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A bright millisecond radio burst of Extragalactic origin

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Science (in press) astro-ph/0709.4301. Talk Outline. Dispersion by the ... A dedicated search. Green Bank Extragalactic Radio Transient Experiment (GERTIE) ... – PowerPoint PPT presentation

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Title: A bright millisecond radio burst of Extragalactic origin


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-gt120 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
  • DM375 cm-3pc!

11
(No Transcript)
12
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)

13
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
  • Doesnt repeat in 20 days of observing

14
Where?
x
X
x
15
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)!!

16
If it is a PSR or RRAT
  • Should repeat
  • Original pulse 100x detection threshold!
  • 40 hours of follow-up _at_ 20cm
  • Nothing!

17
What then?
  • Points to a one-off event?
  • Distance?
  • If DM (MWGSMC 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 nsns coalescence
  • Also Hyperflares on Magnetars?
  • 100s per day and still invisible

18
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

19
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)

20
A dedicated search
  • Green Bank Extragalactic Radio Transient
    Experiment (GERTIE)
  • 3x 85 telescopes (3 square degree coverage)
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