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1998-2003 : Concordance model

1998-2003 : Concordance model. SNe Ia prefer a non zero L. Today’s question : Cosmological Constant, Vacuum Energy or Dark Energy ?. Outline:. Cosmology with SNe Ia Why keep studying SNe Ia ? SNLS - the SuperNova Legacy Survey. Cosmology with SNe Ia.

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1998-2003 : Concordance model

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  1. 1998-2003 : Concordance model SNe Ia prefer a non zero L Today’s question : Cosmological Constant, Vacuum Energy or Dark Energy ? Reynald Pain

  2. Outline: • Cosmology with SNe Ia • Why keep studying SNe Ia ? • SNLS - the SuperNova Legacy Survey Reynald Pain

  3. Cosmology with SNe Ia Luminosity distance : dL(z) SNe Ia ? Reynald Pain

  4. SNe Ia are not standard candles Very Luminous events • visible at cosmological distances Show little intrinsic dispersion Reynald Pain

  5. Measuring distances SNe Ia Show Light Curve Shape Relationships (similar to Cepheids P-L relation) => Allows to measure distances to better than 5-8% precision Reynald Pain

  6. SN Ia Spectral features From fainter to brighter… Reynald Pain

  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. Reynald Pain

  8. Why keep collecting SNe Ia ? • Probe Dark Energy Cosmological constant or Dark Energy ? • Study sytematics - Extinction : Host galaxy/inter-galactic « grey » dust - Evolution : Are nearby and distant SNe Ia alike ? Reynald Pain

  9. 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 Reynald Pain

  10. “Morphological” Hubble diagram SCP 2002 Is there a host galaxy effect ? Reynald Pain

  11. SNe at higher redshift (Goods/ACS survey) Probe the deceleration era Find Sne at z>1.2 using HST Reynald Pain

  12. GOODS/ACS 2004: HST Supernovae Expansion went from deceleration to acceleration Exclude grey dust Reynald Pain

  13. Probe Dark Energy Cosmological constant : p=-r Other sources : w = p/r Source w Matter 0 Radiation 1/3 Cosmo Cte -1 Scalar field (cte) -1 Cosmic strings -1/3 Domain wall -2/3 “Quintessence” <~-0.8 “Phantom Energy” <-1 Reynald Pain

  14. But: Ongoing 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 Reynald Pain

  15. SNLS – The SuperNova Legacy Survey http://cfht.hawaii.edu/SNLS/ Reynald Pain

  16. Imaging survey with Megacam at CFHT CFHT :  3.6 m (1979) Megacam (CEA/DAPNIA) : 1 deg2 , 4O CCD 2k*4K, = 328 Mpixel First light : fall 2002 Reynald Pain

  17. Observation strategy : “Rolling Search” Part of the CFHTLS/Deep survey ~ 40 nights/yr during 5 years Repeated observations (every 3-4n) of 4 sq. deg. in ugriz Reynald Pain

  18. XMM deep VIMOS SWIRE GALEX Cosmos/ACS VIMOS SIRTF XMM … Groth strip Deep2 ACS … XMM deep CFHT Legacy Survey/deep Four 1 deg² fields (0226-04, 1000+02, 1419+53, 2215-18) superb image quality (0.5-0.6 arc sec.) queue scheduling, excellent temporal sampling depth i’>24.5 (S/N=8, 1 hr); r’ > 28 in final stacked image Reynald Pain

  19. SNLS- The Spectroscopic survey Goals : - spectral id of SNe up to z~0.9 - redshift (host galaxy) - detailled study of a subsample of SNe, Type IIs (complementary programs, …) Where? : - VLT Large program (service) : 240h in 2003+2004 - Gemini : 60h/semester - Keck : 3n/year (1st semester) - Magellan : 2n/semester Reynald Pain

  20. Find candidates: How it works • Two independent search pipelines • PSF-match the “reference” and “new” images • Subtract… • … and search the difference images PSFmatch errors from saturated objects easily rejected Real candidate Reynald Pain

  21. Search/follow-up of SNe Reynald Pain

  22. Current status – typical light-curves Typical time-sampling and light-curve coverage Reynald Pain

  23. June 2003 i’ 1 hr z=0.281 SN Ia-p t=-7d Reynald Pain

  24. Current status – VLT spectroscopy z=0.550 z=0.610 z=0.815 z=0.988 Reynald Pain

  25. SNLS: Spectroscopy obs. June 03- Oct. 04 ~160 SN Ia as of Dec 04 Reynald Pain

  26. SNLS Progress Reynald Pain

  27. Current status – N(z) SNe from Sep 2003  Sep 2004 ~115 SN Ia from a 12 month period Distribution appears as expected out to z=0.9 Total predicted number of spectroscopically followed SNe Reynald Pain

  28. SNLS : 1st year Hubble diagram constraint on w (flat Universe) 72 SN at z = 0.2 - 0.95 + historical Calan-Tololo SNe Reynald Pain

  29. Summary • SNe Ia are excellent distance indicators • Ongoing SN experiments are reaching the systematic limit • 2nd generation projects are getting more and higher quality data. Toward building a Hubble diagram with ~1000 SN Ia • SNLS has collected ~160 SNIa in ~1.5 yr. 4 more years to go: expect many more SNe Reynald Pain

  30. Reynald Pain

  31. Precision cosmology with SN Ia Detect/follow SN Ia from Spacee.g. SNAPProposed 1999 Now running for NASA/DOE JDEM AO (2006?) Reynald Pain

  32. SNAP concept Observables : Light Curves Images Redshift & spectral properties M and L w and w’ Spectra data analysis physics Reynald Pain

  33. 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 Reynald Pain

  34. An alternative observing strayegy Basic concept Many SNe - Precise space imaging Ground based spectroscopy Survey: 100 sq deg. (UBVRIZ, I=26) + 10 sq. deg. (IZJHK, I=28) Cadence: 4days (50% on deep survey) Photométric id of SNe (UBV restframe) Ground based spectroscopy (host galaxies) => 12000 SNe 0.1<z<2 in ~18 months better statistical uncertainties on w, w’ calibration/systematic uncertainties ? Reynald Pain

  35. SNAP: testing quintessence models w´= 0.08 w0=0.05 Reynald Pain

  36. JDEM/DESTINY Selected by NASA for « Einstein Probes 2yr Conceptual Studies » f=1.8m telescop 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) Reynald Pain

  37. Dark Universe Explorer (DUNE) Proposed (2004) as weak lensing probe 1.2-1.5 m telescope 0.25-0.5 sq. deg. Imager visible only - 1-2 filter In phase O study at French Space Agency If approved .. launch by 2011-12 ? A SN program for DUNE ? 100 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 ~9 months statistical uncertainties on w, w’ o(80%xSNAP) calibration/systematic uncertainties ? Reynald Pain

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