2015 Theses Doctoral

A study of Pulsar Wind Nebulae and non-thermal filaments with the NuSTAR observatory

Nynka, Melania Christina

NuSTAR, the first high-energy focusing X-ray telescope, has provided an unprecedented view of the universe above 10 keV. I first briefly describe the fabrication and calibration campaign of the NuSTAR optics at Columbia University. I then present two main areas of research with NuSTAR: the pulsar wind nebula (PWN) G21.5-0.9, and the investigation of several filamentary structures within 0.5 deg. of the Galactic Center.

G21.5-0.9 is a well-studied PWN, and was observed by NuSTAR with ∼ 280 ks in the first months of its mission. I used both spectral and spatial image analysis of the emission to probe the validity of various magnetohydrodynamic models. Image deconvolution reveals the existence of non-thermal emission up to 20 keV, likely the supernova shell.

Next I discuss three non-thermal filaments found near the Galactic Center. The Cannonball is a known high-velocity neutron star escaping the radio shell of Sgr A East with an extended radio and soft X-ray tail. NuSTAR extended its non-thermal spectrum to 30 keV and measured a magnetic field of ∼ 313−550μG. I analyze filament G359.97-0.038 by incorporating broad-band morphological and spectral data from radio (5.5 and 8.3 GHz) and X-ray data with NuSTAR data. I conclude that it is not a PWN but more likely the result of an interaction between the Sgr A East remnant and the nearby molecular cloud. Lastly I observe the filament G0.13-0.11, likely a PWN elongated by the ram pressure from the nearby Radio Arc.