Pair Production Supernovae:Theory and Observation Evan Scannapieco Kavli Insitute for Theoretical Physics- UCSB
Heger & Woosley (2002) Pair Production Supernovae Barkat etal (1967) Fraley (1968) Appenzeller (1970) Ober, El Id, & Frike (1983) Bond, Arnet, & Carr (1984) Fryer, Woosley and Heger (2001) Umeda & Nomoto (2003) Heger & Woosley (2002) A. Songaila 2001 Nonrotating stars that end their lives with 140-260 M
Why Metal Free? • 1. Because Pop III stars are thought to form with higher intrinsic masses.
The 1st Objects: Why Massive? H2 cooling takes you to a typical density of 104 cm-3 & T of 100 K …. LTE Mjeans ~ 1000 Msun Abel, Byran, Norman (2001)
Why Metal Free? • 1. Because Pop III stars are thought to form with higher intrinsic masses due to where H2 goes into LTE. (Bromm; Abel, Bryan and Norman) • 2. Because of mass loss in lower-Z stars.
Kudritski (2002) 300 M 100 M (nonrel. gas) =3nkT-3nkT (rel. gas) =aT-3aT=0! 2 M Z1/2 or steeper 3 See also Vink etal (2001) Hyd. Bal.: EG=-3pV Very Massive Stars are Very Weakly Bound ETot=V(<K>-3p) Caveat: Talk By Nathan Smith
Why Metal Free? • 1. Because Pop III stars are thought to form with higher intrinsic masses due to where H2 goes into LTE. (Bromm; Abel, Bryan and Norman) • 2. Because of mass loss in higher-Z stars (due to line driven winds) • 3. Because sufficiently high-mass stars are not seen today, even in very young clusters.
P<0.002 P<0.02 P<0.12 P<0.47 Figer (2005) Oey & Clarke (2005)
p M24/3 M2/3 r4 4 r2dp = -G dMM dr dr r2 unstable Gas + photons Degeneracy Pressure Losses no longer important
He/C/O Pair Production Supernovae H/He
Quick Facts: Ekin: 10-100x1051 ergs Mass: 140-260 M v: ~5,000 km/s Mass Metals: 20-200 M Large Odd-Even Effect C,O->Mg,Si,S,Ni56 H/He
What do PPSNe look like? ES, P. Madau, S. Woosley, A. Heger, A. Ferrara (2005) Kepler, implicit (1-D) hydrodynamic code Single-temperature radiative diffusion, grey opacity. Includes radioactive decay.
PPSN Evolution ES, P. Madau, S. Woosley, A. Heger, A. Ferrara (2005) Breakout Adiabatic Expansion + H recombinations 3. Ni56 decay 4. Becomes optically thin
PPSN Evolution Dependent on: Progenitor Size Ni56 Mass Mixing is key
PPSN Lightcurves 1. Not Always Brighter 2. Long Evolution Times 3. Hydrogen V-band,B-band,U-band
When Did They Happen? H2 cooling takes you to a typical density of 104 cm-3 & T of 100 K …. LTE Mjeans ~ 1000 Msun H2 Cooling Abel, Byran, Norman (2001) Tegmark, Silk, Rees, Blanchard, Abel, & Palla (1997)
When Did Then Happen? Msun/yr/Mpc3 Enrichment is an extended process that depends on ejection efficiency ES, R. Schneider, A. Ferrara (2003) “First Galaxies [PopII.5]” Most metal free SF is going to occur in Tvir 104 K
Visible PPSNe: I-band 0.01 Msun/yr/Mpc3 0.01 x SFRobs IfA Deep Survey: IAB > 26, 2.5 deg2 COSMOS: IAB > 27, 2 deg2 (general survey)
DESTINY (spec) SNAP (phot) JEDI (phot) Visible PPSNe: NIR 3 Versions of JDEM 0.01 Msun/yr/Mpc3 0.01 x SFRobs
Where do they end up locally? ES, D. Kawata, C. Brook, R. Schneider, A. Ferrara, B. K. Gibson (2006) Although the oldest stars should be near the center of the galaxy, does extended primordial SF history change spatial distribution? (Tumlinson Talk) • CDM “zoom in” sim. of 8x1011 M galaxy. • Pick out all objects above 104 K limit. • Use 1D model (varying wind efficency) to find positions of metal-free stars.
Milky Way Implications Lots of 1st stars end up in the solar Neighborhood
Bad News: Odd even effect, Lack of Zn are not observed <1/2 Fe from Pop II.5 is from PPSN Tumlinson Venkatesan & Shull (2004) No Metal free observed stars: Mmin 0.8 M Good News for PPSN:
Conclusions • PPSN -- Where and When? • From metal-free stars (formation models, winds, observations) • Extended redshift range (enrichment is local) • z>4 is interesting for direct constraints • products of metal-free stars end up in the solar neighborhood (good for high mass, bad for yields) • PSSN- Why? • Losses from e+e- production moves ≈4/3 star to ≤4/3. • Explosive O/Si burning unbinds the star. • PPSN- How? • Distinguished by: Hydrogen lines, slightlybrighter than Ia, long evolution times -- possibly with 2 local maxima • Best method is NIR surveys that cover a large area of sky.