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C.W. James for the ANTARES collaboration Thanks to J. Schmid , C. Rivière , and P. Baerwald

A search for neutrinos from long-duration GRBs with the ANTARES underwater neutrino telescope arxiv 1307.0304. C.W. James for the ANTARES collaboration Thanks to J. Schmid , C. Rivière , and P. Baerwald. Gamma-Ray Bursts (GRBs). GRBs: Intense flashes of gamma rays

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C.W. James for the ANTARES collaboration Thanks to J. Schmid , C. Rivière , and P. Baerwald

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  1. A search for neutrinos from long-duration GRBs with the ANTARES underwater neutrino telescope arxiv 1307.0304 C.W. James for the ANTARES collaboration Thanks to J. Schmid, C. Rivière, and P. Baerwald

  2. Gamma-Ray Bursts (GRBs) • GRBs: • Intense flashes of gamma rays • Duration: < 2 s (‘short’), > 2s (‘long’) • Emission from highly-relativistic jet (‘fireball’) • Long-duration GRBs: jet from collapse of massive star • Neutrinos? • Jet shocks + electrons: observed gamma rays • Jet shocks also accelerate protons… • Protons + photons = neutrinos! • Neutrino search: • Test link between GRBs and CR • Possible point-source candidates Woosley & Bloom, 2006 C.W. James forthe ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013

  3. ANTARES: a reminder • Main detection channel: • Muons from CC interactions of cosmic neutrinos • Main background: • muons/neutrinos from cosmic rays C.W. James forthe ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013

  4. GRB sample • 296 selected GRBs, Dec. 2007-Dec. 2011 • total 6.6 hr duration ANTARES visibility (selection based on GCN notices) C.W. James forthe ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013

  5. Expected neutrino flux in fireball paradigm • Standard treatment: • Guettaet al. 2004 (based on Waxman & Bahcall, 1997) • Individual GRB predictions based on observed gamma-flux • Analytic treatment: neutrinos from delta-resonance • NeuCosmA(Hümmeret al. 2012) • Numerical calculation • Full photohadronic cross-sections (inc. delta-production) • Secondary particles followed • Energy-loss before decay • Neutrino mixing • … C.W. James forthe ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013

  6. Comparison of predictions • NeuCosmA: • Lower integrated flux • Greater high-energy component GRB 110918 Guettaet al.spectral break energies Same for Different for NeuCosmA C.W. James forthe ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013

  7. NeuCosmA predictions for all GRBs* • Very wide range of flux magnitudes • GRB 110918 dominates above ~1 PeV TOTAL individual *Thanks to P. Baerwald, W. Winter C.W. James forthe ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013

  8. Background estimation: from data • GRBs: short, localised • Can use data as a statistically- independent background estimation • Background calculation: • Local detector coordinates • Detector conditions at time of GRB • Assume constant rate over detection region C.W. James forthe ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013

  9. Search principles • Event selection: • Within observed GRB duration (~1 minute/GRB) • Reconstructed direction: within 10o of GRB direction • Quality cuts (exclude down-going muons from cosmic rays) • Extended maximum likelihood (signal vs background) on remaining data • Search optimisation: • Signal from NeuCosmA • Background from data • Resolution: • ~0.3o-1o for muons • ~10o for showers GRB 110918 C.W. James forthe ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013

  10. Discovery potential • Estimate using pseudo-experiments • 1010background sims per GRB • 105source sims per ns per GRB • Require 2 signal events from a single GRB for a 5σ detection Probability of detection True expected source flux (events) GRB 110918 C.W. James forthe ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013

  11. Expected signal: 0.06 events Expected background: 0.05 events Expectations • 10 most-promising GRBs: C.W. James forthe ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013

  12. Results… no coincident events observed • 90% C.L. on combined neutrino flux from 296 bursts (NeuCosmA, Guetta): • All limits compatible with NeuCosmA predictions Summed flux from 296 GRBs All-sky, time-averaged flux IceCube: Abbasiet al., ANTARES 2007: Adrian-Martinez et al. C.W. James forthe ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013

  13. Conclusions • ANTARES limit set on neutrinos from long-duration GRBs • Neutrinos from GRBs still possible! • NeuCosmA: more detailed physical modelling • Fireball model predictions below current limits • Nearby, powerful GRBs can dominate • (better to be lucky than good) • Near-future promising: current neutrino telescope limits close to flux predictions C.W. James forthe ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013

  14. References • This paper: ICRC2013 0760; arxiv1307.0304 • Abbasi et al, Nature 484 (2012) 351 • Adrian-Martinez et al, JCAP (2013) 006 • Aguilar et al, Proc. ICRC v8, p232 • Hümmer S., Baerwald P, Winter W., Phys.Rev.Lett. 108 (2012) 231101 • Guettaet al.,AstropartPhys 20 (2004) 429 • NeuCosmA: courtesy P. Baerwald, W. Winter • Fermi: http://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html • Swift: http://swift.gsfc.nasa.gov/docs/swift/archive/grb_table.html • GCN: http://grbweb.icecube.wisc.edu C.W. James forthe ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013

  15. Background estimation: from data • GRBs: short, localised • Can use data as a statistically- independent background estimation • Background calculation: • Local detector coordinates • Detector conditions at time of GRB • Assume constant rate over detection region Detector response Short-term variation Long-term variation Normalisation to observed variability C.W. James forthe ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013

  16. Source simulation: point-spread function • PSF for GRB 110918 • Muons: 0.3ofitted angular resolution • Cascades: >10o (since improved) ~ C.W. James forthe ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013

  17. Statistical tests • Test-statistic Q: • Model discovery potential: • Maximise MDP via quality-cut parameter λ C.W. James forthe ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013

  18. Mention sigma after trial factor 296 Backup 1: distribution of test statistic • Test statistic for different numbers of signal events ns (0, 1, 2, 3, 4, 5) C.W. James forthe ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013

  19. Test statistics: null hypothesis • Number of signal events ns =0 C.W. James forthe ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013

  20. Test statistics: null hypothesis • Number of signal events ns =0 C.W. James forthe ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013

  21. Test statistics: null hypothesis • Number of signal events ns =0 C.W. James forthe ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013

  22. Test statistics: null hypothesis • Number of signal events ns =0 C.W. James forthe ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013

  23. Test statistics: null hypothesis • Number of signal events ns =0 C.W. James forthe ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013

  24. Test statistics: null hypothesis • Number of signal events ns =0 C.W. James forthe ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013

  25. ANTARES as a gamma-ray telescope • Tri’s picture here C.W. James forthe ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013

  26. Limit on strongest GRB in sample • 104 weaker than predicted gamma-ray flux • Sensitive to rare GRB (e.g. 100 times closer) Technique: Astraatmadja, T.L., MNRAS 418, 1774 C.W. James forthe ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013

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