extragalac)c*cosmic*rays*above* the*iron*knee* · 2016-03-02 · mcmc*likelihood*scan:*...
TRANSCRIPT
10-5
10-4
10-3
10-2
10-1
100
101
102
1014 1015 1016 1017 1018 1019 1020
x-2.7
x-3.1
"Knee"
"Ankle"
SNR p SNR Fe extragal.?
E2 dN/d
E
E [eV]
Extragalac)c Cosmic Rays above the Iron Knee
Andrew Taylor Based on Phys.Rev. D92 (2015) 6, 063011 astro-ph/1505.06090
1
10-5
10-4
10-3
10-2
10-1
100
101
102
1014 1015 1016 1017 1018 1019 1020
x-2.7
x-3.1
"Knee"
"Ankle"
SNR p SNR Fe extragal.?
E2 dN/d
E
E [eV]
Separate Probes of the Transi)on Energy
Where does the energy flux go? (or do these CR propagate unimpeded?)….energy is conserved aJer all
Anisotropy constraint- Pierre Auger Collab. astro-ph/1212.3083
2
Why Consider UHECR to Understand the Galac)c/Extragalac)c Transi)on? • Since the ankle feature appears at an energy of ~1018.6 eV, a
new extragalac)c source class is presumed to begin to dominate here (in the first instance)
• Informa)on obtained from inves)ga)ons into the UHECR sources may provide new insights into Galac)c-‐Extragalac)c transi)on energy
0.01
0.1
1
10
100
1000
17.5 18 18.5 19 19.5 20 20.5
E2 dN
/dE
[eV
cm-2
s-1
sr-1
]
log10 Energy [eV]3
Cosmic Ray Proton Interac@ons
p γ
R =2m2
p
E2p
Z1
✏2dN�
d✏
Z 4Ep✏/mp
0kp�✏
0�p�(Ep, ✏0)d✏0
4
Composi@on-‐ Consider Nuclei?
���
���
���
���
���
�� ���� �� ���� ��
�������
������
��������
����
����������
���
����� ������ ����
����� ����
��
��
��
��
��
��
��
��
�� ���� �� ���� ��
�������
������
��������
����
����� �
�������
���
����� ������ ����
����� ����
5
Cosmic Ray Nuclei Interac@ons
γ N
R =2m2
N
E2N
Z1
✏2dN�
d✏
Z 4EN✏/mN
0kN�✏
0�N�(EN, ✏0)d✏0
6
Sources of Cosmic Ray Nuclei Must be Nearby
���
���
���
���
���
�� ���� �� ���� ��
�������
������
��������
����
����������
���
����� ������ ����
����� ����
��
��
��
��
��
��
��
��
�� ���� �� ���� ��
�������
������
��������
����
����� �
�������
���
����� ������ ����
����� ����
7
Nuclei Propaga@on and Disintegra@on
From astro-ph/1107.2055 8
Assump)ons on Source Popula)on
dN
dVC/ (1+ z)n
EZ,max
= (Z/26)⇥EFe,max
dN
dE/ E�↵
exp[�E/EZ,max
]
z < zmax
n = �6, �3, 0, 3
9
MCMC Likelihood Scan: Spectral + Composi)on Fits
n=3 evolu)on result
L(fp, fHe, fN, fSi,Emax,↵) / exp(��2/2)
0.01
0.1
1
10
100
1000
17.5 18 18.5 19 19.5 20 20.5
E2 dN
/dE
[eV
cm-2
s-1
sr-1
]
log10 Energy [eV]
EFe, max=1020.2 eV
α=0.6
A=1-2A=3-6
A=7-19A=20-39A=40-56
650
700
750
800
850
17.5 18 18.5 19 19.5 20 20.5
<Xm
ax>
[g c
m-2
]
log10 Energy [eV]
protons
Iron
Auger 2014
10
20
30
40
50
60
70
80
17.5 18 18.5 19 19.5 20 20.5
RM
S(X m
ax) [
g cm
-2]
log10 Energy [eV]
protons
Iron
Auger 2014
10
MCMC Likelihood Scan: Spectral + Composi)on Fits
0.01
0.1
1
10
100
1000
17.5 18 18.5 19 19.5 20 20.5
E2 dN
/dE
[eV
cm-2
s-1
sr-1
]
log10 Energy [eV]
EFe, max=1020.5 eV
α=1.8
A=1-2A=3-6
A=7-19A=20-39A=40-56
!"#$
!%$$
!%#$
!&$$
!&#$
!'%(# !'& !'&(# !') !')(# !*$ !*$(#
+,-./0!12!3-4*5
672'$!89:;2<!1:=5!
>;7?79@
A;79
BC2:;!*$'D
!"#
!$#
!%#
!&#
!'#
!(#
!)#
!*#
!")+' !"* !"*+' !", !",+' !$# !$#+'
-./012345!67!82
9$:
;<7"#!=>?@7A!6?B:!
C@<D<>E
F@<>
GH7?@!$#"&
n=-‐6 evolu)on result
L(fp, fHe, fN, fSi,Emax,↵) / exp(��2/2)
11
MCMC Results Table
Hard spectra preferred for source evolu)on following that of the SFR
Flafer spectra preferred for nega)ve source evolu)on
12
High Spectral Peaked Blazar Evolu)on
From astro-‐ph/1310.0006 (Ajello et al. 2014)
• Reminder: Blazar -‐> BL Lac (FR1) -‐> HSP • Supports idea that FSRQ (gas accre)ng) AGN evolve into BL Lac (gas starved) AGN
n=-‐6 evolu)on result
Archetypal HSP example Mrk 501
13
Secondary (Guaranteed) Gamma-‐Ray Fluxes From >1018.6eV Component
107 108 109 1010 1011 1012 1013 1014
E [eV]
10�1
100
101
102
103
E2 J
[eV
cm�
2s�
1sr�
1 ]
Fermin = 0 / proton onlyn = 3 / mixedn = 0 / mixedn =�3 / mixedn =�6 / mixed
n=3 to -‐6 evolu)on scenarios give rise to between 40% and 12% of Fermi limit
0.01
0.1
1
10
100
1000
17.5 18 18.5 19 19.5 20 20.5
E2 dN
/dE
[eV
cm-2
s-1
sr-1
]
log10 Energy [eV]
EFe, max=1020.5 eV
α=1.8
A=1-2A=3-6
A=7-19A=20-39A=40-56
n=-‐6 evolu)on result
0.01
0.1
1
10
100
1000
17.5 18 18.5 19 19.5 20 20.5
E2 dN
/dE
[eV
cm-2
s-1
sr-1
]
log10 Energy [eV]
EFe, max=1020.2 eV
α=0.6
A=1-2A=3-6
A=7-19A=20-39A=40-56
n=3 evolu)on result
14
Does a Separate Class of Extragalac)c Source Dominate at Lower Energies?
0.01
0.1
1
10
100
1000
10000
17 17.5 18 18.5 19 19.5 20 20.5
EFe, max=1020.50eV
α=2.0
E2 dN
/dE
[eV
cm-2
s-1
sr-1
]
log10 Energy [eV]
A=1-2A=3-6
A=7-19A=20-39A=40-56
Nega)ve evolu)on (HSP)
Posi)ve evolu)on (ISP + LSP)
15
Cascade Contribu)on from Second Source Popula)on
0.01
0.1
1
10
100
1000
10000
17 17.5 18 18.5 19 19.5 20 20.5
EFe, max=1020.50eV
α=2.0
E2 dN
/dE
[eV
cm-2
s-1
sr-1
]
log10 Energy [eV]
A=1-2A=3-6
A=7-19A=20-39A=40-56
n=3 to -‐6 evolu)on scenarios give rise to between 100% and 40% of Fermi limit
16
General Problem for Cascade Contribu)on?
Fermi Collabora@on (2015)-‐ astro-‐ph/1511.00693
dN
dS/ S�↵
I =
ZSdN
dSdS
“Our analysis permits us to es)mate that point sources, and in par)cular blazars, explain almost the totality (86+16-‐14 %) of the >50 GeV EGB.”
Energy [MeV]210 310 410 510
]-1 s
r-1
s-2
dN
/dE
[MeV
cm
2 E
-610
-510
-410
-310
Total EGB
IGRB
°Resolved sources, |b|>20
IGRB - Abdo et al. 2010
17
107 108 109 1010 1011 1012 1013 1014
E [eV]
10�1
100
101
102
103
E2 J
[eV
cm�
2s�
1sr�
1 ]
Fermin = 0 / proton onlyn = 3 / mixedn = 0 / mixedn =�3 / mixedn =�6 / mixed
Cascade Contribu)on from Second Source Popula)on
nuclei above 1018.6 eV
protons and nuclei above 1017.8 eV
18
An Alterna)ve Interpreta)on of the Nega)ve Source Evolu)on Result
The nega)ve evolu)on scenarios help resolve both: • “hard spectrum” • “IGRB excess” problems……but extragalac)c protons at lower energies appear to be problema)c, par)cularly for posi)ve evolu)on scenarios. Alterna)vely, these scenarios may simply be encapsula)ng the fact that we’ve a local dominant source and our value for the UHECR sea level is not typical!
19
Conclusions • A nega)ve source evolu)on allows for an E-‐2 type spectra to explain CR above the ankle (such an evolu)on is observed for the HBL blazars)
• The posi)ve evolu)on of other blazar classes (ISP + LSP or FRSQ), would give rise to sub Ankle extragalac)c cosmic rays (which again allow an E-‐2 type spectra for this component)
• New es)ma)ons of the diffuse gamma-‐ray background are challenging for all evolu)on scenarios accoun)ng for sub Ankle extragalac)c protons
20
Secondary Neutrino Fluxes
1013 1014 1015 1016 1017 1018 1019 1020
E [eV]
10�3
10�2
10�1
100
101
E2 J
[eV
cm�
2s�
1sr�
1 ]
ARA-37 (3yr)n = 0 / proton onlyn = 3 / mixedn = 0 / mixedn =�3 / mixedn =�6 / mixed
21
Cascade Contribu)on Limit
From astro-‐ph/1206.2923 (Inoue et al. 2012)
Limit on Cascade Component is around 40% of Fermi limit
Constraints also placed on evolu)on of contributors to cascade component
22
General Problem for Cascade Contribu)on?
Fermi Collabora)on (2015)-‐ astro-‐ph/1511.00693
dN
dS/ S�↵
I =
ZSdN
dSdS
“Our analysis permits us to es)mate that point sources, and in par)cular blazars, explain almost the totality (86+16-‐14 %) of the >50 GeV EGB.”
10-2
10-1
100
101
102
10-13 10-12 10-11 10-10 10-9 10-8
x(2-1.65)
x(2-2.5)
S2 dN/d
S [c
m-2
s-1 s
r-1]
S [cm-2 s-1]
23
From astro-‐ph/1506.06554 (Padovani et al. 2015)
Similar Evolu)on Observed for Non-‐Blazar AGN?
Radio Loud AGN are suggested to have posi)ve evolu)on (n=2) up to z=0.5, followed by nega)ve evolu)on (n=-‐4) beyond this.
24
What About the Contribu)on from Other FR1 AGN (LSP + ISP)?
HSP AGN
ISP + LSP AGN
25
Intermediate/Low Spectral Peaked Blazar Evolu)on
From astro-‐ph/1310.0006 (Ajello et al. 2014) 26
Source RedshiJs Contribu)ng to Arriving Flux
0.01
0.1
1
10
100
1000
10000
17 17.5 18 18.5 19 19.5 20
EFe, max=1020.20eV
α=0.60
E2 dN
/dE
[eV
cm-2
s-1
sr-1
]
log10 Energy [eV]
totalz<7e-4
7e-4<z<2e-32e-3<z<6e-36e-3<z<2e-22e-2<z<6e-26e-2<z<2e-12e-1<z<6e-1
0.01
0.1
1
10
100
1000
10000
17 17.5 18 18.5 19 19.5 20
EFe, max=1020.50eV
α=1.80
E2 dN
/dE
[eV
cm-2
s-1
sr-1
]
log10 Energy [eV]
totalz<7e-4
7e-4<z<2e-32e-3<z<6e-36e-3<z<2e-22e-2<z<6e-26e-2<z<2e-12e-1<z<6e-1
27
Injec)on Species Contribu)ng to Arriving Flux
0.01
0.1
1
10
100
1000
17.5 18 18.5 19 19.5 20 20.5
E2 dN
/dE
[eV
cm-2
s-1
sr-1
]
log10 Energy [eV]
EFe, max=1020.2 eV
α=0.6
pHe
NSi
Fe
0.01
0.1
1
10
100
1000
17.5 18 18.5 19 19.5 20 20.5
E2 dN
/dE
[eV
cm-2
s-1
sr-1
]
log10 Energy [eV]
EFe, max=1020.5 eV
α=1.8
pHe
NSi
Fe
28