Hope College Physics Department
Research Experiences for Undergraduates
|Project Title:||Are Radio Pulsars Standard Candles?|
|Student Name:|| Raina Khatri
|Student's Home Institution:||Hope College|
|Research Advisor:||Dr. Peter Gonthier
|Source of Support:||This material is based upon work supported by the National Science Foundation under NSF-RUI Grant No. AST-0307365, Michigan Space Grant Consortium, and the National Aeronautics and Space Administration Astrophysics Theory Program.|
Our previous studies of pulse profiles from radio pulsars have used a core with a single cone beam. We propose an improved model, featuring a core with two cones coaxial to the magnetic pole, to account for profiles with up to five components. We follow recent results suggesting that the radius of the inner cone is independent with frequency, while the outer cone has the standard radius-to-frequency mapping. Fits of pulse profiles of radio pulsars with accurate parallax distances allow us to estimate the total intrinsic luminosity of each beam component. These fit parameters can be used to test the standard candle nature of radio pulsars. In developing this new model, we have fit the best available five-peaked profiles with the core-two-cone model, as well as the three-peaked profiles previously fitted. We will include this model in our population statistics simulation of radio and g-ray pulsars within the context of polar cap and outer gap emission models. Performing a new statistical study of the number of peaks in the radio and g-ray profiles will aid in distinguishing these high-energy emission models and the location of the accelerator.