Transcript Astrophysical sources of High Energy Neutrinos

The beginning of extra-galactic neutrino
astronomy:
What have we learned from IceCube’s neutrinos?
E. Waxman
Weizmann Institute
arXiv:1312.0558
arXiv:1311.0287
J. Bahcall, “Neutrino Astronomy” (1989): “The title is more of an
expression of hope than a description of the book’s content…”
The main driver of HE n astronomy:
The origin of CRs
Where is the G/XG transition?
log [dJ/dE]
E-2.7
Galactic
Protons
UHE
X-Galactic
E-3
Source: Supernovae(?)
Heavy Nuclei
Source?
Lighter
Light Nuclei?
Source?
1
106
Cosmic-ray E [GeV]
1010
Consider the rate of CR energy production
at
UHE, >1010 GeV;
Intermediate E, 1-100 PeV;
“Low” E, ~10 GeV.
UHE: Composition
Auger 2010
[Wilk & Wlodarczyk 10]*
HiRes 2010 (& TA 2011)
HiRes 2005
[*Possible acceptable solution?, Auger collaboration 13]
UHE: Energy production rate & spectrum
Protons
Mixed composition
cteff [Mpc]
GZK
log(dQ/d log e) [erg/Mpc3 yr]
[Katz & EW 09]
dQ/d log e =Const.
=0.5(+-0.2) x 1044 erg/Mpc3 yr
[Allard 12]
Collisionless shock acceleration
• The only predictive model.
• No complete basic principles theory, but
- Test particle + elastic scattering assumptions gives
[Krimsky 77]
v/c<<1: dQ/d log e=Const.,
v/c~1: dQ/d log e=Const.xe-2/9 (G>>1, isotropic scattering), [Keshet & EW 05]
- Supported by basic principles
plasma simulations,
[Spitkovsky 06, Sironi & Spitkovsky 09, Keshet et al.
09, …]
- dQ/d log e=Const Observed in a wide
range of sources
(lower energy p’s in the Galaxy,
radiation emission from accelerated e-).
200c/wp
40c/wp
RL (e  e thermal ) 
c
wp
, RL  e
Intermediate energy: Neutrinos
• p+gN+p
p0  2g ; p+  e+ + ne + nm + nm
 Identify UHECR sources
Study BH accretion/acceleration physics
• For all known sources, tgp<=1:
 dQ / dlog e  GeV
 44
 2
3
 10 erg/Mpc yr  cm s sr
f ( z )  1, (1  z ) 3
djn
en
  WB  10 8 
de n
2
  1, 5 for
• If X-G p’s:
djn
en
(1019 eV)   WB
den
[EW & Bahcall 99;
Bahcall & EW 01]
2
 Identify primaries, determine f(z)
[Berezinsky & Zatsepin 69]
“Hidden” (n only)
sources
Violating UHECR
bound
BBR05
Bound implications: >1Gton detector
Fermi
2 flavors,
dQ / dloge
 0 .5
44
3
10 erg/Mpc yr
IceCube: 37 events at 50Tev-2PeV
~6s above atmo. bgnd.
[02Sep14 PRL]
e2n =(2.85+-0.9)x10-8GeV/cm2sr s =e2WB= 3.4x10-8GeV/cm2sr s
Consistent with Isotropy and
with ne:nm:nt=1:1:1 (p deacy + cosmological prop.).
IceCube’s detection: Implications
• Unlikely Galactic: Isotropy,
and e2g~10-7(E0.1TeV)-0.7GeV/cm2s sr [Fermi]
 e2n ~10-9(E0.1PeV)-0.7GeV/cm2s sr << WB
• DM decay?
The coincidence of 50TeV<E<2PeV n flux, spectrum (& flavor)
with the WB bound is unlikely a chance coincidence.
• XG distribution of sources,
(dQ/d log e)PeV-EeV~ (dQ/d log e) >10EeV, tgp(pp)>~1 [“Calorimeters”]
Or
(dQ/d log e)PeV-EeV>> (dQ/d log e) >10EeV, tgp(pp)<<1
& Coincidence over a wide energy range.
• (dQ/d log e) ~ e0 implies: p, G-XG transition at ~1019eV.
Candidate CR calorimeters:
Starburst galaxies
• Candidate UHECR sources are NOT expected to be “calorimeters”
for <100PeV p’s [e.g. Murase et al. 2014].
• Radio, IR & g-ray (GeV-TeV) observations
 Starbursts are calorimeters for E/Z reaching (at least) 10PeV.
• Most of the stars in the universe were formed in Starbursts.
• If CR sources reside in galaxies
and
Q~Star Formation Rate (SFR),
Then
n(en<1PeV)~WB .
•
(And also a significant fraction of
the g-bgnd, see Irene’s talk).
[Loeb & EW 06]
Low Energy, ~10GeV
dQ / dlog e Galaxy
dQ

  SFR / V  z 0
SFR Galaxy
dloge
• Our Galaxy- using “grammage”



dQ
e
 erg / Mpc 3 yr,   0.1 - 0.2
~ 2 10 44 
dloge
 10Z GeV 
• Starbursts- using radio to g observations
dQ
(e ~ 10GeV, z  0)  2 10 44 erg / Mpc 3 yr
dloge
 Q/SFR similar for different galaxy types,
dQ/dlog e ~Const. at all e!
[Katz, EW, Thompson & Loeb 14]
The cosmic ray spectrum
[From Helder et al., SSR 12]
The cosmic ray generation spectrum
A single source?
MW CRs,
Starbursts
(+ CRs~SFR)
XG n’s
XG CRs
[Katz, EW, Thompson & Loeb 14]
Source candidates & physics challenges
• Electromagnetic acceleration in astrophysical sources requires
[Lovelace 76; EW 95, 04; Norman et al. 95]
L> 1014 LSun (G2/b) (e/Z 1020eV)2 erg/s
• GRB:
1019LSun, MBH~1Msun, M~1Msun/s,
G~102.5
AGN:
1014 LSun, MBH~109Msun, M~1Msun/yr,
G~101
• No steady sources at d<dGZK  Transient Sources (AGN flares?),
Charged CRs delayed compared to g’s.
Energy extraction;
Jet acceleration and
content (kinetic/Poynting)
Particle acceleration,
Radiation mechanisms
Identifying the sources
• IC’s n’s are produced by the “calorimeters” surrounding the sources.
• DQ~1deg  Identification by angular distribution impossible.
• Our only hope:
Identification of transient sources by temporal ng association.
• Requires:
Wide field EM monitoring,
Real time alerts for follow-up of high E n events,
and
Significant increase of the n detector mass at ~100TeV
[n(source) may be << n(calorimeter)~WB [ e.g. n(GRB) ~0.1 WB]].
What will we learn from ng associations?
• Identify the CR sources.
Resolve key open Qs in the accelerators’ physics
(BH jets, particle acceleration, collisionless shocks).
• Study fundamental/n physics:
- p decay  ne:nm:nt = 1:2:0 (Osc.) ne:nm:nt = 1:1:1
[Learned & Pakvasa 95; EW & Bahcall 97]
 t appearance,
- GRBs: n-g timing (10s over Hubble distance)
[EW & Bahcall 97; Amelino-Camelia,et al.98;
 LI to 1:1016; WEP to 1:106 .
Coleman &.Glashow 99; Jacob & Piran 07]
• Optimistically (>100’s of n’s with flavor identification):
Constrain CP, new phys.
[Blum, Nir & EW 05; Winter 10; Pakvasa 10;
… Ng & Beacom 14; Ioka & Murase 14;
Ibe & Kaneta 14; Blum, Hook & Murase 14]
Summary
• IceCube detects extra-Galactic n’s. n=WB at 50TeV-2PeV.
•
Flux & spectrum of ~1010GeV CRs, ~1PeV n (and ~10 GeV CRs)
Consistent with
CR p sources in galaxies, dQ/dlog e~Const., Q~SFR.
* IceCube’s detection consistent with the predicted n(en<1PeV)~WB
from sources residing in starbursts.
[A flurry of models post-dicting IceCube’s results by arbitrarily
choosing model parameters to match the flux.]
* A single type of sources?
• The sources are unknown.
* UHE: L>1047(50)erg/s, GRBs or bright (to be detected) AGN flares.
• Temporal ng association is key to:
CR sources identification, Cosmic accelerators’ physics,
Fundamental/n physics.
What is required for the next stage
of the n astronomy revolution
• The number of events provided by IceCube
(~1/yr @ E>1 PeV, ~10/yr @ E>0.1PeV)
will not be sufficient for an accurate determination of
spectrum, flavor ratio and (an)isotropy.
 n telescopes Meff(100TeV) expansion to ~10Gton
(IceCube, Km3Net).
• Wide field EM monitoring.
• Adequate sensitivity for detecting the ~1010GeV GZK n’s.
Backup Slides
UHE, >1010GeV, CRs
J(>1011GeV)~1 / 100 km2 year 2p sr
3,000 km2
Auger:
3000 km2
Fluorescence
detector
Ground array
Where is the G-XG transition?
@ E<1018eV ?
• Fine tuning
• Inconsistent with
Fermi’s XG g (<1TeV) flux
[Gelmini 11]
e2(dQ/de) =Const  @ E~1019eV
[Katz & EW 09]
UHE: Do we learn from (an)isotropy?
Biased
(rsource~r
rgal>r
)
gal for
CR intensity
map
(rsource
~rgal
gal)
Galaxy density integrated to 75Mpc
[Kashti & EW 08]
[EW, Fisher & Piran 97]
• Anisotropy @ 98% CL; Consistent with LSS
[Kotera & Lemoine 08; Abraham et al. 08… Oikonomou et al. 13]
• Anisotropy of Z at 1019.7eV implies
Stronger aniso. signal (due to p) at (1019.7/Z) eV
Not observed  No high Z at 1019.7eV
[Lemoine & EW 09]
p production: p/A—p/g
•
p decay  ne:nm:nt = 1:2:0 (propagation) ne:nm:nt = 1:1:1
• p(A)-p: en/ep~1/(2x3x4)~0.04 (epeA/A);
- IR photo dissociation of A does not modify G;
- Comparable particle/anti-particle content.
• p(A)-g: en/ep~ (0.1—0.5)x(1/4)~0.05;
- Requires intense radiation at eg>A keV;
- Comparable particle/anti-particle content,
ne excess if dominated by D resonance (dlog ng/dlog eg<-1).
[Spector, EW & Loeb 14]
IceCube’s GRB limits
• No n’s associated with ~200 GRBs (~2 expected).
• IC analyses overestimate GRB flux predictions,
and ignore model uncertainties.
1
• IC is achieving relevant sensitivity.
 e g ,b  2
 G TeV  1PeV
en ,b  500
 GRB
[Hummer, Baerwald, and Winter 12;
see also Li 12; He et al 12]
 1MeV 
 0.2 WB
2 .5
[EW & Bahcall 97]
Are SNRs the low E CR sources?
• So far, no clear evidence.
Electromagnetic observations- ambiguous.
E.g.: “p decay signature”
[Ackermann et al. 13]: