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Brent Limyansky - Analyzing Pulsar “Glitches” Using the Fermi LAT
Toggle Cloak Cloak Pulsars are rapidly rotating neutron stars which produce pulsed emission across the electromagnetic spectrum. Abrupt and unpredictable changes in emission frequency are known as “glitches”. In young pulsars, theory predicts that glitches are the result of a starquake-induced change in geometry of the neutron star’s crust. These types of glitches have the potential to produce gravitational waves, although they are not believed to be detectable with current technology. In rotation-powered pulsars, glitches are believed to come from interactions between surface and interior regions of the neutron star. Glitches are challenging to observe with pointed instruments, as the time of their occurrence cannot be predicted. The Fermi LAT, which continually monitors over 200 gamma-ray pulsars, is not hindered in this manner and is therefore well suited to observation and study of glitches. In this project, I will examine previously detected pulsars over the full time range of the mission. Glitches will be identified and catalogued, with subsequent analysis having the potential to investigate the glitching mechanism, the nature of neutron star interiors, and glitches as a source of gravitational waves.
Tiffany Lewis - A First-Principles Radiative Transport Model for Steady-State Blazar Spectra
Toggle Cloak Cloak Blazars are luminous sources across the entire electromagnetic spectrum, but the spectral formation mechanisms in these sources are not well understood. We have developed a new model for blazar spectra in which we numerically integrate the first-principles electron transport equation to generate the electron number distribution with respect to energy. Our transport model considers shock acceleration, adiabatic expansion, stochastic acceleration due to MHD waves, Bohm diffusion, synchrotron radiation, and inverse-Compton radiation. We implement the full Klein-Nishina cross-section for interactions with photons from dust and 26 individual lines from the broad line region. We use the solution for the electron distribution to predict multi-wavelength SED spectra for 3C 279. This new self-consistent model provides an unprecedented view into the jet physics at play in this source, especially the relative strength of the shock and stochastic acceleration components and the size of the acceleration region. We show that our new Compton + synchrotron blazar model is the first to successfully fit the FermiLAT gamma-ray data for this source based on a first-principles physical calculation.
- Sambid Wasti - Title
- Hester Schutte
- Cori Fletcher
- Tiaan Bezuidenhout
- Tejaswita Sharma
- Isabella Mereu
Supporting Material
Liz's favorite page on livetime and exposure: [http://fermi.gsfc.nasa.gov/ssc/data/analysis/documentation/Cicerone/Cicerone_Likelihood/Exposure.html]
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