The Hunt for Pulsars . Rowan County Pulsar Astronomers. Cameron Blankenbuehler, Zachary Jones, David Donathan.
Rowan County Pulsar Astronomers
Cameron Blankenbuehler, Zachary Jones, David Donathan
The Pulsar Search Collaboratory(PSC) is an organization for young pulsar astronomers, more specifically high school students, to help professional astronomers in the search for elusive pulsars. The scientific value of finding pulsars is to help in the research of theoretical gravitational waves, which have only been indirectly studied in pulsar binary systems. To search for these elusive neutron stars, a radio telescope such as the Green Bank Telescope (GBT) is used to collect radio waves being emitted from pulsars. The program that makes it possible for us to analyze data then converts the raw data into a readable format. This body is the result of 186 analyzed pointings consisting of 4,375 plots of noise and 1,802 plots of Radio Frequency Interference(RFI), of the total plots analyzed. The findings of the group are of noise and known sources of RFI, and have not directly helped the goal, but we may still help the PSC with this research.
Out of 186 pointings, Zero pulsars were discovered or re-observed. Noise and RFI were both found in parts of 70.83% and 29.17% appropriately. Noise is a radio signal from space that is not a pulsar. Radio Frequency Interference(RFI) which is radio waves from earth by man-made electronics. Often RFI is received from satellites orbiting through and obstructing the view of the radio telescope.
Pulsars are rapidly rotating neutron stars that emit radio waves from the magnetic field poles. The PSC in West Virginia that uses the GBT to capture the radio waves that are emitted from the pulsar, and uses a program called PRESTO that turns the radio the a line of pulses and then folds that line into thousands of different patterns, PRESTO then gives astronomers the thirty best plots to look at and analyze to decide whether there is a pulsar in the data from that pointing of sky. The PSC was established because professional astronomers need help analyzing all the data that was collected from the GBT when the GBT was under repair. Professional astronomers are trying to indirectly detect gravitational waves do fact exist by using millisecond pulsars, as Einstein predicted in the early 1920’s
This plot is identified as RFI because the DM peaks very close to zero, and is in the rouge gallery as a known source of RFI.
The data used for research was provided by the Green Bank Telescope (GBT) in West Virginia.
This data was collected while the GBT was immovable and under repairs and was unable to move for over 300 hours (over 12 days) in 2007. During this period of time the GBT was left “on” to collect data while facing directly upwards. While collecting data the only variation of declination was fairly minute and the right ascension rotated along with the earth.
The DM of this RFI peaks at zero thus identifying it as such. On the lower graph, a single point is placed wherever a signal is received.
Radio Frequency Interference (RFI) is encountered very often when RFI is distinguishable from other data by a Dispersion Measure (DM) close to zero or a narrow band signal.
Examples #1 and #2 below both display RFI. One plot has a very low DM and the other with a narrow band signal. J0944-1354 and J0944-1354are prime examples of pulsars with ideal DM’s and wideband signals.
The RFI found was located mostly on declination of negative 15 which seems to be the hotspot of RFI for the pointing's observed, and is because the majority of data is observed in that swath of sky.
A narrow band signal such as in the above plot is an indicator of RFI (due to the fact that pulsars emit all wavelengths within 320-390 MHz.
The time domain (graph on the far bottom left) normally appears to have a nearly solid vertical line surrounded by some static.
The work done by the group has only, thus far, observed what has already been seen and made only a small contribution to the goal of finding pulsars, but we did help rule out some section of the sky while doing so, and felt proud while doing it. There may not of been any great discovery of a new RFI source nor any known pulsars, but the work we have done will help those that come after to know some of the sky has been observed and to not look there again, unless they have more powerful radio telescopes.