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Paris - Apr29, 2005Reynald Pain 1998-2003 : Concordance model Today’s question :  Cosmological Constant, Vacuum Energy  or Dark Energy ? SNe Ia prefer.

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Presentation on theme: "Paris - Apr29, 2005Reynald Pain 1998-2003 : Concordance model Today’s question :  Cosmological Constant, Vacuum Energy  or Dark Energy ? SNe Ia prefer."— Presentation transcript:

1 Paris - Apr29, 2005Reynald Pain : Concordance model Today’s question :  Cosmological Constant, Vacuum Energy  or Dark Energy ? SNe Ia prefer a non zero 

2 Paris - Apr29, 2005Reynald Pain Outline: Cosmology with SNe Ia Why keep studying SNe Ia ? SNLS - the SuperNova Legacy Survey

3 Paris - Apr29, 2005Reynald Pain Cosmology with SNe Ia Luminosity distance : d L (z) SNe Ia ?

4 Paris - Apr29, 2005Reynald Pain SNe Ia are not standard candles Very Luminous events  visible at cosmological distances Show little intrinsic dispersion

5 Paris - Apr29, 2005Reynald Pain SNe Ia Show Light Curve Shape Relationships (similar to Cepheids P-L relation) => Allows to measure distances to better than 5-8% precision Measuring distances

6 Paris - Apr29, 2005Reynald Pain From fainter to brighter… SN Ia Spectral features

7 Paris - Apr29, 2005Reynald Pain ModelsObservations Using radiative transfer codes, this relationship is reproduced simply by increasing the abundance of 56 Ni in the explosion. Here this is characterized by increasing the effective temperature of the atmosphere. SNe Ia modelisation

8 Paris - Apr29, 2005Reynald Pain 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 ?

9 Paris - Apr29, 2005Reynald Pain HST measured color SCP SN photometrically followed with HST  allows event by event extinction correction Updated Hubble diagram Using a low extinction subset

10 Paris - Apr29, 2005Reynald Pain “Morphological” Hubble diagram SCP 2002 Is there a host galaxy effect ?

11 Paris - Apr29, 2005Reynald Pain SNe at higher redshift (Goods/ACS survey) Probe the deceleration era Find Sne at z>1.2 using HST

12 Paris - Apr29, 2005Reynald Pain GOODS/ACS 2004: HST Supernovae Expansion went from deceleration to acceleration Exclude grey dust

13 Paris - Apr29, 2005Reynald Pain Probe Dark Energy 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 Other sources : w = p/  Cosmological constant : p=- 

14 Paris - Apr29, 2005Reynald Pain 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

15 Paris - Apr29, 2005Reynald Pain SNLS – The SuperNova Legacy Survey

16 Paris - Apr29, 2005Reynald Pain Imaging survey with Megacam at CFHT CFHT :  3.6 m (1979) Megacam (CEA/DAPNIA) : 1 deg 2, 4O CCD 2k*4K, = 328 Mpixel First light : fall 2002

17 Paris - Apr29, 2005Reynald Pain 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

18 Paris - Apr29, 2005Reynald Pain CFHT Legacy Survey/deep XMM deep VIMOS SWIRE GALEX Cosmos/ACS VIMOS SIRTF XMM … Groth strip Deep2 ACS … XMM deep Four 1 deg² fields ( , , , ) superb image quality ( arc sec.) queue scheduling, excellent temporal sampling depth i’>24.5 (S/N=8, 1 hr); r’ > 28 in final stacked image Redshift Total Ia Ib/c + II —————76 Expected nb of SN per semester

19 Paris - Apr29, 2005Reynald Pain 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 Gemini : 60h/semester - Keck : 3n/year (1 st semester) - Magellan : 2n/semester

20 Paris - Apr29, 2005Reynald Pain Find candidates: How it works Two independent search pipelines PSF-match the “reference” and “new” images Subtract… … and search the difference images Real candidate PSFmatch errors from saturated objects easily rejected

21 Paris - Apr29, 2005Reynald Pain Search/follow-up of SNe

22 Paris - Apr29, 2005Reynald Pain Current status – typical light-curves Typical time-sampling and light-curve coverage

23 Paris - Apr29, 2005Reynald Pain June 2003 i’ 1 hr z=0.281 SN Ia-p t=-7d

24 Paris - Apr29, 2005Reynald Pain Current status – VLT spectroscopy z=0.550z=0.610 z=0.815z=0.988

25 Paris - Apr29, 2005Reynald Pain SNLS: Spectroscopy obs. June 03- Oct. 04 ~160 SN Ia as of Dec 04

26 Paris - Apr29, 2005Reynald Pain SNLS Progress

27 Paris - Apr29, 2005Reynald Pain Current status – N(z) Total predicted number of spectroscopically followed SNe Distribution appears as expected out to z=0.9 ~115 SN Ia from a 12 month period SNe from Sep 2003  Sep 2004

28 Paris - Apr29, 2005Reynald Pain SNLS : 1st year Hubble diagram 72 SN at z = historical Calan-Tololo SNe constraint on w (flat Universe)

29 Paris - Apr29, 2005Reynald Pain 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

30 Paris - Apr29, 2005Reynald Pain

31 Paris - Apr29, 2005Reynald Pain Precision cosmology with SN Ia Detect/follow SN Ia from Space e.g. SNAP Proposed 1999 Now running for NASA/DOE JDEM AO (2006?)

32 Paris - Apr29, 2005Reynald Pain Images Spectra Redshift & spectral properties Light Curves dataanalysisphysics  M and   w and w’ SNAP concept Observables :

33 Paris - Apr29, 2005Reynald Pain 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  M (statistics + systematics) nearby SNe z>0.1

34 Paris - Apr29, 2005Reynald Pain 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) => SNe 0.1

35 Paris - Apr29, 2005Reynald Pain SNAP: testing quintessence models  w´= 0.08  w 0 =0.05

36 Paris - Apr29, 2005Reynald Pain JDEM/DESTINY Selected by NASA for « Einstein Probes 2yr Conceptual Studies »  =1.8m telescop 0.25 deg. carrés - NIR 0.9->1.7  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

37 Paris - Apr29, 2005Reynald Pain Dark Universe Explorer (DUNE) Proposed (2004) as weak lensing probe m telescope sq. deg. Imager visible only filter In phase O study at French Space Agency If approved.. launch by ? A SN program for DUNE ? 100 sq deg. (UBVRIZ, I=26) - cadence: 4days Photométric id of SNe (UBV restframe) Ground based spectroscopy (host galaxies) => SNe 0.1


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