# Presentation: 320214

## The  Accelerating  Universe

**Probing**** Dark Energy ****with Supernovae**

**Eric Linder **
**Berkeley Lab**

## Evidence for Acceleration

- Supernovae Ia:
-        **DE** , w=p/ , w ́=dw/dz
-     *Observation -- Magnitude-redshift relation*

- Age of universe:
-   Contours of t**0** parallel CMB acoustic peak angle: t**0****=**14.0±0.5 Gyr
**    **[*Flat universe, adiabatic perturbations*]

- CMB Acoustic Peaks:
-     Substantial dark energy, *e.g.* 0.49 < ****< 0.74
-    [*Small GW contribution, LSS, H****0***]

- Large Scale Structure:
-       Power spectrum P**k**, Growth rate, “looks”
-     [*simulations*]

## Supernova Cosmology

## A Dark Energy Universe

- Tyson

## Correlation of Age with CMB Peak Angle

**Correlation of Age with CMB Peak Angle**

**Knox et al.**

- DASI data only

## CMB Power Spectrum and 

**Tegmark**

## CMB Power Spectrum

## Matter Power Spectrum

## CMB + 2dF (no SN)

**CMB + 2dF (no SN)**

- Efstathiou et al.

## MAP Sky Coverage

- Wright

- Nov ‘01

- Jan ‘02

- Apr ‘02

- Oct ‘02

- Wright

## Supernova data shows an acceleration of the expansion, implying that the universe is dominated by a new Dark Energy!
Remarkable agreement between Supernovae & recent CMB results.

**Remarkable agreement between Supernovae & recent CMB results.**

**Dark Energy**

- Credit STScI

## Dark Energy Theory

- 1970s – Why **M **~ **k**?
- 1980s – Inflation! Not curvature.
- 1990s – Why **M **~ ****?
- 2000s – Quintessence! Not ?

- Cosmological constant is an ugly duckling
- Dynamic scalar field is a beautiful swan

- Lensing 		 =0.7+0.1-0.2		Chiba & Yoshii
- Supernovae	 =0.72+0.08-0.09	SCP, HiZ
- Ly Forest	 =0.66+0.09-0.13	D. Weinberg et al.

## : Ugly Duckling

- Astrophysicist:
- Einstein equations –
- gab
**      ********	****p = -******
- Naturally, **** =const= ******PL**
**********= 10****120**
- Today  **************M**

- Field Theorist:
- Vacuum – Lorentz invariant
- Tab ~ab = diag { -1, 1, 1, 1}
-         ****   **p = -******
- Naturally, Evac ~ 1019 GeV
-           E**** ~ meV
******=0?**

** ****Fine Tuning Puzzle – why so small?**
** ****Coincidence Puzzle – why now?**

## Scalar Field: Beautiful Swan

- Astrophysicist:
- Friedmann equations –
-     (å/a)2=(8/3)(m+)
-         ä/a=-(4/3)(m++3p)

- Field Theorist:
- Lagrangian –
*  **L*=(1/2)a a-V()(1/2)2-V
-  Tab= ab - *L *gab

******=K+V****	****p=K-V****	****	****w=p/******** = (K+V) / (K-V)  ******** [-1, +1]**

- Slow Roll (Inflation)
- 	**K << V   ********	****p=-******** ****	**** ******** ****	****w=-1**
- Free Field (kination)
- 	**V << K   ******** ****	****p=+******** ****	**** ******** ****	****w=+1**
- Coherent Oscillations (Axions)
- 	**<V>=<K> ******** ****	****p=0 ****	**** ******** ****	****w=0 (matter)**

- .

## Fundamental Physics

********** ****(****a)**** ****= ************ ****(****0)**** ****e****-3********dlna(1+w)**** ~ a****-3(1+w)**** ****	****	****w(z)=w****0****+w’z**

**Astrophysics****	******** ****	****Cosmology****	******** ****	****Field Theory**
**	****r(z)****	********	****Equation of state w(z)  ******** ****	****V(********)**
**V ( ********(**** ****a(t)**** ****)**** )**

**SN**
**CMB**
**etc.**

*“**Would be number one on my list of things to figure out”*
- 	- Edward Witten
*“**Right now, not only for cosmology but for elementary particle theory this is the bone in our throat”*
- 	- Steven Weinberg

**Is ********=0 ?**

**What is the dark energy?**

## Type Ia Supernovae

-  Characterized by no Hydrogen, but with Silicon
-  Progenitor C/O White Dwarf accreting from companion
-  Just before Chandrasekhar mass, thermonuclear runaway
**Standard explosion from nuclear physics**

## 1 Parameter Family Homogeneity

## Hubble diagram – low z

## Hubble diagram - SCP

**Hubble diagram - SCP**

**0.2**

**0.5**

**1**

**In flat universe: ********M****=0.28 [********.085 stat][********.05 syst]**
**Prob. of fit to ********=0 universe: ****1%**

**redshift *****z***

**0.2**

**0.4**

**0.6**

**0.8**

**1.0**

## Supernova Cosmology

## Supernovae Probes - Generations

- Original

- Current (offset)

- Near Term

- Proposed

**Supernovae Probes - Generations**

## SNAP: The Third Generation

## Dark Energy Equation of State

## Hubble Diagram

## Dark Energy Exploration with SNAP

**Current ground based ****compared with**
**Binned simulated data ****and a sample of**
**Dark energy models**

## Probing Dark Energy Models

## From Science Goalsto Project Design

**From Science Goals****to 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 Requirements**

- Identified 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)

- •
- •
- •

- •
- •
- •

## Mission Design

## SNAP Survey Fields

## GigaCAM

- Approximately 1 billion pixels
- ~140 Large format CCD detectors required, ~30 HgCdTe Detectors
- Larger than SDSS camera, smaller than H.E.P. Vertex Detector (1 m2)
- Approx. 5 times size of FAME (MiDEX)

**GigaCAM**

## Focal Plane Layout with Fixed Filters

## Step and Stare and Rotation

## High-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 NOAO

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

- Near-earth asteroids
- Seyfert galaxy black holes
- 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 using
- LBNL CCD’s:

- Blue is H-alpha
- Green is SIII 9532Å
- Red is HeII 10124Å.

## Science Goals – F21

## Integral Field Unit Spectrograph Design

- Slit Plane

- Detector

- Camera

- Prism

- Collimator

- SNAP Design:

## What makes the SN measurement special?Control of systematic uncertainties

*Images*

*Spectra*

*Redshift & SN Properties*

*Lightcurve & Peak Brightness*

**data**

**analysis**

**physics**

******M****  and ************ **
**Dark Energy Properties**

- At every moment in the explosion event, each individual supernova is “sending” us a rich stream of information about its internal physical state.

- What makes the SN measurement special?Control of systematic uncertainties

## Time Series of Spectra = SN “CAT Scan”

**Time Series of Spectra = SN “CAT Scan”**

## Lightcurves 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

## Supernova Requirements

**Supernova Requirements**

## Advantages of Space

**Advantages of Space**

## Science Reach

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

- -

- -

## SNAP: The Third Generation

## Dark Energy Equation of State

## Precision Cosmology

**Tegmark**

- SNAP

## Primary Science Mission Includes...

**Primary Science Mission Includes...**

- Weak lensing galaxy shear
- observed from space vs. ground

**Bacon, Ellis, Refregier 2000**

## ...And Beyond

- 10 band ultradeep imaging survey
- Feed NGST, CELT (as Palomar 48” to 200”, SDSS to 8-10m)
- Quasars to z=10
- GRB afterglows to z=15
- Galaxy populations and morphology to coadd m=32
- Galaxy evolution studies, merger rate
- Stellar populations, distributions, evolution
- Epoch of reionization thru Gunn-Peterson effect
- Low surface brightness galaxies in H’ band, luminosity function
- Ultraluminous infrared galaxies
- Kuiper belt objects
- Proper motion, transient, rare objects

## SNAP Collaboration

- 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)

- 12 institutions, ~50 researchers

## SNAP at the American Astronomical Society Jan. 2002 Meeting

**Oral Session 111. Science with Wide Field Imaging in Space:**
- The Astronomical Potential of Wide-field Imaging from Space 	S. Beckwith (Space Telescope Science Institute)
- Galaxy Evolution: HST ACS Surveys and Beyond to SNAP 	G. Illingworth (UCO/Lick, University of California)
- Studying Active Galactic Nuclei with SNAP 		P.S. Osmer (OSU), P.B. Hall (Princeton/Catolica)
- Distant Galaxies with Wide-Field Imagers 		K. M. Lanzetta (State University of NY at Stony Brook)
- Angular Clustering and the Role of Photometric Redshifts 	A. Conti, A. Connolly (University of Pittsburgh)
- SNAP and Galactic Structure 			I. N. Reid (STScI)
- Star Formation and Starburst Galaxies in the Infrared 	D. Calzetti (STScI)
- Wide Field Imagers in Space and the Cluster Forbidden Zone	M. E. Donahue (STScI)
- An Outer Solar System Survey Using SNAP		H.F. Levison, J.W. Parker (SwRI), B.G. Marsden (CfA)
**Oral Session 116. Cosmology with SNAP:**
- Dark Energy or Worse				S. Carroll (University of Chicago)
- The Primary Science Mission of SNAP		S. Perlmutter (Lawrence Berkeley National Laboratory)
- SNAP: mission design and core survey 		T. A. McKay (University of Michigan
- Sensitivities for Future Space- and Ground-based Surveys	G. M. Bernstein (Univ. of Michigan)
- Constraining the Properties of Dark Energy using SNAP	D. Huterer (Case Western Reserve University)
- Type Ia Supernovae as Distance Indicators for Cosmology	D. Branch (U. of Oklahoma)
- Weak Gravitational Lensing with SNAP		A. Refregier (IoA, Cambridge), Richard Ellis (Caltech)
- Strong Gravitational Lensing with SNAP		R. D. Blandford, L. V. E. Koopmans, (Caltech)
- Strong lensing of supernovae			D.E. Holz (ITP, UCSB)
**Poster Session 64. Overview of The Supernova/Acceleration Probe:**
- Supernova / Acceleration Probe: An Overview 		M. Levi (LBNL)
- The SNAP Telescope				M. Lampton (UCB)
- SNAP: An Integral Field Spectrograph for SN Identification	R. Malina (LAMarseille,INSU), A. Ealet (CPPM)
- SNAP: GigaCAM - A Billion Pixel Imager		C. Bebek (LBNL)
- SNAP: Cosmology with Type Ia Supernovae		A. Kim (LBNL)
- SNAP: Science with Wide Deep Fields			E. Linder (LBNL)

**Notes:**
Two GSFC scientists at both the DoE preview and SAGENAP.

## 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**