Aris Karastergiou

Abstract:

This contribution to the proceedings of "A New Golden Age for Radio Astronomy" is simply intended to give some of the highlights from pulsar observations with LOFAR at the time of its official opening: June 12th, 2010. These observations illustrate that, though LOFAR is still under construction and astronomical commissioning, it is already starting to deliver on its promise to revolutionize radio astronomy in the low-frequency regime. These observations also demonstrate how LOFAR has many "next-generation" capabilities, such as wide-field multi-beaming, that will be vital to open a new Golden Age in radio astronomy through the Square Kilometer Array and its precursors.

Abstract:

Flux monitoring of compact radio quasars has revealed dramatic radio-wave lensing events which challenge our understanding of the interstellar medium. However, the data on these events remain very sparse. Here we consider how the Goonhilly radio astronomical facility can make an impact on this problem by dedicating one or more dishes to flux monitoring for a period of one year. Such an experiment would be able to identify \sim6 new events and study them in detail.

Abstract:

We present the first polarization measurements of the radio emission from RRAT J1819-1458. Our observations, conducted in parallel to regular timing sessions, have yielded a small number of bright and polarized pulses. The polarization characteristics and integrated profile resemble those of normal pulsars with average spin-down energy Ė: moderate to low linear polarization in the integrated profile despite relatively high polarization in the individual pulses. On average, a small degree of circular polarization is also observed. The polarization position angle (PA) executes a remarkably smooth, steep S-shaped curve, interrupted by two orthogonal jumps. Based on the shape of the PA swing, we place some constraints on the emission geometry. We compare these polarization properties to those of other radio-emitting neutron star populations, including young pulsars, pulsars with a high surface magnetic field and radio-emitting magnetars. From the polarization measurements, the Faraday rotation measure of this rotating radio transient is derived. © 2009 The Authors. Journal compilation © 2009 RAS.

Abstract:

We present the first polarization measurements of the radio emission from RRAT J1819$-$1458. Our observations, conducted in parallel to regular timing sessions, have yielded a small number of bright and polarized pulses. The polarization characteristics and integrated profile resemble those of normal pulsars with average spin-down energy (Edot): moderate to low linear polarization in the integrated profile despite relatively high polarization in the individual pulses. On average, a small degree of circular polarization is also observed. The polarization position angle executes a remarkably smooth, steep S-shaped curve, interrupted by two orthogonal jumps. Based on the shape of the PA swing, we place some constraints on the emission geometry. We compare these polarization properties to those of other radio emitting neutron star populations, including young pulsars, pulsars with a high surface magnetic field and radio emitting magnetars. From the polarization measurements, the Faraday rotation measure of this RRAT is derived.