IceCube: Neutrino Messages from GRBs Alexander Kappes Univ. Erlangen / Univ. Wisconsin-Madison Deciphering the Ancient Universe with GRBs 19. – 23. April 2010, Kyoto (Japan)
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 Alexander Kappes, GRB’10, Kyoto, 23. April 2010
Principle of neutrino detection muon cascade nuclear ν μ reaction time & position of hits PMT amplitudes energy µ (~ ν ) trajectory
Background: atmospheric muons and neutrinos cosmic p rays μ ν μ cosmic atmosphere ν μ μ ν μ p • Flux from above dominated by atmospheric muons • Neutrino telescopes mainly sensitive to neutrinos from below 4 Alexander Kappes, GRB’10, Kyoto, 23. April 2010
Sky visibility in neutrinos above Horizon below 5 Alexander Kappes, GRB’10, Kyoto, 23. April 2010
IceCube at the South Pole South Pole IceCube surface area
The IceCube observatory • IceTop Air shower detector • InIce 86 strings (5160 PMTs) -1450 m Instrumented volume: 1 km 3 Current status: 79 strings deployed -2450 m 7 Alexander Kappes, GRB’10, Kyoto, 23. April 2010
Current Status of GRB Searches with IceCube 8 Alexander Kappes, GRB’10, Kyoto, 23. April 2010
Neutrinos from GRBs Fireball model EeV neutrinos PeV neutrinos TeV neutrinos Precursor Prompt ~-100 s T 0 ~100 s > 1000 s Smoking gun evidence for hadronic acceleration → sources of UHECR 9 Alexander Kappes, GRB’10, Kyoto, 23. April 2010
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 Alexander Kappes, GRB’10, Kyoto, 23. April 2010
Analysis methods • GCN-satellite triggered searches Off-time On-time (blind) Off-time prompt background T 0 precursor wide window (~100 s) (several hours) very low background → 1 event can be significant ! • Untriggered “rolling window” searches time 1 evt 2 evt 1 evt 11 Alexander Kappes, GRB’10, Kyoto, 23. April 2010
Prompt phase: individual GRBs • Individual analysis of bright GRBs worthwhile • Example “naked-eye” GRB: Expected 0.1 events (9 strings) Abassi et al., ApJ 701 (2009) GRB 080319B 90% CL upper limit ν μ Γ = 300 • Expect O (1) event from bright GRBs with 86 strings 12 Alexander Kappes, GRB’10, Kyoto, 23. April 2010
Prompt phase: stacked searches • 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) preliminary • Sum expected events = 2.8; no signal found 13 Alexander Kappes, GRB’10, Kyoto, 23. April 2010
Prompt phase: stacked searches 90% CL upper limits ν μ for 117 bursts AMANDA final (using 416 bursts) Achterberg et al., ApJ 674 (2008) Waxman-Bahcall spectrum IceCube 40-strings (using 117 bursts) preliminary Individual spectra • IceCube starts to constrain fireball model parameters 14 Alexander Kappes, GRB’10, Kyoto, 23. April 2010
Precursor phase 90% CL upper limits ν μ • Jets with low Γ still inside progenitor star all SNe have choked jets → TeV neutrinos Rolling window AMANDA, cascades • Possibly large fraction Achterberg et al., ApJ 664 (2007) of “choked” bursts Triggered IceCube, 22-strings → only detectable with Abbasi et al., ApJ 710 (2010) “rolling window” Razzaque et al., PRD 68 (2003) (H progenitors) 15 Alexander Kappes, GRB’10, Kyoto, 23. April 2010
SN 2008d: neutrinos from core-collapse supernovae • First direct observation of Distance: 27 Mpc SN shock breakout • X-ray flash yields precise SN time • “Slow-jet” model 90% CL upper limits ν μ (IceCube 22-strings) (Razzaque, Meszaros, Waxman, Ando, Beacom) preliminary • ~ 0.1 evts expected in IceCube 22-strings Ando & Beacom, PRL 95 (2005): - jet points to Earth - Γ b =3, E j =3 × 10 51 • No signal found 16 Alexander Kappes, GRB’10, Kyoto, 23. April 2010
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 ν μ upper limit (90% CL) per burst for E -2 flux: → 6.6 × 10 − 5 erg cm − 2 (3 TeV–2.8 PeV) 17 Alexander Kappes, GRB’10, Kyoto, 23. April 2010
Model independent Approach for “arbitrary” time scales: • Start with search in small window and 0.015 Weighted Entries / bin increase it consecutively 0.010 • Trial factor important • IceCube 40-strings: No signal found 0.005 Icecube 40 E -2 Muon Neutrino Flux Limits Sensitivity ν μ (90%CL; IceCube 40-strings) Per-Burst Normalization (GeV � cm -2 ) per-burst normalization (GeV cm -2 ) 0.000 12 -40 -20 0 20 40 60 GRB Trigger Time Difference 90% Upper Limit 11 3.0 ! 10 -3 preliminary 90% Sensitivity 10 Muon Neutrino Events 9 2.5 ! 10 -3 8 2.0 ! 10 -3 7 6 1.5 ! 10 -3 5 4 1.0 ! 10 -3 3 2 5.0 ! 10 -4 1 0.0 ! 10 0 0 10 s 100 s 1000 s 10000 s emission window (s) � t (s) 18 Alexander Kappes, GRB’10, Kyoto, 23. April 2010
Future Perspectives with IceCube 19 Alexander Kappes, GRB’10, Kyoto, 23. April 2010
Observational program 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 20 Alexander Kappes, GRB’10, Kyoto, 23. April 2010
Optical follow-up • IceCube coincidence triggers optical follow-up - angular window 3.5° - time window 100 s SN/GRB Institute in the North Optical telescopes Iridium IceCube • Delay neutrino detection → start of optical observations: < 5 min Alexander Kappes, GRB’10, Kyoto, 23. April 2010
Observational program • Prompt observation (first night): Search for fast decreasing GRB afterglow magnitude - 10 short (5 s obs. time) - 10 medium (20 s obs. time) - 20 long (60 s obs. time) Kahn et al., 2006 1E-4 0.01 1 100 t (days after burst) • Follow-up observations (14 following nights): Slowly rising supernova light-curve - 8 long (60 s obs. time) per night Strizinger et al. (2003) 20 0 40 60 t (days after burst) 22 Alexander Kappes, GRB’10, Kyoto, 23. April 2010
ROTSE telescope network • Fully robotic • 24 hour (almost) all sky coverage • Large field of view (1.85˚ × 1.85˚) McDonald, Texas TUG, Turkey H.E.S.S., Namibia SSO, Australia Alexander Kappes, GRB’10, Kyoto, 23. April 2010
Image processing – = „New“ „Reference“ Subtraction • Automatic candidate selection Simulated SN light-curve • Test of algorithms with simulated SN light-curve extracted -mag. (SN light-curve model by P. Nugent (SN1999ex)) McDonald, Texas TUG, Turkey Measured mag. • System successfully running Limiting mag. since end of 2008 • Data analysis underway T+0 T+10 T+20 T+30 time [days] 24 Alexander Kappes, GRB’10, Kyoto, 23. April 2010
Summary • With IceCube, the first km 3 -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 Alexander Kappes, GRB’10, Kyoto, 23. April 2010
The IceCube collaboration • Uppsala University • Stockholm University University of Oxford • Universität Mainz • Humboldt Univ., Berlin • DESY, Zeuthen • Universität Dortmund • Universität Wuppertal • Univ Alabama, Tuscaloosa Chiba • MPI Heidelberg • Univ Alaska, Anchorage University • RWTH Aachen • UC Berkeley • Universität Bonn • UC Irvine • Clark-Atlanta University • Universite Libre de Bruxelles • U Delaware / Bartol Research Inst • Vrije Universiteit Brussel • Georgia Tech • Université de Mons-Hainaut • University of Kansas • Universiteit Gent • Lawrence Berkeley National Lab • EPFL, Lausanne • University of Maryland • The Ohio State University Univ. of Canterbury, Christchurch • Pennsylvania State University • University of Wisconsin-Madison • University of Wisconsin-RiverFalls • Southern University, Baton Rouge Alexander Kappes PANIC'08, Eilat 16 Alexander Kappes, GRB’10, Kyoto, 23. April 2010
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