Hope College Department of Physics and Engineering
Research Experiences for Undergraduates
Summer 2003
Project Summary

 
 

Project Title: Enhancing Simulations of Population Statistics of Radio and Gamma-ray Pulsars
Student Name: Robert VanGuilder
Studentís home institution: University of Colorado, Denver
Research Advisor(s): Dr. Peter Gonthier
Source of Support: NSF-REU
 

We have made four main enhancements to a Monte Carlo simulation code developed by Professor Peter Gonthier, including research students under his direction. The code is a C/C++ program that simulates neutron star population statistics. These four enhancements are as follows. 1) We have implemented a harmonic summing model to increase the sensitivity threshold of the Parkes-Multibeam survey. This model is based on Crawford's thesis, http://triluminary.cs.haverford.edu/people/fcrawfor/thesis.html, and is discussed in Manchester et al. 328, MNRAS, 17, 2001. Crawford provided us with an IDL code that we converted to C++ to implement into our model. 2) We have also implemented a sky sensitivity map for the AGILE observatory to be launched in 2005. This map was shared with us by Dr. Pellizzoni. The survey sensitivity map is implemented along with an interpolation routine to have a more realistic sensitivity for the AGILE instrument. 3) A new Galactic potential model was implemented to replace the existing model developed by Paczynski, 348, ApJ, 485, 1990. The new model is based on the Galactic model of Dehnen and Binney, 294, MNRAS, 429 1998, which is currently the most realistic model of the mass distribution in the Milky Way. Dr. Dehnen provided us with their C++ code, which we then implemented into our Monte Carlo simulation. 4) The fourth area of enhancement was implementing a 5th-order adaptive step Runge-Kutta routine to evolve the neutron star through the Galactic potential model from its birth to the present. Apart from adding computational efficiency, the 5th-order Runge-Kutta routine evolves neutron stars through the Galactic potential conserving total energy more accurately. This has reduced by a factor of 50 the number of previously generated bad events that occur when neutron star trajectories do not conserve energy. By reducing the number of bad events, we eliminate the possibility of introducing a bias towards certain trajectories.

Slide show of Robert VanGuilder's work (Requires Microsoft PowerPoint or a PowerPoint viewer.)

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Publications:

Radio-loud and radio-quiet, gamma-ray pulsars from the Galaxy and the Gould Belt, P.L. Gonthier, R. VanGuilder, A.K. Harding, I.A. Grenier and C.A. Perrot, Multiwavelength Approach to Unidentified Gamma-Ray Sources, Hong Kong, China, June 1-4, 2004, Edited by K.S. Cheng and G.E. Romero, Springer, 2005 ISBN: 1-4020-3214-5, p. 71-80.
Radio-loud and radio-quiet, gamma-ray pulsars from the Galaxy and the Gould Belt, P.L. Gonthier, R. VanGuilder, A.K. Harding, I.A. Grenier and C.A. Perrot, 2005, Astrophysics and Space Science, 297, no. 1-4, pp. 71-80.