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

Understanding Dark Energy Talks at this meeting

Type Ia Supernovae for Cosmology Riess et al Perlmutter et al First evidence for acceleration

Type Ia Supernovae for Cosmology Advantages: small dispersion single objects (simpler than galaxies) can be observed over wide z range Challenges: dust (grey dust) chemical composition evolution photometric calibration (e.g., Vega) environmental differences lensing Systematics Step 2

Type Ia supernovae as distance indicators

Luminosity Distances

Characterizing the Equation of State

Finding Supernova Candidates High z Supernova Team

Supernova Spectra Perlmutter et al Type Ia SN diagnostics (restframe): Si II – 4130 A Ca II – 3950 A Fe blends

Spectra of Supernovae Even without spectra, colors turn out to be an extremely effective means of distinguishing Type Ia and II supernovae. Riess et al Type II Type I

State of the Art Knop et al. 2003

State of the Art Knop et al. 2003

State of the Art Riess et al HST ACS data 177 supernovae; 7 new objects 1.25 < z < 1.8 Evidence for deceleration at earlier matter-dominated epoch.

GOODS/ACS Supernova Candidates Riess et al. 2004

GOODS / ACS Light Curves & Spectra Riess et al. 2004

Constraints on Equation of State Riess et al. 2004; Knop et al Assuming:  m = 0.27 § 0.04 Corrections for reddening, metallicity, evolution well-understood w 0 = § 0.2 § 0.1

Equation of State and Dark Matter Density : Combined Constraints Tegmark et al (2004) Assume flat universe Consistency with cosmological constant w = -1

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

Recall Assumptions: flatness  m = 0.3 § 0.04

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

Minimizing Systematics in era of precision cosmology

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

Galactic Extinction Law Cardelli, Clayton and Mathis 1989 A B / E(B-V) = 4.1 A I / E(B-V) = 1.7 B I V R V = A V / E(B-V) A U / E(B-V) = 4.9 U

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

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

Goals measurement of w to 5% measurement of w’ to 12% SNAP: Joint constraints with weak lensing  (better for SUGRA)

CFHT Legacy Survey ESSENCE Carnegie Supernova Project (CSP) Supernova Cosmology Project (SCP) GOODS Present/Future Supernova Projects LOTOSS (KAIT) SN Factory CSP High z: Low z: Future Supernova Projects: LSST, Panstarrs Giant Magellan SNAP DESTINY

Ground-based supernova searches over next 5 years - 100s of supernovae - decreasing systematics

ugriz light curves observations to I’ ~ 28 mag CFHT MegaCam 2000 SN over 5 years 0.1 < z < 1 CFHT Legacy Survey (SNLS)

ESSENCE VRI light curves CTIO 4m Mosaic Imager 200 SN over 5 years share nights with Supermacho project observe each field every 4 nights 0.1 < z < 0.8 NOAO Science Archive: High z Supernova Team

Automated supernova search UBVRI light curves Lick Observatory 0 < z < ~0.15 LOTOSS / KAIT

Supernova Factory Wood – Vasey et al 2004 spectrophotometry Univ. Hawaii 0.32 – 1  m NEAT, Palomar (search) ~150 SNae per year 3 years 2002: 35 candidates Same search techniques as distant searches

Followup supernova projects

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

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

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

Overview of Carnegie Supernova Project Swope 1-meterMagellan 6.5-meterDupont 2.5-meter Low z:High z: u’BVr’I’YJH photometry 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

Goals: minimize systematics accurate reddenings, K-corrections H 0 (H-band observations for Cepheids + SNIa)  dark energy peculiar flows physics of SNI and II Carnegie Supernova Project Magellan Jha 2002 PANIC

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

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

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

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

Future supernova projects s of supernovae - similar precision at high redshifts to upcoming low redshift surveys - decreased systematics

Highly ranked in Decadal Survey Optimized for time domain 7 square degree field 6.5m effective aperture 24th mag in 20 sec 15 TBytes/night (current ESSENCE 20 GBytes/night) Real-time analysis Large Synoptic Survey Telescope (LSST) Panstarrs

Future Plans (Carnegie High z) Magellan The Giant Magellan Telescope (GMT) Roger Angel mirrors Seven 8.4-meter mirrors; f/ 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 2. Wide field, optical spectroscopy Dark Matter (lensing) and dark energy studies. Supernovae 1<z<2

HST Treasury (Large) Proposals (Cycle 13) Riess et al. : Double high z sample Filippenko et al. : UV nearby survey

Future Surveys (Space): JDEM SNAP SNAP focal plane DESTINY: Dark Energy Space Telescope

SNAP Target Precision

Current Status of Cosmological Parameter Measurements WMAP (+ one of H 0, LSS, SNae) is consistent with a FLAT universe Consistent model with h = 0.72  m = 0.27   = 0.73 w = -1 Wright, 2004