Adam G. RiessSpace 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
(reds
hift)
(Distance)
1, M
1, M
1, M
Mass isdestiny
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
0.00.40.81.21.7
0.41.02.34.38.0
…a required feature of a mixed dark matter/dark energy Universe
Searching for the Epoch of
z
0.00.40.81.21.7
0.41.02.34.38.0
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>1.2
EffectEffect Factors of (1+z)Factors of (1+z)geometrical dilutiongeometrical dilution 22
redshift of energy densityredshift of energy density 11
dilation of integration timedilation of integration time 11
Decline of SN Ia SEDDecline of SN Ia SED~0.9-1.0 ~0.9-1.0
~1~1
Decline in QE of detectorsDecline in QE of detectors~0.9-1.0~0.9-1.0
~1~1
Total=6Finding SNe Ia at 1.2<z<1.8 is 10 to 40 times harder than at z=0.5 (a.k.a., 1998)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 ToOfor 6-8 SNe Iaat 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 orbitsof deep imagingfor extragalacticstudies
Searching for SNe Ia with ACSSearching for SNe Ia with ACS
5 z-band epochs, spaced by 45 days, simultaneous v,i band, 120 tilesCDFS=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<z<1.8, <z>=1
SN Color Differences
zi
v
SN Ia UV deficit
Most Common SN types: type Ia and type II
Color Discrimination
Our first higher-z SN Ia, AphroditeAphrodite (1<z<1.5)
ACS grism spectrum
NICMOS F110W
ACS F850lp
viz
The Rise and Fall of Aphrodite
Aug 1Sept 22Oct 1Oct 5Oct 10Oct 20Oct 30Oct 31Nov 17Nov 25
Our Second Higher-z SN Ia, ThothEpoch 3Epoch 2 Epoch 3-2
red, ellipticalhost
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<2.2Colors, 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 onthe Number of Dimensions Either “Sees”
Number of DimensionsNumber of Dimensions Intensity/Distance LawIntensity/Distance Law
11 Independent of DistanceIndependent of Distance
(I ~ 1/R(I ~ 1/R0)0)
22 Reciprocal of DistanceReciprocal of Distance
I ~ 1/RI ~ 1/R11
33 Inverse Square LawInverse Square Law
I ~ 1/RI ~ 1/R22
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 Morphologyz<0.7
z>1.3
high fraction of hosts with well-defined structure
high fraction of irregulars and ERO hosts
Top Related