Pulsar Emission at 10 – 100 GeVPulsar Emission at 10 – 100 GeV

Alice K. Harding (NASA Goddard)

• Spectral cutoffs

• TeV component from ICS predicted by outer gap models

• Millisecond pulsars

Measuring spectral cutoffsMeasuring spectral cutoffs

Polar cap r = 2R

Outer gap r/rLC = 0.6

r/rLC = 0.7

r/rLC = 0.8

Polar cap r = 2R

Outer gap r/rLC = 0.6

r/rLC = 0.7

r/rLC = 0.8

TeV inverse compton scattering TeV inverse compton scattering

Konopelko et al. 2005

Millisecond pulsarsMillisecond pulsars

Pulsed emission Pulsed emission from a few from a few millisecond pulsars millisecond pulsars may be detectable may be detectable above 50 GeV (and above 50 GeV (and more above 10 GeV) more above 10 GeV) for favorable viewing for favorable viewing angle (small angle to angle (small angle to magnetic axis)magnetic axis)

Emission above 10 Emission above 10 GeV from millisecond GeV from millisecond pulsars must come pulsars must come polar cap acceleratorpolar cap accelerator

SummarySummary

100 GeV threshold

• Constrain or rule out some outer gap models

• Measure or constrain ICS TeV component (but need sensitivity)

50 GeV threshold

• Measure high-energy cutoffs in some pulsars (e.g. 1951+32)

• Detect few most energetic millisecond pulsars (e.g. 1957+21, 1821-24) at favorable viewing angles

10 GeV threshold

• Detect a range of millisecond pulsars, even at unfavorable viewing angles

• Measure HE cutoffs in all EGRET and many GLAST pulsars