N. Globus, D. Allard, E. Parizot and T. Piran, 2017, ApJ Letters, 839, 2

PoS (ICRC2017) 516

Probing  the  extragalactic  cosmic-­‐ray  origin  with  gamma-­‐ray  and  neutrino  backgrounds    

The UHECRs interact with 1) extragalactic magnetic fields 2) extragalactic photon backgrounds

source

Gamma-­‐ray  and  neutrinos  as  probe  of  UHECR  sources  

energy  losses  =>  emission  of    

secondary  messengers

ν, γ

ν, γ

ν, γ

ICRC  2017,  12-­‐20  July,  Bexco,  Busan,  Korea  

ICRC  2017,  12-­‐20  July,  Bexco,  Busan,  Korea  

ElectromagneBc  cascades  

γ+γEBLà  e++e- pair production

e+γEBLà  e'+γ ICS

   =>  The  cosmic  evolu/on  of  cosmic-­‐ray  sources  have  a  strong  influence  on  the  cosmogenic  neutrinos  and  photons  fluxes  

=>The  νs  energy  range  is  PeV-­‐EeV,  the  γ-­‐rays  cascade  down  to  GeV-­‐TeV  

Allard  05  

Mixed  composition  model  

17.0 17.5 18.0 18.5 19.0 19.5 20.0 20.5log10 E (eV)

1023

1024

1025

E3 dN/d

E (e

V2 m-2s-1

sr-1) Auger (2013)

KG EPOS-LHCKG electron rich (H+He)Total extragal. (GRBs) with β= 2.0 to 2.5 (indicated)

Total Gal + extragal. (GRBs) with β= 2.4 and β= 2.5

H+He Gal + extragal (GRBs) β= 2.4 and 2.5

2.52.4

Total  Galac/c  +  extragalac/c  

Total  light  (H+He)  

Propagated  spectrum  

ICRC  2017,  12-­‐20  July,  Bexco,  Busan,  Korea  

Phenomenological  mixed  composi/on  model:    

1)  EGCR:  hard  nuclei  spectra  +  spectral  index  of  the  proton  component  2.0  <  β <  2.5  The  proton  spectrum  needs  to  be  soMer  to  fit  Kascade-­‐GRANDE  data  =>  it  will  contribute  significantly  to  the  expected  cosmogenic  γ-­‐ray  flux    "Low-­‐Emax"  model  =>  less  νs  due  to  the  lack  of  cosmic  rays  accelerated  above  the  pion  producBon  threshold      

2)  GCR:  rigidity  dependent  (Emax(p)  =  knee  energy)  

Injec/on  spectra  (EGCR)  

ICRC  2017,  12-­‐20  July,  Bexco,  Busan,  Korea  

109 1010 1011 1012

E (eV)

1

10

100

1000E2 J(

E) [e

V.cm

-2.s

ec-1.s

r-1]

EGB Model A Model Buncertainties in the modeling of the Galactic foreground

UHECR from GRBs, β= 2.0 to 2.5

misAGN

SFG

UHECR from non evolving sources, β= 2.0 to 2.5

blazars

UHECR (GRBs) + misAGN + SFG + blazars

UHECR (non evol) + misAGN + SFG + blazars

Resulting  gamma-­‐ray  fluxes  

Two different models for the Galactic foreground(Ackermann+  2015)    

Globus, Allard, Parizot and Piran 2017, ApJ  LeZers,  839,  2  

 

sum of all contributions

- SFGs (Ackermann et al. 2012, Fermi Collab.)- misaligned AGNs (Inoue 2011) - blazars (Ajello et al. 2015)

seems compatible with Model B...

ICRC  2017,  12-­‐20  July,  Bexco,  Busan,  Korea  

109 1010 1011 1012

E (eV)

100

1000E2 J(

E) [e

V.cm

-2.s

ec-1.s

r-1] EGRB Model A Model B

uncertainties in the modeling of the Galactic foreground

UHECR (GRBs) + other contributionsUHECR (GRBs) + lower limit of other contributionsother contributions (SFG + misAGN + blazars)lower limit of other contributionsUHECR (GRBs) (β= 2.0 to 2.5)

...even compatible with Model A if one consider the uncertainties on the SFG, misAGN and blazars models

+ uncertainties in the Galactic foreground ?

Resulting  gamma-­‐ray  fluxes  (GRB  or  SFR)  

ICRC  2017,  12-­‐20  July,  Bexco,  Busan,  Korea  

(Z16)   (A16)

What  about  most  recent  estimates  of  PS  contributions  ?    

2 recent studies: - Ackermann et al. 2016 (A16)- Zechlin et al. 2016 (Z16) (based on a method by Malyshev & Hogg 2011)

ICRC  2017,  12-­‐20  July,  Bexco,  Busan,  Korea  

(Z16)   (A16)

What  about  most  recent  estimates  of  PS  contributions  ?    

2 recent studies: - Ackermann et al. 2016 (A16)- Zechlin et al. 2016 (Z16) (based on a method by Malyshev & Hogg 2011)

ICRC  2017,  12-­‐20  July,  Bexco,  Busan,  Korea  

0 1 2 3 4 5 6α

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

z max

GRB

SFR

MLLAGN

HLLAGN

clusters

BL Lacs

80%

90%

100%

110%

120%

130%

104%

117%

130%

143%

156%

169%

% all contributions to EGB Model A % all contributions to EGB Model B Band 4 (10.4 - 50 GeV)

Central value of PS+misAGN+SFG models

Allowed  cosmological  evolutions  

TDEs?  

ICRC  2017,  12-­‐20  July,  Bexco,  Busan,  Korea  

Resulting  neutrinos  fluxes  

1015 1016 1017 1018 1019 1020

E (eV)

0.01

0.10

1.00

10.00

100.00E2 J(

E) [e

V.cm

-2.s

ec-1.s

r-1]

IceCube

ARIANNA (5 yrs)

GRAND (3 yrs)

β = 2.0

2.5

mixed composition GRB (as main UHECR sources) non evol. (as main UHECR sources)

1015 1016 1017 1018 1019 1020

E (eV)

0.01

0.10

1.00

10.00

100.00

E2 J(E)

[eV.

cm-2.s

ec-1.s

r-1]

IceCube

ARIANNA (5 yrs)

GRAND (3 yrs)

pure proton sources GRB (as main UHECR sources) non evol. (as main UHECR sources) FR-II (as main UHECR sources)

1015 1016 1017 1018 1019 1020

E (eV)

0.01

0.10

1.00

10.00

100.00E2 J(

E) [e

V.cm

-2.s

ec-1.s

r-1]

IceCube

ARIANNA (5 yrs)

GRAND (3 yrs)

β = 2.0

2.5

mixed composition GRB (as main UHECR sources) non evol. (as main UHECR sources)

1015 1016 1017 1018 1019 1020

E (eV)

0.01

0.10

1.00

10.00

100.00

E2 J(E)

[eV.

cm-2.s

ec-1.s

r-1]

IceCube

ARIANNA (5 yrs)

GRAND (3 yrs)

pure proton sources GRB (as main UHECR sources) non evol. (as main UHECR sources)

pure  protons  

mixed  composition  

ICRC  2017,  12-­‐20  July,  Bexco,  Busan,  Korea  

Summary  

- The mixed composition model is compatible with the spectrum and composition data (Globus, Allard, Parizot Phys. Rev. D 92, 021302) and is consistent with the anisotropy constraints on galactic protons (Tinyakov +16)  - We showed that this model is compatible with both the most recent Fermi-LAT measurements and with current IceCube limits (Globus, Allard, Parizot & Piran ApJ  LeZers,  839,  2)Only very strong evolution (FR-II) are excluded by the current observations

- There is a large uncertainty in the Galactic foreground subtraction=> neutrinos will help us to distinguish between models (proton "dip" model seems to be already ruled out for SFR and stronger evolution see Heinze +16)

ICRC  2017,  12-­‐20  July,  Bexco,  Busan,  Korea  

thank  you    

ICRC  2017,  12-­‐20  July,  Bexco,  Busan,  Korea  

BACK-­‐UP    

ICRC  2017,  12-­‐20  July,  Bexco,  Busan,  Korea  

Resulting  composition  

15 16 17 18 19 20log10 E (eV)

0.01

0.10

1.00

Rela

tive a

bundance

1H

1H galactic

He

Z=3-8

Z=21-26

Z=21-26 galactic

17.0 17.5 18.0 18.5 19.0 19.5 20.0log10 E (eV)

600

650

700

750

800

850

< X

max >

(g. cm

-2)

proton

Fe

SIBYLL 2.1

QGSJet II-4

EPOS-LHC

17.0 17.5 18.0 18.5 19.0 19.5 20.0log10 E (eV)

0

20

40

60

80

!X

max (

g. cm

-2)

proton

Fe

SIBYLL 2.1

QGSJet II-4

EPOS-LHC

17.0 17.5 18.0 18.5 19.0 19.5 20.0log10 E (eV)

600

650

700

750

800

850

< X m

ax >

(g. c

m-2)

proton

Fe

Auger LOFAR

SIBYLL 2.1 QGSJet II-4EPOS-LHC

17.0 17.5 18.0 18.5 19.0 19.5 20.0log10 E (eV)

0

20

40

60

80

σX m

ax (g

. cm

-2)

proton

Fe

SIBYLL 2.1 QGSJet II-4EPOS-LHC

⇒  The  model  provides  a  good  descrip/on  of  the  evolu/on  of  the  composi/on                  PredicBon:  the  dominant  class  of  nuclei  between    ∼6  1018  eV  and  ∼5  1019  eV  should  be  CNO  

Globus, Allard and Parizot, 2015, Phys.  Rev.  D  92,  021302      

Extragalactic γ-ray sources

EGRB  spectrum  by  Fermi  Large  Area  Telescope  (Fermi  LAT)  collaboraBon  between  100  MeV  and  820  GeV  

(Ackermann  et  al.  2015)    (Ackermann  et  al.  2015)    

•  resolved: blazars

•  unresolved: misaligned AGNs, SFGs,...

•  truly diffuse in origin: - the electromagnetic cascades initiated by both very high energy γ-rays and UHECRs interacting with the EBL - dark matter annihilation/decay

Comparison  with  total  EGB  

 (considering  the  mean  values  of  the  SFG+misAGN  models)