Adam G. Riess Space Telescope Science Institute

How (we think) Nature makes a SN Ia Homogeneity: 1.4 Mo, ergs Negligible hydrogen, lots of IME Mature progenitors Models (delayed-detonation) good fit to observations

“Standard” Candles Bright=near dim=far dust dim & red=closer!

Expansion History of the Universe ( redshift ) (Distance) Mass is destiny

By 1998 two teams measured ~100 SNe Ia at 0.01 <z<1.0 Surprise! The Universe is accelerating, propelled by dark energy. High-z SCP The Accelerating Universe

Searching for the Epoch of z …a required feature of a mixed dark matter/dark energy Universe

Searching for the Epoch of z Our current goal: 6-8 SNe Ia at 1.2<z<1.8

“Difficulty” Or why its so hard to find type Ia supernovae at z>1.2Effect Factors of (1+z) geometrical dilution 2 redshift of energy density 1 dilation of integration time 1 Decline of SN Ia SED ~ ~1 Decline in QE of detectors ~ ~1 Total=6 Finding SNe Ia at 1.2<z<1.8 is 10 to 40 times harder than at z=0.5 (a.k.a., 1998)

The GOODs ACS Treasury Program and The Hubble Higher-z Supernova Search Team “A Higher-z Supernova Search Piggybacking on the ACS Survey” 134 orbits ToO for 6-8 SNe Ia at 1.2<z<1.8 Riess (STScI) Strolger (STScI) Tonry (UH) Filippenko (UCB) Kirshner, (CfA) Challis, (CfA) Casertano, (STScI) Dickinson (STScI) Giavalisco (STScI) Ferguson (STScI) 399 orbits of deep imaging for extragalactic studies

Searching for SNe Ia with ACS 5 z-band epochs, spaced by 45 days, simultaneous v,i band, 120 tiles CDFS=08/02-02/03 HDFN=11/02-05/03

What we are finding… ~5-6 SNe per search epoch (~0.3 SNe/ACS pointing) ~1/2 type Ia, ~1/2 core-collapse, 0.3 =1

SN Color Differences z i v SN Ia UV deficit Most Common SN types: type Ia and type II

Color Discrimination

Our first higher-z SN Ia, Aphrodite Aphrodite (1<z<1.5) ACS grism spectrum NICMOS F110W ACS F850lp viz

The Rise and Fall of Aphrodite Aug 1Sept 22 Oct 1 Oct 5Oct 10 Oct 20 Oct 30Oct 31Nov 17Nov 25

Our Second Higher-z SN Ia, Thoth Epoch 3Epoch 2Epoch 3-2 red, elliptical host Keck VLT z=1.3

Our Third Higher-z SN Ia, Nanna OII, Keck Epoch 1 Epoch 2 difference

And Some Even More Distant… We are off to a great start…results coming soon to a journal near you… Athena: phot-z: 1.8<z<2.2 Colors, mag SN Ia at z~1.8 Osiris: Colors, mag SN Ia at 1.5<z<1.8 ACS f850lp viz

Dilution of Light or Gravity Depends on the Number of Dimensions Either “Sees” Number of Dimensions Intensity/Distance Law 1 Independent of Distance (I ~ 1/R 0) 2 Reciprocal of Distance I ~ 1/R 1 3 Inverse Square Law I ~ 1/R 2 Essential component of String Theory: photons move in 3 dimensions, Gravitons leaks into 5,10 or 11 D long-range decay of gravity (Dvali et al 2001)

The Future Is Bright for SNe Ia! New tests of the new cosmology (searching for past deceleration) Deeper understanding of SNe Ia (progenitors) Probing the nature of Dark Energy

The End

3 SNe Followed in 1 ACS Field ! SN Ia 2002hp SN 2002hq SN Ia 2002fw

The New Cosmological Model; circa 2002 ? ??

SN Ia Host Morphology z<0.7 z>1.3 high fraction of hosts with well-defined structure high fraction of irregulars and ERO hosts