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Dark Energy and Supernovae

Dark Energy and Supernovae. Wendy Freedman Carnegie Observatories, Pasadena CA Beyond Einstein, May 13, 2004. Type Ia Supernovae for Cosmology. Advantages: small dispersion single objects (simpler than galaxies) can be observed over wide z range . Challenges: dust (gray dust)

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Dark Energy and Supernovae

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  1. Dark Energy and Supernovae Wendy Freedman Carnegie Observatories, Pasadena CA Beyond Einstein, May 13, 2004

  2. Type Ia Supernovae for Cosmology Advantages: • small dispersion • single objects (simpler than galaxies) • can be observed over wide z range • Challenges: • dust (gray dust) • chemical composition • evolution • photometric calibration • environmental differences

  3. State of the Art Knop et al. 2003 Riess et al. 2004

  4. Current Supernova Constraints on Dark Energy Assume flat universe Dark energy density as a function of redshift 1- constraints on density of matter and dark energy Consistency with cosmological constant  -----  x(0) Redshift z Wang & Tegmark (2004)

  5. Equation of State and Dark Matter Density Tegmark et al (2004)

  6. Does the Dark Energy Density Vary with Time? Wang & Tegmark (2004)

  7. Present/Future Supernova Projects Low z: High z: • CFHT Legacy Survey • ESSENCE • Carnegie Supernova • Project (CSP) • GOODS • Perl. • LOTOSS (KAIT) • SN Factory • CSP • LSST • Giant Magellan • SNAP • DESTINY Future Supernova Projects:

  8. Ground-Based Supernova Searches • CFHT Legacy Survey (SNLS): • ugriz light curves • observations to I’ ~ 28 mag • CFHT MegaCam • 2000 SN over 5 years • 0.1 < z < 1

  9. High z Supernova Searches e.g., CFHT Legacy candidates Confirming VLT Spectrum (VLT, Gemini, Magellan) REF DIFF • Try to catch supernovae on • the rise for followup. • IAB ~ 22 – 25 mag

  10. Ongoing Supernova Searches High z: Low z: • CFHT Legacy Survey : • ugriz light curves • CFHT MegaCam • 2000 SN over 5 years • 0.1 < z < 1 • LOTOSS (KAIT) : • UBVRIlight curves • Lick • 0 < z < ~0.15 • ESSENCE : • VRIlight curves • CTIO 4m Mosaic Imager • 200 SN over 5 years • 0.15 < z < 0.75 • SN Factory: • spectophotometry, UH • 3200 – 10000 Ao • NEAT, Palomar • ***E.g., redshifts posted on web within 2 days!!!!!

  11. ESSENCE survey implementation • NOAO Survey on CTIO 4m, MOSAIC • Same frame subtraction pipeline as SuperMacho project, scheduled in “other” halves of SuperMacho nights • ~ 200 supernovae with 0.1 < z < 0.8 • 3 band photometry: V,R,I (observer frame) • 2 sets of fields, so Dt=4 days • Goal is to determine a distance modulus in each bin (of Dz = 0.1) to 2% • ~3% photometry at peak SN brightness

  12. Large Synoptic Survey Telescope Highly ranked in Decadal Survey Optimized for time domain 7 square degree field 6.5m effective aperture 24th mag in 20 sec > 5 TBytes/night Real-time analysis Simultaneous multiple science goals

  13. LSST: Massively Parallel Astronomy • Multiband source catalog as shakedown project: early impact • Near Earth Objects • Trans-Neptunian Objects • Time-resolved stellar photometry, parallaxes & proper motions in MW • RR Lyrae throughout the entire local group • Gravitational microlensing across the entire sky • Gamma Ray Bursts (both with and without gamma rays!) • Weak lensing maps across wide fields, with photometric redshifts • Lensed QSO microlensing and time delays • Line-of-sight mass structures via dispersion of Ia distance moduli …Plus substantial potential for discovery!

  14. Computer Evolution is Staggering ~1990 (MACHO era) 60 MHz CPUs 2 GB disks K$’s Real-time DoPhot analysis on 5 Gbytes/night Today (SuperMacho/ESSENCE era) arrays of > 2 GHz CPUs are routine Scripting languages 250 Gbyte drives for $400 Algorithmic Advances Real-time subtractions on 20 Gbytes/night “Commercial” databases seem up to the task Tomorrow (LSST era) Real-time reduction of 15 Terabytes/night Entire image archive on spinning disk (1000s of Terabytes)

  15. LSST Challenges • Large effective aperture wide field telescope(s) • Monster focal plane(s) • Real-time analysis pipeline and “alert” distribution • Variability Classification (85% SN, 15% AGN…?) • On-the-fly detection efficiencies, for rates • Aggregating detections into objects • Database representation and indexing structures • Optimal co-adding of images • Joint science optimization (bands, cadence: SWG)

  16. A staged approach Today LSST design and tradeoff studies LSST precursor projects: Software and database prototyping 2 - 5 years Dedicated 1.5 – 2.5m wide-field facilities? 10-15 years: Full LSST operations PanStarrs Array? APO 2.5m post-SDSS?

  17. The LSST Opportunity Current trend is towards fewer (albeit larger aperture ) telescopes with open access… LSST goes in the other direction: Multiple projects fed from a common image stream No proprietary data period Exploits the 3 enabling technologies of our era: Large aperture telescopes Silicon detector arrays Computing and mass storage technology Highly Efficient multitasking system

  18. SuperMacho and ESSENCE Images Raw frames: ftp://archive2.tuc.noao.edu/SM_SN/ NOAO Science Archive: http://archive.noao.edu/nsa/

  19. SN rates: reality vs. aspirations • Goal is 200 type Ia light curves in 5 seasons • This implies 40/yr, we got 15. What’s up? • First of 3 lunations was first epoch: templates • Expect 1.5x as many in future ~ 22 • Seeing was usually worse than 1.5 arcseconds! • 3. Opportunity to use SDSS for detection out to z~0.3, where 4m is inefficient

  20. Discrimination (on a 1K x 4K amp) 130 Detections in R band difference image 21 Detections in R band survive cuts DoPhot PSF chi-squared Npix >0 Masked DoPhot object type Npix<0 Saturated 808 Detections in I band difference image 119 Detections in I band survive cuts 114 Detections in V band difference image 30 Detections in V band survive cuts Spatial coincidence in 2 or more filters: A single candidate

  21. Ongoing Supernova Searches High z: Low z: • CFHT Legacy Survey : • ugriz light curves • CFHT MegaCam • 2000 SN over 5 years • 0.1 < z < 1 • LOTOSS (KAIT) : • UBVRIlight curves • Lick • 0 < z < ~0.15 • ESSENCE : • VRIlight curves • CTIO 4m Mosaic Imager • 200 SN over 5 years • 0.15 < z < 0.75 • SN Factory: • spectophotometry, UH • 3200 – 10000 Ao • NEAT, Palomar • ***E.g., redshifts posted on web within 2 days!!!!!

  22. Supernova Factory 2002 candidates Wood – Vasey et al 2004 (see article supernova factory in dark e folder

  23. KAIT

  24. Future Surveys SNAP SNAP focal plane

  25. 2004 Standard Cosmological Model A universe with a flat geometry composed of one third matter density, and two thirds dark energy. Wm = 0.3 WL= 0.7 0 = 1 h = 0.7 w = -1 dw/dz = 0

  26. Current Evidence for Dark Energy • Supernovae at high z Riess et al. 2004 Knop et al. 2003 • CMB anisotropies + Galaxy power • spectrum Page, 2004

  27. Constraints on Equation of State Riess et al. 2004; Knop et al. 2003 Assuming: m = 0.27 § 0.04 Corrections for reddening, metallicity, evolution well-understood Measurements of w0 to § 0.1

  28. Grey Dust? There is no evidence to date for gray dust. The data are consistent with the presence of dark energy. Riess et al. 2004

  29. Galactic Extinction Law AU / E(B-V)= 4.9 U AB / E(B-V)= 4.1 B V AI / E(B-V) = 1.7 I R V = AV / E(B-V) Cardelli, Clayton and Mathis 1989

  30. E(B-V) Distributions for SN1a Knop et al. 2003

  31. Supernova Ia Metallicities • Lower fluxes for • higher metallicity • Variation in level • of UV continuum optical UV .03 x solar IR 10x solar Lentz et al. 1999 models

  32. The Carnegie Supernova Project (CSP)A restframe I-band Hubble diagram

  33. Carnegie Supernova Project (CSP) Why an I-band Hubble diagram? • Advantages: - dust - chemical composition - low dispersion => reduce systematics [Why hasn’t this been done? HARD! IR detectors on large telescopes]

  34. Wavelength-Redshift Coverage • CSP: • 0<z<0.2 • comparison • UBVRIJHK • 0.3<z<0.8 • VRI restframe • HST: • 0.5<z<1.5 • UBV(R) • restframe HST Essence CFHTLS CSP CSP

  35. Overview of Carnegie Supernova Project Swope 1-meter Dupont 2.5-meter Magellan 6.5-meter Low z: High z: • u’BVr’I’YJHphotometry • Dupont spectroscopy • r’i’YJ photometry • Magellan spectroscopy • ~200 nights over 5 years • ~200 SNIa • 0.2 < z < 0.8 • C40 9 month campaigns • over 5 years • densely sampled photometry • and spectroscopy 0 < z < 0.2 • SNIa and SNII

  36. Carnegie Supernova Project • Goals: • minimize systematics • accurate reddenings, • K-corrections • H0 (H-band observations • for Cepheids + SNIa) • WL • peculiar flows • physics of SNI and II Magellan Jha 2002

  37. Carnegie Supernova Project Recent results on Nearby supernovae: • ~30 observed to date • UBVRIJHK light curves • excellent sampling Krisciunas et al. (2002) SN2001el

  38. Carnegie Supernova Project • decline rate versus magnitude • BVIH • H-band promising as • distance indicator Krisciunas et al.

  39. Carnegie Supernova Project • decline rate versus • magnitude • JHK Krisciunas et al. (2004)

  40. Carnegie Supernova Project JHK Hubble diagrams Extinction-corrected apparent magnitude at maximum Redshift in CMB frame (km/sec) Krisciunas et al.

  41. PANIC: Magellan 6.5-meter IR Imager • 1024 x 1024 array • 1 – 2.5 micron imager • 2’ x 2’ FOV • 0.125 “/pixel Antennae PANIC: Eric Persson • 25 nights of • Magellan time • November 03 • through March 04 • optical r’I’imaging • near-IR YJimaging • optical spectroscopy

  42. Magellan PANIC Images J-band Y-band ESSENCE SNIa : z = 0.33 (d149) 36-minute dithered exposures

  43. Magellan PANIC Images J-band Y-band CFHT SNIa : z = 0.55 (1022) 36-minute dithered exposures (total exposures 2 hours per filter) Stay tuned…

  44. Future Plans (Carnegie High z) • The Giant Magellan Telescope (GMT) • Roger Angel design concept • Seven 8.4-meter mirrors; f/0.7 • 21.5-meter aperture, 25.3-meter baseline • A consortium of partners currently • including Carnegie, Harvard/Smithsonian, • University of Arizona, MIT, and the • University of Michigan * • Funds are in place for the 18-month • conceptual design phase • Highest Priority Capabilities: • 1. Narrow field, high dynamic range AO • [Exoplanets, disks, star formation, • Galactic Center, KBOs; QSOs, AGNs] • 2. Wide field, optical spectroscopy • [Galaxy Formation & Evolution, Cosmology, • Stellar Populations, Large Scale Structure] • Dark Matter (lensing) and dark energy studies. Supernovae 1<z<2 Magellan

  45. Current Status of Cosmological Parameter Measurements • WMAP (+ one of • H0 , LSS, SNae) is consistent with a FLAT universe • Consistent model • with h = 72 • m = 0.27 •  = 0.73 Wright, 2004

  46. Redshift and Sample Wavelengths High z: U and B restframe observations • Large k-corrections • More susceptibility to metallicity and reddening • differences Reddening and metallicity effects are degenerate. Need empirical constraints (nearby surveys).

  47. Supernova Ia Metallicities/Ages Nomoto et al. (2003)

  48. Photo-redshifts Type II Even without spectra, colors turn out to be an extremely effective means of distinguishing Type Ia and II supernovae. Type I Riess et al. 2004

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