Neutrino Astronomy with KNO

Team: Dongsu Ryu, Kyujin Kwak, Kwangeon Seong, Chang Hee Son, Bok Kyun Shin, Namuk Lee

1/20 Astrophysical neutrinos I: produced through interactions with cosmic ray particles Proton-proton interaction Proton-photon interaction 1. In inelastic p-p collisions, charged and neutral 1. pions, kaons and neutrons are produced by pions are produced. proton-photon interaction. ± 0 푷푪푹 + 푃푡ℎ푒푟푚푎푙 → 휋 + 휋

2. Neutral pion decays into two high-energy gamma-rays. 2. pions, kaons and neutrons decay into neutrinos 휋0 → 훾훾

3. Charged pion decays into muon and muonic neutrino. ± ± 휋 → 휇 + 휈휇(휈휇)

4. Muon decays into electron, electronic neutrino and muonic neutrino. ± ± 휇 → 푒 + 휈푒(휈ഥ푒) + 휈휇(휈휇)

➔ these neutrinos have “high” energies from GeV, TeV, PeV, and up to EeV. 2/20 Astronomical objects of high energy neutrinos Clusters of galaxies AGNs (active galactic nuclei) GRBs (gamma-ray bursts) – neutrinos of ~10 TeV – 1 PeV – highest energy neutrinos – TeV and PeV neutrinos (?)

Coma cluster: shocks and turbulence Galactic SNRs (supernova remnants) → cosmic rays → neutrinos SBGs (star burst galaxies) – mostly GeV and TeV neutrinos Galactic PWNs (pulsar wind nebulae) – neutrinos of ~10 TeV – 1 PeV – mostly GeV and TeV neutrinos

3/20 Astrophysical neutrinos II: neutrinos from stellar nucleosynthesis

Neutrino flux from the SUN

in “low” mass stars including the Sun → pp chain is dominant → neutrinos with E < ~1 MeV in “high” mass main sequence stars → CNO cycle is dominant → neutrinos with E ≈ 1 - 2 MeV 4/20 neutrinos from supernovae

→ supernova neutrinos have the energy around ~ 10 MeV on average

5/20 thermal neutrinos produced in high temperature and high density environments such as the cores of evolved stars thermal neutrino (From K. Seong) production rate in the core of a RSG (red super-giant) photo- pair- star 20 Mʘ during the neutrino neutrino carbon burning stage

plasmon bremsstrahlung decay neutrino neutrino (Guo & Gian 2016)

thermal neutrino energy spectrum during the carbon burning stage neutrinos peaks around E ~ 1 MeV, depending on temperature and density 6/20 Astronomical sources of MeV neutrinos O type stars the Sun ν with ν with E ~ 1 MeV E < ~1 MeV

(long) X-ray burster possibly due to carbon burning (?) ν with E ~ 1 MeV

RSGs supernovae (red supergiant stars) ν with ν with E ~ 1 MeV E ~ 10 MeV

also from neutron star merger, accretionthermal disks, neutrinos and7 /20etc Existing facilities for neutrino astronomy

IceCube: a neutrino telescope constructed in KM3NET (Cubic Kilometre Neutrino Telescope): a Antarctica (south pole). European neutrino telescope constructed at the It consists of optical bottom of the Mediterranean Sea. sensors with PMTs, It is a water which detect the Cherenkov Cherenkov radiation detector with emitted through instrumented interactions with water volume of in the ice. several cubic It is kilometres. optimized for It is optimized for astrophysical astrophysical neutrinos in neutrinos in the the energy energy range of range of ~0.1 ~0.1 TeV – 1 PeV. PeV – higher. 8/20 More are coming! P-ONE, the Baikal-GVD, a deep underwater Pacific Ocean neutrino telescope on the cubic Neutrino kilometer Explorer

Comparison of KM3NET, IceCube, & Baikal-GVD 9/20 Neutrino astronomy with existing facilities

IceCube: optimized for astrophysical neutrinos KM3NET: optimized for neutrinos in the energy range with ~ 0.1 PeV – higher, sees neutrinos mostly from of ~ 0.1 TeV – 1 PeV, exepct to observe neutrinos from AGNs, and also expects to see neutrinos from SBGs Galactic SNRs and PWNs and also see those from SBGs the astrophysical neutrino ~10-20 events for a flux observed by IceCube number of Galactic (Ahlers & Halzen 2015) sources in 5 (The KM3NET Collaboration 2019)

expected number of events for neutrino from blazar Galactic sources TXS 0506+056 in five years of (The IceCube data taking Collaboration 2018)

10/20 Sources and facilities for neutrino astronomy KNO (Vitagliano et al 2020)

supernovae

Thermal neutrinos from evolved stars

SN remnants Pulsar wind nebulae Star burst galaxies Galaxy clusters 104 cm2 Effective area for upward neutrinos AGNs

1 cm2

IceCube KM3NET direct detection upward neutrinos 10-4 cm2 with KNO with KNO From B. K. Shin 11/20 Could we observe “GeV” neutrinos with KNO? (From N. Lee) Predicted neutrino fluxes of galactic sources relative to the Predicted energy spectrum of atmospheric neutrino flux: open triangle - cone of 1o radius, neutrinos from galactic sources filled circles - cone of 2.5o radius cone of 1o radius,

upward neutrinos with KNO

Need enough events to statistically separate those from atm events!12/20 Predicted events in KNO (From B. K. Shin) of neutrinos from Vela Jr. of atmospheric neutrinos

~0.15 event with 5 years’ data taking ~1.5 event with 5 years’ data taking Doing “GeV” neutrino astronomy with KNO looks unfeasible! 13/20 Could we do MeV neutrino astronomy with KNO? O type stars the Sun ν with ν with E < ~1 MeV E < ~1 MeV

(long) X-ray burster due to carbon burning ν with E ~1 MeV

RSGs supernovae (red supergiant stars) ν with ν with E ~ 1 MeV E ~ 10 MeV

Need to be explored in detail!thermal neutrinos14/20 Possible neutrino astronomy with KNO

Solar neutrinos: Supernova neutrinos: could be detected if SN hundreds are expected explosions in the Local Group (distance <~ 1 Mpc). to be observed in KNO. long history of solar prediction for HK neutrino observations (Totani et al 1998) expected rate of core collapse from 1960s, including SNs in the Local Group: Homestake, Kamiokande, 1 in ~ 50 years (~ 20 – 100 years) SNO, HK, DUNE…

angular distribution of Virtually all neutrino solar neutrinos for experiments will see 3.49 to 19.5 MeV (The SN neutrinos if SNs in SK Collaboration 2018) the Local Group!

What else could we do with KNO ? 15/20 RSGs look most promising!

massive stars with M > ~12 M become, sun He-burning – not enough neutrinos blue supergiants, C-burning – perhaps enough neutrinos red supergiants and long lifetime (RSGs), and then O-burning – lifetime too short explode as SNs 16/20 - Lifetime of C-burning: ~ 1,000 years - SN rates in our Galaxy: ~ 1/100 years

→ ~ 10 C-burning RSGs in our Galaxy! (Messineo & Brown 2019)

Catalog of nearby RSGs: 10 within 1 kpc (From C. H. Son) Alias SIMBAD ID Spectral Type Distance T_eff Lum Mass [pc] [K] [Lum_sol] [M_sol] +ퟐퟕ +ퟖퟑ,ퟎퟎퟎ alf Ori M1-M2la-lab ퟏퟔퟖ−ퟏퟓ 3,600± 200 ퟏퟐퟔ, ퟎퟎퟎ−ퟓퟎ,ퟎퟎퟎ 16.5~19 +ퟒퟎ,ퟎퟎퟎ Betelgeuse & Antares: Antares alf Sco M0.5lab 170 3,660± 200 ퟗퟖ, ퟎퟎퟎ−ퟐퟗ,ퟎퟎퟎ 11~14.3 5 Lacertae 5 Lac K9la 505.05 3,713± 56 17,473± 3,344 5.11± 0.18 the closest RSGs +ퟐퟏ,ퟎퟎퟎ +ퟐ.ퟎퟎ 119 Tauri 119 Tau M2lab-lb 550 3,820± 135 ퟔퟔ, ퟎퟎퟎ−ퟐퟎ,ퟎퟎퟎ ퟏퟒ. ퟑퟕ−ퟐ.ퟕퟕ d ~ 170 pc NO Aurigae NO Aur M2lab 600 3,700 67,000 - V424 Lacertae V424 Lac K5lb 623 3,790± 110.5 11176.69 - KQ KQ Pup M1lab 659 3,660± 170 59,800 13~20 - Gaia data: there are MZ Puppis MZ Pup M1lab-lb 703 3,745± 170 19586.643 - about ~ a few x 1,000 +ퟏퟒퟎ +ퟏퟏퟏ,ퟎퟎퟎ μ Cephei mu Cep M2la ퟗퟒퟎ−ퟒퟎ 3,551± 136 ퟐퟔퟗ, ퟎퟎퟎ−ퟒퟎ,ퟎퟎퟎ 15~20 RSGs in our Galaxy V419 Cephei V419 Cep M2Ib 941 3,660± 170 17693.234 - - Less than 1% of RGSs - The chance that one would have C-burning core is several %! have C-burning in the - Nevertheless, would it be possible to detect neutrinos from core 17/20 them, if they have C-burning core? Summary 1. Neutrino astronomy, as a part of multi-messenger astronomy, has a great potential for future astronomy. 2. IceCube, optimized for PeV neutrinos, sees neutrinos mostly from AGNs. KM3NET, optimized for TeV neutrinos, is expected to detect neutrinos from Galactic SNRs and PWNs as well as SBGs. 3. KNO could do astronomy with MeV neutrinos. 4. KNO will do very good jobs with Solar neutrinos and SN neutrinos. 5. KNO could detect of order 10 events of neutrinos with E > 1 MeV during 5 years for nearby RSG stars. 6. Capturing low energy neutrino events, possibly down to ~ 1 MeV, will be THE KEY for possible MeV neutrino astronomy with KNO. 7. Neutrino astronomy with KNO is still in the early stage.

More studies should be done. 20/20