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Reynald Pain LPNHE, Univ. Paris, France

Probing Dark Energy with Supernovae. Reynald Pain LPNHE, Univ. Paris, France. Dark Energy with SNe : an active field. 1998. ?. 2015?. 2003. Today. Outline. Why/how supernovae ? Past and more recent SN constraints Today’s landscape Expected constraints from Future SN programs.

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Reynald Pain LPNHE, Univ. Paris, France

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  1. Probing Dark Energy with Supernovae Reynald Pain LPNHE, Univ. Paris, France EDEN, Dec 7 2005

  2. Dark Energy with SNe : an active field 1998 ? 2015? 2003 Today EDEN, Dec 7 2005

  3. Outline • Why/how supernovae ? • Past and more recent SN constraints • Today’s landscape • Expected constraints from Future SN programs EDEN, Dec 7 2005

  4. Cosmology with SNe Ia EDEN, Dec 7 2005

  5. SNe Ia are not standard candles Very Luminous events • visible at cosmological distances Show little intrinsic dispersion EDEN, Dec 7 2005

  6. Measuring distances SNe Ia Show Light Curve Shape Relationships (similar to Cepheids P-L relation) => Allows us to measure distances to better than 5-8% precision EDEN, Dec 7 2005

  7. SNe Ia modelisation Models Observations Using radiative transfer codes, this relationship is reproduced simply by increasing the abundance of 56Ni in the explosion. Here this is characterized by increasing the effective temperature of the atmosphere. EDEN, Dec 7 2005

  8. Past and more recent SN projects • ~1990->1998 : pioneer work : find distant SNe, measure LC, z => Discovery of the acceleration of the expansion of the Universe • 1999 -> 2004 : More supernovae, higher redshifts Study of systematics (measure color, host galaxy types HST follow-up observations Search/discoveries with HST => confirmation, first constraints on w EDEN, Dec 7 2005

  9. 1998: first (precise enough) results 2 (independent) groups (High-z Team and SCP) present new results based on 42 (SCP) and 10 (HZT) high-redshift SNe and20-40 low-redshift SNe. EDEN, Dec 7 2005

  10. 1998 : HZT & SCP first “constraint” on w w (cste, flat Universe) < -1/3 (99% CL) EDEN, Dec 7 2005

  11. 2003 : HST measured color • SCP 2003 • +11 SN photometrically followed with HST • allows event by event extinction correction Updated Hubble diagram • Using a low extinction subset EDEN, Dec 7 2005

  12. SCP 2003 (Knop et al.) +CMB+2dF : w = -1.05+0.15-0.20 (stat) +/- 0.09 (syst) EDEN, Dec 7 2005

  13. 2003 results from HZT (Tonry et al.) Hubble diagram of ~230 published SNe (70 z>0.3) WM,WL= 0.3, 0.7 0.3, 0.0 1.0, 0.0 EDEN, Dec 7 2005

  14. HZT 2003 (Tonry et al.) • -1.48 < w < -0.72 at 95% confidence • Assuming flat universe and WM from 2dF EDEN, Dec 7 2005

  15. SNe at higher redshift (Goods/ACS survey) Probe the deceleration era Find SN at z>1.2 using HST EDEN, Dec 7 2005

  16. GOODS/ACS 2004: HST Supernovae Expansion went from deceleration to acceleration Exclude grey dust EDEN, Dec 7 2005

  17. HST SNe : Riess et al. 2004 (GOODS/ACS) - w (flat+CMB+LSS) = -1.02 +0.13 - 0.19 (w<-0.76 95%CL) - first “constraints” on w’ EDEN, Dec 7 2005

  18. 1990-2004: the discovery phase The « 1st generation » High-z SN projects (SCP, HZT, HHZT) have o(200) SN Ia up to z=1.7 (about 20 above z=1). The projected statistical uncertainties will match estimated level of systematic uncertainties • Need « 2nd generation » experiments with both high statistics o(1000) and better control of possible systematics Both for high-redshift and low-redshifts SNe EDEN, Dec 7 2005

  19. SNe Ia : Today’s landscape low-z (z<0.1): Cfa (Harvard, UCB, ...) Carnegie (+IR) SN Factory/SNIFS z ~ 0.1-0.3 : SDSS/SN high- z: ESSENCE SNLS ACS/HST : PANS (Riess et al) Clusters (Perlmutter et al) EDEN, Dec 7 2005

  20. SNLS – The SuperNova Legacy Survey EDEN, Dec 7 2005

  21. Imaging observing strategy : “Rolling Search” Each lunation (~18 nights) : repeated observations (every 3-4 night) of 2 fields in four bands (griz)+u for as long as the fields stay visible (~6 months) for 5 years: expected total nb of SN : ~2000 (detected) EDEN, Dec 7 2005

  22. SNLS-04D3gx z=0.91 SNLS-04D3fk z=0.3578 SNLS :example of 2nd generation high-z survey As of Nov 15, 2005 : 226 SNe Ia+ Ia? Expect ~700 by survey end (2008.5) EDEN, Dec 7 2005

  23. SNLS First year Hubble diagram Final sample : 45 nearby + 71 SNLS SN In a w=-1 Flat LCDM universe: WM = 0.263 +/- 0.042 (stat) +/- 0.032 (syst) EDEN, Dec 7 2005

  24. SNLS first year constraint on Dark Energy solid contours : SNLS dotted contours : Baryon Acoustic Peak (BAO), Eisenstein 2005 (68.3, 95.5 and 99.7% CL) WM = 0.271 +/- 0.021 (stat) +/- 0.007 (syst) w = -1.023 +/- 0.090 (stat) +/- 0.054 (syst) EDEN, Dec 7 2005

  25. Future SN programs • SNLS/ESSENCE and planned 4m surveys • Other future ground based projects • Space projects EDEN, Dec 7 2005

  26. Future SN programs By 2008-9 SNLS/ESSENCE + Nearby SNe should reach : - dw (cte)~0.07 - no (significant) constraints on w’ (wa) will reach a new(theirs) systematic floor  also very difficulty with upcoming 4m Wide Field projects : DES, DarkCam EDEN, Dec 7 2005

  27. Future ground based SN projects • Pan Starrs : Simultaneous observing with Four 1.8m telescopes of 3 deg2 fov (0.3’’ pixels) • LSST : One 8m telescope with 9 deg2 fov => 250000 SN/an ! EDEN, Dec 7 2005

  28. Precision cosmology with SN Ia Detect/follow SN Ia from Spacee.g. SNAPProposed 1999 Now running/waiting for NASA/DOE JDEM AO (2007+) EDEN, Dec 7 2005

  29. Lightcurves and Spectroscopy from space - Multicolor high S/N lightcurves up to z~2 - SN spectral identification up to redshifts z~1.7 EDEN, Dec 7 2005

  30. SNAP: strategy - precision on w Area : 2x7.5 sq. deg. Cadence : 4 days Total duration : 3 yr 60% imaging - 40% spectro Total nb of SN : ~ 2000 contraints on w vs WM (statistics + systematics) + 300 nearby SNe z>0.1 EDEN, Dec 7 2005

  31. SNAP: probing DE models w´= 0.08 w0=0.05 EDEN, Dec 7 2005

  32. JDEM/DESTINY Selected by NASA for « Einstein Probes 2yr Conceptual Studies » f=1.8m telescope 0.25 deg. carrés - NIR 0.9->1.7 m all grism R=100 (spectrophotometry) L2 orbit Survey: 4 h exposure 7.5 sq. deg. 1.5 sq. deg./day (cadence 5 days) 2000 SNe 0.5<z<1.7 in 2 yrs Calibration with ESSENCE/LSST (z<1) EDEN, Dec 7 2005

  33. Dark Universe Explorer (DUNE) Proposed (2004) as weak lensing probe 1.2 m telescope 0.5 sq. deg. Imager visible only - 1 filter Currently in phase O study at French Space Agency If approved .. launch by 2011-12 ? A SN program for DUNE 2x60 sq deg. (UBVRIZ, I=26) - cadence: 4days Photométric id of SNe (UBV restframe) Ground based spectroscopy (host galaxies) => 10000 SNe 0.1<z<1 in ~18 months statistical uncertainties on w, w’ o(80%xSNAP) calibration/systematic uncertainties ? EDEN, Dec 7 2005

  34. SNLS vs DUNE vs SNAP EDEN, Dec 7 2005

  35. Summary • SNe Ia are excellent distance indicators. Significant constraints on w require combining with constraints from other experiments (WM) • « 1st generation » SN experiments have reached their systematic limit • 2nd generation projects are getting more and higher quality data. Toward building a Hubble diagram with ~1000 SN Ia Expected precision on (flat Univ., constant) w by 2008-9 : +/- 0.05 (stat) +/-0.05 (syst) • Percent precision on w and significant precision on w’ (wa) with SN will require experiment in space. EDEN, Dec 7 2005

  36. EDEN, Dec 7 2005

  37. SNLS s = 0.033 nearby 3 bands: color compatibility (UBV rest frame) DU3= U(measured) – U(from B + V) SNe Ia UBV relations seems reproducible and redshift independent: - Redundancy of distances - small uncertainties in k-corrections Use (redundant) imaging to id SNe and control systematics ? EDEN, Dec 7 2005

  38. SNAP concept Observables : Light Curves Images Redshift & spectral properties M and L w and w’ Spectra data analysis physics EDEN, Dec 7 2005

  39. SNLS vs DUNE vs SNAP (simulation) SNAP/Destiny (goal:2000 SNe) DUNE (goal:10000 SNe) SNLS (goal:700 SNe) SNF (goal:300 SNe) EDEN, Dec 7 2005

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