Team Taylor Observations with the GBT

1. Team Taylor Observations with the GBT Sonny Ernst, Taylor Barber, Alex Dittmann, & Allie Lee-Fasching GBT There are two types of pulsar plots: prepfold plots which are the most common out of the data sets. They make up 30 out of the 35 plots .. The Dispersion Measure (DM) is a measure of how much the signal has dispersed or scattered as it passes through space, and can be very roughly equated to distance. If the DM is too small the signal is probably Radio Frequency Interference (RFI). Reduced is a measure of how close the signal matches a model of noise, the closer to 1 the closer it is to noise. In the pulse profile, the top left plot, we are looking for a pulse well above the noise floor, which is present in all plots. In the time-domain plot, below the pulse profile, we are looking for vertical lines, which signify that the signal was constant throughought the observation, and occurred periodically. In the sub-band plot we are also looking for vertical lines, this time showing that the emission occurred at multiple frequencies. What is a Pulsar? When a star about three to four times more massive than the sun reaches the end of its life cycle, it explodes and collapses onto itself, forming an incredibly dense neutron star. These neutron stars are about as wide as Washington DC and is more massive than the sun. A teaspoon of the material that makes up a neutron star would weigh as much as an oil tanker. Because of the conservation of angular momentum, the new, much smaller star, spins with a velocity that is much greater than it had when it was full sized. This neutron star can rotate almost once every millisecond. The neutron star has a very strong magnetic field, the polarity of which is out of alignment with the star’s geographic poles. As the neutron star rotates, it shoots electromagnetic radiation from its magnetic poles, creating a periodic sort of lighthouse effect as the pulsar spins. Pulsars exhibit a periodic sort of brightness for this reason, their luminescence on earth being seen as sorts of pulses. Pulsars can be used as incredibly accurate clocks, as well as ways to test relativistic circumstances. Projects such as NANOGrav are using pulsars to search for cases of the theoretical phenomenon called Gravitational Waves. Pulsars can additionally be used to map the universe, but they also have many more uses beyond this. We had the 3:00 am slot to 5:00 am in this time we observed tow potential candidates . We also got to fold the data and control the GBT. It was an amazing experience especially whit the grad students JOE and FRENANDO. Unfochintly we did not find any thing. But it was an unforgettable experience. Fernando helping Alex . How is a Pulsar found? The first pulsar was found in 1968 by Jocelyn Bell in Cambridge, England by using a 4 ½ acre array of dipole antennas. Most pulsars today are discovered by using a radio telescope. Pulsars can be observed in Radio, optical and X-ray wavelengths. Joe being Joe Candidates When a plot or dataset looks like it has a unknown Pulsar, students submit it to one of the astronomers at Green Bank so they can Follow up on it to see if it is a really a pulsar. There is a grading system for a plot that helps form a conclusion. They are graded with scores ranging from 1-3. 1 being the worst and 3 being the best. If the total score is around 12, then it is likely to be a Pulsar. Always be sure to check the ATNF pulsar catalogue if you think you see a candidate because it might have already been found. There is the pulse profile, Sub band, Time domain and DM plot What is the PSC? In 2007 the Green Bank Telescope (GBT) went down for maintenance. Instead of shutting the telescope down, it continued recording data as the sky passes over it. This produced 30 Terabytes of data to look through, a hugely significant amount. It was decided that this data would be divided between graduate, undergraduate, and High School students. The portion of the data allocated to High School students is handled through the Pulsar Search Collaboratory (PSC), started by Sue Ann Heatherly, and supported by the National Science Foundation, the University of West Virginia, and the National Radio Astronomy Observatory among others. The PSC involves High School Students in searching for pulsars in the GBT data. The PSC has found 6 pulsars so far. The Summer Institute is a program of the PSC during which a small group of students spends a week in Green Bank. While there, the students study astronomy, attend lectures by proffessors such as Duncan Lorimer and Maura McLaughlin, as well as the graduate students Joe Swiggum and Fernando Cardoso. Students gained a deeper understanding of the properties of pulsars and what all the data in the plots means. Students also practiced soldering and using telescopes. Students used both the old-fasioned 40-ft telescope and the high-tech GBT. Conclusion http://outreach.atnf.csiro.au/education/everyone/pulsars/ http://www.jodcast.net/archive/200706/