Precision Cosmology with SNAP and Possibilities for Future Ground Supernova Surveys. Alex Kim Lawrence Berkeley National Laboratory

Transcription

1 Precision Cosmology with SNAP and Possibilities for Future Ground Supernova Surveys Alex Kim Lawrence Berkeley National Laboratory

2 Lest We Forget... Type Ia Supernovae are... Pathfinding: Provided the first evidence for the Accelerating Expansion of the Universe Sensitive: Give strongest weight in constraining dark-energy parameters today Mature: Systematic uncertainties identified, strengths and limitations understood Easy: Expansion history only, no structure formation What place is there for new initiatives in supernova surveys?

3 Why go for Supernovae z>1.2 Linder & Huterer (2003) Supernovae at matterdominated epochs provide significant probative power in the measurement of dark-energy parameters. This is evident when systematic uncertainties are considered

4 Why Space? 10 2 photon flux in aperture z=0.1 Sky zodiac 10-4 z=1 z=2 wavelength (nm) 1000

5 Continuous Viewing Zones The number of hours visibility for the SNAP field (Dec = 56 ), over the course of a year at Mauna Kea. The curves are for airmass χ < 3.0, χ < 2.0, and χ < 1.5. Shows limitation of observing at low-airmass light-curves of time-dilated high-redshift supernovae with low Galactic extinction

6 Redshift-Measurement Requirements 10 5 Total Distance Modulus K-corr + Extinct stretch Redshift-measurement bias propagates into dm/dz 0 corrected magnitude & dark-energy parameter -5 Huterer, Kim, Krauss, Broderick (2004) z bias. dz~0.001 systematic per redshift bin gives 10% degradation in w in the SNAP SN survey

7 SNAP Collaboration LBNL Berkeley Caltech Fermi National Laboratory Indiana U. IN2P3-Paris -Marseille JPL LAM (France) University of Michigan University of Pennsylvania University of Stockholm SLAC STScI Yale U. G. Aldering, S. Bailey, C. Bebek, W. Carithers, T. Davis, K. Dawson, C. Day, R. DiGennaro, S. Deustua, D. Groom, M. Hoff, S. Holland, D. Huterer, A. Karcher, A. Kim, W. Kolbe, W. Kramer, B. Krieger, G. Kushner, N. Kuznetsova, R. Lafever, J. Lamoureux, M. Levi, S. Loken, B. McGinnis, R. Miquel, P. Nugent, H. Oluseyi, N. Palaio, S. Perlmutter, N. Roe, H. Shukla, A. Spadafora, H. Von Der Lippe, J-P. Walder, G. Wang M. Bester, E. Commins, G. Goldhaber, H. Heetderks, P. Jelinsky, M. Lampton, E. Linder, D. Pankow, M. Sholl, G. Smoot, C. Vale, M. White J. Albert, R. Ellis, R. Massey, A. Refregier, J. Rhodes, R. Smith, K. Taylor, A. Weintein J. Annis, F. DeJongh, S. Dodelson, T. Diehl, J. Frieman, D. Holz, L. Hui, S. Kent, P. Limon, J. Marriner, H. Lin, J. Peoples, V. Scarpine, A. Stebbins, C. Stoughton, D. Tucker, W. Wester C. Bower, N. Mostek, J. Musser, S. Mufson P. Astier, E. Barrelet, R. Pain, G. Smadja, D. Vincent A. Bonissent, A. Ealet, D. Fouchez, A. Tilquin D. Cole, M. Frerking, J. Rhodes, M. Seiffert S. Basa, R. Malina, A. Mazure, E. Prieto B. Bigelow, M. Brown, M. Campbell, D. Gerdes, W. Lorenzon, T. McKay, S. McKee, M. Schubnell, G. Tarle, A. Tomasch G. Bernstein, L. Gladney, B. Jain, D. Rusin R. Amanullah, L. Bergström, A. Goobar, E. Mörtsell W. Althouse, R. Blandford, W. Craig, S. Kahn, M. Huffer, P. Marshall R. Bohlin, D. Figer, A. Fruchter C. Baltay, W. Emmet, J. Snyder, A. Szymkowiak, D. Rabinowitz, N. Morgan snap.lbl.gov

8 SNAP Telescope 2-m primary aperture, 3-mirror anastigmatic design. Provides a wide-field flat focal plane. 8

9 Instrumentation: Imager 0.7 square degrees 9 passbands microns REU program, N.A.Sharp/NOAO/AURA/NSF 9

10 Spectrograph Integral field unit based on an imager slicer- Data cube. Input aperture is 3 x 3 reduces pointing accuracy requirement Simultaneous SNe and host galaxy spectra. Internal beam split to visible and NIR. 10

11 SNAP Survey Point-Source Depth SN Survey: 15 square degrees, 4-day cadence, 1.5 years Lensing Survey: square degrees Extension?: π in the sky Magnitude depth for a point source with S/N=5. Supernova - 15 square degrees, Lensing 300 square degrees. HDF has depth in four filters, sq deg. 11

12 Simulated Light Curves SNAP 6.5-m groundbased telescope z=1.6

13 PSF Number counts vs size Stable PSF, fine resolution gives more galaxies at higher redshifts courtesy of J. Rhodes

14 Probing Dark Energy Shown is the w 0,w' confidence region of this Monte Carlo realization of the SNAP experiment. There is a prior on Ω M and 300 low-z SNe. An irreducible systematic is included. 14

15 Possibilities for Future Ground-Based SN Cosmology Depth Ground-obervatory features Science Interest Low z High z Very wide-field imagers Cheap spectroscopy Very wide-field imagers produce too many supernovae Multi-object spectroscopy allows for making a dent in fractional followup Fewer than at high-z: important lever-arm SN physics laboratory, e.g. spectropolarimetry Overlap surveys with SNAP Cosmology with clever systematic reduction and random spectroscopic followup Magnification maps and weak lensing Rare events, e.g. Strong lensing Rates and progenitor systems Light-curve heterogeneity & z evolution Characterization of SNAP fields Development of SNAP discovery, analysis algorithms