Laguna Beach Collaboration Meeting AMANDA / ICECUBE Michael Stamatikos † [3/29/03]

1. Searching for High Energy Neutrinos from Gamma Ray Bursts with AMANDA:1997-2000 UW Analysis - Review & Update Laguna Beach Collaboration Meeting AMANDA/ICECUBE Michael Stamatikos† [3/29/03] [† In collaboration with Dr. Rellen Hardtke & A.J. Carver]

2. “The most incomprehensible thing about the universe is that it is comprehensible” -Albert Einstein

3. Raffaello Sanzio’s “The School of Athens”

4. Raffaello Sanzio’s “The School of Athens” Socrates Aristotle Plato Ptolemy Sanzio Zeno Pythagoreas Euclid

6. Cosmology Comes of Age • Irony - Cosmology is one of the oldest subjects yet one of the newest sciences. • Reason?- Lack of experimental evidence made it impossible to test theories – era of “arm-chair cosmologists” (i.e. metaphysics, philosophy etc.). • Turning Point(s) – (CMB) (1960’s) dramatic verification of Big Bang Theory leads to Inflation, (BBN), etc. • 20th Century - Cosmology is given the tools to test its theories (e.g. telescopes, satellites, occasional funding…). • 21st Century?– “Synergy of Science”, nascent fields such as high- energy particle astrophysics and ν-astronomy. The age of precision cosmology – great discoveries are on the horizon.

7. The Birth of Enigmas • Many great discoveries or solutions to older problems often generate new and tougher problems. • Problems which are handed down from generation to the next come to be known as enigmas.

8. Some enigmatic discoveries are not made in the pursuit of pure science.

9. CIA Discovers Gamma-Ray Bursts (GRBs)! • 1963 Nuclear Test Band Treaty • How would we know if anyone is cheating? • Nuclear reactions produce gamma radiation. • Vela satellites were launched in pairs (1963-1964). • The six satellites monitored earth for terrestrial nuclear explosions. • Discovered short, randomly distributed, non-repeating eruptions of gamma rays of non-terrestrial in origin! (July 2, 1967, by Vela 4A). • Information was finally declassifed and published in 1973 (Klebesadal, et al., Ap. J. Lett.)

11. What could they be? The wavelength (λ ) of peak thermal radiation decreases as the temperature of the object increases: Materialλ of peak thermal radiation ISM Radio Humans Infrared Stars Visible/UV AGN, BH X-rays

12. Compton Effect • In addition to nuclear reactions, gamma rays are produced in the collision of relativistic particles with low energy photons (Compton Effect). • This points to very energetic process such as the merger of compact objects such as black holes or neutron stars. • Earliest debates on GRBs were focused on their location (i.e. cosmological vs. galactic)

13. Slow GRB Progress (1970s-1980s) • Lack of observational data • Plethora of ideas • Crucial questions: Are they cosmological? What is the progenitor(s)? How is that much energy produced?

14. GRB Publications Kevin Hurley, 5th Huntsville Symposium 10/22/99

15. Detecting Gamma Radiation • Gamma radiation is highly penetrating and does not ionize matter, hence indirect methods must be used for detection. • Types of gamma interactions include: (1). Photoelectric absorption (E  300) (2). Compton scattering (~ 300 keV < E < 8 MeV) (3). Electron-positron pair creation (E  8 MeV) • In the above processes, charged particles are created which can be detected.

16. Properties of Gamma Detectors • High density – high γ-interaction probability. • Ability to transform the energy of e+/e- into a measured quantity. • Natural choice is a scintillator - γ-interaction leads to creation of optical photons – low resolution (100 eV).

17. Inorganic Scintillators • Based upon the lattice structure of crystals – valence and conduction bands.

18. Burst and Transient Source Experiment (BATSE) • Onboard NASA’s Compton Gamma Ray Observatory (CGRO) and is just 1 of 4 other experiments (EGRET, COMPEL & OSSE). • Full-sky monitoring (4π steradians) via 8 thin scintillation modules (one on each corner), the detection plane of each was different leading to an accuracy of ~ 1° - 10° depending on burst strength.

19. Burst and Transient Source Experiment (BATSE) Each module consisted of 2 detectors: (1). Large-Area Detector (LAD): Optimized for sensitivity and directional response. (2). Spectroscopy Detector (SD): Optimized for broad energy coverage and energy resolution.

20. http://www.batse.msfc.nasa.gov/batse/instrument/cgro.gif CGRO 12.7 cm PMT Energy range of LAD ~ 20 keV – 1.9 MeV (Typically 50-300 keV) Plastic scintillator Provides active shielding. Thickness: 6.35 mm Thin lead & tin passive shield LAD NaI Scintillator Diameter: 50.4 cm Thickness: 1.27 cm Sensitive Area: 2025 cm2 VELA CeI Scintillators Sensitive Area: 10 cm3 E(V5): 0.2 – 1 MeV E(V6): 0.3 – 1.5 MeV http://www.batse.msfc.nasa.gov/batse/instrument/module.mov

21. http://www.batse.msfc.nasa.gov/batse/instrument/mod.gif http://www.batse.msfc.nasa.gov/batse/instrument/cgro.gif NaI(T1) Scintillator ρ = 3.67 g/cm3 λmax = 415 nm n =1.85 τDecay = 230 ns tRise = 3.67 μs (10%-90%) Light Yield = 38,000 photons/MeV Energy Resolution = 7% FWHM @ 662 keV SD NaI(T1) Scintillator Diameter: 12.7 cm Thickness: 7.62 cm Sensitive Area: 127 cm2 Directly coupled to a 12.7 cm PMT. SD has E ~ 100 MeV (pair-production) Beryllium Window (0.68 mm) good transmission to ~ 7 keV http://www.batse.msfc.nasa.gov/batse/instrument/

22. The BATSE Revolution (1991-2000) • GRB triggered BATSE if signal was > 5.5σ. • Detected ~1 GRB/day with (1/3) sky coverage • Led to many of the breakthroughs in our understanding of GRB’s http://www.batse.msfc.nasa.gov/batse/pulsar/ Burst and Transient Satellite Experiment

23. The BATSE Revolution (1991-2000) A total of (8) detectors, one on each corner of the (CGRO) • GRB triggered BATSE if signal was > 5.5σ. • Detected ~1 GRB/day with (1/3) sky coverage • Led to many of the breakthroughs in our understanding of GRB’s Signal Strength – # of counts in detectors, Position = Relative # of counts/detector Burst and Transient Satellite Experiment

24. Triggered vs. Non-Triggered GRB’s • Triggered GRB Bursts: GRB’s emitting -ray’s within (20-50), (50-100), (100-300) and (>300) keV energy bands were recorded by BATSE with trigger timescales of (64), (256) and (1024) milliseconds. Such bursts are modeled by the Fireball model and the Waxman-Bahcall flux. • Non-Triggered GRB Bursts: GRB’s which were not recorded by BATSE due to a weak flux, fluence or satellite downtown time were discovered by Jeff Kommers and Boris Stern. Analysis shows convincing light curves and corroboration via the Ulysses satellite. These bursts are not modeled by the Fireball model or the Waxman-Bahcall flux due to their low energy.

25. BATSE’s Orbit http://www.batse.msfc.nasa.gov/batse/instrument/gro_position.html Orbital inclination ~ 28° Average Altitude ~ 470 km

27. Galactic coordinates Location algorithm LOCBURST was used to set GRB positions [Pendleton, G. et. al. Astrophysical Journal, 512: 362-376, 2/10/99] Isotropy was an indicator of origin at cosmological distances

28. No “typical” GRB • Temporal structure varies from t < (0.01)s to t > (100)s • This implies that the object must be compact.

29. GRB Durations • Two classes?

30. GRB 6891 Channel 1 (20 < E < 50 keV) Channel 2 (50 < E < 100 keV) Channels 1-4 (E > 20 keV) Channel 4 (E > 300 keV) Channel 3 (50 < E < 100 keV)

31. Most Energetic Events Since the Big Bang * No humans were harmed in the act of making this calculation.

32. GRBs are the Most Energetic Events Since the Big Bang! GRBs make Supernovae look like a Camp Fires!! * No humans were harmed in the act of making this calculation.

33. GRB Positional Error of BATSE Pendleton, G. et. al., The Structure and Evolution of LOCOBURST: The BATSE Burst Location Algorithm, Astrophysical Journal, 512: 362-376, 2/10/99

34. Human Hair (900x) (L) (D) θ ~ ½º The Hubble Deep Field View θ ~ 1/60º

35. http://www.jgiesen.de/SME/details/basics/astro/stposengl.htm

36. BATSE, BeppoSAX, and Follow-up Observations with Keck & HST • Afterglows in longer wavelengths • Redshifts  cosmological (zmax ~ 4.5) • Not at galactic centers • Star-forming regions • Possible supernovae connection • Relativistic outflow • Beaming

37. What Does a GRB Look Like? GRB970228 During Burst (2/28/99) 3 Days Later

38. What does a GRB Afterglow Look Like? This Hubble telescope image of GRB 990123 was captured two weeks after the gamma-ray blast wave passed Earth on January 23, 1999. The image covers a square region about the gamma-ray burst, 3.2 arc seconds on each side. The fading fireball, a point source at the center of the image, is near an irregular galaxy that could be home of whatever exploded.

39. Merger of Neutron Star and Black hole

40. Fireball Model • Waxman-Bahcall (WB); Halzen & Hooper (HH); Alvarez-Muniz, Halzen & Hooper (AHH) • Explosion powered by merger of two blackholes/neutron stars or collapse of supermassive star • Relativistically expanding plasma of , e+ and e- • -rays produced by synchrotron radiation of e’s • Internal shocks accelerate fireball • External shocks with surrounding matter generate afterglows

41. GRBs and Neutrinos • Can not see the inner engine of GRBs • If GRBs accelerate protons as well, neutrinos will be produced: p +  ±m± + nm e ± + ne + nm • Proton acceleration will tell us about what object(s) power the inner engine and the physics of the explosion

42. Waxman-Bahcall GRB  Spectrum Convolution of photon and proton spectra:

43. Fireball Successes • Temporal variation • Afterglows • Solves compactness problem • May explain source of highest energy cosmic rays

44. A Brief Review of the History of the (1998) GRB Data

45. To Surface • Recall that when an “event” or “hit” registers in a particular (PMT), the signal must first travel up the cables to the surface before it receives its time stamp.

46. To Surface • This travel time is known as (to) and varies for each (PMT) due to its placement in the array. • One must then work backwards and subtract the signal’s travel time from the time stamp in order to determine the “true” event time. • Typical off set times are (~ nanoseconds).

47. Austral Summer Strings Deployed Total PMT’s In Ice Detector Name 1995-96 4 86 AMANDA-B4 1996-97 6 302 AMANDA-B10 1997-98 3 428 AMANDA-B13 1999-2000 6 680 AMANDA-II (B19) In (1998) we only had (13) Strings

48. Unfortunately, • Strings (11, 12 & 13) had the wrong(to’s) associated with them. • This led to systematic errors which propagated in a non-linear manner throughout the (PMT’s) associated with these strings.

49. Consequently, (1). There was a loss of good reconstruction candidates. (2). The number of bad or mis-reconstructed events increased. (3). Much of the signal was lost after the mass reconstruction via this (to) error.

50. We had two options, (1). Re-filter the entire (1998) data set with the correct (to’s). - OR - (2). Generate a new Monte Carlo which accounted for the effects of the erroneous (to’s).