Neutrino Fingerprints in Compact Objects Irene Tamborra Niels Bohr - - PowerPoint PPT Presentation

Compact Objects for All February 11, 2020

Irene Tamborra

Niels Bohr Institute, University of Copenhagen

Neutrino Fingerprints in Compact Objects

Neutrinos

Ghostly Abundant Elusive

νe

νµ

ντ

Ideal Messengers

Escaping unimpeded, neutrinos carry information about sources not otherwise accessible.

Photon Proton Neutrino

Astro-Neutrino Detectors

HALO SNO+ MicroBooNE NovA LVD Borexino Baksan KamLAND Super-Kamiokande [Hyper-Kamiokande] Daya Bay IceCube [IceCube-Gen2]

Fundamental to combine astrophysical signals from detectors employing different technologies.

Km3NeT [DUNE] [RENO-50, JUNO]

Dawn of the Multi-Messenger Era

Core-collapse supernovae explode because of

NEUTRINOS!

10 neutrinos are emitted

58

Core-Collapse Supernova Explosion

neutrino cooling by diffusion

Implosion (Collapse) Explosion

Neutrinos carry 99% of the released energy (~ 10 erg).

53

Detection Frontiers

Supernova in our Galaxy (one burst per 40 years). Excellent sensitivity to details. Supernova in nearby Galaxies (one burst per year). Sensitivity to general properties. Diffuse Supernova Background (one supernova per second). Average supernova emission. Guaranteed signal.

Beacom & Vagins, PRL 93:171101,2004

The Next Nearby Supernova (SN 2XXXa)

Figure from Nakamura et al., MNRAS (2016).

38 40 42 44 46 48 50 52 54 3 6 9 progenitor pre-SN νe Log (luminosity [erg s-1]) Log (time relative

• 2

2 4 6 8 SBO plateau to bounce [s]) νe νe νx GW EM

Supernova Explosion Mechanism

Si n, p

ν ν ν

Si

ν

Accretion O

evival”:

shock rgy to sion ar

wave

• neutron star

Neutron star Shock wave

Shock wave forms within the iron core. It dissipates energy dissociating the iron layer. Neutrinos provide energy to the stalled shock wave to start re-expansion.

Recent reviews: Janka (2017). Mirizzi, Tamborra et al. (2016).

Fingerprints of the Explosion Mechanism

Tamborra et al., PRL (2013), PRD (2014). Andresen et al., MNRAS (2017). Kuroda et al., ApJ (2017). Walk, Tamborra et al., PRD (2018), PRD (2019).

−5 5 A×[cm] 100 200 300 400 500 600 Time [ms] −5 5 A+[cm] 100 200 300 400 500 600 Time [ms] Equator Pole

50 100 150 200 20 40 60 80 100 120

27 Msun 20 Msun 11 Msun Frequency [Hz] Power spectrum IceCube

SASI frequency

• SASI modes

Tamborra, Hanke, Janka, Mueller, Raffelt, Marek, ApJ (2014). Janka et al., ARNPS (2016). Glas et al., (2018), Vartanyan et al., MNRAS (2019), O’Connor & Couch, ApJ (2018).

Lepton-number emission asymmetry (LESA): Large-scale feature with dipole character.

νe > ¯ νe

LESA: Neutrino-Driven Instability

Neutrino lepton-number flux (11.2 M )

sun

νe > ¯ νe

νe < ¯ νe

Sukhbold et al., ApJ (2016). Ertl et al., ApJ (2016). Horiuchi et al., MNRSL (2014). O’Connor & Ott, ApJ (2011). O’Connor, ApJ (2015). Kuroda et al., MNRAS (2018).

• Low-mass supernovae can form black holes.
• Neutrinos reveal black-hole formation.
• Failed supernovae up to 20-40% of total.

Successful explosions Failed explosions Fallback supernovae

100 200 300 400 500

t - tbounce [ms]

50 100 150 200

Lν [1051 erg s-1]

Lνe Lν

_

e

Lνx

BH-forming Supernova (40 M ) abrupt termination

sun

Neutrinos Probe Black Hole Formation

SASI frequency evolution = shock radius evolution SASI Neutrino (and gravitational waves) probe black-hole formation.

Walk, Tamborra, Janka, Summa, arXiv: 1910.12971.

Neutrinos Probe Black Hole Formation

Neutrino Alert

Network to alert astronomers of a burst (neutrinos reach Earth earlier than photons). SuperNova Early Warning System (SNEWS).

ν ν ν ν ν ν ν ν ν ν ν

Determination of supernova direction with neutrinos. Crucial for vanishing or weak supernova.

Flavor Evolution

νe

νµ ντ

Neutrino Interactions

interactions

ν − ν

Non-linear phenomenon

(−)

ν

(−)

ν

(−)

ν

(−)

ν

Z

• e,µ,

fermion (p, n, e)

Z

e,µ,

all flavors

• Neutrinos interact with neutrons,

protons and electrons (MSW enhanced conversions).

• W

e e

electron

• Angular distributions crucial!

Rν

SN envelope Vacuum Earth

(Earth Matter Effect)

• sphere

ν MSW resonance

∆m2

MSW resonance

δm2

vacuum oscillations

[not in scale]

Slow self-induced conversions Shock wave

Simplified Picture of Flavor Conversions

Fast Pairwise Neutrino Conversions

Izaguirre, Raffelt, Tamborra, PRL (2017). Tamborra et al., ApJ (2017). Shalgar & Tamborra, ApJ (2019). Capozzi et al., PRD (2017). Dasgupta et al., PRD 2018. Sawyer, PRD (2005), Sawyer, PRL (2016). Azari et al., PRD (2019).

Flavor conversion may occur close to neutrino decoupling region. Further work needed. Can occur without masses/mixing. No net lepton flavor change. νe(p) + ¯ νe(k) → νµ(p) + ¯ νµ(k) νe(p) + νµ(k) → νµ(p) + νe(k) Pairwise flavor exchange by scattering:

ν − ν

Growth rate: vs. . p 2GF (nνe n¯

νe) ' 6.42 m−1

∆m2 2E ' 0.5 km−1 “Fast” conversions Flavor conversion (vacuum or MSW): . Lepton flavor violation by mass and mixing. νe(p) → νµ(p)

Fast self-induced conversions?

Rν

SN envelope Vacuum Earth

(Earth Matter Effect)

• sphere

ν MSW resonance

∆m2

MSW resonance

δm2

vacuum oscillations

[not in scale]

Slow self-induced conversions Shock wave

Simplified Picture of Flavor Conversions

Neutron Star Properties

Gallo Rosso et al., JCAP (2018). Lattimer & Steiner, ApJ (2014). Gendreau & Arzoumanian, Nature (2017). Lattimer & Prakash, Phys. Rep. (2007). LIGO and Virgo, PRL (2018).

Late time neutrino signal can determine neutron star radius with 50-10% precision. Complementary information with respect to EM and gravitational wave determination (few %).

νe species νe species νx species

5 10 15 20 25 30 35 0.00 0.05 0.10 0.15

R reconstructed [km] Probability [km-1]

(a) Default case

ν ν ν

Probability [km-1]

(a) νe species

Diffuse Supernova Neutrino Background

time

z = 0

z = 1

z = 5

neutrinos neutrinos

DSNB detection will happen soon with, e.g., upcoming JUNO and Gd-Super-K project (sensitivity strongly improved).

Diffuse Supernova Neutrino Background

Recent review papers: Mirizzi, Tamborra et al. (2016). Lunardini (2010). Beacom (2010). Super-Kamiokande Collaboration, Astrop. Phys. (2015). Beacom & Vagins, PRL (2004). JUNO Coll., 2015.

10 10 10 10

Φνβ [MeV−1 cm−2 s−1]

¯ νe

5 10 15 20 25 30 35 40

E [MeV]

10-3 10-2 10-1 100

Fiducial DSNB model RSN(0) variability fBH−SN = 9% fBH−SN = 41% SFHo CC-SN + fast BH-SN IO Moller, Suliga, Tamborra, Denton, JCAP (2018). Nakazato et al., ApJ (2015). Horiouchi et al., MNRAS (2018). Priya and Lunardini, JCAP (2017).

Fingerprints of the Supernova Population

¯

HK (Gd) + JUNO + DUNE

0.0 0.1 0.2 0.3 0.4 0.5

fBH−SN

0.8 1.0 1.2 1.4 1.6

RSN(0) [10−4 Mpc−3 yr−1]

1σ 2σ 3σ > 3σ

BH−SN

• Independent test of the local supernova rate (~30% precision).
• Constraints on fraction of failed supernovae.

Compact Binary Mergers

Figure credit: Price & Rosswog, Science (2006).

Neutrinos and Compact Binary Mergers

Figure from Deaton et al., ApJ (2013).

Compact binary mergers are neutrino rich environments (similarly to supernovae).

Deaton et

Neutrino Emission Properties

Figures from Wu, Tamborra et al., PRD (2017), Tamborra et al., PRD (2014).

Mergers exhibit excess of anti-neutrinos over neutrinos (conversely to supernovae). Neutron star merger remnant

5 10 15 L [1052 erg/s] − νe νe 6 8 10 12 14 16 18 20 <ε> [MeV] − νe νe 1 10 100 time [ms]

Core-collapse supernova

1 2 3 4 Neutrino Energy Loss Rate [10

52 erg s

• 1]

νe νe νµ/τ

50 100 150 200 250 300 350 Time After Bounce [ms] 8 9 10 11 12 13 14 Mean Energy [MeV]

νe νe νµ/τ

Stellar Nucleosynthesis

Supernovae and neutron-star mergers Ni Cu Zn Ag Au Hg Pb

+

νe

p e−

n

+ +

p

n

+

¯ νe

e+

Synthesis of new elements could not happen without neutrinos.

Figures taken from: Metzger & Fernandez, MNRAS (2014); Kasen et al., Nature 2017.

Red and Blue Kilonova Components

Blue kilonova (n/p < 3) Red kilonova (n/p > 3)

dyn

ν − driven

visc BH torus jet

vdyn ∼ 0.2c

vvis ∼ 0.05c

vν ∼ 0.1c

Mvis ∼ 102M Mdyn ∼ 102M

Mν ∼ 103M

What About Neutrinos?

George, Wu, Tamborra, et al., to appear. Wu, Tamborra, et al., PRD (2017). Wu & Tamborra, PRD (2017). Kyutoku & Kashiyama, PRD (2018).

• Poor detection chances of MeV neutrinos from compact binary mergers.
• Neutrino may play an “indirect” major role in element production around the polar region.
• Possible implications for blue kilonova component.

10−8 10−7 10−6 10−5 10−4 10−3 10−2 10−1 100 40 60 80 100 120 140 160 180 200 220 mass fraction, X(A) mass number, A (b) no osc.

• sc.

Conclusions

Neutrinos: Fundamental in most energetic phenomena in our Universe. Ideal messengers. Carry imprints of the source inner workings. Rule the element formation in astrophysical sources.

Thank you!