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A bright millisecond radio burst of Extragalactic origin

A bright millisecond radio burst of Extragalactic origin. Duncan Lorimer, Matthew Bailes, Maura McLaughlin, David Narkevic and Froney Crawford Science (in press) astro-ph/0709.4301. Talk Outline. Dispersion by the interstellar medium Pulsar Surveys RRATs Giant Pulses

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A bright millisecond radio burst of Extragalactic origin

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  1. A bright millisecond radio burst of Extragalactic origin Duncan Lorimer, Matthew Bailes, Maura McLaughlin, David Narkevic and Froney Crawford Science (in press) astro-ph/0709.4301

  2. Talk Outline • Dispersion by the interstellar medium • Pulsar Surveys • RRATs • Giant Pulses • LMC/SMC Pulsar Survey • An enormous pulse • Location • Potential • Future directions

  3. Pulse Dispersion

  4. Standard pulsar search

  5. Single pulse search

  6. The RRATs • McLaughlin et al. (2006) • Discovered repeating impulsive bursts at the same DM • Gap ~4->120 minutes

  7. RRAT Properties • Power law distribution of energies • Regular gaps between pulses • Associated with • Rotating • Radio • Transients • Another manifestation of neutron stars • Luminosity not enough to see beyond Milky Way Galaxy

  8. Giant Pulses • Unresolved on us timescales • From young or millisecond pulsars • Power-law distribution of energies

  9. Pulsar Surveys with Parkes Burgay Survey Burgay Survey Swinburne Surveys MB Survey Swinburne Surveys SMC/LMC surveys

  10. LMC/SMC bursts? • Searched DM 0-5000 cm-3 pc. • Found 3 giants from one pulsar • Seen already by Johnston & Romani • Der Wunderpuls… • DM=375 cm-3pc!

  11. Giant Pulse Characteristics • Seen in 3/13 beams • Side-lobes suggest 20 Jy intensity • Analog level setting suggests 40 Jy • Adopt (30+/-10) Jy. • Width fn(frequency)

  12. An astrophysical origin • Knows about Cold Plasma Dispersion law • Knows about Kolmogorov Scattering law • Appears only in 3 adjacent beams out of 13 • From the sky direction • Doesn’t repeat in 20 days of observing

  13. Where? x X x

  14. SMC Pulsar DMs • 70 pc/cc (far from H-alpha) • 76 pc/cc (far from H-alpha) • 105 pc/cc (Near H-alpha) • 125 pc/cc (Near H-alpha) • 201 pc/cc (Near H-alpha emission) • 375 pc/cc (far from any H-alpha)!!

  15. If it is a PSR or RRAT • Should repeat • Original pulse 100x detection threshold! • 40 hours of follow-up @ 20cm • Nothing!

  16. What then? • Points to a one-off event? • Distance? • If DM (MWG+SMC ~ 70 units) • Up to 1 Gpc! • Adopt 500 Mpc - first detection ionized IGM! • 1040 ergs in radio required! • Event rate (1/20 days/5 sq deg) • Could be SNe, GRB or ns+ns coalescence • Also Hyperflares on Magnetars? • 100s per day and still invisible

  17. Worrying bits • 100x detection threshold • Might expect power law distribution • More distant events fainter • Different orientations fainter too? • Proximity to SMC • Only place people have looked! • Re-processing in progress… • Swinburne Surveys • SMC/LMC Surveys

  18. If we find more • Great synergy with other wavebands • Sub-arcsec position from VLBI • “Host Galaxy” Redshift Determination • Integrated baryonic content of Universe • ~100% ionised • Many VLBI events • Baryonic density of the Universe(Z)

  19. A dedicated search • Green Bank Extragalactic Radio Transient Experiment (GERTIE) • 3x 85’ telescopes (3 square degree coverage)

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