Hope College Physics Department
Research Experiences for Undergraduates
Summer 2007
Project Summary

 

Project Title:

Radio Pulsar Profiles

Student Name: Rachel Austin
Student's Home Institution: Hope College
Research Advisor: Dr. Peter Gonthier
Source of Support: This material is based upon work supported by the Michigan Space Grant Consortium, the Nathional Science Foundation under NSF-REU Grant No. 0452206 and NSF-RUI Grant No. 0307365 and the NASA-Astrophysics Theory Program.

The object of this research is to fit radio pulsar profiles and compare our results with those that Mitra & Rankin have in their 2002 paper. Mitra & Rankin have separated certain pulsars into three different groups, A, B and C, because they believe all these groups of pulsars to be drastically different from one another. The goal is to see if our results agree with the interpretation of Mitra & Rankin. To fit the pulsar profiles, Igor Pro by Wavemetrics, Inc. is used. The program has to know the period, the spectral index, radio flux at 400 MHz, and the frequency in MHz associated with the measured pulse profile. Once the data is loaded in to the code, we are able to fit the profile using our radio beam geometry model. A global model is then obtained to fit all the frequencies of a single pulsar in one model. The widths of the pulsars are first compared. The angles of the viewing geometry, alpha and beta, the radii and the widths of the annulus of the cone beam have common values for all the frequencies. While we use the beam geometry of Kijak & Gil, our results are similar to those obtained by Mitra & Rankin. In one case, we allow the fit to obtain the best alpha. In another case, we use the alpha quoted in the work of Mitra & Rankin's alpha. The results of the two cases are in good agreement, particularly groups A and B. In the case of the pulsars from group C, the characteristics widths are independent of observing frequency as discussed in Mitra & Rankin.