Session 3 Prepfold Plots

This week, you are going to use a radio telescope to collect data on your adopted pulsar and we are going to dive into how these plots are created and what the different parts mean.

This is an important week!

 Dr. Ryan Lynch, who works at the Green Bank Observatory explains prepfold (also called FFT) plots in this video.


Bonus video: Joe Swiggum’s video on the ATNF Catalog. Joe is an astronomer at the University of Wisconsin- Milwaukee.



Here’s how to set up your Pulsar Observation:

Log in to > My Observatory > Radio Observing > Add New Observation

Window One:

  • In the Target Lookup Window, type PSR _ space _ the name of your pulsar exactly. For Example: PSR J0814+7429 (copy and paste  the name of your pulsar from the google sheet)
  • The RA and Dec should fill in.
  • If your pulsar has a Dec. of -40 degrees or lower, change the min elevation to 10 or even 5
  • Click “Save and Continue”

Window Two:

  • Receiver Data Acquisition Mode: Low resolution
  • Filter: HI filter
  • Check Box: Pulsar mode
  • Click “Save and Continue”

Window 3:

  • Path type: Track
  • Duration: 300- 1800 seconds– weaker pulsars need longer observations.
  • Integration time: divide the period by 30 and enter that number
  • Click “Save and Continue”
  • Click “Submit”

3. Investigate Dispersion Measure.

Your data will look like this: Here’s a pulsar plot with the different parts labeled. You can find the DM of your pulsar in the Header.

plot anatomy

Use the DM tool located  here , to find out the distance to your pulsar, and its location in the Milky Way. (You can see a picture of its location by clicking on the XY plot.)