the spatial morphology of the secondary emission in the
TRANSCRIPT
TheSpatialMorphologyoftheSecondaryEmissionintheGalacticCenterGamma-Ray
ExcessChrisGordon(UniversityofCanterbury)
Basedon:ThomasLacroix,OscarMacias,CG,PaoloPanci,CelineBœhm,andJosephSilk,PRD,2016
�2�
0�
2�
Galactic
Latitude
(b)
�2�0�2�
Galactic Longitude (l)
Sgr CSgr A*
the Arc
Sgr B
2FGLJ1748.6-2913
bkgA
40
80
120
160
200
240
280
Counts
�2�
0�
2�
Galactic
Latitude
(b)
�2�0�2�
Galactic Longitude (l)
Sgr CSgr A*
the Arc
Sgr B
2FGLJ1748.6-2913
bkgA
15
30
45
60
75
90
105
Counts
�2�
0�
2�
Galactic
Latitude
(b)
�2�0�2�
Galactic Longitude (l)
Sgr CSgr A*
the Arc
Sgr B
2FGLJ1748.6-2913
bkgA
30
45
60
75
90
105
120
135
Counts
Fermigamma-ray
data
DiffuseGalactic
Background
DarkMatter
orMSPs
• WeusedFermi-toolswith45
monthsofpass7data,and300
MeVto100GeV energyrange.
100 101 102
E� [GeV]
10�7
E2dN/dE
[GeV
cm
�2s
�1]
2 ⇥ 10�8
Inner slope:� = 1.2
MDM = 30 GeV, 100% bb̄
MSPorDarkMatterSpectrum
100 101
E� [GeV]
10�8
10�7
10�6
E2dN/dE
[GeV
cm
�2s
�1]
MDM = 10 GeV13e+e� + 1
3µ+µ� + 1
3⌧+⌧�
Spectra + SpatialTotal emission
Prompt
IC
Bremss
�3 �2 �1 0 1 2 3Latitude (b) [deg]
0.0
0.2
0.4
0.6
0.8
1.0
Relative
Flux
IC+Brem+Prompt (1st band)
Prompt (1st band)
IC+Brem+Prompt (5th band)
Prompt (5th band)
Teststatisticofsecondaries=2Log(Likelihood withsecondaries/likelihood withoutsecondaries)=102
P-valueofspectralfitforpromptonly=8⨉10-5
P-valueofspectralfitforprompt+secondaries=8⨉10-2
100 101
E� [GeV]
10�8
10�7
10�6
E2dN/dE
[GeV
cm
�2s
�1]
MDM = 10 GeV13e+e� + 1
3µ+µ� + 1
3⌧+⌧�
Spectra onlyTotal emission
Prompt
IC
Bremss
100 101
E� [GeV]
10�8
10�7
10�6
E2dN/dE
[GeV
cm
�2s
�1]
MDM = 10 GeV13e+e� + 1
3µ+µ� + 1
3⌧+⌧�
Spectra + SpatialTotal emission
Prompt
IC
Bremss
TestStatisticof secondaries=2Log(Likelihood withsecondaries/likelihood withoutsecondaries)=102
P-valueofspectralfitforpromptonly=8⨉10-5
P-valueofspectralfitforprompt+secondariesusingspatialinfo=8⨉10-2
P-valueofspectralfitforprompt+secondaries=1⨉10-3
�3 �2 �1 0 1 2 3Latitude (b) [deg]
0.0
0.2
0.4
0.6
0.8
1.0
Relative
Flux
IC+Brem+Prompt (1st band)
Prompt (1st band)
IC+Brem+Prompt (5th band)
Prompt (5th band)
100 101
E� [GeV]
10�8
10�7
10�6
E2dN/dE
[GeV
cm
�2s
�1]
MDM = 10 GeV
0.25µ+µ� + 0.75⌧+⌧�
Spectra + SpatialTotal emission
Prompt
IC
Bremss
TestStatisticof secondaries=2Log(Likelihood withsecondaries /likelihood withoutsecondaries)=6.5
P-valueofspectralfitforpromptonly=4⨉10-4
P-valueofspectralfitforprompt+secondaries=1⨉10-3
Usedadeltafunction injectionof20GeVelectronsandpositrons forthesecondaries.
TestStatisticof secondaries=2Log(Likelihood withsecondaries /likelihood withoutsecondaries)=42
P-valueofspectralfitforpromptonly=0.2
P-valueofspectralfitforprompt+secondaries=0.2
100 101
E� [GeV]
10�9
10�8
10�7
10�6
E2dN/dE
[GeV
cm
�2s
�1]
Millisecond Pulsars
Spectra + SpatialTotal emission
Prompt
IC
Bremss
�3 �2 �1 0 1 2 3Latitude (b) [deg]
0.0
0.2
0.4
0.6
0.8
1.0
Relative
Flux
IC+Brem+Prompt (1st band)
Prompt (1st band)
IC+Brem+Prompt (5th band)
Prompt (5th band)
Conclusions
• ExaminedmodelsoftheGalacticCenterGeVgamma-rayexcesswhich
havesignificantsecondaryemission.
• Developedamethodfortestingthegoodnessoffitwhensecondary
emissionhasdifferentmorphologytothepromptemission.
• Foundanexamplewheretheneedforsecondarieswasnotrevealed
byexaminingtheTestStatisticbutinsteadrequiredexaminingthefit
ofthespectrum.
InterstellarMediumParameters
• Magneticfield:
• Diffusion:
• Interstellarradiationfield:GALPROP• AtomicandmoleculargasDensity3Dmaps:Ferriereetal.(2007)