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Björn Ahlgren --- Photospheric emission in gamma-ray bursts. Abstract
Toggle Cloak Cloak This is a short review of the current status of the research on photospheric prompt emission in gamma-ray bursts (GRBs). While GRB spectra are usually fitted with Band functions, these give little understanding of the underlying emission mechanisms, which has prompted several new approaches to the problem. With the analysis of FERMI data and numerical simulations of GRB prompt emission, the aim is to be able to produce both light curves and spectral curves and to be able to fully explain the phenomenon. In this talk I will focus on models for subphospheric dissipation, in which dissipation of kinetic energy below the photosphere gives rise to spectra which can differ significantly from a simple blackbody. In particular, I will discuss how different parameters such as the Lorentz factor and the optical depth at which the dissipation occurs affect the resulting spectra. My current work involves fitting such models to data for the first time. Lee Yacobi --- Constraints on the hadronic content of Fermi GRBs. Abstract
Toggle Cloak Cloak Recently the Fermi-LAT has detected approximately 35 GRBs with gamma ray emission above 100 GeV. Several models have been proposed to explain this high-energy emission, including hadronic models, where photon-hadron process produces charged pions and subsequently the 100 TeV neutrinos. We are using the data from Fermi-GBM to calibrate the photon (representing electrons) energy content of the GRB jet. Given the non-detection of GRB neutrinos, we aim to put upper limits on the proton (turned pion) energy content. The same photon-hadron process that is expected to produce the charged pions and subsequently the 100 TeV neutrinos, would also generate neutral pions that decay to photons of similar energy. These high-energy photons have been hypothesized to cascade through pair production processes down to the GeV regime, where they can escape the jet and be observed by Fermi-LAT. These high-energy photons have been hypothesized to cascade through pair production processes down to the GeV regime, where they can escape the jet and be observed by Fermi-LAT. Within this scenario, we are using the observed GeV photon fluence to put another upper limit on the energy content of the protons in the jet. Within this scenario, we are using the observed GeV photon fluence to put another upper limit on the energy content of the protons in the jet. Henrike Fleischhack --- A template method for measuring the iron spectrum in cosmic rays with Cherenkov telescopes. Abstract
Toggle Cloak Cloak The energy-dependent abundance of elements in cosmic rays is an important part of the understanding of acceleration and propagation of cosmic rays. Imaging Air Cherenkov Telescopes, used mainly in gamma ray astronomy, can measure the direct Cherenkov light emitted by heavy nuclei as well as the Cheronkov light emitted by their air showers. Thus they are sensitive to the charge of the primary particles. I will introduce a template method that can be used to reconstruct charge and energy of primary particles simultaneously. With this, we can separate heavy nuclei from lighter cosmic rays, and thus measure the abundance and spectrum of these nuclei in the range of tens to hundreds of TeV. - 1 Slide:
- Kimberly Zoldak
- Ramesh Koirala
- James Lau
Supporting Material
Really useful usage notes page! [Likelihood Usage Notes]
Things to do and Eat
These are places we've gone in the past for food:
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