1. 1 Shedding Light on Dark Energy with the SuperNova/Acceleration Probe (SNAP) Gregory Tarlé Physics Department University of Michigan 2005 Aspen Winter Conference The Highest Energies February 17, 2005

2. February 17, 2005Gregory Tarlé ASPEN05 The Highest Energies2 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 m 3 empty box pictured here is 6.3  10 -10 J. 1 m

3. February 17, 2005Gregory Tarlé ASPEN05 The Highest Energies3 MM  WMAP  DE = 0.7,  M = 0.3 for a flat universe New Standard 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

4. February 17, 2005Gregory Tarlé ASPEN05 The Highest Energies4 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

5. February 17, 2005Gregory Tarlé ASPEN05 The Highest Energies5 Or alternatively in ten years we could say: The dark energy is a cosmological constant whose equation of state today is w (z = 0)  w 0 = -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 ! 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)  w 0 = -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!

6. February 17, 2005Gregory Tarlé ASPEN05 The Highest Energies6 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. 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 ~ 10 9 g/cm 3 ) and complete thermonuclear deflagration of the star. Each one is a strikingly similar explosion event with nearly the same peak intensity. Look Here!

7. February 17, 2005Gregory Tarlé ASPEN05 The Highest Energies7 The Expansion History of the Universe Need lots of precision data to study this region

8. February 17, 2005Gregory Tarlé ASPEN05 The Highest Energies8 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.

9. February 17, 2005Gregory Tarlé ASPEN05 The Highest Energies9 The SNAP Collaboration LBNLG. 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 BerkeleyM. Bester, E. Commins, G. Goldhaber, H. Heetderks, P. Jelinsky, M. Lampton, E. Linder, D. Pankow, M. Sholl, G. Smoot, C. Vale, M. White CaltechR. 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. Vincent A. Bonissent, A. Ealet, D. Fouchez, A. Tilquin JPLD. 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 SLACW. Althouse, R. Blandford, W. Craig, S. Kahn, M. Huffer, P. Marshall STScIR. Bohlin, D. Figer, A. Fruchter Yale U.C. Baltay, W. Emmet, J. Snyder, A. Szymkowiak, D. Rabinowitz, N. Morgan † Institutional affiliation

10. February 17, 2005Gregory Tarlé ASPEN05 The Highest Energies10 Instrument Concept Baffled Sun Shade Solar Array, ‘Sun Side’ 3-mirror anastigmat 2-meter Telescope Spacecraft Bus Solar Array, ‘Dark Side’ Instrument Radiator Instrument Suite

11. February 17, 2005Gregory Tarlé ASPEN05 The Highest Energies11 Instrument Concept Baffled Sun Shade Solar Array, ‘Sun Side’ 3-mirror anastigmat 2-meter Telescope Spacecraft Bus Solar Array, ‘Dark Side’ Instrument Radiator Instrument Suite

12. February 17, 2005Gregory Tarlé ASPEN05 The Highest Energies12 Fixed filters atop the sensors Focal plane Guider Spectrograph port VisibleNIR Focus star projectors Calibration projectors D=56.6 cm (13.0 mrad) 0.7 square degrees! Integral Field Spectrograph

13. February 17, 2005Gregory Tarlé ASPEN05 The Highest Energies13 Supernova measurements 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. 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

14. February 17, 2005Gregory Tarlé ASPEN05 The Highest Energies14 SNAP will probe the variability of w, providing an essential clue to the nature of DE. measure w 0 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. z max =1.7 z max =0.7 w w0w0

15. February 17, 2005Gregory Tarlé ASPEN05 The Highest Energies15 Rest frame B and V shift to NIR Simulated SNAP observations of high redshift SNe NIR Bands Rest frame V Rest frame B Z = 0.8Z = 1.2Z = 1.6 Optical Bands

16. February 17, 2005Gregory Tarlé ASPEN05 The Highest Energies16 Optical Bands 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 = 0.8Z = 1.2Z = 1.6 NIR Bands

17. February 17, 2005Gregory Tarlé ASPEN05 The Highest Energies17 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

18. February 17, 2005Gregory Tarlé ASPEN05 The Highest Energies18 SNAP Deep & Time Domain Survey  Basic SNAP SNe survey: 15 square degrees near ecliptic poles.  ~ 6000x as large as ACS deep field, to m AB = 30.4 in nine optical and IR bands.  Provides ≥ 100 epochs over 16 months (each to m AB = 27.8) for time domain studies in all nine bands. GOODS Survey area Hubble Deep Field The Moon

19. February 17, 2005Gregory Tarlé ASPEN05 The Highest Energies19 Understanding Dark Energy

20. February 17, 2005Gregory Tarlé ASPEN05 The Highest Energies20 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 measure  M to  0.01 and w 0 to  0.05.

21. February 17, 2005Gregory Tarlé ASPEN05 The Highest Energies21 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 universe with prior  M measured to  0.03, SNAP will measure w 0 to  0.05 and w to  0.27.

22. February 17, 2005Gregory Tarlé ASPEN05 The Highest Energies22 SNAP works and plays well with others w 0 and w

23. February 17, 2005Gregory Tarlé ASPEN05 The Highest Energies23 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

24. February 17, 2005Gregory Tarlé ASPEN05 The Highest Energies24 THE END