Theoretical FNAL: Dark Energy Breakout session, DOE Review May 17, 2006

Pre-SN work on Natural Dark Energy Models Frieman, Hill, Stebbins, & Waga 1995 Very small mass scale of quintessence field ( eV) related to ratio of explicit breaking scale and spontaneous breaking scale: M is neutrino mass and f close to Planck mass

Understood importance of CMB/LSS for testing models Coble, Dodelson, & Frieman 1997

Model with Early Dark Energy Dodelson, Kaplinghat, & Stewart 2000  Tweaks tracker model, with exponential potential  Solves “Why now?” problem  Important to bear in mind when planning experiments

Analyzed early CMB data to prove flatness Dodelson & Knox 1999 Coupled with constraints on matter density, flatness is evidence for dark energy

Radiation Ripples From Big Bang Illuminate Geometry of Universe By JAMES GLANZ (NYT) 1571 words Published: November 26, 1999 Like the great navigators who first sailed around the world, establishing its size and the curvature of its surface, astronomers have made new observations that show with startling directness the large-scale geometry of the universe and the total amount of matter and energy that it contains. … And that leads astronomers to their next conclusion: because the amount of matter found by astronomers cannot produce a flat universe, Dr. Dodelson said, ''the inescapable conclusion is that there is some unknown form of energy contributing to the total density.'' (This unknown energy is distinct from so-called dark matter, once described as the missing mass of the universe.)

Took the lead in analyzing early SDSS data, leading to robust constraints on matter density Dodelson et al One of 6 papers analyzing early SDSS data w/ Frieman, Hui, Johnston, Scranton, Sheth, Stebbins, Zehavi Γ is Ω m h, so SDSS implies a matter density much smaller than critical

More evidence for dark energy in correlation of CMB and SDSS Scranton et al w/ Stebbins, Frieman, & Johnston SDSS galaxies are nowhere near last scattering surface, but are correlated w/ WMAP because potential wells decay in a universe w/ dark energy.

1.Cosmology and the Bispectrum. Emiliano Sefusatti et al. e-Print Archive: astro-ph/ Emiliano Sefusatti 2.What can gamma ray bursts teach us about dark energy? Dan Hooper (Fermilab), Scott Dodelson (Fermilab & Chicago U., Astron. Astrophys. Ctr.) e-Print Archive: astro-ph/ Dan HooperFermilabScott DodelsonFermilabChicago U., Astron. Astrophys. Ctr. 3.Testing Gravity Against Early Time Integrated Sachs-Wolfe Effect. Pengjie Zhang (Shanghai, Astron. Observ. & Fermilab) e-Print Archive: astro-ph/ Pengjie ZhangShanghai, Astron. Observ.Fermilab 4.Learning from the scatter in type ia supernovae. Scott Dodelson (Fermilab & Chicago U., Astron. Astrophys. Ctr.), Alberto Vallinotto (Fermilab & Chicago U.). e-Print Archive: astro-ph/ Scott DodelsonFermilabChicago U., Astron. Astrophys. Ctr.Alberto VallinottoFermilabChicago U. 5.Comments on backreaction and cosmic acceleration. Edward W. Kolb (Fermilab & Chicago U., Astron. Astrophys. Ctr. & Chicago U., EFI), Sabinio Matarrese (Padua U. & INFN, Padua), Antonion Riotto (CERN) e-Print Archive: astro-ph/ Edward W. KolbFermilabChicago U., Astron. Astrophys. Ctr.Chicago U., EFISabinio MatarresePadua U.INFN, PaduaAntonion RiottoCERN 6.Statistics of physical properties of dark matter clusters. Laurie Shaw, Jochen Weller et al. e-Print Archive: astro-ph/ Laurie ShawJochen Weller 7.Reduced shear power spectrum. Scott Dodelson (Fermilab & Chicago U., Astron. Astrophys. Ctr. & Northwestern U.), Charles Shapiro (Chicago U. & KICP, Chicago), Martin J. White (UC, Berkeley, Astron. Dept. & UC, Berkeley). Published in Phys.Rev.D73:023009,2006Scott DodelsonFermilabChicago U., Astron. Astrophys. Ctr. Northwestern U.Charles ShapiroChicago U.KICP, ChicagoMartin J. WhiteUC, Berkeley, Astron. Dept.UC, Berkeley 8.Mapping dark matter with cosmic magnification. Pengjie Zhang (Fermilab), Ue-Li Pen (Canadian Inst. Theor. Astrophys.). Published in Phys.Rev.Lett.95:241302,2005Pengjie ZhangFermilabUe-Li PenCanadian Inst. Theor. Astrophys. 9.On cosmic acceleration without dark energy. E.W. Kolb et al. e-Print Archive: astro-ph/ E.W. Kolb 10.The dark energy survey. By Dark Energy Survey Collaboration (T. Abbott et al.). Oct pp. White Paper submitted to Dark Energy Task Force. e-Print Archive: astro-ph/ T. Abbott et al. 11.Constraining dark energy with the dark energy survey: theoretical challenges. White Paper submitted to Dark Energy Task Force. e-Print Archive: astro-ph/ Dark energy studies: challenges to computational cosmology. By DES Collaboration White Paper submitted to Dark Energy Task Force. e-Print Archive: astro-ph/ Probing dark energy via weak gravitational lensing with the Supernova Acceleration Probe (SNAP). By SNAP Collaboration White Paper to Dark Energy Task Force. e-Print Archive: astro-ph/ Supernova Acceleration Probe: Studying dark energy with Type Ia supernovae. By SNAP Collaboration White Paper to Dark Energy Task Force. e-Print Archive: astro-ph/ Seeing the nature of the accelerating physics: It's a SNAP. By SNAP Collaboration White Paper to the Dark Energy Task Force. e-Print Archive: astro-ph/ Dark Energy Papers over the Past 12 Months

One Focus: Gravitational Lensing Constraints on dark energy via growth of structure

Compute power spectrum of cosmic shear Background galaxy ellipticities sensitive to reduced shear, differs from cosmic shear at the 1-10% level Dodelson, Shapiro, & White 2005

Biases Cosmological Parameters … unless corrected for. Showed that analytic correction formula agrees with simulations.

Additional information contained in higher point functions, e.g. bispectrum Green curve uses power spectrum only; blue curve adds in bispecturm Sefusatti et al. 2006

To use this information, must understand covariance of power spectrum and bispectrum. Requires semi-analytic and numerical calculations of 5- and 6- point functions Sefusatti et al. 2006

Square Kilometer Array galaxies was ?? Million Light Years Lensing of Radio Galaxies

Magnification Maps Zhang & Pen 2005 Galaxies behind large potential wells are magnified → get more, fainter galaxies. Use galaxy counts to infer projected potential.

Supernova Hubble Diagram CFHT Supernova Legacy Survey Astier etal 05 Needed: more, better data at low and intermediate redshift SDSS Another Focus: Type Ia Supernovae

SDSS II Supernova Survey Sept-Nov  Obtain ~200 high-quality SNe Ia light curves in the `redshift desert’ z~ : continuous Hubble diagram  Probe Dark Energy in z regime less sensitive to evolution than, and complementary to, deeper surveys  Study SN Ia systematics with high photometric accuracy  Search for additional parameters to reduce Ia dispersion  Determine SN/SF rates/properties vs. z, environment  Rest-frame u-band templates for z >1 surveys

~130 spectroscopically confirmed Type Ia Supernovae from the Fall 2005 Season First cosmology results expected this summer

Monte Carlo prediction Confirmed Ia’s Different Selection criteria from Monte Carlo

SN 2005 ff z = 0.07, confirmed at WHT Preliminary gri light curve and fit from low-z templates BeforeAfter Composite gri images

SN 2005 gb z = 0.086, confirmed at ARC 3.5m Preliminary gri light curve and fit from low-z templates BeforeAfter Composite gri images

SDSS II SN Follow-up 2005  Spectroscopy: mainly SN typing, redshift ARC 3.5m (31 half-nights), HET (>60 hrs), MDM 2.4m (~37 nights), Subaru (share 6 nights), WHT (6 nights), Supernova Factory (low-z targets), Keck (opportunity, 1 night)  NIR imaging: extinction/reddening and low-z light curves Carnegie Supernova Project (selected targets)  Optical imaging: follow high-z light curves beyond SDSS limit NMSU 1m, MDM, UH 88in (6.5 nights), VATT (7 nights), WIYN (3 nights shared), INT (1 night), Liverpool Telescope (4 hours)

Follow-up Spectra from Subaru

Conclusions  Long history of pioneering work on dark energy  Continues today with theory, phenomenology, and experiment