Investigating Pulsars with DC2 and GLAST Data

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Investigating Pulsars with DC2 and GLAST Data
Alice K. Harding (NASA Goddard)

• Review of possible DC2 source classes
• What we can learn about GLAST capabilities
• What we can learn about the DC2 pulsars
• Suggestions for investigation

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Possible DC2 source classes

• Radio-loud pulsars (real and simulated)
• all in radio ephemeris file (DC2_pulsardb_v2.fi
  ts)
• some (but possibly not all) in point source
  catalog
• Radio-quiet pulsars (mostly simulated)
• not in radio ephemeris file
• some in point source catalog
• Normal and millisecond pulsars (RL and RQ)
• EGRET pulsars
• Simulation attempted realistic spatial, P, P,
  inclination, viewing angle and flux distributions
• Variety of profiles and spectral shapes (model
  dependent)

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Detected and Simulated Radio Pulsars
978 normal pulsars
38 ms pulsars
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Defining GLAST capabilities for pulsar detection

• Effect of diffuse and plerionic background on
  point source and pulsed detection limits with and
  without radio ephemeris

Courtesy of Isabelle Grenier
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Defining GLAST capabilities for pulsar detection

• Effect of diffuse and plerionic background on
  point source and pulsed detection limits with and
  without radio ephemeris

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Defining GLAST capabilities for pulsar detection

• Testing of blind search algorithms (G. Kanbach)
• How source detection depends on energy cuts
• Measurement of spectral shapes and cutoffs
• High-energy spectral sensitivity

Vela pulsar
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Things to explore with DC2 pulsar data

• I. Population characteristics
• 1. Numbers of radio-loud and radio-quiet pulsars
• Ratio of RL/RQ is very model dependent
• how do we count RQ pulsars? Number gt blind
  search level?

Predictions
of Slot gap (Gonthier et al. 2004) and Outer gap
model (Jiang Zhang 2006) models
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2. Luminosity vs. ESD

• Turnover at ESD?
• Different groups?
• Model discrimination?

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2. Spectral index vs. age

• EGRET pulsar spectra harden with age

Thompson et al. 1994
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4. Galactic distribution

• Scale height
• Sky distribution
• Different for RL and RQ pulsars?

Normal pulsars Millisecond pulsars
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Things to explore with DC2 pulsar data

• II. Individual source characteristics
• 1. High energy spectral cutoff
• exponential (outer gap or slot gap)
• or super-exponential (polar cap)
• All purpose fitting formula (de Jager et al.
  2000)
• Find b for bright pulsars

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Things to explore with DC2 pulsar data

• II. Individual source characteristics
• 1. High energy spectral cutoff
• Any trend with B?
• Pair creation
• Photon splitting (B gt 1013 G)

Thompson 2003
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2. Pulse profiles
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Pulse profile may not uniquely identify model!
Vela
SLOT GAP MODEL a 450, zobs1130
POLAR CAP MODEL a 100, zobs160
OUTER GAP MODEL a 650, zobs820
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Slot gap (two-pole caustic) model
Outer gap model
c 700
No off pulse emission in traditional OG model
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3. Phase resolved spectroscopy
Can use fselect in ftools to select phase ranges
from output file of gtpphase
gt 100 MeV
gt 5 GeV
Thompson 2003
Fierro et al. 1998
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Suggested goals for DC2 pulsar analysis

• Catalog of radio loud and radio quiet pulsars
• Threshold for blind pulsed detection in and out
  of plane
• Measurement of spectral indices and high energy
  cutoff parameters
• How high in energy can pulsations be detected?