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: 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 C.W. James for the ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013 2 Woosley & Bloom, 2006

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

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 for the ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013 4

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

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

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 for the ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013 7

8. 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 for the ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013 8 Background estimation: from data

9. Search principles Event selection: Within observed GRB duration (~1 minute/GRB) Reconstructed direction: within 10 o 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: ~0.3 o -1 o for muons ~10 o for showers GRB 110918 C.W. James for the ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013 9

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

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

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

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 for the ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013 13

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 Guetta et al.,Astropart Phys 20 (2004) 429 NeuCosmA: courtesy P. Baerwald, W. Winter Fermi: http://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html http://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html Swift: http://swift.gsfc.nasa.gov/docs/swift/archive/grb_table.html http://swift.gsfc.nasa.gov/docs/swift/archive/grb_table.html GCN: http://grbweb.icecube.wisc.edu http://grbweb.icecube.wisc.edu C.W. James for the ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013 14

15. 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 for the ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013 15 Background estimation: from data Detector response Short-term variation Long-term variation Normalisation to observed variability

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

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

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

19. Test statistics: null hypothesis Number of signal events n s =0 C.W. James for the ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013 19

20. Test statistics: null hypothesis Number of signal events n s =0 C.W. James for the ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013 20

21. Test statistics: null hypothesis Number of signal events n s =0 C.W. James for the ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013 21

22. Test statistics: null hypothesis Number of signal events n s =0 C.W. James for the ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013 22

23. Test statistics: null hypothesis Number of signal events n s =0 C.W. James for the ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013 23

24. Test statistics: null hypothesis Number of signal events n s =0 C.W. James for the ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013 24

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

26. Limit on strongest GRB in sample 10 4 weaker than predicted gamma-ray flux Sensitive to rare GRB (e.g. 100 times closer) C.W. James for the ANTARES Collaboration, 33rd ICRC, Rio de Janeiro, Brazil 2013 26 Technique: Astraatmadja, T.L., MNRAS 418, 1774