Presenter Information

Stella Ocker, Oberlin CollegeFollow

Location

King Building 237

Start Date

4-27-2018 5:30 PM

End Date

4-27-2018 6:50 PM

Abstract

Pulsars are extremely dense, highly magnetized stars that emit pulses of radio emission every millisecond or so. The arrival times of their radio signals at Earth observatories can be used as a clock precise enough to detect gravitational waves. Performing such a detection requires the mitigation of interference effects from the interstellar medium: the slightly ionized, mostly hydrogen gas that the radio waves traverse as they travel from the pulsar to Earth. We investigate radio wave delays using a powerful tool: scintillation arcs, fluctuations in frequency and time of the pulsar signal intensity that are manifested as parabolic arcs in the pulsar’s secondary spectrum. While scintillation arcs were first observed by Oberlin students almost two decades ago, the structures that cause them are still unknown. We explore a simple, one-dimensional model for the production of scintillation arcs. A measure of the frequency dependence of scintillation arc widths for the pulsar B1133+16 is suggested for use as an empirical test of scintillation arc models.

Keywords:

astrophysics, pulsars, interstellar medium

Notes

Session VII, Panel 19 - Physical | Science
Moderator: Dan Stinebring, Francis D. Federighi Professor of Physics

Major

Physics

Advisor(s)

Stephen FitzGerald, Physics and Astronomy

Project Mentor(s)

Dan Stinebring, Physics and Astronomy

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Apr 27th, 5:30 PM Apr 27th, 6:50 PM

Testing the Production of Scintillation Arcs with the Pulsar B1133+16

King Building 237

Pulsars are extremely dense, highly magnetized stars that emit pulses of radio emission every millisecond or so. The arrival times of their radio signals at Earth observatories can be used as a clock precise enough to detect gravitational waves. Performing such a detection requires the mitigation of interference effects from the interstellar medium: the slightly ionized, mostly hydrogen gas that the radio waves traverse as they travel from the pulsar to Earth. We investigate radio wave delays using a powerful tool: scintillation arcs, fluctuations in frequency and time of the pulsar signal intensity that are manifested as parabolic arcs in the pulsar’s secondary spectrum. While scintillation arcs were first observed by Oberlin students almost two decades ago, the structures that cause them are still unknown. We explore a simple, one-dimensional model for the production of scintillation arcs. A measure of the frequency dependence of scintillation arc widths for the pulsar B1133+16 is suggested for use as an empirical test of scintillation arc models.