From supernovae to neutron stars Yudai Suwa 1,2 1 Yukawa Institute - PowerPoint PPT Presentation

From supernovae to neutron stars Yudai Suwa 1,2 1 Yukawa Institute for Theoretical Physics, Kyoto University 2 Max Planck Institute for Astrophysics, Garching

Supernovae make neutron stars Baade & Zwicky 1934 2 Yudai Suwa @ Stellar physics meeting, AIfA, Bonner Universität 3/12/2015 /31

Key observables characterizing supernovae Explosion energy: ~10 51 erg measured by fj tting Ejecta mass: ~ M ⦿ SN light curves Ni mass: ~0.1M ⦿ measured by NS mass: ~1 - 2 M ⦿ binary systems fj nal goal of fj rst-principle ( ab initio ) simulations 3 Yudai Suwa @ Stellar physics meeting, AIfA, Bonner Universität 3/12/2015 /31

Fe Standard scenario of core-collapse supernovae Final phase of stellar Neutron star formation Neutrinosphere formation evolution (core bounce ） （ neutrino trapping ） Neutron Fe Neutrinosphere Star Si O,Ne,Mg C+O HeH ρ c ~10 14 g cm -3 ρ c ~10 11 g cm -3 ρ c ~10 9 g cm -3 shock stall shock revival Supernova! HOW? NS Si O,Ne,Mg C+O HeH 4 Yudai Suwa @ Stellar physics meeting, AIfA, Bonner Universität 3/12/2015 /31

Current paradigm: neutrino-heating mechanism heating region shock cooling region absorption neutron staremission Energy is transferred by neutrinos Most of them are just escaping from the system, but are partially absorbed In gain region, neutrino heating overwhelms neutrino cooling 5 Yudai Suwa @ Stellar physics meeting, AIfA, Bonner Universität 3/12/2015 /31

Physical ingredients In these violent explosions, all known interactions are involving and playing important roles; Strong Weak - nuclear equation of state - neutrino interactions σ ν ~10 -44 cm 2 (E ν /m e c 2 ) 2 - structure of neutron stars R NS ~10-15 km - ~99% of energy is emitted by ν ’s max(M NS )> 2 M ⊙ - cooling of proto-neutron star - nucleosynthesis - heating of postshock material Electromagnetic Gravitational - energy budget - Coulomb collision of p and e E G ~3.1x10 53 erg(M/1.4M ⊙ ) 2 (R/10km) -1 - fj nal remnants are ~0.17M ⊙ c 2 pulsars ( B~10 12 G) - inducing core collapse magnetars ( B~10 14-15 G) - making general relativistic objects magnetic fj elds a fg ect dynamics (NS/BH) 6 Yudai Suwa @ Stellar physics meeting, AIfA, Bonner Universität 3/12/2015 /31

What do simulations solve? Numerical Simulations Hydrodynamics equations Neutrino Boltzmann d ρ equation dt + ρ ∇ · v = 0 , Solve 1 − µ 2 � ∂ f � � d ln ρ � � � cdt + µ ∂ f df + 3 v + 1 ρ d v ∂ r + µ simultaneously cdt cr r ∂ µ dt = −∇ P − ρ ∇ Φ , � � d ln ρ � � + 3 v − v E ∂ f µ 2 + cdt cr cr ∂ E de ∗ e ∗ + P �� � � dt + ∇ · = − ρ v · ∇ Φ + Q E , E 2 v = j (1 − f ) − χ f + c ( hc ) 3 dY e � � � � Rf ′ dµ ′ − f dt = Q N , � 1 − f ′ � dµ ′ (1 − f ) R . × △ Φ = 4 π G ρ , ρ : density , v : velocity , P : pressure , Φ : grav. f : neut. dist. func, µ : cos θ , E : neut. energy, potential, e * : total energy, Y e : elect. frac., j : emissivity, χ : absorptivity, R : scatt. Q : neutrino terms kernel 7 Yudai Suwa @ Stellar physics meeting, AIfA, Bonner Universität 3/12/2015 /31

1D simulations fail to explode Rammp & Janka 00 Liebendörfer+ 01 shock shock By including all available physics to simulations, we concluded that the explosion cannot be obtained in 1D! (The exception is an 8.8 M ⦿ star (O-Ne-Mg core); Kitaura+ 06) Thompson+ 03 Sumiyoshi+ 05 shock shock 8 Yudai Suwa @ Stellar physics meeting, AIfA, Bonner Universität 3/12/2015 /31

Neutrino-driven explosion in multi-D simulation We have exploding models driven by neutrino heating with 2D/3D simulations comparison between 1D and 2D Müller, Janka, Marek (2012) Brruenn et al. (2013) 800 ms 6000 3000 0 3000 Suwa+ PASJ, 62 , L49 (2010) (2D) ApJ, 738 , 165 (2011) 6000 -9000 -6000 -3000 0 3000 6000 9000 ApJ, 764 , 99 (2013) ymmetry axis [km] PASJ, 66 , L1 (2014) ApJ, in press. [arXiv:1406.6414] MNRAS, 454 , 3073 (2015) 9 Yudai Suwa @ Stellar physics meeting, AIfA, Bonner Universität 3/12/2015 /31

Dimensionality and numerical simulations ※ grid-based codes only, not completed Only the simulations in this region can judge the neutrino-driven explosion Dimension Blondin+, 07 Iwakami+, 08 Takiwaki, Kotake, & Suwa, 12 3D Mikami+, 08 Hanke+, 13 Scheidegger+, 08 Lentz+, 15 Nordhaus+, 10 Hanke+, 12 Müller, 15 Couch, 13 Handy+, 14 2D Kotake+, 03 Burrows+, 06 Yamada & Sato, 94 (axial-sym.) Buras+, 06 Blondin & Mezzacappa, 03 Ohnishi+, 06 Ott+, 08 Obergaulinger+, 06 Murphy+, 08 Suwa+, 10 Takiwaki+, 09 Müller+, 12 Sekiguchi+, 11 Bruenn+, 13 Obergaulinger+,14 Pan+, 15 O’Connor+, 15 1D Rampp & Janka, 00 (spherical-sym.) Liebendörfer+, 01 Thompson+, 03 Sumiyoshi+, 05 O’Connor+, 13 Spectral transport cooling only Adiabatic or Neutrino Treatment ��������������������������������������������������������� heat by hand 10 Yudai Suwa @ Stellar physics meeting, AIfA, Bonner Universität 3/12/2015 /31

3D simulation with spectral neutrino transfer [Takiwaki, Kotake, & Suwa, ApJ, 749 , 98 (2012); ApJ, 786 , 83 (2014)] M ZAMS =11.2 M ⊙ 384(r)x128( θ )x256( φ )x20(E ν ) XT4 T2K-Tsukuba K computer 11 Yudai Suwa @ Stellar physics meeting, AIfA, Bonner Universität 3/12/2015 /31

Dimensionality and initial perturbation [Takiwaki, Kotake, & Suwa, ApJ, 786 , 83 (2014)] 2D 3D 1D 12 Yudai Suwa @ Stellar physics meeting, AIfA, Bonner Universität 3/12/2015 /31

Impacts of rotation M ZAMS =27M ⦿ w/o rotation w/ rotation 13 Yudai Suwa @ Stellar physics meeting, AIfA, Bonner Universität 3/12/2015 /31

To explode or not to explode M ZAMS =27M ⦿ rapidly rotating (3D) slowly rotating (3D) nonrotating (1D) Takiwaki, Kotake, Suwa, in prep. 14 Yudai Suwa @ Stellar physics meeting, AIfA, Bonner Universität 3/12/2015 /31

Note: there are problems Explosion energy of simulations ( O(10 49-50 ) erg) is much smaller than observational values ( O(10 51 ) erg) Results from di fg erent groups are contradictory What are we missing? 15 Yudai Suwa @ Stellar physics meeting, AIfA, Bonner Universität 3/12/2015 /31

By the way In the following, I focus on neutron star (NS) formation with supernova (SN) simulations Once we obtain shock launch and mass accretion onto a proto- neutron star (PNS) ceases, PNS evolution is (probably) not a fg ected by explosion details 17 Yudai Suwa @ Stellar physics meeting, AIfA, Bonner Universität 3/12/2015 /31

1. NS crust formation 18 Yudai Suwa @ Stellar physics meeting, AIfA, Bonner Universität 3/12/2015 /31

From SN to NS [Suwa, Takiwaki, Kotake, Fischer, Liebendörfer, Sato, ApJ, 764 , 99 (2013); Suwa, PASJ, 66 , L1 (2014)] ejecta shock NS mass ~1.3 M � NS Progenitor: 11.2 M ⊙ (Woosley+ 2002) Successful explosion! (but still weak with E exp ~10 50 erg) The mass of NS is ~1.3 M ⊙ The simulation was continued in 1D to follow the PNS cooling phase up to ~70 s p.b. 19 Yudai Suwa @ Stellar physics meeting, AIfA, Bonner Universität 3/12/2015 /31

From SN to NS [Suwa, PASJ, 66 , L1 (2014)] ν Crust formation! Z=50 Γ xThermal energy (C)NASA = Coulomb energy Z=70 Z=26 Γ ≡ ( Ze ) 2 rk B T = Coulomb energy Thermal energy ∼ 200 20 Yudai Suwa @ Stellar physics meeting, AIfA, Bonner Universität 3/12/2015 /31

From SN to NS: Implications Crust formation time should depend on EOS (especially symmetry energy?) We may observe crust formation via neutrino luminosity evolution of a SN in our galaxy Cross section of neutrino scattering by heavier nuclei or nuclear pasta is much larger than that of neutrons and protons Neutrino luminosity may suddenly drop when we have heavier nuclei! Magnetar (large B- fj eld NS) formation competitive process between crust formation and magnetic fj eld escape from NS 21 Yudai Suwa @ Stellar physics meeting, AIfA, Bonner Universität 3/12/2015 /31

2. Binary NS formation 22 Yudai Suwa @ Stellar physics meeting, AIfA, Bonner Universität 3/12/2015 /31

Ultra-stripped type-Ic supernovae M ej 0.2M ⊙ 0.1M ⊙ SN 2005ek Tauris+ 2013 new class of SNe rapidly evolving light curve -> very small ejecta mass possible generation sites of Tauris & van den Heuvel 2006 binary neutron stars (synergy w/ gravitational wave obs.!) 23 Yudai Suwa @ Stellar physics meeting, AIfA, Bonner Universität 3/12/2015 /31

Ultra-stripped type-Ic supernovae [Suwa, Yoshida, Shibata, Umeda, Takahashi, MNRAS, 454 , 3073 (2015)] 24 Yudai Suwa @ Stellar physics meeting, AIfA, Bonner Universität 3/12/2015 /31

Ultra-stripped type-Ic supernovae [Suwa, Yoshida, Shibata, Umeda, Takahashi, MNRAS, 454 , 3073 (2015)] shock radius [km] Time after bounce (ms) Ejecta mass ~O(0.1)M ⊙ , NS mass ~1.4 M ⊙ , explosion energy ~O(10 50 ) erg, Ni mass ~O(10 -2 ) M ⊙ ; everything consistent w/ Tauris+ 2013 25 Yudai Suwa @ Stellar physics meeting, AIfA, Bonner Universität 3/12/2015 /31