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Team Taylor Observations with the GBT
Sonny Ernst, Taylor Barber, Alex Dittmann, & Allie Lee-Fasching
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.
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 𝑥 2
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.
GBT
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.
Unfochint ly 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
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.
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
Pulsar
Period
DM
J0944-1354
570ms
21.3pc/cm^3
J0820-1350
1238ms
41.0pc/cm^3
J2010-1323
5.2ms
22.2pc/cm^3
J1311-1228
40.7ms
36.3pc/cm^3
J1643-1224
4.6ms
62.4pc/cm^3
J1946-1312
983.7ms
62.9pc/cm^3
Conclusion
Pulsar
Rotational Energy
Approximate Distance
from Earth
Approximate
distance from the
Galactic Plane
J0944-1354
5.54x10^39J
410pc
199pc
J0820-1350
2.42x10^38J
1367pc
284pc
J2010-1323
6.66x10^43J
740pc
277pc
J1311-1228
1.09x10^42J
1210pc
927pc
J1643-1224
8.51x10^43J
2080pc
779pc
J1946-1312
1.86x10^39J
2097pc
578pc
http://outreach.atnf.csiro.au/educatio
n/everyone/pulsars/
http://www.jodcast.net/archive/200706/