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Supernovae and the Mystery of Dark Energy

Supernovae and the Mystery of Dark Energy. Chris Pritchet U. Victoria. large-scale repulsive force , ρ =const. Golden Moments in Cosmology : General Relativity (1915). Golden Moments in Cosmology: Expansion of the Universe. “… Einstein’s greatest blunder …”. Hubble 1929 : v = H o d.

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Supernovae and the Mystery of Dark Energy

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

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

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

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

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

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

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

  8. Chaco Canyon, NM July 5th, 1054AD www.astro.uvic.ca/~pritchet

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

  10. Why are Supernovae Interesting? • L~1010Lsun ~LMW • Source of almost all heavy elements (12C - …) • Neutrinos, gravitational waves, … • Great physics! • Extinction events? www.astro.uvic.ca/~pritchet

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

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

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

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

  15. Rocky Horror Show – Tucson 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 “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 www.astro.uvic.ca/~pritchet

  16. Why did I decide to do astronomy? big.fits Greatest discovery in cosmology since Hubble 1927! too big.fits biases.fits excessive.fits Really big.fits Flats.fits www.astro.uvic.ca/~pritchet

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

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

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

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

  21. Canada-France-Hawaii Telescope (Canada 42.5%) www.astro.uvic.ca/~pritchet

  22. Telescope Aperture vs. Focal Plane Area total area in 3m+ telescopes [m2] total CCD area [Megapix] www.astro.uvic.ca/~pritchet

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

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

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

  26. CFHT Legacy Survey 470 nights (dark-grey) over 5 years (2003-2008) • 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 www.astro.uvic.ca/~pritchet

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

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

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

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

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

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

  33. Raw Frame (full) Illuminated Slit NOD A Shuffled image NOD B CCD1 CCD2 CCD3 Spatial Spectral direction www.astro.uvic.ca/~pritchet

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

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

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

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

  38. 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! www.astro.uvic.ca/~pritchet

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

  40. 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! www.astro.uvic.ca/~pritchet

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

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

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