Anna Zajczyk

polski / English

scientific work

I work as a Postdoctoral Research Associate at the Physics Department of Washington University in St. Louis (MO, USA). I am part of the research group led by Prof. Henric Krawczynski and Dr. Matthias Beilicke.

Currently I am involved in analysis and interprtation of astronomical data obtained at gamma-ray energies with VERITAS Cherenkov telescope and Fermi/LAT instrument. Here sources of my interest are pulsar wind nebulae with their pulsars and supernova remnants.

I am also interested in semiconductor detectors, in particular CdZnTe and CdTe, and their application in X-ray astronomy and medicine. My work in this area involves fabrication, testing and optimisation of pixelated CdZnTe/CdTe detectors.

Between 2007 and 2012 I was a PhD student at Nicolaus Copernicus Astronomical Center and simultaniously at Universite Montpellier 2 (2009-2012). The main subject of my research work was pulsars (PSRs) and pulsar wind nebulae (PWNe). Prof. Bronek Rudak (NCAC, Toruń) and Dr. Yves Gallant (LUPM, UM2) were my PhD supervisors. I am a member of Torun Pulsar Group.

I successfully defended my PhD thesis and was awarded a PhD degree on October 26th, 2012. As a result of the joint doctorate supervision (cotutelle) I was awarded a PhD degree from Nicolaus Copernicus Astronomical Center (in astronomy) and from Universite Montpellier 2 (in physics). The title of my PhD thesis was: "Studies of the influence of magnetospheric pulsar winds on the pulsar surroundings". My research work focused on the following subjects:

Rotation-powered pulsars belong to the most important gamma-ray sources in our Galaxy according to the preliminary results of the Fermi Gamma-ray Space Telescope. The Fermi LAT detector is collecting data of superb quality for the brightest pulsars, and is expected to discover about 100 new pulsars in gamma-rays, including 'Geminga'-type pulsars. Moreover, the second phase of the HESS project is expected to start operation in 2011; its capabilities should allow us to detect a handful of pulsars in the very-high-energy gamma-ray domain, mostly millisecond pulsars.

1. Pulsars (PSRs)

The first aim of the project is to analyse the high-energy radiation characteristics inferred from gamma-ray observations and to interpret them in the context of major present-day models of magnetospheric activity of pulsars. Three-dimensional numerical modeling of electromagnetic cascades for different accelerating gaps, with subsequent confrontation with the data, should then constrain and/or modify the models. In particular, the shape, location and geometrical extension of the gaps should be derived in the cases with the best photon statistics. It is expected that the gap properties will strongly depend on the pulsar's spin-down luminosity and to some extent on its evolutionary status (classical or millisecond pulsar).

2. Pulsar wind nebulae (PWNe)

With radiative processes in pulsar magnetospheres modeled properly it is then possible to calculate the properties of magnetospheric winds for various types of pulsars. The main component of such winds are pairs of electrons and positrons created and accelerated in the magnetosphere. In the case of young classical pulsars these pairs are ultimately responsible for the diffuse, steady synchrotron and inverse Compton emission of a pulsar wind nebula (PWN). Examples of such nebulae will be studied using existing and proposed follow-up observational data. In particular, the near-infrared band will be exploited to obtain constraints on the properties of optically obscured PWNe. Polarisation observations of synchrotron emission will be used to infer constraints on the nebular magnetic geometry, while studies of [FeII] and other line emission will yield constraints on the nebular dynamics.

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last update: April 2014