0.27. Gregory Tarlé ASPEN05 The Highest Energies

22. SNAP works and plays well with others w0 and w Gregory Tarlé ASPEN05 The Highest Energies

23. Conclusions 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. Gregory Tarlé ASPEN05 The Highest Energies

24. THE END Gregory Tarlé ASPEN05 The Highest Energies