lsst-snap complementarity

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R. Pain 9/18/2008 LSST-SNAP complementarity Reynald Pain IN2P3/LPNHE Paris, France Page 1

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LSST-SNAP complementarity. Reynald Pain IN2P3/LPNHE Paris, France. LSST vs SNAP (and vice-versa). True: Target Dark Energy (and Dark Matter) as primary science Use wide field imager as (main) instrument Hope to start operating in ~2015 A re competing for (some of) the same money But …. - PowerPoint PPT Presentation

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Page 1: LSST-SNAP complementarity

R. Pain 9/18/2008

LSST-SNAP complementarity

Reynald Pain

IN2P3/LPNHE Paris, France

Page 1

Page 2: LSST-SNAP complementarity

R. Pain 9/18/2008

True:

1. Target Dark Energy (and Dark Matter) as primary science2. Use wide field imager as (main) instrument 3. Hope to start operating in ~20154. Are competing for (some of) the same money

But …

LSST vs SNAP (and vice-versa)

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R. Pain 9/18/2008

LSST & SNAP apparatus

• Primary mirror : ~2m• Field-of-view : ~ 1 deg2

• 6 filters in the visible : 320 nm -> 1100 nm• 3 filters in NIR (->1700 nm)• low-z spectrograph

• Primary mirror : 8.4 m• Field-of-view : ~ 10 deg2

• 6 filters in the visible : 320 nm -> 1100 nm

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LSST & SNAP surveys

SNAP Survey Area(sq.deg) Depth(AB mag) ngal(arcmin-2) Ngal

Deep/SNe 15 30.3 250 107

Wide 4000 27.8 100 108.5

Panoramic 7000-10000 26.7 40-50 109

LSST Survey

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SNAP & LSST strategies for Supernovae

SNAP: Area : 2x7.5 sq. deg.

Cadence : 4 days

Imaging and spectroscopy

Total nb of SN : ~ 2000

Need for “nearby” SN (ground)

Light curve modeling requires lots of SN

LSST: full sky, twice a week

=> 250000 SN/yr !

well measured subsample at z<1

Some DE models require SN at z>1

Dust modeling requires IR meas.

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SNAP & LSST strategies for Weak Lensing

9-band photometry (incl NIR) helps for phot-z

LSST: 200 exposures per sky patch will yield negligible PSF induced shear systematics

SNAP: increase the number of resolved galaxies (spatial resolution) and PSF stability

Cosmic shear signal

Stars

SNAP and LSST will have very different systematic uncertainties

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R. Pain 9/18/2008

Rely on the same techniques (SN, WL, BAO, ..) to constraint DE but use a very different instrumental approach

DE is a difficult measurement. Improving on current (+ near future) constraints will be extremely

difficult and will in fine come to how well one does on controlling the systematic uncertainties

LSST and SNAP are complementarity in particular when dealing with systemactic uncertainties

Combined, they will yield improved constraints on Dark Energy

LSST and SNAP

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Cosmological parameters (1st year)Cosmological parameters (1st year)

68.3, 95.5 and 99.7% CL68.3, 95.5 and 99.7% CLGreen SNLS, Blue SDSS/BAO 2005Green SNLS, Blue SDSS/BAO 2005

MM = 0.271 +/- 0.021 (stat) +/- = 0.271 +/- 0.021 (stat) +/- 0.007 (syst)0.007 (syst)

w = -1.023 +/- 0.090 (stat) +/- w = -1.023 +/- 0.090 (stat) +/- 0.054 (syst)0.054 (syst)