1. www.astro.uvic.ca/~pritchet Supernovae and the Mystery of Dark Energy Chris Pritchet U. Victoria

2. www.astro.uvic.ca/~pritchet Golden Moments in Cosmology : General Relativity (1915) large-scale repulsive force ρ=const large-scale repulsive force, ρ=const

3. www.astro.uvic.ca/~pritchet v = H o d Hubble 1929: v = H o d v d Golden Moments in Cosmology: Expansion of the Universe “Edwin Hubble …” - Gail Christianson “… Einstein’s greatest blunder …”

4. www.astro.uvic.ca/~pritchet Cosmology – A Search for 2 Numbers?  Hubble constant - Ho – gives age and size of the Universe  Omega - Ω – matter and energy density – ultimate fate of the Universe

5. www.astro.uvic.ca/~pritchet The Hubble Diagram (m vs z) (what Hubble actually did) faintbright nearby distant V [km/s] Ω=1 Ω<1 Ω>1 Standard candle Universe expands forever Universe eventually collapses

6. www.astro.uvic.ca/~pritchet Gunn and Oke 1975 “… although the heterogeneity of the sample makes conclusions about cosmology slightly suspect.” -2 < Ω <0 +2 < Ω < +4 Kristian, Sandage and Westphal 1978 >400 nights of Palomar 200” time! evolution (mass and age)

7. www.astro.uvic.ca/~pritchet Supernovae

8. July 5 th, 1054AD Chaco Canyon, NM

9. www.astro.uvic.ca/~pritchet Crab Nebula and Pulsar

10. www.astro.uvic.ca/~pritchet Why are Supernovae Interesting?  L~10 10 L sun ~L MW  Source of almost all heavy elements ( 12 C - …)  Neutrinos, gravitational waves, …  Great physics!  Extinction events?

11. www.astro.uvic.ca/~pritchet Type Ia Supernovae Standard candles

12. www.astro.uvic.ca/~pritchet (Hubble Space Telescope, NASA) Supernova Cosmology

13. www.astro.uvic.ca/~pritchet Supernovae and Dark Energy  Supernovae fainter than expected  Universe is accelerating, not decelerating!  Universe dominated by dark energy  Large scale repulsive force  Constant density  Einstein was right! Riess et al. 1998 Perlmutter et al. 1999

14. www.astro.uvic.ca/~pritchet Matter and Energy in the Universe – A

15. www.astro.uvic.ca/~pritchet “On a good day I can think of 3 or 4 plausible candidates for dark matter. The same cannot be said for dark energy.” “On a good day I can think of 3 or 4 plausible candidates for dark matter. The same cannot be said for dark energy.” - Rocky Kolb, Tucson, Mar 2004 “Our theoretical understanding is so limited right now …” - Rocky Kolb, Tucson, Mar 2004 “… not understood sufficiently to answer the basic questions …” - Rocky Kolb, Tucson, Mar 2004 Rocky Horror Show – Tucson 2004

16. www.astro.uvic.ca/~pritchet Why did I decide to do astronomy? excessive.fits big.fits Really big.fits too big.fits Flats.fits biases.fits

17. www.astro.uvic.ca/~pritchet CFHT Supernova Legacy Survey (SNLS)

18. www.astro.uvic.ca/~pritchet

21. Canada-France-Hawaii Telescope Canada-France-Hawaii Telescope (Canada 42.5%)

22. www.astro.uvic.ca/~pritchet Telescope Aperture vs. Focal Plane Area total CCD area [Megapix] total area in 3m+ telescopes [m 2 ]

23. www.astro.uvic.ca/~pritchet “Size matters …” Anon. MegaCam – 1 deg x 1 deg

24. www.astro.uvic.ca/~pritchet MegaCam at CFHT  1 deg x 1 deg field  40 x (2048 x 4612) chips (~ 400Megapixels)  good blue response “Size matters …” Anon.

25. www.astro.uvic.ca/~pritchet Toronto Group Ray Carlberg, Mark Sullivan, Andy Howell, Kathy Perrett, Alex Conley French Group Reynald Pain, Pierre Astier, Julien Guy, Nicolas Regnault, Jim Rich, Stephane Basa, Dominique Fouchez UK Gemini PI: Isobel Hook + Justin Bronder, Richard McMahon, Nic Walton Victoria Group Chris Pritchet, Don Neill, Dave Balam, Eric Hsiao, Melissa Graham USA LBL: Saul Perlmutter CIT: Richard Ellis Plus: Many students and associate members throughout the world

26. www.astro.uvic.ca/~pritchet CFHT Legacy Survey  Supernova Legacy Survey (SNLS)  202 nights over 5 years  four 1 deg² fields (0226-04, 1000+02, 1419+53, 2215-18)  4 filters, obs every 3-4 days, queue scheduling  depth i’>24.5 (S/N=8, 1 hr); r’ > 28 in final stacked image  ~700 SNeIa over 5 yrs Goal: value of “w”, nature of dark energy Goal: value of “w”, nature of dark energy 470 nights (dark-grey) over 5 years (2003-2008)

27. www.astro.uvic.ca/~pritchet ~1000 since Aug 2003! Detections 04D2ca z=0.83 Mar 10 ACS

28. www.astro.uvic.ca/~pritchet June 2003 (c030622-07) z=0.281 SN Ia

29. www.astro.uvic.ca/~pritchet z’ as well

30. www.astro.uvic.ca/~pritchet Spectroscopy CFHTGemini-N

31. www.astro.uvic.ca/~pritchet

32. Follow-up Spectroscopy Keck (~8 nights/yr) Magellan (15 nights/ yr) Carnegie /Toronto: VLT (120 hr/yr) France/UK: Gemini N & S (120 hr/yr) Canada/UK/US More 8-10m time than CFHT time

33. www.astro.uvic.ca/~pritchet Gemini Gemini Acquisition image : 300s in i Host SN Example i(AB)=24.0 45”

34. www.astro.uvic.ca/~pritchet Raw Frame (full) NOD A NOD B Illuminated Slit Shuffled image CCD1CCD2CCD3 Spectral direction Spatial

35. www.astro.uvic.ca/~pritchet Combined 2 x 4 frames (mosiaced) SN

36. www.astro.uvic.ca/~pritchet N(z) to July 2005 (N≈200)

37. www.astro.uvic.ca/~pritchet First Year Cosmology (Astier et al. 2005, astro-ph/0510447) First year results (72 SNe Ia) consistent with an accelerating Universe: Ω M =0.263 in a flat universe Intrinsic disp.: 0.13 ± 0.02 Low-z: 0.15 ±0.02 SNLS: 0.12 ± 0.02

38. www.astro.uvic.ca/~pritchet w = -1.02 ± 0.09 w = -1.02 ± 0.09  Dark Energy acts exactly like Einstein’s cosmological constant  SNLS 1st Year Results – already the best available! Astier et al 2006

39. www.astro.uvic.ca/~pritchet Future  500-700 supernovae by 2008  Greatly improved limits on how dark energy differs from a pure cosmological constant  First measurements of how dark energy changes with time  Constraints on nature of dark energy  Amazing stuff on nature of supernovae!

40. www.astro.uvic.ca/~pritchet JDEM/SNAP/…

41. www.astro.uvic.ca/~pritchet Conclusions  Dark Energy is not to be confused with dark matter.  Dark Energy is a major (~70%) constituent of the Universe  This is probably the most amazing discovery in cosmology since the discovery of the expansion of the Universe.  Dark energy resembles pure Einstein cosmological constant.  Currently SNLS (Canada-France) is leading the world in probing dark energy  Future prospects are bright!

42. www.astro.uvic.ca/~pritchet More SNLS information  http://legacy.astro.utoronto.ca/  http://legacy.astro.utoronto.ca/ - database http://legacy.astro.utoronto.ca/  www.cfht.hawaii.SNLS  www.cfht.hawaii.SNLS – people, papers, … www.cfht.hawaii.SNLS

43. www.astro.uvic.ca/~pritchet