Multi-Messenger GRB Astrophysics

1. GSFC Multi-Messenger GRB Astrophysics Michael Stamatikos Center for Cosmology and AstroParticle Physics (CCAPP) Fellow The Ohio State University (OSU) Michael.Stamatikos-1@nasa.gov The Inaugural CCAPP Symposium 2009 The Ohio State University Department of Physics October 12, 2009

2. Overview • Prompt • Afterglow I. GRB Electromagnetic Emission II. GRB Satellite Missions III. Neutrino Astronomy IV. Summary & Future Outlook • Swift (BAT, XRT & UVOT) • Fermi (LAT & GBM) • Correlative observations of GRBs • Fireball phenomenology & GRB Neutrinos • Discrete Neutrino flux • IceCube/ANTARES/NESTOR/KM3NET • Decade of science synergy

3. Gamma-Ray Bursts (GRBs): Prompt Emission • GRBs are unique, varying from burst to burst and class to class (short, long, X-ray rich, non-triggered). • Super-Eddington luminosities imply relativistic expansion. • Millisecond temporal variability implies compact objects R ≤ 2G2cDt. • Compactness problem resolved via ~100 ≤ GBulk≤ ~1000, ensuring transparent optical depth to observed g-ray photons, i.e. tgg≤ 1. AMANDA-II IceCube ANTARES /NESTOR KM3NET Briggs et al., ApJ 459: 40 (1996) “Short” GRBs are “hard” BATSE GRBs T90 (seconds)≡ Time required to accumulate from 5% to 95% of total counts in 50-350 keV band. Number of Bursts Number of Bursts Durations span 6 orders of magnitude! “Long” GRBs are “soft” “Long” GRBs ~1301 s “Short” GRBs ~0.02 s Number of Bursts T90 (seconds) Kouveliotou et al., ApJ 413: 101 (1993)

4. GRBs: Multi-Wavelength EM Afterglows Spectroscopically observed Doppler redshifts from optical transient (OT) afterglows. Isotropic Emission Beamed Emission Isotropic Emission: ~ 1 GRB/Day → RGRBiso~ 0.5 GRB/(Gpc3·yr). Beamed (Jet) Emission: Corrections → RGRBiso·(4/Ωb) sr and Egiso·(Ωb/4) sr. Where: Wb ≡ Beaming solid angle (sr).

5. “Swifts fly expertly on their first try. Regardless of their introduction to flight, all young are adept at it soon after they take their initial leap.” – National Geographic Society Boeing Delta II expendable launch vehicle ignition blasted NASA's Swift spacecraft from Complex 17A, Cape Canaveral Air Force Station, FL on Nov. 20 at 12:16:00.611 p.m. EST in 2004.

6. The Swift MIDEX Mission

7. The Swift MIDEX Mission BAT UVOT XRT • Burst Alert Telescope (BAT) 15-150 keV • Coded array of 32,768 CdZnTe detectors. • Sensitivity~ 10-8 ergs/cm2/sec • Detects ~100 GRBs per year • Energy resolution ~7 keV • PSF = 17’, 1-4 arcmin positions • X-Ray Telescope (XRT) 0.2-10 keV • Arcsec positions 23.6”x 23.6” FOV • Sensitivity ~2x10-14 ergs/cm2/s • 1 mcrab in 104 sec • CCD spectroscopy • (UVOT) UV/Optical Telescope • Sub-arcsec imaging, 17”x17” FOV • Grism spectroscopy • 24th mag sensitivity (1000 sec) • 170 nm - 600 nm, 6 colors • Sensitivity~ B=24 in white light in 1000 s Autonomous re-pointing, DQ = 50 < ~75 s, Orbit of 600 km x 21 inclination. XRT Image < 90 s UVOT Image GRB Triggers BAT T< 300 sec T < 10 sec sR < ~4 arcmin BAT Error Circle

8. Temporal Decay of Afterglows: XRT & UVOT GRB 050525A ~400 Swift GRBs 95% with XRT @ T < 200 ks ~60% with optical (UVOT + ground) ~10% Short GRBs Gehrels et al., New Journal of Physics 9:37 (2007) Fluxes decrease by orders of magnitude in first hours! • Afterglow Curves, Breaks, Flares, etc. • SGRB Redshift within elliptical galaxy • SGRB with extended soft emission • Over 133 Swift GRBs have redshifts. • GRB 090423 z ~ 8.0! (GCN 9215), i.e. ~85 Gpc or ~ 13 Gyr look back time. UVOT XRT Over ¾ of all GRB x-ray afterglows and redshift are based upon Swift bursts! < z > = 2.3 Number 0.001 0.01 0.1 1 10 Redshift

9. Large Area Telescope (LAT) GLAST Burst Monitor (GBM) Fermi (LAT & GBM) • Large Area Telescope(LAT) - < 20 MeV to > 300 GeV - Field of View (FOV) ~ 2.5 sr • GLAST Burst Monitor (GBM) - 8 keV – 30 MeV • 12 Sodium Iodide (NaI) Scintillation Detectors • Energy Range: • 8 keV – 1 MeV • Wide FOV (~8 sr) • Onboard Burst Trigger • 2 Bismuth Germanate (BGO) Scintillation detectors • Energy Range: • 0.15 – 30 MeV • Provides important overlap with LAT energy range.

10. Correlative Observations: Mutual Science Benefit! BATSE Epeak Distribution Y. Kaneko et al 2006, ApJS 166, 298 Comparison of Effective Areas 12 NaI (8 keV to 1 MeV) 2 BGO (0.15 to 30 MeV) LAT (20 MeV to >300 GeV) Stamatikos arXiv:0904.2755 • BAT increases GBM’s ~20-100 keV effective area by a factor of ~ 3. • Most GRBs have Epeak above BAT energy range. BAT-GBM GRBs↑ Epeaks. • BAT localization precision ~2-3 orders of magnitude better, ↑ follow-up (z). • Test validity of Epeak-Eiso redshift relationships (~35% Swift GRBs have z). • Broad-band spectral/temporal evolution ~ 6 energy decades (keV-GeV) for BAT-GBM, and ~11 energy decades for UVOT/XRT/BAT/GBM/LAT!! Has been realized in GRB 090510: LAT/GBM (GCN 9334/9336) and BAT/XRT/UVOT (GCN 9331).

11. BAT-GBM Joint Spectral Fit of GRB 080810 Left plate: Swift-BAT light curve for GRB 080810 with T0 = 13:10:12.3 UTC. Blue line indicates Swift slew-time. Red and green lines indicate 1st and 2nd joint fit interval, respectively. Center plate: Joint Swift-BAT/Fermi-GBM energy spectral fit for 1st interval, with fit parameters of α ~ 0.94 (+0.13, -0.15) and Epeak ~ 674 (+493, -237) keV (χ2/dof~1.33). Right plate: Joint fit for 2nd interval, resulting in fit parameters of α ~ 1.15 (+0.09, -0.10) and Epeak ~ 406 (+189, -106) keV (χ2/dof~1.15). Both intervals were best fit via a Comptonized model. Although consistent within their error bars, the 2nd (brighter) interval provides a better Epeak constraint . BAT-GBM Inter-calibration has ~50 common GRBs. Joint analysis is in preparation.

12. Magnetic Field Electron Low-Energy Photon -ray Electron -ray Synchrotron Radiation Self-Compton Scattering Prompt -ray emission of GRB is due to non-thermal processes such as electron synchrotron radiation or self-Compton scattering. --- The Fireball Phenomenology: GRB-n Connection GRB Prompt Emission (Temporal) Light Curve • Shock variability is a unique “finger-print” reflected in the complexity of the GRB time profile. • Implies compact object. Counts/sec Time (seconds) External Shocks Multi-wavelength Afterglows Span EM Spectrum Internal Shocks -ray e- p+ Optical X-ray Radio Prompt GRB Emission Afterglow E  1051 – 1054 ergs Optical Afterglow Radio Afterglow Spatial & temporal coincidence with prompt GRB emission R < 108 cm R  1014 cm T  3 x 103 seconds Spectral Fit Parameters R  1018 cm T  3 x 1016 seconds Ag, a, b, egb, egP Prompt GRB Photon Energy Spectrum – Characterized by the “Band Function” Photomeson interactions involving relativistically ( 300) shock-accelerated protons (Ep 1016 eV) and synchrotron gamma-ray photons (E 250 keV) in the fireball wind yield high-energy muonic neutrinos (E 1014 – 1015 eV).

13. Fireball Phenomenology: GRBs & n’s en(eV)ArrivalAstrophysical Mechanism/Comments 107 Before Progenitor Collapse/Merger 109 – 1010 Before Baryonic (n, p) Longitudinal decoupling 1012 - ≤ 1014 Before “Precursor” (pp/pg) 1014 – 1015 During Prompt (Photomeson/internal shocks) 1017-1018 After Afterglow (Photomeson/External shocks) • Fireball Phenomenology + Relativistic Hadronic Acceleration Neutrinos. • “Smoking gun” signature of hadronic acceleration  cosmic rays • Assuming GRBs were CR accelerators  Diffuse flux prediction. • AMANDA 1 PeV Diffuse Flux Upper Limits: TeV-PeV muon neutrinos  spatio-temporal coincidence “Background free” search Razzaque, Meszaros & Waxman PRD 69 023001 (2004) Stamatikos, M. et al., AIP Conference Proceedings 727, 146-149 (2004) Waxman, E. Physical Review Letters 75, 386-389 (1995) Stamatikos et al. astro-ph/0510336 Waxman & Bahcall, Phys. Rev. D 59 023002 Achterberg et al., ApJ 664: 397 (2007) Achterberg et al., ApJ 674: 357 (2008)

14. Motivation for Discrete Approach • Diffuse flux methodology  All GRBs described by same energy spectrum • Based upon average values for observables  contradicts observations. • Distributions: • 1. Span orders of magnitude, • 2. Differ from burst to burst • 3. Class to class, and are • 4. Effected by selection effects. 5 orders of magnitude Few GRBs produce detectable signal • Fluctuations enhance neutrino production, e.g. GRB 941017. • EM variance  neutrino variance. Halzen & Hooper ApJ 527, L93-L96 (1999) Alverez-Muniz, Halzen & Hooper Phys. Rev. D 62, (2000) • GRB030329  Case study. Stamatikos et al. astro-ph/0510336 Guetta et al., Astroparticle Physics 20 (2004) 429-455

15. Parameterization of Muon Neutrino Spectrum Neutrino Flux Models Model 1: Discrete Isotropic Model 2: Discrete Jet Model 3: Average Isotropic Neutrino spectrum is expected to trace the photon spectrum. Stamatikos et al. astro-ph/0510336 Guetta et al., Astroparticle Physics 20, 429-455 (2004)

16. Conclusions • Science Synergy: Swift-Fermi affords spectral & temporal evolution analysis over an unprecedented 11 energy decades (UVOTLAT)! • Expect ~1-3 BAT-GBM GRBs/month (~3217/year). • Can constrain/determine Epeakfor all coincident bursts, use redshift to determine burst luminosity and test empirical redshift relations. • Facilitate multi-messenger searches, e.g. neutrino astronomy via IceCube/ANTARES/NESTOR and KM3NET. (See Stamatikos et al 2009, Astro2010 Decadal Whitepaper.)