IceCube: Neutrino Messages from GRBsinoue/GRB... · Alexander Kappes, GRB’10, Kyoto, 23. April 2010 Waxman-Bahcall spectrum Individual spectra Prompt phase: stacked searches •

Alexander KappesUniv. Erlangen / Univ. Wisconsin-MadisonDeciphering the Ancient Universe with GRBs19. – 23. April 2010, Kyoto (Japan)

IceCube: Neutrino Messages from GRBs

Alexander Kappes, GRB’10, Kyoto, 23. April 2010

Outline

• Neutrino detection & the IceCube observatory

• Current status of GRB searches with IceCube- Prompt neutrinos- Precursor neutrinos- Model independent searches

• Future perspectives with IceCube- Observational program- Optical follow-up

2

Principle of neutrino detection

muon

νμ nuclearreaction

cascade

time & position of hits

µ (~ ν) trajectory energy

PMT amplitudes


Background: atmospheric muonsand neutrinos

4

p

atmosphere

cosmicrays

μνμ

νμcosmic

p

μνμ

• Flux from above dominated by atmospheric muons• Neutrino telescopes mainly sensitive to neutrinos from below


Sky visibility in neutrinos

5

Horizon

above

below

IceCube at the South Pole

South Pole

IceCube surface area


The IceCube observatory

7

• IceTopAir shower detector

• InIce86 strings (5160 PMTs)Instrumented volume: 1 km3

Current status: 79 strings deployed-1450 m

-2450 m

Alexander Kappes, GRB’10, Kyoto, 23. April 2010 8

Current Status ofGRB Searches with IceCube


Neutrinos from GRBs

9

Fireball model

Precursor

~-100 s T0 ~100 s > 1000 s

TeV neutrinosPeV neutrinos

EeV neutrinos

Prompt

Smoking gun evidence for hadronic acceleration → sources of UHECR


Detection channels

Muons:• Good angular resolution

(IceCube <1° for E > 1 TeV)• Rather poor energy resolution (factor ~3)

Cascades:• Sensitive to all flavors• Better energy resolution• Reduced directional information

10


• GCN-satellite triggered searches

very low background → 1 event can be significant !

• Untriggered “rolling window” searches

Analysis methods

11

On-time (blind) Off-timeOff-time

T0prompt

precursor (~100 s)

wide window (several hours)

background

time1 evt2 evt

1 evt


Prompt phase: individual GRBs

• Individual analysis of bright GRBs worthwhile• Example “naked-eye” GRB: Expected 0.1 events (9 strings)

• Expect O(1) event from bright GRBs with 86 strings

12

Γ = 300

90% CL upper limit νμ

GRB 080319BAbassi et al., ApJ 701 (2009)


• Individual modeling of bursts using satellite data(fireball model á la Guetta et al.)

• IceCube 40-strings: 117 GCN bursts (northern hemisphere; mainly Swift + Fermi)

• Sum expected events = 2.8; no signal found

Prompt phase: stacked searches

13

preliminary


Waxman-Bahcall spectrum

Individual spectra

Prompt phase: stacked searches

• IceCube starts to constrain fireball model parameters

14

90% CL upper limits νμ for 117 bursts

AMANDA final(using 416 bursts)Achterberg et al., ApJ 674 (2008)

IceCube 40-strings(using 117 bursts)preliminary


Precursor phase

• Jets with low Γ still inside progenitor star

→ TeV neutrinos

• Possibly large fraction of “choked” bursts

→ only detectable with “rolling window”

15

90% CL upper limits νμ

Rolling windowAMANDA, cascadesAchterberg et al., ApJ 664 (2007)

Triggered IceCube, 22-stringsAbbasi et al., ApJ 710 (2010)

all SNe havechoked jets

Razzaque et al., PRD 68 (2003)(H progenitors)


SN 2008d: neutrinos from core-collapse supernovae

16

90% CL upper limits νμ (IceCube 22-strings)

Distance: 27 Mpc• First direct observation of SN shock breakout

• X-ray flash yields precise SN time

• “Slow-jet” model(Razzaque, Meszaros, Waxman, Ando, Beacom)

• ~0.1 evts expected in IceCube 22-stringsAndo & Beacom, PRL 95 (2005):- jet points to Earth- Γb=3, Ej=3×1051

• No signal found

preliminary


Model independent

• Model-independent approaches important→ choice of time window→ energy spectrum

• Simple approach: fixed (wide) time window

- IceCube 22 strings (41 GRBs): -1 to +3 h around GRB; No signal found

→ Average νμ upper limit (90% CL) per burst for E-2 flux: 6.6×10−5 erg cm−2 (3 TeV–2.8 PeV)

17


0 1 2 3 4 5 6 7 8 9

10 11 12

10 s 100 s 1000 s 10000 s0.0 ! 100

5.0 ! 10-4

1.0 ! 10-3

1.5 ! 10-3

2.0 ! 10-3

2.5 ! 10-3

3.0 ! 10-3

Muo

n N

eutr

ino

Eve

nts

Per-

Bur

st N

orm

aliz

atio

n (G

eV

cm-2

)

t (s)

Icecube 40 E-2 Muon Neutrino Flux Limits

90% Upper Limit90% Sensitivity

Approach for “arbitrary” time scales:• Start with search in small window and

increase it consecutively

• Trial factor important

• IceCube 40-strings: No signal found

Model independent

18

Sensitivity νμ (90%CL; IceCube 40-strings)

per

-bur

st n

orm

aliz

atio

n (G

eV c

m-2

)

GRB Trigger Time Difference

Weig

hte

d E

ntr

ies / b

in

-40 -20 0 20 40 600.000

0.005

0.010

0.015

emission window (s)

preliminary


Future Perspectives with IceCube


Observational program

20

Detector sensitivity still increasing significantly during next (analysis) years; operation for at least for 10 years

• Triggered searches- Stacked analysis (model dependent + independent)- Individual analyses of exceptional bursts- Satellite “coverage”:

• Present: Swift 2010 + 4 years, Fermi 2013 (+ 5 years)• Future: SVOM (planned 2012 – ?), UFFO (planned 2015 – ?),

EXIST (2017?) . . .

• Rolling-window searches important !

• All-flavor searches (cascades) underway

• Optical follow-up


• IceCube coincidence triggers optical follow-up- angular window 3.5°- time window 100 s

• Delay neutrino detection → start of optical observations: < 5 min

Optical follow-up

SN/GRB

Institute in the North Optical telescopes

IridiumIceCube


Observational program

Kahn et al., 2006

t (days after burst)1E-4 0.01 1 100

Strizinger et al. (2003)m

agni

tud

e

t (days after burst)20 40 600

• Prompt observation (first night):Search for fast decreasing GRB afterglow- 10 short (5 s obs. time)- 10 medium (20 s obs. time) - 20 long (60 s obs. time)

• Follow-up observations (14 following nights): Slowly rising supernova light-curve- 8 long (60 s obs. time) per night


• Fully robotic• 24 hour (almost) all sky coverage• Large field of view (1.85˚× 1.85˚)

ROTSE telescope network

H.E.S.S., Namibia

McDonald, Texas TUG, Turkey

SSO, Australia


Image processing

– =„New“ „Reference“ Subtraction

• Automatic candidate selection• Test of algorithms with simulated

SN light-curve(SN light-curve model by P. Nugent (SN1999ex))

• System successfully running since end of 2008

• Data analysis underway

Simulated SN light-curve

extr

acte

d -

mag

.

TUG, TurkeyMcDonald, Texas

Limiting mag.Measured mag.

time [days]T+0 T+10 T+20 T+30


Summary

• With IceCube, the first km3-scale neutrino telescope is nearing completion

• GRBs highly interesting targets for neutrino telescope

• Analyses cover wide range of scenarios;already starting to constrain models

• Optical follow-up program extends IceCube’s physics potential significantly

25


The IceCube collaboration

Alexander Kappes PANIC'08, Eilat 16

• Univ Alabama, Tuscaloosa • Univ Alaska, Anchorage • UC Berkeley• UC Irvine • Clark-Atlanta University• U Delaware / Bartol Research Inst• Georgia Tech• University of Kansas • Lawrence Berkeley National Lab• University of Maryland• The Ohio State University• Pennsylvania State University• University of Wisconsin-Madison• University of Wisconsin-RiverFalls• Southern University, Baton Rouge

• Universität Mainz • Humboldt Univ., Berlin • DESY, Zeuthen• Universität Dortmund• Universität Wuppertal• MPI Heidelberg • RWTH Aachen • Universität Bonn

• Uppsala University• Stockholm University

Chiba University

• Universite Libre de Bruxelles• Vrije Universiteit Brussel• Université de Mons-Hainaut• Universiteit Gent • EPFL, Lausanne

Univ. of Canterbury, Christchurch

University of Oxford

Documents

IceCube: Neutrino Messages from GRBsinoue/GRB... · Alexander Kappes, GRB’10, Kyoto, 23. April 2010 Waxman-Bahcall spectrum Individual spectra Prompt phase: stacked searches •