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Short Bursts

Short Bursts. Daniel Perley Astro 250 9 November 2005. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations

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Short Bursts

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  1. Short Bursts Daniel Perley Astro 250 9 November 2005

  2. Classes of GRBsLong Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions Long Bursts GRB Classes GRBs have long been known to fall into two general categories: l o n g b u r s t 45 s count rate (ct/s) time (seconds) Daniel Perley Short Bursts 9 November 2005

  3. Classes of GRBs Long BurstsShort Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions Short Bursts GRB Classes GRBs have long been known to fall into two general categories: 0.8 s short burst count rate (ct/s) time (seconds) Daniel Perley Short Bursts 9 November 2005

  4. Classes of GRBs Long Bursts Short BurstsDurations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions Burst Durations GRB Classes The separate populations are statsitcally robust, although intersecting. N 10-2 10-1 1 10 100 1000 T90 (seconds) Daniel Perley Short Bursts 9 November 2005

  5. Classes of GRBs Long Bursts Short BurstsDurations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions Burst Durations GRB Classes The separate populations are statsitcally robust, although intersecting. l o n g b u r s t s N short bursts 10-2 10-1 1 10 100 1000 T90 (seconds) Daniel Perley Short Bursts 9 November 2005

  6. Classes of GRBs Long Bursts Short Bursts DurationsDuration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions Duration/Hardness GRB Classes The two populations have different hardnesses: short bursts Hardness (S3/S2) l o n g b u r s t s T90 (seconds) Daniel Perley Short Bursts 9 November 2005

  7. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. HardnessDuration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions Duration/Fluence GRB Classes Other intrinsic differences have also been noticed. 10-4 l o n g b u r s t s 10-5 Ftot (erg/cm2) 10-6 10-7 short bursts 10-8 10-2 1 10 100 1000 10-1 T90 (seconds) Figure 1, Balasz et al. 2004 Daniel Perley Short Bursts 9 November 2005

  8. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before SwiftLong Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions Long Burst Localization Before Swift First GRB (long burst) localized and first host identified in 1997. Many have followed since then. • All long GRBs located in star-forming galaxies • All long GRBs located in regions with massive stars • Coincident type Ic supernova observed in one case → Long bursts are associated with supernovae. However, short GRBs long eluded localization, and no similar conclusions could be made. Daniel Perley Short Bursts 9 November 2005

  9. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst LocalizationShort Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions Short Burst Localization Before Swift The intrinsically short duration of a short burst makes determining the position of the prompt gamma emission even more difficult than usual. "Best" localizations (5-50 square arcmin) generally from Interplanetary Network. 5 ' Daniel Perley Short Bursts 9 November 2005

  10. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions Afterglow Nondetections 1 = 000607 5.6 arcmin2 2 = 001025B 24.5 arcmin2 3 = 001204 6 arcmin2 4 = 010119 3.3 arcmin2 = long burst detected = long burst limit Before Swift Before thist year, no short burst afterglow had been found in any IPN or burst detection error box. Daniel Perley Short Bursts 9 November 2005

  11. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow NondetectionsGalaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions Galaxy Correlations Before Swift (Recent) study computes correlation function of BATSE short burst positions with nearby galaxies. Result: correlation significant to 2σ No correlation seen for long bursts. Estimate of 5-25% of GRBs from <100 Mpc Daniel Perley Short Bursts 9 November 2005

  12. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions Burst Models Burst Models A large number of models had been proposed – mostly of the same which had been previously proposed for GRBs in general. • Black hole evaporation • SGR (magnetar) giant flares • Neutron star – neutron star mergers • Neutron star – black hole mergers • Collapsar • Neutron star collapse (supranova) Daniel Perley Short Bursts 9 November 2005

  13. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst ModelsPrimordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions Primordial Black Holes N 10-2 10-1 1 10 100 1000 T90 (seconds) Burst Models An early suggestion: GRBs may be the evaporation of black holes produced in the early universe. Mass: 7 × 1014 g (mc2 = 5 × 1035 erg) → Distance: ~few parsecs Burst duration: <50-200 ms cannot explain most short bursts Daniel Perley Short Bursts 9 November 2005

  14. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black HolesMagnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions Magnetar Giant Flare Burst Models Massive flare on the surface of highly magnetized neutron star. Catastrophic magnetic field reorganization. Some previous flares: - 5 March 1979 event: 4 × 1044 ergs (SGR 0526-66, LMC) 0.2 s - 27 August 1998 event: 8 × 1043 ergs (SGR 1900+14) 0.2 s Duration and hardness consistent with short GRBs. Distance for GRB: 4 Mpc (Virgo cluster: 20 Mpc) But could there be much larger flares? Daniel Perley Short Bursts 9 November 2005

  15. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black HolesMagnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions Magnetar Giant Flare Burst Models - 5 March 1979 event: 4 × 1044 ergs (SGR 0526-66, LMC) 0.2 s - 27 August 1998 event: 8 × 1043 ergs (SGR 1900+14) 0.2 s - 27 December 2004 event 2 × 1046 ergs (SGR 1806-20) 0.5 s Most energetic Galactic event since Tycho. 0.8 erg/cm2 over 0.5s Sirius: 10-4 erg/cm2/sFull Moon: 1 erg/cm2/s Daniel Perley Short Bursts 9 November 2005

  16. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black HolesMagnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions Magnetar Giant Flare Burst Models - 5 March 1979 event: 4 × 1044 ergs (SGR 0526-66, LMC) 0.2 s - 27 August 1998 event: 8 × 1043 ergs (SGR 1900+14) 0.2 s - 27 December 2004 event 2 × 1046 ergs (SGR 1806-20) 0.5 s Duration and hardness consistent with short GRBs. (long ringing 'tail' would not be detectable at great distance) Distance for GRB: 30 Mpc (Virgo cluster: 20 Mpc) Magnetars all young: ~104 year lifetime (restricted to star-forming galaxies/regions) Repetition possible over long time scales Daniel Perley Short Bursts 9 November 2005

  17. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant FlareNS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions Neutron Star-Neutron Star Merger Burst Models Closely orbiting neutron stars (d ~< solar radius) lose energy from gravitational radiation. Systems known to exist (binary pulsars) Must eventually merge. Post-merger object quickly collapses to black hole Very high angular momentum of system : accretion disk forms; falls onto black hole. G M2 R Gravitational binding energy: ~ 1053 erg → Mpc/Gpc distances Timescale for collapse: <~1 second Daniel Perley Short Bursts 9 November 2005

  18. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS MergerNS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions Neutron Star-Black Hole Merger Burst Models Closely orbiting neutron star / black hole pair also loses energy to gravitational radiation and merges. Neutron star is tidally disrupted into accretion disk; falls onto black hole. Gravitational binding energy: MNSc2 ~ 1054 erg → Mpc/Gpc distances Timescale for accretion: <~1 second Supernovae can 'kick' binary out of Galaxy. Daniel Perley Short Bursts 9 November 2005

  19. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant FlareNS-NS MergerNS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions Compact Object Mergers Burst Models Either type of merger: Inspiral takes ~ 1 Gyr. • Star formation may have ceased. • System may have migrated from point of origin – supernova explosions cankick the binary well outside galacticinterior Possibility of "mini-supernova" due to production of radioactive elements in ejected matter. Daniel Perley Short Bursts 9 November 2005

  20. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH MergerCollapsar Summary Short Bursts since Swift GRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions Collapsar Burst Models Collapsar (hypernova) model highly successful in describing long bursts. Collapse of iron core of highly massive star to black hole + accretion of material (0.1-5 Msun). Relativistic jet penetrates stellar envelope Energies ~ 1050 erg : cosmological distances Fallback time for stellar core: ~few seconds too slow for short GRBs. Significant uncertanties in calculation; Breakout flash could be shorter? Massive stars short-lived: would be bound to star-forming regions (like long GRBs) Daniel Perley Short Bursts 9 November 2005

  21. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH Merger CollapsarSummary Short Bursts since Swift GRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions Model Summary Burst Models Daniel Perley Short Bursts 9 November 2005

  22. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since SwiftGRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions GRB 050509B The Swift Era First Swift short burst. First X-ray afterglow: XRT provided 2.8' localization This position is very close to large elliptical at center of low-z cluster. T90 = 0.040 S = 1 × 10-10 E = 3 × 1048 Large ellipticalz = 0.2248 XRT all units CGS blue Daniel Perley Short Bursts 9 November 2005

  23. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since SwiftGRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions GRB 050509B The Swift Era Is the burst associated with the elliptical? Chance alignment probability very small. inside galaxy cluster: 3% within 45" of center: 0.07% (no long GRB ever seen in a cluster) T90 = 0.040 S = 1 × 10-8 E = 3 × 1048 Large ellipticalz = 0.2248 XRT 40 kpc blue Daniel Perley Short Bursts 9 November 2005

  24. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since SwiftGRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions GRB 050509B The Swift Era Is the burst associated with the elliptical? Chance alignment probability very small. inside galaxy cluster: 3% within 45" of center: 0.07% (no long GRB ever seen in a cluster) Additional arguments: • Extremely short duration even for short GRBs – putting at high redshift (z~2) requires unrealistically short intrinsic duration. • Energetics of putting at high-z similarly difficult for very short durations. T90 = 0.040 S = 1 × 10-8 E = 3 × 1048 Daniel Perley Short Bursts 9 November 2005

  25. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since SwiftGRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions GRB 050509B The Swift Era No counterpart seen at other wavelengths. Cannot be a supernova (if in cluster). No mini-supernova observed. T90 = 0.040 S = 1 × 10-8 E = 3 × 1048 SNIapeak Daniel Perley Short Bursts 9 November 2005

  26. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509BGRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions GRB 050709 The Swift Era HETE-II short burst. X-ray afterglow seen. Unambiguously in low-z galaxy. Optical transient (first ever for short GRB) detected coincident with X-ray position. T90 = 0.070 S = 3 × 10-7 E = 2 × 1049 Star-forming irregularz = 0.160 XRT 3.8 kpc HST Transient Daniel Perley Short Bursts 9 November 2005

  27. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509BGRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions GRB 050709 The Swift Era Optical light curve: power-law decay with jet break (like long burst – no supernova bump) Radio T90 = 0.070 S = 3 × 10-7 E = 2 × 1049 Optical X-ray Daniel Perley Short Bursts 9 November 2005

  28. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509B GRB050709GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions GRB 050724 The Swift Era Optical and radio (first for short GRB) transients seen. Unambiguously associated with non star-forming galaxy (within last Gyr) at low-z. Not in a cluster. T90 = 3 S = 6 × 10-7 E = 1 × 1050 Early-typez = 0.258 2.6 kpc XRT Transient Daniel Perley Short Bursts 9 November 2005

  29. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions GRB 050813 The Swift Era X-ray afterglow, but no optical/radio transient. Inside a cluster - numerous possible hosts. Ellipticalz = 0.722 XRT T90 = 0.6 S = 6 × 10-7 E = 1 × 1050 Ellipticalz = 0.719 Ellipticalz = 0.73 Daniel Perley Short Bursts 9 November 2005

  30. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509B GRB050709 GRB050724 GRB050813GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions GRB 050906 The Swift Era No X-ray afterglow detected. BAT position consistent with IC 326. p ~ 0.1% BAT IC 326 z = 0.0308 T90 = 3 S = 6 × 10-8 E = 1 × 1047at 133 Mpc IC 327 Daniel Perley Short Bursts 9 November 2005

  31. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509B GRB050709 GRB050724 GRB050813 GRB050906GRB050925 GRB051103 GRB051105A Summary Conclusions GRB 050925 The Swift Era Soft, thermal spectrum. Galactic latitude: b = - 0.1° Strong radio source – no optical or X-ray detections. SGR flare ('new' SGR) T90 = 0.13 S = 8 × 10-8 E = 1 × 1040at 20 kpc Daniel Perley Short Bursts 9 November 2005

  32. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925GRB051103 GRB051105A Summary Conclusions GRB 051103 The Swift Era IPN detection of bright short GRB. Consistent with outer regions of M81. M 82Irr z = 0 p ~ 0.5% M 81Sb z = 0 T90 = 0.17 S = 2 × 10-5 E = 5 × 1046at 4 Mpc (M81)~ 1051at 500 Mpc Daniel Perley Short Bursts 9 November 2005

  33. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103GRB051105A Summary Conclusions GRB 051105A The Swift Era No X-ray afterglow detected. BAT T90 = 0.13 S = 2 × 10-8 E = ? Daniel Perley Short Bursts 9 November 2005

  34. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105ASummary Conclusions Recent Short Bursts The Swift Era energy (erg) Daniel Perley Short Bursts 9 November 2005

  35. Classes of GRBs Long Bursts Short Bursts Durations Duration vs. Hardness Duration vs. Fluence Short Bursts before Swift Long Burst Localization Short Burst Localization Afterglow Nondetections Galaxy Correlations Short Burst Models Primordial Black Holes Magnetar Giant Flare NS-NS Merger NS-BH Merger Collapsar Summary Short Bursts since Swift GRB050509B GRB050709 GRB050724 GRB050813 GRB050906 GRB050925 GRB051103 GRB051105A Summary Conclusions Conclusions The Swift Era • Most short bursts are due to compact object mergers. • Short bursts are beamed. • Some short bursts may be due to magnetar giant flares in other galaxies, but a definitive example is still lacking. • Short bursts occur more frequently per volume than long bursts (or are beamed less), but are intrinsically fainter. Daniel Perley Short Bursts 9 November 2005

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