1. Comments on Supernovae Riess 2004 sample of SNIa Comments on SNIa systematics Next SNIa surveys Some Kosmoshow analysis of present SNIa data Charling TAO April 2004, Toulouse

2. SN Ia 2004 : Riess et al, astro-ph 0402512 Fits well the concordance model :  2 = 178 /157 SNe Ia 183 SNIa selected  Gold set of 157 SN Ia

3. SNIA 2004: Riess et al, astro-ph 0402512 * Low z : 0.01 < z < 0.15 Calan-Tololo (Hamuy et al., 1996) : 29 CfA I (Riess et al. 1999): 22 CfA II (Jha et al, 2004b): 44 (not published yet) 16 new SNIA with HST (GOOD ACS Treasury program) 6 / 7 existing with z >1.25 + Compilation (Tonry et al. 2003): 172 with changes… * Knop et al, 2003, SCP : 11 new 0.4 < z < 0.85 reanalysis of 1999 Perlmutter et al. * 15 / original 42 excluded: inaccurate colour measurements and uncertain classification * 6 /42 and 5/11 : fail « strict SNIA » sample cut * Barris et al, 2003, HZT: 22 new varying degrees of completeness on photometry and spectroscopy records * Blakesly et al, 2003 : 2 with ACS on HST

4. Determination of Cosmological parameters Riess et al, astro-ph 0402512 w=p/  w= w 0 +w’ z

5. Determination of acceleration Riess et al, astro-ph 0402512

6. New physics? Cosmological constant Dark Energy: Dynamical scalar fields, quintessence…. General equation of state p=w r  r = R -3(1+w) Perhaps a bit early !!! « Experimentalist » point of view…

7. Constraints on cosmological parameters  m= 0.2 - 0.3 effect!

8. Systematic error on magnitude 3 fit with no prior 20% calibration error on intermediate fluxes gives no cosmological constant Use Kosmoshow: an IDL program by A. Tilquin! marwww.in2p3.fr/~renoir/kosmoshow.html

9. Riess gold set sensitivity Kosmoshow, A. Tilquin

10. A  m=0.27 shift of low z data  No need for   But Universe is not flat! Shift z <0.15 data by  m= 0.27   m = 0.43 +/-0.2 and   = 0 +/-0.34 Use Kosmoshow: an IDL program by A. Tilquin!

11. Systematic differences between methods

12. A 3 steps method: oDiscovery: subtraction of an image with a reference one. oSupernova type identification and redshift measurement: spectrum. oPhotometric follow-up: light curve.  Final analysis: Hubble diagram. The “classical” observation method

13. m(z) = M + 5 log (D L (z,  M,  L ))-5log(H 0 )+25 The Hubble diagram Absolute magnitude Less luminous/z => Accelerated expansion less matter or more dark energy Too luminous/z => Slowed down expansion => deceleration More matter, less dark energy

14. –Light Curve in local reference frame – K correction –Galactic extinction correction - Standardisation methods : stretch (SCP), MLC2k2 (HiZ),  m 15,... mag Magnitude at maximum light curve

15. Standardisation: stretch method Before: m B After : m Bcor = m B –  (s-1)

16. Precision on the magnitude dominated by intrinsic dispersion:  m int  0.15 Stretch uncorrected Stretch corrected Precision on the magnitude at the maximum

17. Fit cosmological parameters –From Hubble diagram, fit best cosmological model agreeing with observations. –Determine dark energy parameters  , ou (  X, w, w’)  and matter density  M

18. Spectroscopy needed SN Ia Identification –Spectrum structure Redshift z measurement –From position of identified lines from spectra SN and/or underlying galaxy

19. dataanalysisphysics The « classical » method Images Spectra + identification. Ia magnitude z(redshift) galaxy Hubble

20. Systematic effects Extragalactic environment Supernova environment reduction/correlations SNIa contamination Selection bias Inter calibration filters local Normal Dust absorption Lensing Grey Dust SN evolution

21. Systematic effects Observational problems –Standardisation method –Light curve fitting –Subtractions –Calibrations –Atmospheric corrections –K-corrections –Selection bias –Heterogeneity of SN data –SNIa identification SN evolution Internal extinction not negligible in spiral galaxies Corrections for peculiar velocity effects Grey dust Lensing Rowan-Robinson astro-ph/021034 Perlmutter & Schmidt 0303428

22. Knop et al (2003) light curves

23. Spectrum is dilated by (1+z) : The integrated flux in a filter is  Shifted. Filters responses are not flat Sometimes, need different filters  Correct for differences  systematic effects Le flux est intégré sur un filtre pour un point de photométrie Redshift calibration

24. SNIa sample contamination Need strict selection criteria  Gold sample is probably well selected

25. Supernovæ identification With Spectra Main stamp of the SNe Ia: Si II at 6150 Å: o Hardly observable beyond z > 0.4-0.5. Otherwise, search for features in the range 3500-5500 Å (supernova rest frame): o Ca H&K, SiII at 4100 Å, SII, … Ca H&K SiII 4100 Simulation of a SN Ia spectrum at z  0,5

26. Spectroscopy : a Supernovae

27. Atmospheric transmission (ground) Reduction of transmission in visible Absorption water & O 2 reduce visibility in IR. Reduced efficiency Not homogeneous filters Redshift dependent !!! Seeing + weather + moon + field not always visible absorption

28. Les Atmospheric emission

29. Spectroscopy : Subtract galaxy

30. Dependence on SN Environment Blue have a lower metallicity Can be seen further

31. Supernovae evolution Peak magnitude can change –Explosion changes with environment –Difference of chemical elements around SN –Depends on galaxy morphology, age, type,… Sullivan et al (2002) SCP SNIa host galaxy morphological classification  Not a large effect, but statistics are low

32. Extinction and Dust Extinction by dust from Our or SN galaxy Rv=3.1 +/- 0.3 for OUR galaxy  Very large correction Grey dust: not well known, intergalactic,? Before extinction After correction Correction factor to the magnitude A = R* E(B-V)  Measurements in many filters  Select minimal dust regions ?

33. A strong limit on grey dust? A 24.7 hr Chandra exposure of QSO 1508- 5714 z=4.3 shows no dust scattering halo Upper limit on mass density of large grained (>1  m) intergalactic dust:  dust < 2 10 -6 Peerels, Tells, Petric, Helfand (2003)

34. Dust and evolution ? Evolution: shift due to progenitor mass? metallicity? Ni distribution? Other effects? Dust : Homogeneous gray intergalactic dust? Galactic dust responsible for extinction? Sensitivity to dark energy decrease for z > 0.6 Is there a region of deceleration? Needs to go to z> 1

35. Gravitational Lensing

36. Some estimates of Systematics

37. Effect of de/amplification Systematics

38. Astrophysical effects Internal extinction not negligible in spiral galaxies – Increase of the fraction of star-forming systems with z  average host galaxy extinction should be higher? –DeVaucouleurs prescription (1976) Corrections for peculiar velocity effects Grey dust Lensing

39. Understand environment To classify and correct Need precise measurements with statistics Perlmutter SN demographics studies

40. Summary Ideally Many SN for a negligible statistical error and study of systematic conditions.  wide field Detect deceleration zone (z>1)  measure in IR (or have large local UV sample for SNIa identification) Control the correction precision for SNIA standardisation (environment and measurement corrections) Control non corrected systematic effects to the same level  Very precise light curves and spectra to determine the explosion parameters, at all distances.

41. spac e Ground limitation at z around 1 due to atmosphere ground simulation Hubble diagrams: Space vs ground

42. Advantage of space More galaxy surface density Less impact from a more constant PSF More information on shape same observation in space and from ground Optimisation of mission

43. SNAP a dedicated satellite Large statistics: 2000 Sne Ia/yr redshift to z<1.7, Minimal selection Ia identification 2m wide field telescope

44. Science Measure  M and  Measure w and w (z) Data Set Requirements Discoveries 3.8 mag before max Spectroscopy with S/N=10 at 15 Å bins Near-IR spectroscopy to 1.7  m Statistical Requirements Sufficient (~2000) numbers of SNe Ia …distributed in redshift …out to z < 1.7 Systematics Requirements Identified and proposed systematics: Measurements to eliminate / bound each one to +/–0.02 mag Satellite / Instrumentation Requirements ~2-meter mirrorDerived requirements: 1-square degree imager High Earth orbit Spectrograph ~50 Mb/sec bandwidth (0.35  m to 1.7  m) Mission : % level

45. Need same precision on extracted magnitude Fit the magnitude on light curve after corrections of stretch, galactic extinction, K-corrections, everything that modifies luminosity  Study models and parameter extraction  Determine camera properties reach 1 to 2 % on cosmological parameters SNAP goals

46. dataanalysisphysics SNAP: Observation method Images Spectra + same spectra, allows identification. SiII Ia magnitude  M,   z(redshift) galaxy Hubble The same !! But optimised for systematics

47. Discovery maximum 2 days (RF) after explosion ( max + 3.8 magnitude), Ligth curve: At least 10 points in photometry until plateau (+2.5 m) Spectrum very precise at maximum (identification, systematics, calibration) SNAP SNIa strategy

48. Hubble Deep Field Weak Lensing Survey Supernova Survey Surveys: Supernova Survey: 2X7,5 sq. deg. 2X16 months R<30.4 (9 bands) Weak Lensing Survey 300 sq. deg. 0.5-1 year R<28.8 (9 bands) Each field is est observed ~4 days All images are cumulated Observe repeatedly same sky area SNAP survey Wide field !!

49. SNAP: control evolution systematics

50. Light curves Multi band Photometry Peak measurement 2 % K correction Selection bias Very precise measurement of beginning and end of light curve

51. Simulated SNAP Light Curves z=0.8 z=1.0 Rest R-band Rest B-band Rest V-band z=1.2 z=1.4 z=1.6 Rest B-band Rest V-band

52. SNIa Spectra Wide lines! SII 5350Å,  w = 200Å SII “W”,  w = 75Å SiII 6150Å,  w= 200Å Study of spectra and correlation of line variations with explosion parameters and luminosity Need MODELS

53. Quantification of systematics Metallicity effect Velocity differences Data Models Modelisation of explosion (T, v, M) Control of evolution

54. Present errors on   : (flat universe case) statistics 0.085 systematics (determination SCP) Malmquist bias0.04 K correction/Calibration0.025 Extinction by ordinary dust0.03 Extinction (galactic)0.04 Non SNIa0.05 Gravit. Lensing <0.06 not determined grey dust ? SNIa evolution ? SNAP 2000 SN Detection at explosion Adjust filters in B+ intercalibration spectra  colours SDSS/SIRF Spectra Id Average on many SN spectra NIR + z>1 spectra z>1 A method for each systematics

55. Résultats-diagramme de Hubble SNAP Expectations

56. SNAP expected results Weak Lensing + CMB

57. How to constraint systematic effects and get precise measurements? Ideally in space: SNAP/JDEM Problem: > 2014 In the meantime: More statistics from as homogeneous samples as possible CFHTLS and ESSENCE + Nearby

58. Low z activities Nearby SuperNova Factory –300 SNIa (2004-…) –http://snfactory.lbl.gov/http://snfactory.lbl.gov/ Physics of SNIa explosions Supernovae at CfA (ongoing…) –Expect ~ 100 –http://cfa- www.harvard.edu/cfa/oir/Research/supernova.html

59. Low z: Nearby Supernova Factory (2004-…) Goals –~100/yr 0.03<z<0.08 –10 spectro-photometric between –14D and +40D –Spectra: 320-1000 nm Tools –Discovery: Two cameras (one wide field) 1.2 m ground based telescopes: NEAT –Lightcurve follow-up with YALO –Photo-spectro follow-up with Field Integral spectrometre (SNIFS) for ground based 2.2m telescope (Hawaii) Collaboration –France: CRAL,IPNL, LPNHE –US: LBNL, U.Chicago

60. Intermediate z (2003-2014) ESSENCE at CTIO –~50 SN Ia/year –http://www.ctio.noao.edu/wproject/sne/http://www.ctio.noao.edu/wproject/sne/ SNLS with MEGACAM of CFHT Legacy Survey –MEGACAM working since march 2003 –http://snls.in2p3.fr/http://snls.in2p3.fr/ –Foreseen : 700 SNIa z < 1.

61. The CFHT Legacy Survey Supernovæ Program

62. SNLS : the instruments A wide field camera (1 square degree, MEGACAM 0.35 Giga pixels) on 3.6 m CFHT (Hawaii) telescope

63. The Deep Survey of the CFHTLS Characteristics: o 4 fields of 1°x1° (RA=2h, 8h, 14h and 22h). o Each field observed every 2-3 dark/grey nights (6 months/year). o Each field observed with different filters: [u’ (15 min)], g’ (15 min), r’ (30 min), i’ (60 min) and z’ (30 min). o ~200 dark/grey nights exclusively dedicated to the survey (5 years). o Seeing < 0.9 arcsec. Pre-survey started in: March 2003. Scientific objectives of the Deep Survey: o Confirm acceleration with statistical significant study of systematics o Characterization of the equation of state of the Dark Energy. o Evolution of galaxies and quasars. o Detection of transient phenomenæ. o…

64. SNLS: Detections

65. –Discovery –Identification of the SN type and redshift measurement of the host galaxy –Photometric follow-up Multiplexing: large field. Quality and homogeneity of the data: seeing, always the same filters, … Regular time sampling (mode “continuous”): oLight curve between [-10,15] days in the rest frame. oOptimization of the spectroscopic trigger: date and magnitude of the maximum. Light curves in different bands: measurement of the E(B-V) to correct of the extinction. Spectroscopy with 8-10 meters class telescope Images with the CFHT The “continuous” method of the CFHTLS

66. Supernovæ discovery Redshift0.30.40.50.60.70.80.91.01.11.2Total Ia70 80110130140150 160 1310 Ib/c + II120160200160120—————760 + AGNs, quasars, variable stars + Unexpected variable objects ? Discovery: o Subtraction of an image with a reference one. o Operation performed directly at the CFHT base camp. Light curves not complete for several SNe: “edge effects ”. Estimate of the number of SNe with a complete light curve after 5 years

67. Simulation of a SNIa light curve at z=0.49 Multiplexing: detection and follow-up on the same image. Light curve: o Usable between 0.3 < z < 0.9: about 700 SNe Ia in 5 years. o Between [-10,+15] days in the SN rest frame. o Multi-wavelength: [g’], r’, i’ et z’. Spectroscopic trigger: estimate of the magnitude and the date of the maximum. Photometric follow-up

68. The spectroscopic program Supernova type identification and redshift measurement. Require 8-10 meters class telescope. About 12 SNe/field/lunation to be identified Telescope allocation : Large Program on the ESO FORS/VLT: 240 hours spread over 4 semesters Service mode. Gemini: 3 Canada, 2 UK and 1 US nights/year requested. Service mode. Keck: Visitor mode. 4 nights/year requested

69. Beginning of the pre-survey: o March 2003. As expected, data not optimal at the beginning (engineering time): o New optics (Megaprime), new camera (Megacam), new softwares, … Dedicated spectroscopy program started July 2003 ~ 50 well measured SNIa todate! The CFHT LS pre-survey and survey

70. Reference Image Subtraction Sn2003fh: SN Ia at z=0.25

71. R6D4-9 Candidate Ia: z = 0.94 Age = -1 days Preliminary

72. The CFHT Legacy Survey Supernovæ Program Canada and France Extra collaborators for the spectroscopy: VLT: ESO, Portugal, Sweden, UK. Keck: US. Gemini: UK, US.

73. Simulation after a 5 years survey   =0.72 and  M =0.28. SNFactory (300 SNe) CFHTLS (700 SNe) A new generation of Hubble diagram

74. SNLS : expected results   contraint SN only :   ~0.1 and  w~0.2 limited to z<0.95 (atmosphere)

75. Flat Only statistical errors 68 % Comparison with present measurements

76. SNLS present conclusions The CFHT LS /SNLS, a high redshift supernovæ factory: o Survey started officially in August 2003. o Sample increased by ~10: 700 Sne between 0.3<z<0.9. o Very good quality and homogeneity of the data. o Systematic errors at high redshift better controlled. o Measurement of the w parameter at  w  0.1. o… First results soon! (Already > 50 well measured SNIa)

77. Present situation: 183 SN from Riess 2004 Astro-ph0402512

78. Curve for Gold sample Fit, for a full sample, no prior Simulation and analysis tool: Kosmoshow developed in IDL by André Tilquin (CPPM) Kosmoshow analysis marwww.in2p3.fr/~renoir/Kosmoshow.html

79. Riess 2004, gold sample  m =0.445  0.105  X =0.972  0.190  k =-0.418  0.283

80. Large present  r ? Blanchard et al., (+ others) large  r (0.1-0.2) for CMB possible

81. Riess gold sample radiative component Simulation and analysis tool: Kosmoshow (A.Tilquin) Add  r in D L equation: (1+z) 4 component  Strong correlation  r with  M  Positive  r component not excluded!  BUT always NEED large  

82. Full fit on gold sample  T =1±0.1 Flat Universe  m =0.27±0.04

83. How can present  r0 be large? Expected  r0 =   (1 + f N )   = 5.06 10 -5 h 2 70 N = number of relativistic species T rec ~ 0.26 eV f = numerical factor = 0.227 for neutrinos Expected (low z)  r0 ~< 10 -4 !!! With (1+z) 4 evolution  r,z=1100 is 10 3 higher than  m with (1+z) 3 evolution

84. Bias from the time evolution of the equation of state astro-ph/0403285 Virey et al. Quantitative analysis of the bias on the cosmological parameters from the fitting procedure, ie, assuming a constant w, when it is not! With present statistics, can be ignored Not the case with larger samples!

85. Example of bias: large w 1 w 0 F =-0.7 w 1 F = 0.8 Suggestion Maor et al... 4-fit M s,  M, w 0, w 1 3-fit, M s,  M, w 0

86. Comments on Supernovae: a summary Riess 2004 sample of SNIa: a strict selection Comments on SNIa systematics. Not all understood! Next SNIa surveys Some Kosmoshow analysis of present SNIa data Charling TAO April 2004, Toulouse