What do we know about the identity of CR sources?
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Transcript of What do we know about the identity of CR sources?
What do we know about the
identity of CR sources?
Boaz Katz, Kfir BlumEli Waxman
Weizmann Institute, ISRAEL
The cosmic-ray spectrum & Composition
Cosmic-ray E [GeV]
log [dJ/dE]
1 106 1010
E-2.7
E-3
Heavy Nuclei
Protons
Light Nuclei?
Galactic
X-Galactic)?(
[Blandford & Eichler, Phys. Rep. 87; Axford, ApJS 94; Nagano & Watson, Rev. Mod. Phys. 00]
Source: Supernovae)?(
Source?
Source?Lighter
Intra-cluster CRs
• Observed in radio, HXR• Will not be discussed here
• See D. Kushnir’s talk: [arXiv:0903.2271, 0903.2275, 0905.1950]
* Likely origin- Accretion shocks * Predictions for Fermi, TeV (HESS, MAGIC)
Galactic CR sources: Constraints
• Max >~1015eV
• Energy production rate LG,CR~(AdiskhCR)UCR/tCR
* UCR~1 eV/cm3,
* Propagation: 2nd-ary (& primary) composition
LG,CR~cAdiskUCR(disk/sec)~1049.5erg/100yr
25.0
secsec g/cmGeV10
/7.8,)/()(
Z
Zm
n
mnnij p
ii
p
ijji
[Blandford & Eichler, Phys. Rep. 87; Axford, ApJS 94]
Galactic CR sources: SNe?
• Motivation for SNe as sources: * LG,CR~10-1.5 LG,SN
* Max ~1015eV * e- acceleration to 1015eV from X emission
• TeV photons from SNRs (RXJ1713.7-3946,RXJ0852.0-4622)
* Claim: must be due to pp pion production Confirms CR ion production
[e.g. Koyama et al. 95]
[e.g. Aharonian et al. 04--07]
TeV must be due to e- IC
• pp origin in contradiction with radio, thermal-X
(non detection of thermal X n<~0.1/cm3):
• TeV consistent with e- IC, including “cutoffs”:
• Claims RE e- IC inconsistency: Detailed spectral shape near hc, where
theoretical predictions are highly uncertain
100
10
/
cm/1.05
1GHz
TeV
1
23.
L
Ln
L
L pe
Synch
pp
2
..
10BermTherm
pp
L
L
TeVcm/1.0
10,keVcm/1.0
11
3,
1
3.,
nh
nh cICcSynch
[Katz & Waxman 07]
SNR TeV lessons
• Search at high n SNRs: Strong Thermal X, weak non-Thermal
• Difficult to prove pp based on EM obs. Highly simplified, phenomenological models (and plenty of room for complications: inhomogeneous plasma, particle spectra…)
[Katz & Waxman 07]
3
1
2
GeV1cm/110
/3
n
L
L pe
IC
pp
PAMELA: New e+ sources?
• Apply
anti-p, e+ consistent with 2ndary origin
• Radiative e+ losses- depend on propagation in Galaxy (poorly understood)
* At 20GeV: frad~0.3~f10Be
* Above 20GeV: If PAMELA correct slightly rising frad()[Katz, Blum & Waxman 09]
)/()( sec Zm
n
mnnij p
ii
p
ijji
pp /
)/( eee
410
310
210
110
GeV10 GeV100
radf
What do we know about >1019eV CRs?
• Max : LB>1012 (2/) (/Z 1020eV)2 Lsun
(see Dermer’s talk)
• Composition
[Waxman 95, 04]
Composition clues
HiRes 2005
Westerhoff (Auger) 2009
What do we know about >1019eV CRs?
• Max : LB>1012 (2/) (/Z 1020eV)2 Lsun
• Composition: HiRes –protons, Auger- becoming heavier @
3x1019eV? !!Uncertain interaction cross sections
• Energy production rate: - LB>1012 Lsun & RL=/eB=40p,20kpc Likely X-
Galactic
[Waxman 1995; Bahcall & Waxman 03]
[Katz & Waxman 09]
• 2(dN/d)=2(dQ/d) teff. (teff. : p + CMB N +
Assume: p, dQ/d~(1+z)m-
• >1019.3eV: consistent with protons, 2(dQ/d) ~1043.7 erg/Mpc3 yr + GZK
• 2(dQ/d) ~Const.: Consistent with shock acceleration [Reviews: Blandford & Eichler 87; Waxman 06
cf. Lemoine & Revenu 06]
Flux & Spectrum
cteff [Mpc]GZK (CMB) suppression
log(2dQ/d) [erg/Mpc2 yr]
G-XG Transition at 1018eV?
Fine tuning Inconsistent spectrum
[Katz & Waxman 09]
What do we know about >1019eV CRs?
• Max : LB>1012 (2/) (/Z 1020eV)2 Lsun
• Composition HiRes –protons, Auger- becoming heavier Uncertain interaction cross sections
• Energy production rate - LB>1012 Lsun & RL=/eB=40p,20kpc Likely X-
Galactic - Consistent with protons, 2(dQ/d) ~1043.7 erg/Mpc3 yr + GZK
UHE CR sources• Constraints: - L>1012 (2/) Lsun
- 2(dQ/d) ~1043.7 erg/Mpc3 yr
- d(1020eV)<dGZK~100Mpc
!! No L>1012 Lsun at d<dGZK Transient Sources
• Gamma-ray Bursts (GRBs) ~ 102.5, L~ 1019LSun L/2 >1012 Lsun
(dn/dVdt)*E~10-9.5 /Mpc3 yr *1053.5erg ~1044 erg/Mpc3 yr Transient: T~10s << Tp~105 yr
• Active Galactic Nuclei (AGN, Steady): ~ 101 L>1014 LSun= few brightest
!! Non at d<dGZK Invoke:
* “Dark” (proton only) AGN * L~ 1014 LSun , t~1month flares
(from stellar disruptions)
[Blandford 76; Lovelace 76]
[Waxman 95, Vietri 95, Milgrom & Usov 95]
[Waxman 95]
[Boldt & Loewenstein 00]
[Farrar & Gruzinov 08]
Anisotropy
• Cross-correlation signal: Inconsistent with isotropy @ 98% CL (~1.5) Consistent with LSS
• If anisotropy signal real & no anisotropy at 60EeV/(Z~10)
primaries must be protons See M. Lemoine’s talk [arXiv:0907.1354]
Biased (source~gal for gal>gal )
[Kashti & Waxman 08]
The GRB “GZK sphere”
• LSS filaments: D~1Mpc, fV~0.1, n~10-6cm-3, T~0.1keV
B=(B2/8nT~0.01 (B~0.01G), B~10kpc
• Prediction:
p
D
B
few~)eV103( 20GRBsN[Waxman 95; Miralda-Escude &
Waxman 96, Waxman 04]
BBVGRBs
GRB
BBVp
DelaySpread
BBVp
fDN
R
fDd
c
d
fDd
2220
3
2
2
2052
2/1
20
2/10
10~)eV10(
yrGpc/5.0~
eV10/
Mpc100/yr10~~~
eV10/
Mpc100/3.0
Summary• Galactic <1015eV (<1019eV) - LG,CR~10-1.5 LG,SN & Max ~1015eV (1019eV)
suggest SNR (trans-rel. SN) sources - TeV from low n, non-thermal X SNR: e- IC - Search for pp in high n, strong thermal X SNR pp:IC[@1GeV]~3 (n/1cm3) * Anti-p, e+ data consistent with 2ndary origin Prediction: e+/(e++ e-)<0.2+-0.1 up to ~300GeV PAMELA slightly rising frad() [constrain CR prop. Models]
• X-Galactic >1019eV - Likely protons, 2(dQ/d) ~1043.7 erg/Mpc3 yr, LB>1012 Lsun
suggest: GRBs [AGN flares?] - Anisotropy constrains primary composition
• Difficult to uniquely identify sources via EM observations Search for HE ’s
Back up slides
X-ray filaments
• Claim: X-ray filaments require B>100G, much larger than required for IC explanation of TeV emission (B~10G).
• Claim based on the assumption: Filaments due to e- cooling (vs, e.g., B
variations). * No independent support to this assumption; * X-ray & RADIO filaments (Tycho, SN2006)
inconsistent with this assumption.
What is the e+ excess claim based on?
• On assumptions not supported by data/theory* primary e- & p produced with the same
spectrum, and e- and e+ suffer same frad
e+/e-~sec~-0.5
Or* detailed assumptions RE CR propagation, e.g. isotropic diffusion, D~, within an -independent box frad ~(-1)/2
• If PAMELA correct, these assumptions are wrong
(Correct) detailed CR propagation models must agree with simple, analytic results
derived from sec
• Example: Diffusion models with {D~K0 , box height L}
reproduce data for parameter combinations shown in fig. [Maurin et al. 01]
• Trivial explanation: [Katz, Blum & Waxman 09]
Require sec( =35GeV) to agree with the value inferred from B/Csec =[3.2,3.45,3.9] g/cm2
[green, blue, red]
The 1020eV challenge
RB eBRBR
R
BR
ccV p c
v
c
v
v/
1~
1 2
cec
BRL p
222
v/2
1v
84
v
v
sun122
20,
2
46
2
20
2
L10
erg/s10eV10/v
p
p
cL
2R
tRF=R/c)
l =R/
2 2
[Waxman 95, 04, Norman et al. 95]
Anisotropy clues: I
Galaxy density integrated to 75MpcCR intensity map (source~gal)
[Waxman, Fisher & Piran 1997]
• Auger collaboration: Correlation with low-luminosity AGN @ 99% AGN? • AGN trace LSS Correlation with large-scale structure? Unfortunately… Unclear.
GRB proton/electron acceleration
Electrons• MeV ’s:
• <1:
• e- () spectrum:
• e- ()energy production
erg/s1051L
5.210
2/ eee ddn
yrMpc
erg10erg10
yrGpc
10~
34452
32
e
ee d
nd
yrMpc
erg10erg10
yrGpc
5.03
445.533
[Waxman 95, 04] Afterglow, RGRB~SFR
Protons• Acceleration/expansion:
• Synchrotron losses:
• Proton spectrum:
• p energy production:
erg/s10/1025.22
20,5.50 pL
4/14/320,
2 ms10/10 tp
2/ ppp ddn
yrMpc
erg10
34422
e
ee
p
pp d
nd
d
nd
52
GRB Model Predictions
[Miralda-Escude & Waxman 96]