Investigations of Single Pulses From Radio Pulsar PSR 0540 23

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Investigations of Single Pulses From Radio Pulsar
PSR 054023

• By Emily Alicea Muñoz
• Mentor Dr. Leszek Nowakowski
• Department of Physics
• University of Puerto Rico - Mayagüez

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The Discovery of Pulsars

• Pulsars were discovered in 1967 by Jocelyn Bell,
  a graduate student under the supervision of
  Antony Hewish. The pulsars showed up as periodic
  radio signals.
• Now, we know over 1200 of them.

What is a pulsar?

• The accepted theoretical model indicates that
  pulsars are magnetized, rotating neutron stars,
  which are formed after supernova explosions, as a
  result of the gravitational collapse of the
  remaining core of a massive star.

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Our Main Objective...

• We know how pulsars behave, but we do not know
  why they behave the way they do.
• Our main objective is to find out what is the
  physical process that makes pulsars work.

Instrumentation

• Pulsars are observed using radiotelescopes. We
  are using the Arecibo Radiotelescope, a spherical
  dish with a diameter of 305 meters, which is the
  largest and most sensitive instrument of its kind
  in the world.

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The average profile

• When you take a long stream of pulses and divide
  it into equal pieces of the same length as the
  pulsar period, and then add them up, you get the
  integrated or average profile.
• Each pulsar has a characteristic average profile,
  whose shape, width and structure are unique to
  that pulsar.

What we are analyzing...

• Signal to noise ratio
• Mode switching
• Nulling
• Drifting subpulses
• Core and conal components
• Total power

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Preparation of the data

• Dedispersion
• Baseline removal from individual pulses
• Data
• Sample numbers
• Calibrated or Non-calibrated samples
• Receivers and channels PSPM

PSR 054023 The Procedure

• Visual inspection of the data
• Baseline removal from each pulse
• Normalization
• Integration in intensity bins
• Integration in subwindows
• Histograms

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What have we learned...

• The average profile of PSR 054023 has one strong
  component.
• This pulsar presents some subtle drifting
  subpulses.
• The pulsar also presents nulling.

What we are doing next...

• Use data with higher time resolution, so that we
  can see more details and improve the signal to
  noise ratio.
• Analyze the polarization of the radiation from
  this pulsar.

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References

• Manchester, Richard and Taylor, Joseph. Pulsars.
  W.H. Freeman and Company. San Francisco, 1977.
• Nowakowski, Leszek. New Features in Two Radio
  Pulsars PSR 154109 and PSR 113316. The
  Astrophysical Journal. February, 1996.
• Rankin, Joanna. Toward an Empirical Theory of
  Pulsar Emission - I. Morphological Taxonomy. The
  Astrophysical Journal. November, 1983.
• URL http//www.naic.edu