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

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 @ Nuclear Astrophysics XVIII 16/3/2016 /27

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 @ Nuclear Astrophysics XVIII 16/3/2016 /27

Current paradigm: neutrino-heating mechanism heating region shock cooling region absorption neutron staremission Energy transferred by neutrinos Most of them just escaping from the system, but partially absorbed In gain region, neutrino heating overwhelms neutrino cooling 5 Yudai Suwa @ Nuclear Astrophysics XVIII 16/3/2016 /27

Physical ingredients 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 @ Nuclear Astrophysics XVIII 16/3/2016 /27

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 @ Nuclear Astrophysics XVIII 16/3/2016 /27

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! (There are a few exceptions; 8.8M ⊙ , 9.6M ⊙ ) Thompson+ 03 Sumiyoshi+ 05 shock shock 8 Yudai Suwa @ Nuclear Astrophysics XVIII 16/3/2016 /27

Neutrino-driven explosion in multi-D simulation We have exploding models driven by neutrino heating with 2D/3D simulations 2D (maximum) 2D (minimum) 1D 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) MNRAS, 454 , 3073 (2015) ApJ, 816 , 43 (2016) 9 Yudai Suwa @ Nuclear Astrophysics XVIII 16/3/2016 /27

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 10 Yudai Suwa @ Nuclear Astrophysics XVIII 16/3/2016 /27

Impacts of rotation M ZAMS =27M ⦿ w/o rotation w/ rotation 11 Yudai Suwa @ Nuclear Astrophysics XVIII 16/3/2016 /27

To explode or not to explode M ZAMS =27M ⦿ rapidly rotating (3D) slowly rotating (3D) nonrotating (1D) Takiwaki, Kotake, Suwa, arXiv:1602.06759 12 Yudai Suwa @ Nuclear Astrophysics XVIII 16/3/2016 /27

Neutron star formation In the following, I focus on neutron star (NS) formation with supernova (SN) simulations Once we obtain shock launch and mass accretion onto a protoneutron star (PNS) ceases, PNS evolution is (probably) not a fg ected by explosion details NB) 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 13 Yudai Suwa @ Nuclear Astrophysics XVIII 16/3/2016 /27

1. NS crust formation 14 Yudai Suwa @ Nuclear Astrophysics XVIII 16/3/2016 /27

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. 15 Yudai Suwa @ Nuclear Astrophysics XVIII 16/3/2016 /27

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 16 Yudai Suwa @ Nuclear Astrophysics XVIII 16/3/2016 /27

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 17 Yudai Suwa @ Nuclear Astrophysics XVIII 16/3/2016 /27

2. Binary NS formation 18 Yudai Suwa @ Nuclear Astrophysics XVIII 16/3/2016 /27

How to make binary NSs? M ej 0.2M ⊙ 0.1M ⊙ SN 2005ek Time 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!) 19 Yudai Suwa @ Nuclear Astrophysics XVIII 16/3/2016 /27

Ultra-stripped type-Ic supernovae [Suwa, Yoshida, Shibata, Umeda, Takahashi, MNRAS, 454 , 3073 (2015)] 20 Yudai Suwa @ Nuclear Astrophysics XVIII 16/3/2016 /27

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 21 Yudai Suwa @ Nuclear Astrophysics XVIII 16/3/2016 /27

Ultra-stripped type-Ic supernovae: Implications small kick velocity due to small ejecta mass small eccentricity (e~0.1) , compatible with binary pulsars J0737-3039 (e=0.088 now and ~0.11 at birth of second NS) Piran & Shaviv 05 event rate (~1% of core-collapse SN) Tauris+13, 15, Drout+ 13, 14 SN surveys (e.g., HSC, PTF, Pan-STARRS, and LSST) will give constraint on NS merger rate nucleosynthesis calculations and radiation transfer simulations will be done based on our model 22 Yudai Suwa @ Nuclear Astrophysics XVIII 16/3/2016 /27

3. Magnetar formation 23 Yudai Suwa @ Nuclear Astrophysics XVIII 16/3/2016 /27

Magnetar formation and bright transients B=2 × 10 14 G P=2 ms Kasen+ 2010 B=5 × 10 14 G SLSNe and GRB afterglows can be P=1 ms fj tted by strongly magnetize NS (magnetar) model ※ GRB after glow ALL models based on dipole radiation Dall’Osso+ 2011 formula ( L~B 2 P -4 , Δ t~B -2 P 2 ) B~O(10 14 ) G, P~O(1) ms 24 Yudai Suwa @ Nuclear Astrophysics XVIII 16/3/2016 /27

Magnetar formation and bright transients [Suwa, Tominaga, MNRAS, 451 , 4801 (2015)] P=0.6 ms P=6 ms To make consistent model for GRB & hypernovae, we need O(0.1)M ⊙ of 56 Ni to explain hypernova (optical) components Postshock temperature of shock driven by magnetar dipole radiation should be >5 × 10 9 K For M Ni > 0.2 M ⊙ , (B/10 16 G ) 1/2 (P/1 ms ) -1 >1 is necessary 25 Yudai Suwa @ Nuclear Astrophysics XVIII 16/3/2016 /27

Summary Supernova explosions by neutrino-heating mechanism have become possible in the last decade Consistent modeling from iron cores to (cold) neutron stars is doable now NS crust formation related to neutrino observations, magnetar formation, NS pasta, nuclear EOS... binary NS formation related to gravitational wave observation, binary evolution... magnetar formation related to super-luminous supernovae, hypernovae, gamma-ray bursts... 27 Yudai Suwa @ Nuclear Astrophysics XVIII 16/3/2016 /27