CERNCERN ColloquiumColloquium Zoom, May 20, 2021

Core-Collapse Theory From -driven Explosions to Observations

Hans-ThomasHans-Thomas JankaJanka Max Planck Institute for Astrophysics Garching, Germany Contents

1. Introduction and background

2. Status of “ab initio” 3D core-collapse SN modeling of neutrino-driven explosion mechanism

3. Importance of pre-collapse progenitor asymmetries for SN explosions in 3D

4. Observational implications (; NS kicks; Cas A, SN 1987A)

5. Open questions & perspectives

2 Stellar Collapse and Supernova Stages ) 0 9 9 1 (

s w o r r u B

. A

m o r f

d e t p a d a

3 Neutrinos play a crucial role!

They carry away the gravitational binding energy of the new-born NS:

E = f*GM2/R ~ several 1053 erg.

4 Supernova 1987A

Supernova 1987A (SN 1987A) 5 6 Problems & Questions

● Core collapse SN explosion mechanism(s)

● SN explosion properties; explosion asymmetries, mixing, gaseous remnant properties

● NS/BH formation paths and probabilities

● NS/BH birth masses, kicks, spins

● Neutrino and gravitational-wave signals

● Neutrino flavor oscillations, impact of non-standard physics, e.g. sterile neutrinos

● Heavy-element formation; what are the sites of the r-process(es)?

● What is the equation of state (EOS) of ultra-dense matter?

7 Onion-shell structure of pre-collapse

Star develops onion-shell H structure in sequence of nuclear burning stages He over millions of years C O Si

Fe

(layers not drawn to scale) 8 Onion-shell structure of pre-collapse star

Star develops onion-shell H structure in sequence of nuclear burning stages He over millions of years C O Si

Fe

(layers not drawn to scale) 9 Gravitational instability of stellar core O

Si O Fe

10 Core bounce at nuclear density O Accretion Si Fe

Shock wave

Proto- star 11 Shock stagnation O Accretion Si Fe n, p

Shock wave

Proto- 12 Neutrino heating

Accretion O Si

ν ν ν n, p ν Shock wave Si

Proto-neutron star 13 Shock revival O O O Ni ν ν n, p

n, p, α ν ν Shock wave

Proto-neutron star 14 Explosion and O nucleosynthesis O n, p, α, Ni ν (Zk,Nk) ν

n, p

ν Shock ν wave

Neutrino- driven “wind” 15 Neutrino Heating and Cooling

●

Neutrino heating: 7 0 4

) 2 1 0 2 (

2 6 ● : Neutrino cooling S P N R A

, a k n a J

, . g . e

, e e S

Hydrodynamic instabilities 16 Critical Condition for Explosion

Burrows & Goshy, ApJL (1993)

17 8 2

Universal Critical ) 3D 8 1 0 2 ( Neutrino 2

2D 5 8

J

Luminosity for p A

, . l a

t

Explosion e

a

3D m 2D m u S

18 Necessary Effort:

Self-consistent "ab-initio" 3D neutrino-hydrodynamical simulations of neutrino-driven explosions

19 Predictions of Signals from SNe & NSs hydrodynamics of stellar plasma relativistic gravity (nuclear) EoS neutrino physics progenitor conditions

dynamical models

neutrinos nucleosynthesis LC, spectra

gravitational waves explosion asymmetries, pulsar kicks explosion energies, remnant masses 20 2D and 3D Morphology

(Images from Markus Rampp, RZG)

21 Progenitors: . Density Profiles High M

Progenitor models: Woosley et al. (RMP 2002), Sukhbold & . Woosley (2014), Woosley & Heger (2015) Low M

O'Connor & Ott, ApJ 730:70 (2011) 22 2D and 3D Electron-Capture SN Models

Kitaura et al., A&A 450 (2006) 345; Wolff & Hillebrandt Janka et al., A&A 485 (2008) 199 ECSNe: (stiff) nuclear EoS Explosions of low-mass (~9 Msun) with O-Ne-Mg cores

neutrino heating

50 Eexp ~ 10 erg = 0.1 bethe MNi ~ 0.003 Msun

Gessner & Janka, ApJ 865 (2018) 61 23 3D Core-Collapse SN Explosion Models

9.6 Msun (zero-metallicity) progenitor (Heger 2010)

Fe-core progenitor (Heger 2012) with ECSN-like density profile and explosion behavior.

Melson et al., ApJL 801 (2015) L24

24 Nonradial Hydrodynamic Instabilities

Convection SASI Convective Overturn Standing accretion shock instability

NS NS

Images: Tobias Melson Spiral SASI 25 Laboratory Astrophysics "SWASI" Instability as an analogue of SASI in the supernova core Foglizzo et al., PRL 108 (2012) 051103

Constraint of experiment: No convective activity

26 3D CCSN Explosion Model with Rotation

15 Msun rotating progenitor (Heger, Woosley & Spruit 2005)

Explosion occurs for angular velocity of Fe-core of 0.5 rad/s, rotation period of ~12 seconds (several times faster than predicted for magnetized progenitor by Heger et al. 2005). Produces a neutron star with spin period of ~1‒2 ms.

Janka, Melson & Summa, ARNPS 66 (2016); Summa et al., ApJ 852 (2018) 28 27 3D Core-Collapse SN Explosion Models

20 Msun (solar-metallicity) progenitor (Woosley & Heger 2007)

Explore uncertain aspects of microphysics in neutrinospheric region: Example: strangeness contribution to nucleon spin, affecting axial-vector neutral-current scattering of neutrinos on nucleons

We use: Currently favored ga = 1.26 theoretical & experimental s ga = ‒0.2 (HERMES, COMPASS) value: s ga ~ ‒0.1

Effective reduction of neutral-current neutrino-nucleon Melson et al., ApJL 808 (2015) L42 scattering by ~15% 28 Pre-collapse 3D Asymmetries in Progenitors

29 3D Core-Collapse SN Progenitor Model

18 Msun (solar-metallicity) progenitor (Heger 2015)

3D simulation of last 5 minutes of O-shell burning. During accelerating core contraction a quadrupolar (l=2) mode develops with convective Mach number of about 0.1.

151 s

270 s

294 s B. Müller, Viallet, Heger, & THJ, ApJ 833, 124 (2016) 30 3D Core-Collapse SN Explosion Model

18 Msun (solar-metallicity) progenitor (Heger 2015)

3D simulation of last 5 minutes of O-shell Onset of collapse Onset of collapse burning. During accelerating core contraction a quadrupolar (l=2) mode develops with convective Mach number of about 0.1.

This fosters strong postshock convection and could thus reduces the criticial neutrino Si luminosity for explosion. Si

1.4 s post bounce 1.4 s post bounce

δρ/ρ ~ Maconv

B. Müller, PASA 33, 48 (2016); Müller, Melson, Heger & THJ, MNRAS 472, 491 (2017)31 Neon-oxygen-shell Merger in a 3D Pre-collapse Star of ~19 M sun Flash of Ne+O burning creates large-scale asymmetries in density, velocity, Si/Ne composition

Radial velocity fluctuations Density variations

Yadav, Müller et al., ApJ 890 (2020) 94 32 3D Explosion of ~19 M Star sun Explosion energy saturates at 1051 ergs after 7 seconds 6 0 5 0 1 . 0 1 0 2 : v i X r a

, . l a

t e

g i l l o B

. R

33 3D Core-Collapse SN Explosion Models

Garching/QUB/Monash (Melson+ ApJL 2015a,b; Müller 2016; Janka+ ARNPS 2016, Müller+ MNRAS 2017, Summa+ ApJ 2018, Glas+ ApJ 2019): 9.6, 20 Msun nonrotating progenitors (Heger 2012; Woosley & Heger 2007) 18 Msun nonrotating progenitor (Heger 2015) 15 Msun rotating progenitor (Heger, Woosley & Spuit 2005, modified rotation) 9.0 Msun nonrotating progenitor (Woosley & Heger 2015) ~19.0 Msun nonrotating progenitor (Sukhbold, Woosley, Heger 2018)

Monash/QUB (Müller+ MNRAS 2018, Müller+MNRAS 2019): z9.6, s11.8, z12, s12.5 Msun nonrotating progenitors (Heger 2012) he2,8, he3.0, he3.5 Msun He binary stars, ultrastripped SN progenitors (Tauris 2017)

34 3D Core-Collapse SN Explosion Models

Oak Ridge (Lentz+ ApJL 2015): 15 Msun nonrotating progenitor (Woosley & Heger 2007)

Tokyo/Fukuoka (Takiwaki+ ApJ 2014): 11.2 Msun nonrotating progenitor more massive progenitors with rapid rotation (Woosley et al. 2002,2007)

Caltech/NCSU/LSU/Perimeter (Roberts+ ApJ 2016; Ott+ ApJL 2018): 27 Msun nonrotating progenitor (Woosley et al. 2002), 15, 20, 40 Msun nonrotating progenitors (Woosley & Heger 2007)

Princeton (Vartanyan+ MNRAS 2019, Burrows+ MNRAS 2020): 9–40 Msun suite of nonrot. progenitors (Woosley & Heger 2007, Sukhbold+2016)

Modeling inputs and results differ in various aspects. 3D code comparison is missing and desirable 35 Status of Neutrino-driven Mechanism in 3D Supernova Models

● 3D modeling has reached mature stage. ● 3D differs from 2D in many aspects, explosions more difficult than in 2D.

● Neutrino-driven 3D explosions for progenitors between 9 and 40 Msun (with rotation, 3D progenitor perturbations, or slightly modified neutrino opacities) ● Explosion energy can take many seconds to saturate! 1051 erg possible!

● Progenitors are 1D, but composition-shell structure and initial progenitor-core asymmetries can be crucial for onset of explosion. ● 3D simulations may still need higher resolution for convergence.

36 Observational consequences Direct and indirect evidence for neutrino heating and hydrodynamic instabilities at the onset of stellar explosions:

● Neutrino signals (characteristic time dependencies)

● Gravitational-wave signals

● Neutron star kicks

● Asymmetric mass ejection & large-scale radial mixing

● Light curve shape, spectral features (elmagn. emission)

● Progenitor – explosion – remnant connection

● Nucleosynthesis

37 Detecting Core-Collapse SN Signals

Superkamiokande

IceCube

VIRGO

38 Neutrino-emission features associated with multi-D flows

● SASI induced quasi-periodic modulations

● LESA: dipolar asymmetry of lepton-number emission

39 Neutrino-Signal Features During (Pre-)explosion Phase

Janka H.-T., in: Handbook of Supernovae (2016); arXiv:1702.08713

40 3D Core-Collapse Models: Neutrino Signals 11.2, 20, 27 Msun progenitors (WHW 2002) SASI produces modulations of neutrino emission (and gravitational-wave signal).

27 Msun

at 10 kpc

Tamborra et al., PRL 111, 121104 (2013); PRD 90, 045032 (2014) 41 SASI Period Measures RadiusEvolution Shock

Müller & THJ, ApJ 788 (2014) 82 42 LESA: A New Nonradial 3D Instability Dipole asymmetry of lepton-number emission (LESA)

Lepton number flux: Total energy flux: Originates from νe minus anti-νe νe plus anti-νe plus anisotropic convection heavy-lepton neutrinos inside the proto-neutron star

; ) 6 1 0 2 (

6 6 )

0 S 2 P 0 2 N (

R S A

A , . l R a

N t M e

, . J l H a

T t

; e

) r 4 e 1 g 0 n 2 i (

k 6 c 9 o

t , 2 S

9 ; ) 7

9 J 1 p 0 2 A (

, . l J a p

t A

e ,

. l a r a

r t o e

b s m a l a T G 43 Consequences of LESA

Glas, THJ, Just, Melson, & Stockinger, ApJ (2019)

F −F ν e νe

Consequences of LESA:

Neutron-star kicks (~10~100 km/s) Supernova nucleosynthesis in ν-heated ejecta is direction dependent Viewing-angle dependent lepton flux Neutrino-flavor oscillations are direction dependent 44 Observational consequences Direct and indirect evidence for neutrino heating and hydrodynamic instabilities at the onset of stellar explosions:

● Neutrino signals (characteristic time dependencies)

● Gravitational-wave signals

● Neutron star kicks

● Asymmetric mass ejection & large-scale radial mixing

● Light curve shape, spectral features (elmagn. emission)

● Progenitor – explosion – remnant connection

● Nucleosynthesis

45 Neutron Star Recoil in 3D Explosion Models

W15-2 @ 1.3 s

Gravitational tug-boat mechanism

Wongwathanarat, Janka, Müller, ApJL 725, 106 (2010); A&A 552, 126 (2013); Scheck et al., PRL 92, 011103 (2004), A&A 457, 963 (2006); Janka, ApJ 837, 84 (2017) 46 Asymmetric Ejection of Radioactive Nuclei and IME from Ne to Fe-group

VNS ~ 550 km/s

6 VNS ~ 2 1

A 600 km/s

) 3 1 0 2 (

2 5 5

A & A

, r e l l Large kick ü M

, a k n a J

, t a r a n a h t a w g n o W VNS ~ VNS ~ 100 km/s 300 km/s Moderate kick 47 Neutron Star Kicks and Young SN Remnants

● Analysis of spatial distribution of IMEs (from Ne to Fe- group) in young, nearby SNRs with known NS kick velocities.

Katsuda, Morii, THJ, et al., ApJ 856 (2018) 18;

see also: Holland-Ashford, et al., ApJ 844 (2017) 84; Bear & Soker, ApJ 855 (2018) 82 48 Neutron Star Kicks and Young SN Remnants

● Analysis of spatial distribution of IMEs (from Ne to Fe-group) in young, nearby SNRs with known NS kick velocities.

Katsuda, Morii, THJ, et al. ApJ 856 (2018) 18 49 SN-remnant Cassiopeia A

CAS A

50 X-ray (CHANDRA, green-blue); optical (HST, yellow); IR (SST, red) SN-remnant Cassiopeia A

51 X-ray (CHANDRA, green-blue); optical (HST, yellow); IR (SST, red) Intermediate Mass Element Asymmetries in CAS A Remnant

Red: Ar, Ne, and O (optical) Image: Robert Fesen and Dan Milisavljevic, Purple: Iron (X-ray) using iron data from DeLaney et al. (2010) 52 44Ti Asymmetry in the CAS A Remnant

Grefenstette et al., Nature 506 (2014) 340 NuSTAR observations 53 Neutron Star Recoil and Nickel & 44Ti Distribution

Grefenstette et al., Nature 506 (2014) 340 Wongwathanarat et al., ApJ 842 (2017) 1354 Chemical Asymmetries in CAS A Remnant

Iron in Cas A is visible in three big "fingers" in the remnant shell that is heated by reverse shock from circumstellar medium interaction.

Hot, shocked iron (observed)

Wongwathanarat et al., ApJ 842 (2017) 13 55 Cas A: Gamma-Ray Line Profiles of 44Ti

NS in Cas A has high kick (~500–700 km/s) with small inclination angle (within <40–5 0 degrees) to line of sight.

Consistent with 3D analysis of 44Ti distribution by Grefenstette et al. (2017).

Line centroid of 44Ti decay line strongly redshifted

Jerkstrand et al., MNRAS 494 (2020) 2471 56 Supernova 1987A

SN 1987A

Supernova 1987A (SN 1987A) 573 Supernova 1987A

Supernova 1987A (SN 1987A) 583 Single-star Models for SN1987A: Bolometric Light Curves from 3D Explosions

Utrobin et al., A&A 624 (2019) A116

= B15

Self-consistent 3D simulations of explosions by neutrino heating do not produce sufficient outward mixing of Ni and inward mixing of H in most progenitors. 59 Binary-star Models for SN1987A: Bolometric Light Curves from 3D Explosions

Utrobin et al., arXiv:2102.09686

Menon & Heger (2017); Binary merger progenitors, following an original suggestion by Podsiadlowski and coworkers (1990ff) 60 Binary-star vs. Single-star Models for SN1987A:

Utrobin et al., arXiv:2102.09686 61 3D Geometry of SN1987A: Observations vs. Models

Molecular CO 2-1 and SiO 5-4 30% peak emission observed by ALMA

50% peak

70% peak Abellán et al., ApJL 842 (2017) L24 62 3D Geometry of SN1987A: Observations vs. Models

Molecular CO 2-1 and SiO 5-4 emission observed by ALMA

Abellán et al., ApJL 842 (2017) L24

● ● ● ● W15 L15 N20 B15 63 3D Geometry of SN1987A: Observations vs. Models

Molecular CO 2-1 and SiO 5-4 emission observed by ALMA

Abellán et al., ApJL 842 (2017) L24

● ● ● ● W15 L15 N20 B15 64 SN 1987A: Gamma Lines of 44Ti & 56Co

Boggs et al. (2015): Redshifted 44Ti lines suggest that NS in SN 1987A is likely to have fairly high kick towards us.

Boggs et al., Science 348 (2015) 670

vns ~100 km/s: Incompatible vns ~300 km/s: Better fit!

56 1 Co line 56Co line 7 4 2

) 0 , . 2 l 0 a

2 t ( e

4 d 9 4 n a S r t A s R k r N e J M 65 3D Geometry of SN1987A: Observations vs. Models

3D isosurfaces of iron and silicon ([FeII]+[SiI])

Observer

HST & VLT obs. (Larsson et al., ApJ 833 (2016) 147) 3D model L15 (Janka et al., arXiv:1705.01159) 66 A Compact Object in SN1987A?

High angular resolution ALMA images of dust and molecules in the ejecta of SN 1987A

5-sigma hot "blob" north-east of ejecta center: Compact source would be compatible with recent limits by Alp et al. (ApJ 864 (2018) 174). Luminosity can be explained by energy input from a thermally cooling NS (or, less likely, accretion by BH) (Cigan et al., ApJ 886 (2019) 51; Page et al., ApJ 898 (2020) 125)67 A Compact Object in SN1987A?

High angular resolution ALMA images of dust and molecules in the ejecta of SN 1987A: PWN or thermally cooling neutron star? A

s a C

Luminosity can be explained by energy input from a thermally cooling NS (or, less likely, accretion by BH)

(Page et al., ApJ 898 (2020) 125) 68 Conclusions Neutrino-driven Explosions in Supernova Simulations

Ab initio, self-consistent 2D and 3D simulations demonstrate viability of delayed neutrino-driven explosion mechanism

Multi-D models of neutrino-driven explosions are sufficiently mature to test them against observations

Unsolved aspects: * Nuclear equation of state in neutron stars * Neutrino flavor oscillations in interaction in dense matter * Relevance of rotation and strong magnetic fields

69 Regions of Neutrino-Flavor Conversions

Image: Robert Glas 70 ) t l e f f a R

g r o e G

m o r f

d e t p a d A (

71 Observational Supernova-Progenitor Connection What is the role of rapid rotation? Which progenitors do spin rapidly? Which stars explode by magnetorotational mechanism?

Neutrino-driven explosions

Mazzali et al., MNRAS 432 (2013) 2463 72 GRB-Hypernova & SLSN Central Engines (Most popular, but not exclusive, scenarios)

Jets initiated?

"Collapsar": BH+torus Magnetar "engine" Woosley (1993), MacFadyen Usov (1992), Metzger et al. (2011), Woosley (1999), Lazzati et al. (2013) Bucciantini et al. (2007, 2008, 2009) 73 Thank You!