Search for Ultra-High-Energy Neutrinos from Gamma-Ray Bursts with the Pierre Auger Observatory

Sea ch o
Ul a-High-Ene gy
Neu inos om
Gamma-Ray Bu s s wi h
he Pie e Auge
Obse a o y
XXI Wo kshop on Neu ino Telescopes
The ese Paulsen
Oc obe 2, 2025
The Pie e Auge Obse a o y
•Hyb id de ec o : Su ace De ec o (SD)
and Fluo escence Telescopes
•SD: 1660 wa e Che enko pa icle
de ec o s a ions (WCD)
sp ead o e ≈3000 km2
•4Fluo escence Telescope si es,
wi h 27 elescopes
•Fo WCD: De ec s Ex ensi e Ai Showe s
ia seconda y pa icles a g ound
•Recen Auge P ime upg ade enhances,
i.e., composi ion sensi i i y, bu his
analysis ocuses on Phase I da a
CHAPTER 4
The Pie e Auge Obse a o y
0
10
20
30
40
50
60
70
80
[km]
Coihueco
HEAT
Loma Ama illa
Los Mo ados
Los Leones
Mala güe
CLF
XLF
SD s a ions
Figu e 4.1:
Layou o he Pie e Auge Obse a o y in A gen ina. The black lines indica e he ield
o iew o each elescope. Redone om [187].
47
Figu e made by S ijan Sehgal, Jannis Pawlowsky
XXI Wo kshop on Neu ino Telescopes [email p o ec ed] 2 /14
Neu ino de ec ion p inciple
Inclined neu ino-induced ai showe s can con ain a significan elec omagne ic
componen a g ound − o CR, only he muonic pa eaches he g ound
Figu e made by Michael Schimp
XXI Wo kshop on Neu ino Telescopes [email p o ec ed] 3 /14
Effec i e a ea o neu ino de ec ion
Ins an aneous effec i e a eas as a unc ion o θ(le ) and Eν( igh )
60 65 70 75 80 85 90 95
(deg)
10 5
10 4
10 3
10 2
10 1
100
E ec i e a ea (km2)
Auge ES ,
E
= 1019 eV
Auge ES ,
E
= 1018 eV
Auge DGH,
e
CC,
E
= 1019 eV
Auge DGH,
e
CC,
E
= 1018 eV
Auge DGL,
e
CC,
E
= 1019 eV
Auge DGL,
e
CC,
E
= 1018 eV
1013 1014 1015 1016 1017 1018 1019 1020
E (eV)
10 5
10 4
10 3
10 2
10 1
100
E ec i e a ea (km2)
Auge ES , = 91
o
Auge ES , = 92
o
Auge ES , = 93
o
Auge DGH
e
CC, = 75
o
Auge DGH
e
CC, = 80
o
Auge DGH
e
CC, = 85
o
Auge DGL
e
CC, = 60
o
Auge DGL
e
CC, = 66
o
Auge DGL
e
CC, = 69
o
IceCube CC, [30
o
, 90
o
]
IceCube CC, [ 5
o
, 30
o
]
IceCube CC, [ 30
o
, 5
o
]
IceCube CC, [ 90
o
, 30
o
]
Sou ce: JCAP 11 (2019) 004
XXI Wo kshop on Neu ino Telescopes [email p o ec ed] 4 /14
Fluence limi s o GRB170817A
•Uppe limi s on he neu ino fluence o
Auge , IceCube, and ANTARES,
o wo diffe en pe iods a ound he
e en , uppe panel ±500 s,
lowe panel 14 days
•We wan o compu e he uppe limi o
his sou ce, among o he s, using o he
neu ino emission spec a
Sou ce: A. Albe e al 2017
XXI Wo kshop on Neu ino Telescopes [email p o ec ed] 5 /14

Cons ains in he UHEνemission om GRBs
•Due o he cu en null obse a ion o UHEν, we wan o s udy he uppe fluence
limi s om GRBs
•In gene al, we ha e ha , o a specific neu ino emission model,
Nν=Z Z ϕMODEL
ν(Eν)Ae (Eν, θ( ), )dEνd .
F(Eν)=E2
ν
Nup
νϕMODEL
νT90
REmax
Emin RT90
0ϕMODEL
νAe (Eν, θ( ), )d dE.
•Using a 90%C.L limi wi h he Feldmann-Cousins app oach o 0backg ound and 0
signal, whe e Nup =2.44 e en s a e expec ed
•In he case o ϕMODEL
ν∝E−2,90%o he expec ed de ec ed e en s a he
Obse a o y a e be ween 100 PeV and 25 EeV
XXI Wo kshop on Neu ino Telescopes [email p o ec ed] 6 /14
Gamma- ay bu s s (GRBs)
•Schema ic iew o a GRB, showing a collima ed je con aining shells o diffe en
speeds, colliding shells, esponsible o he gamma- ay emission (In e nal shock
model)
C edi : NASA/Godda d Space Fligh Cen e /ICRAR
XXI Wo kshop on Neu ino Telescopes [email p o ec ed] 7 /14
Luminosi y limi s using de ailed simula ion
o neu ino emission spec um
1041061081010
Ene gy[GeV]
10−13
10−11
10−9
10−7
10−5
E2Fν[GeV/cm2]
IS
PHOTO
ICMART
Auge sensi i e a ea
•Th ee o he spec a a e aken om
De Lia and Tambo a,
JCAP10(2024)054
— In e nal Shock (IS)
— Pho osphe ic (PH)
— In e nal-collision-induced
magne ic econnec ion and
u bulence (ICMART)
•I on p ima y, pho odisin eg a e o
p o ons in he sou ce en i onmen
•Modeled using so-called s anda d
pa ame e s
XXI Wo kshop on Neu ino Telescopes [email p o ec ed] 8 /14
Redshi es ima ion
•As he edshi is only known o z∼16%o he sample, we need a p ocedu e o
es ima e his alue →c ea e dis ibu ion using Ke nal densi y es ima ion (KDE)
Sou ce:PoS(ICRC2025)1093
XXI Wo kshop on Neu ino Telescopes [email p o ec ed] 9 /14
Re e ences o he neu ino spec al shapes
•Following he publica ion by Valen in De Lia and I ene Tambo a 1, we look a h ee
diffe en GRB models: In e nal shock (IS), Pho osphe ic model (PHOTO) and
In e nal-collision-induced magne ic econnec ion and u bulence (ICMART)
—ϵd:Ene gy ac ion dissipa ed in
accele a ion
—ϵX:Ene gy ac ion ha effec i ely
accele a es seed pa icles
—ϵB:F ac ion o ene gy ha con ibu es o
ampli y he magne ic field
—k:Spec al index o p ima y pa icle
1JCAP10(2024)054
XXI Wo kshop on Neu ino Telescopes [email p o ec ed] Backup slides

Dependence o he neu ino fluence on Γ
•Using he ”s anda d pa ame e s”, a ying he Lo en z ac o o he je
•Some o his pa ame e space o IS and PHOTO models canno be p obed by Auge
(Γ∈[10 −80))
JCAP10(2024)054
1041051061071081091010
E(GeV)
1014
1013
1012
1011
1010
109
108
107
106
105
104
103
E2
Fµ+¯
µ(cm2GeV)
IS
1041051061071081091010
E(GeV)
PHOTO
1041051061071081091010
E(GeV)
ICMART
101
102
103

1041051061071081091010
E(GeV)
102
101
100
101
FFe
µ+¯
µ/Fp
µ+¯
µ
IS
1041051061071081091010
E(GeV)
PHOTO
1041051061071081091010
E(GeV)
ICMART
101
102
103

Figu e 7. Same as igu e 6, bu o in es iga ing he dependence o he neu ino luence on (
k
=2
.
2
is ixed o bo h he in e nal shock and he pho osphe ic models, while
k
=2
.
0is used o he ICMART
case). Dec easing inc eases he neu ino luence, wi h he la ge sp ead occu ing o he in e nal
shock and pho osphe ic je models. In ac , o hese models, he in e ac ion adius scales as 
2
,
which implies ha o la ge , in e nal shocks happen a a adius whe e bo h pho on and seed nuclei
ha e lowe densi ies. Howe e , his is no he case o he ICMART model, o which he adius
o in e ac ion is independen o he bulk Lo en z ac o . This explains he milde a ia ion o he
neu ino luence on in he in e nal shock model. A s ong a ia ion o he neu ino luence as a
unc ion o occu s acco ding o he composi ion.
happen a a nea ly cons an adius). This explains he milde dependence o he neu ino
luence on in he in e nal shock model. The ene gy co esponding o he maximum neu ino
luence (
EM
‹
) is s ongly shi ed o lowe ene gies as dec eases; his is because highe pho on
densi ies a e achie ed as dec eases, hence he pho odisin eg a ion imescale inc eases and
c osses he accele a ion imescale a lowe ene gies. This implies ha he cu o ene gy o he
pa en spec um dec eases, which also o ces he neu ino luence o peak a lowe ene gies.
This e ec is less p ominen in Poyn ing- lux je s han in kine ically-domina ed je s since he
accele a ion p ocess is mo e e icien in he o me hanks o he la ge magne ic ields.
The bo om panels o igu e 7also highligh a s ong a ia ion o he neu ino luence
as a unc ion o acco ding o he composi ion. The a io be ween he neu ino luence o
– 20 –
Sou ce: JCAP10(2024)054
XXI Wo kshop on Neu ino Telescopes [email p o ec ed] Backup slides
Dependence o he neu ino fluence on he spec al
index
•Using he s anda d pa ame e s, a ying he spec al index o he injec ed pa en
nucleus
•Smalle spec al index →la ge neu ino fluence
JCAP10(2024)054
1041051061071081091010
E(GeV)
1014
1013
1012
1011
1010
109
108
107
106
105
104
103
E2
Fµ+¯
µ(cm2GeV)
IS
1041051061071081091010
E(GeV)
PHOTO
1041051061071081091010
E(GeV)
ICMART
2.0
2.2
2.4
2.6
2.8
3.0
k
1041051061071081091010
E(GeV)
102
101
100
101
FFe
µ+¯
µ/Fp
µ+¯
µ
IS
1041051061071081091010
E(GeV)
PHOTO
1041051061071081091010
E(GeV)
ICMART
2.0
2.2
2.4
2.6
2.8
3.0
k
Figu e 6. Dependence o he neu ino luence on he injec ion spec al index o he accele a ed
pa en nucleus/nucleon spec a. Top:
‹µ
+
¯‹µ
neu ino luence as a unc ion o he neu ino ene gy
o
k
=2
.
0–3
.
0, using ou benchma k Fe-je (c . able 1) o he in e nal shock, pho osphe ic, and
ICMART je models; he o he je pa ame e s a e de ined as in able 1, in pa icula = 300 is ixed.
Bo om: Ra io be ween he Fe-je neu ino luence and he
p
-je one as a unc ion o he neu ino
ene gy. A smalle
k
allows o a la ge neu ino luence, because i a o s la ge densi ies o seed
nuclei; such end holds independen o he je composi ion.
able 1. Dec easing he powe law index ends o inc ease he neu ino luence, because i
allows o a la ge ac ion o he o al popula ion o be accele a ed a high ene gies. We can
also no e ha dec easing
k
sligh ly inc eases he ene gy
EM
‹
co esponding o he maximum
neu ino luence. Fo ou benchma k je , we also obse e ha
k
mos ly scales he neu ino
luence in a simila ashion o
p
- and Fe-je s, as e iden om he bo om panels o igu e 6.
Figu e 7explo es he impac o on he neu ino emission. Fo ixed composi ion, om
he op panels o igu e 7, we can see ha dec easing  ends o inc ease he neu ino luence,
in a way ha depends on he je model. Fo he in e nal shock and pho osphe ic models,
changes in a ec he adius o in e ac ion (
RIS
= 2
2c˜
a
); when dec eases, in e nal
shocks happen a a adius whe e bo h pho on and seed nuclei ha e la ge densi ies. Howe e ,
his is no he case o he ICMART model, o which he adius o in e ac ion is independen
o he bulk Lo en z ac o (in e nal shocks igge magne ic econnec ion e en s assumed o
– 19 –
Sou ce: JCAP10(2024)054
XXI Wo kshop on Neu ino Telescopes [email p o ec ed] Backup slides