New ways to explode stars Introducing the Palomar Transient Factory
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New ways to explode starsIntroducing the Palomar Transient Factory
Avishay Gal-Yam,
Weizmann Institute of Science
Hubble Fellows Symposium 2010
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Cosmic ExplosionsType Ia Supernova
Long GRBShort GRB
Type II, Ib, Ic Supernova
SHB 050709, Fox et al. 2005
SN 1987A
GRB 980425, Galama et al. 1998
SN 1994D, Challis
?
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New explosion #1: SN 2005E
LOSS discovery
Graham & Li 2005
Type Ib (UCB; CCCP)
Member of the Ca-rich Subclass (Filippenko et al.)
Hagai Perets, Nature, in press
Dave Arnett, Paolo Mazzali, Daniel Kagan, UCB SN group,
CCCP, Anderson & James, Ofek, Bildsten & Co., Quataert & Co.
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A massive star?No star formation to deep limits … unlikely also on theoretical grounds
Perets et al. 2009
r<25.3 (25.9) at 3(2)
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A hyper-velocity SN (HVSN) ?Life in the fast lane?
SN 2005E
11.3 kpc
22.9 kpc
Not likely: chances to observe HVSNe with LOSS are < 1/100
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So what, then?What will nebular spectra reveal?
Peculiar abundances (C, O, Ca, Ni56) = (0.1 0.037 0.135 0.003) solar
Total ejected mass is <0.3 solar !
Mazzali
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Not a single event!6-10 additional siblings, additional early hosts
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What can it be?A double WD (O/Ne+He): accretion induced collapse ?
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NucleosynthesisCan you make so much Ca with no Si and S? (Ca/S >6)
*No (if you burn C/O)
*Yes (if you burn He)Models by Arnett}
He/C/O accretion/merger result an emerging field
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New Explosion #2: Pair Instability Supernovae (PISNE)
(Barkat, Rakavi & Sack 1967 ; Heger & Woosley 2002; Waldman 2008 …)
*Helium cores above ~50 solar masses become pair unstable
“Smoking gun :”
Core mass > 50 solar
*In these low-density high-T cores, e+e- wins over oxygen ignition, heat is converted to mass and implosion follows
“ *This is a uniquely calculable process” (Heger & Woosley 2002); “this is a trivial calculation” (Barkat 2009); “Pretty neat homework problem” (Gal-Yam 1996)
*Inertial oxygen ignition leads to explosion and full disruption Waldman
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SN 2007bi=SNF20070406-008(PTF “dry run”)
Core mass > 50 robustly established;Gal-Yam et al. 2009, Nature, 462, 624; also Young et al. 2009
*Type Ic SN similar to SN1999as. No interaction, no dust, v=12000 km/s
*Luminous peak (-21.3), slow rise (~77 days), 56Co decay
* 4-11 solar masses of 56Ni, ejected mass ~100 solar, Ek~1e53 (scaling)
*Well-fit by models (Kasen)
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Implications(Gal-Yam et al. 2009)
*A helium core ~100 solar detected at Z ~ SMC
* Mass loss models are wrong
* PISNe happen locally, Universally, models are ~ok
* Dwarfs have stars above Galactic limit (>200 solar, probably)
* Hydrogen efficiently removed (pulsations?)
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The Core-Collapse SpectrumLower mass limit unclear :
<7..11 solar; stable C/O core
EC SN?
M: 7-11
AIC
RSG=II-P
M: 8-16
?“The gap”
M: 17-25
“rare IIs?”
W-R = Ib/c?
M: 25-30
HNe, GRB
M: 40-50
NS BH
LBV=IIn
M: 50-150
PP SNe
M> 150
BH No remnant
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And now: news from The Palomar Transient Factory
There is nothing like searching, if you want to find something.
You usually find something, if you search,
but it is not always quite the something you were after.
Thorin Oakenshild
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Luminous blue SNe (Quimby)
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Shocking news (Ofek)
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Baby Supernovae: the first days
SNe Ia: Nugent, Sullivan, Howell, Ellis
Core-collapse SNe: Arcavi
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Supernovae: dwarf vs. giant hosts
Arcavi; HST SNAP survey
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Follow-up is key …
GRB-supernova?
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Thanks
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Concept:
SN 2007bi - “lessons”