1. Parkes’ Potential Pulsars
B.L. Conner, L. A. Hennig, R. D. Mccloud,
R. P. Sharpe, J. A. Stanley
Introduction
Team Parkes folded the experiences and information imparted by PSC instructors, scientists, and mentors to establish a method of attacking the data most efficiently and to answer the question, “Is it a pulsar or is it Memorex?” Team Parkes’ members determined the most effective approach to analyze data sets. During this initial phase of the data analysis process, team members rated plots. When a plot scored two or higher, the entire Parkes Team was assembled for input. Team Parkes studied the interesting plots making a final determination. Team members shared data sets to speed the process. Of all the data sets analyzed, Team Parkes flagged five plots worthy of further investigation.
Radio Frequency Interference (RFI)
Data Distribution
Figure 1 shows RFI due to the error bar being larger than the amplitude of peaks as well as the reduced chi2 being
Figure 1
Figure 2 shows RFI due to vertical banding at a DM of 22, 25, 42 and 45.
Figure 2
Figure 3 shows a diagonal banding in sub-band plot and a period of which is indicative of a harmonic.
Figure 3
Figure 4 is missing bins in the phase-time diagram with a high DM of There are also numerous horizontal bands in the sub-band plot.
The pie chart below shows the percentages of potential candidates versus RFI and “Noise”.
Figure 4
Divide and Conquer
We divided up the data points amongst team members.
Every team member used Duncan’s Pulsar technique (or some form of it).
Dunc’s Rule of Thumb
reduced x2 < 1 bad
reduced x2 < 2 (≈ pulsar)
reduced x2 > 3 (pulsar/RFI)
Results
Figures 5-9 Best Candidates
Figure 5 Was listed in the 350 MHz Drift Scan Survey, but not in the ATNF catalog, but is a known pulsar.
Figure 5
Duncan Lorimer, West Virginia University Professor Department of Physics
Conclusion
Figures 6-8 are unknown and need follow up due to GBT malfunction during team observing time.
“Recipe” for Pulsars
Time Domain Plot: Are there average pulses?
2. Integrated Pulse Profile: Do the pulses match up with the Time Domain Plot?
3. Sub-band Plot: Vertical or Horizontal line? (Vertical = possible pulsar, Horizontal = RFI)
4. DM curve: look for a peak > 0
5. Reduced x2 and Period
Figure 6
Figure 9
Figure 7
Figure 9 shows a single-pulse plot that is unknown and was the prime candidate for our GBT time. We are awaiting confirmation of results.
Acknowledgements
Team Parkes would like to thank:
National Science Foundation (NSF)
National Radio Astronomy Observatory (NRAO)
Pulsar Search Collaboratory (PSC)
Cabell County Public Schools (WV)
Wayne County Public Schools (WV)
Fairfax County Public Schools (VA)
Special thanks to Lucasfilm © for inspiration!
Figure 9
Figure 8
Results are pending from follow-up observations from the GBT.
Image taken from:
Background Image taken from:
PSC Summer 2011