Cosmology with SNAPCosmology with SNAP

G. Aldering, C. Bebek, W. Carithers, S. Deustua, W. Edwards, J. Frogel, D. Groom, S. Holland, D. Huterer*, D. Kasen, R. Knop, R. Lafever, M. Levi, E. Linder, S. Loken, P. Nugent, S. Perlmutter, K. Robinson (Lawrence Berkeley National Laboratory)

E. Commins, D. Curtis, G. Goldhaber, J. R. Graham, S. Harris, P. Harvey, H. Heetderks, A. Kim, M. Lampton, R. Lin, D. Pankow, C. Pennypacker, A. Spadafora, G. F. Smoot (UC Berkeley)

C. Akerlof, D. Amidei, G. Bernstein, M. Campbell, D. Levin, T. McKay, S. McKee, M. Schubnell, G. Tarle , A. Tomasch (U. Michigan)

P. Astier, J.F. Genat, D. Hardin, J.- M. Levy, R. Pain, K. Schamahneche (IN2P3)

A. Baden, J. Goodman, G. Sullivan (U.Maryland)

R. Ellis, A. Refregier* (CalTech)

A. Fruchter (STScI)

L. Bergstrom, A. Goobar (U. Stockholm)

C. Lidman (ESO)

J. Rich (CEA/DAPNIA)

A. Mourao (Inst. Superior Tecnico,Lisbon)

Eric LinderBerkeley Lab

Probing Dark Energy ModelsProbing Dark Energy Models

Supernova RequirementsSupernova Requirements

From Science GoalsFrom Science Goalsto Project Designto Project Design

Science• Measure M and

• Measure w and w (z)

Data Set Requirements• Discoveries 3.8 mag before max

• Spectroscopy with S/N=10 at 15 Å bins

• Near-IR spectroscopy to 1.7 m

Statistical Requirements• Sufficient (~2000) numbers of SNe Ia

• …distributed in redshift

• …out to z < 1.7

Systematics RequirementsIdentified and proposed systematics:

• Measurements to eliminate / bound each one to +/–0.02 mag

Satellite / Instrumentation Requirements• ~2-meter mirror Derived requirements:

• 1-square degree imager • High Earth orbit

• Spectrograph • ~50 Mb/sec bandwidth (0.35 m to 1.7 m) •••

•••

SNAP a simple dedicated experiment to study the dark energy— Dedicated instrument, essentially no moving parts

— Mirror: 2 meter aperture sensitive to light from distant SN

— Photometry: with 1°x 1° billion pixel mosaic camera, high-resistivity, rad-tolerant p-type CCDs and, HgCdTe arrays. (0.35-1.7 m)

— Integral field optical and IR spectroscopy: 0.35-1.7 m, 2”x2” FOV

Mission DesignMission Design

GigaCAM, a one billion pixel arrayApproximately 1 billion pixels ~140 Large format CCD detectors required, ~30 HgCdTe DetectorsLarger than SDSS camera, smaller than H.E.P. Vertex Detector (1 m2)Approx. 5 times size of FAME (MiDEX)

GigaCAMGigaCAM

Focal Plane Layout with Fixed FiltersFocal Plane Layout with Fixed Filters

Q1

Q2

Q3

Q4

Step and Stare and RotationStep and Stare and Rotation

High-Resistivity CCD’sHigh-Resistivity CCD’s

• New kind of CCD developed at LBNL • Better overall response than more costly “thinned” devices in use• High-purity silicon has better radiation tolerance for space applications• The CCD’s can be abutted on all four sides enabling very large mosaic arrays• Measured Quantum Efficiency at Lick Observatory (R. Stover):

LBNL CCD’s at NOAOLBNL CCD’s at NOAO

See September 2001 newsletter at http://www.noao.edu

1) Near-earth asteroids2) Seyfert galaxy black holes3) LBNL Supernova cosmology

Cover picture taken at WIYN 3.5m with LBNL 2048 x 2048 CCD(Dumbbell Nebula, NGC 6853)

Science studies to date at NOAO usingLBNL CCD’s:

Blue is H-alphaGreen is SIII 9532ÅRed is HeII 10124Å.

Slit Plane

DetectorCamera

Prism

Collimator

Integral Field Unit Spectrograph DesignIntegral Field Unit Spectrograph Design

F o re -o p tic s(a n a m o rp h o s is )

T e le s c o p e e x it p u p il

S L IC E R M IR R O R

P U P IL M IR R O R S

S L IT M IR R O R S

Im a g e d th e re

In th e te le s c o p efo c a l p la n e

T e le s c o p e fo c a l p la n e im a g e d b y th efo re -o p tic s o n th e s l ic e r m ir ro r

S lic e s im a g e d b y th e p u p ilm ir ro rs o n th e s l i t m ir ro rs

E n tra n c e o f th es p e c tro g ra p h

S q u a re f ie ld

1 x 2 p ro p o r tio n e dim a g e

SNAP Design:

Lightcurves and Spectra from SNAPLightcurves and Spectra from SNAP

• Goddard/Integrated Mission Design Center study in June 2001: no mission tallpoles

• Goddard/Instrument Synthesis and Analysis Lab. study in Nov. 2001: no technology tallpoles

Science ReachScience Reach

Key Cosmological Studies• Type II supernova • Weak lensing• Strong lensing • Galaxy clustering• Structure evolution• Star formation/reionization

A Resource for the Science CommunityA Resource for the Science Community

• SNAP main survey will be 4000x larger (and as deep) than the biggest HST deep survey, the ACS survey

• Complementary to NGST: target selection for rare objects

• Can survey 1000 sq. deg. in a year to I=29 or J=28 (AB mag)

• Archive data distributed

• Guest Survey Program

Whole sky can be observed every few months

• Galaxy populations and morphology to coadded m=31 • Quasars to redshift 10• Epoch of reionization through Gunn-Peterson effect• Lensing projects: Mass selected cluster catalogs Evolution of galaxy-mass correlation function Maps of mass in filaments