This tutorial was written by Gary Marchiny from Lincoln High School:
When you go to the main site (www.pulsarsearchcollaboratory.com), just below the Green Bank Telescope picture, you will see the panels for entering information (labeled RA and DEC). This correlates to information on the pointings you see on the test.
When you take the test, or are looking through the pointings after the test, and see a pointing which you think may contain a pulsar, you can look at the ATNF catalog to see whether it is a known pulsar or not. If you do not see a pulsar listed in the ATNF, you may have found a new one!
Here’s how to use it:
On the actual pointing you are viewing, in the upper right-hand corner there is all of that numerical information. Towards the top of that information, you will see RA: xx:xx:xx and DEC: xx:xx:xx (x being the numbers you see in the actual pointing separated by colons). This is what you will want to enter into the panels on the Collaboratory site.
There are two panels for each of these. Two for RA and two for DEC. The first two numbers you see on the pointing are all you need to enter.
Say my pointing has the information RA: 07:22:01 and DEC: -13:41:08 listed in the upper right hand corner. I need to take 07 and 22 from that and input them into the boxes on the Collaboratory site (07 in first box, 22 in the second box). Then I move on to DEC. I put -13 in the first box and 41 in the second box (the last numbers on both of these are not needed). The box that says "radius" should be kept at 3 degrees.
After you have entered this information in the boxes, click "Search this Field." This will bring you to the ATNF Catalog. At the top of this page you will see something that looks like this,
# PSRJ RAJ DECJ P0 DM
(hms) (dms) (s) (cm^-3 pc)
If there is anything listed under this heading, that will be the information of a pulsar that has already been found in that particular field (the numbers you entered).
Now, if there are known pulsars that come up on this screen, and you want to know if the one in your pointing is already on there, do this:
- In that heading above, all the way to the right you see DM(cm^-3 pc). This is the dispersion measure of the pulsar that is listed in the ATNF.
- What you need to do is go back to the pulsar candidate that you found (possibly in the test). Remember where you found the RA and DEC in the upper right hand corner? Not too far below that you will see Dispersion Measure(DM)= and a number.
- This is the dispersion measure of the candidate that you are wondering about. So can you guess what’s next?
- You got it! Compare the dispersion measure of your candidate and the dispersion measure of the pulsars already listed on the ATNF. If they are fairly close (they usually are not exactly the same to all decimal places), then the candidate that you are looking at has already been found. The name of the pulsar is listed under the heading PSRJ.
If you have found an already known pulsar, you should copy the name (the number of the pulsar that matches yours) and enter that number in your pointing candidate where it says "Known Pulsar Name" to indicate that your candidate is indeed a pulsar and it has already been identified (this is an example of a pulsar name I found on the ATNF: J0729-1448).
If your dispersion measure does not match the ATNF pulsar, you may have discovered a new pulsar!
When you check the ATNF Catalog for your specific field, you may not always see any pulsars listed. This means one of two things:
- It could mean that you have found an undiscovered pulsar.
- It could mean that you do not have a pulsar.
This process is important to follow when you take the tests.