RadioLoud and RadioQuiet, Gammaray Pulsars from the Galaxy and the Gould Belt

1
Radio-Loud and Radio-Quiet, Gamma-rayPulsars
from the Galaxy and the Gould Belt

• Peter L. Gonthier
• Hope College
• Robert Van Guilder
• University of Colorado
• Alice Harding
• NASA Goddard Space Flight Center
• Isabelle Grenier
• Université Paris VII Service dAstrophysique,CEA
  Saclay
• Christophe Perrot
• Stanford Linear Accelerator Center
• June 2, 2004 - Hong Kong, China

2
Population Synthesis Study

• Radio and gamma-ray pulsars
• Galactic plane
• Gould Belt

3
The Gould Belt

• Perrot Grenier 2003, AA, 404, 519
• Age 26.4 0.4 Myr

4
Assumptions I

• Galactic plane - based on Gonthier et al. 2002,
  ApJ, 565, 482 Gonthier et al. 2004, ApJ, 604,
  775
• Uniform birth rate back to
• 1 Gyr for the Galactic plane distribution of
  Paczynski, 1990, ApJ, 348, 485
• 5 Myr for the Gould Belt distribution of Perrot
  Grenier 2003, AA, 404, 519
• Radio beam geometry and velocity kick
  distribution Arzoumanian, Chernoff Cordes
  (2002)
• Muslimov Harding (2003) g-ray slot gap emission
• Currently no discrimination of pulse profile -
  just average flux

5
Assumptions II

• Birth period
• Flat distribution - 0 to 150 ms
  
• Birth field
• Gaussian (log) - 12.75 13.0 means
• - 0.4 0.7
  widths
• - 2 to 1 ratio
  
• Magnetic field decay constant of 2.8 Myr
• Filter radio flux through a set of 9 radio
  surveys (including Parkes Multibeam)
• Normalizing
• to 978 radio pulsars (Galactic plane)
• to 120 supernovae in the Gould Belt
• All sky threshold maps for EGRET AGILE
• In and out of plane thresholds for GLAST
  

6
Predictions

• Birth rate for pulsars in the Galactic plane
• Number of radio-quiet radio-loud, g-pulsars
  simulated for EGRET, AGILE and GLAST
• Galactic plane
• Gould Belt

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Radio Pulsars from the plane

• Reduce the radio luminosity by a factor of 60
• Field decay at 2.8 Myr
• Birth rate of 1.4 neutron stars per century
• - compared to 2.5 (Tammann et al. 1994)

Observed
Sim. from the plane
Sim. from the Gould Belt
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Radio pulsars in the Galactic plane
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Radio-Loud and Radio-Quiet, Gamma-ray Pulsars
from the Plane
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Radio-Loud Radio-Quiet, g-pulsars from the Plane
Birth rate of 1.4 (1.5) per century Without
the Parkes MB survey
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Radio Pulsars
Expect only 120 neutron Stars and to See Only
13 radio pulsars
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Gamma-ray Pulsars from the Gould Belt
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Selection of Viewing Geometry and Age of Pulsars
from the Gould Belt
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Characteristics of Radio-Loud and Radio-Quiet,
Gamma-ray Pulsars from the Gould Belt

• Simulated EGRET pulsars are younger and closer
  than radio pulsars with similar velocity
  distributions
• Simulated EGRET radio-loud pulsars have short
  periods and are, therefore, radio core dominated
  - need small betas to see radio emission
• EGRET radio-quiet, gamma-ray pulsars tend be
  somewhat closer than radio-loud and tend to have
  large viewing angles relative to the magnetic
  axis (large betas), where the radio emission is
  weak

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Summary
Plane Gould Belt