Master's thesis defense by Simone Juul Jakobsen – Niels Bohr Institutet - Københavns Universitet

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Master's thesis defense by Simone Juul Jakobsen

Simone Juul Jakobsen is defending her master's thesis Friday 21 June 2013 at 15:00, in room 071 at Rockefeller.

Title: Supernova remnants and pulsar wind nebulae in the Norma region

Abstract: This thesis reports on the discovery of a new extended X-ray source that is well descri- bed by the expected properties of a moving pulsar driving a so called pulsar wind nebula. The discovery was done with the Chandra X-ray observatory in connection to a scheduled survey of the Norma region. The source exhibits a spectrum fitted well with an absorbed power law model. Comparing the Chandra spectrum of the source with one obtained from an archived XMM Newton observation results in best fit parameters nH∼ 17 × 1022 cm−2 and Γ ∼ 1.25. A spatial spectral investigation performed using Chandra data shows signs of spectral softening with increasing radius from the emission peak. Inferring a lower bound on the distance to the source of ∼ 14kpc based on the large ab- sorbing column, a spin-down luminosity of E ̇ ∼ 7 × 1036 erg s−1 is estimated for the pulsar candidate. Combining the Chandra data with radio data from the Molonglo Galactic Plane Survey epoch-2 (MGPS-2), reveals a cometary structure in X-rays and an elongated tail-like struc- ture in radio. The emission is consistent with what is expected for a pulsar wind nebula and the observed structure is therefore used in order to calculate a Mach number M ≈ 3 for the supposed pulsar. A light curve was extracted to search for pulsations, but no useful information could be extracted, because of the poor photon statistics. Additionally this work presents the first detection of X-ray emission from an arc like structure in connection to the supernova remnant G337.2+00.1. The emission is deemed significant based on the result of an F-test and is interpreted as the forward shock interacting with a molecular cloud, based on the fact that it is nicely correlated with radio emission from the remnant. The detected remnant shell is positioned at a distance of ∼ 109arcsec from the center of the remnant, and this value is used together with the Sedov-Taylor self-similar solutions to achieve an approximate age of the remnant of ∼ 1400 yr. This is a value similar to what has been found previously and makes G337.2+00.1 a member of the historical supernova remnants with the explosion occurring sometime in the 7th century. Finally I present in this thesis the first Chandra detection of the mixed-morphology remnant G337.8- 00.1.