Gamma-ray astronomy

Abstract:

We measured a sample of 150 pulsar Rotation Measures (RMs) using the 20-cm receiver of the Parkes 64-m radio telescope. 46 of the pulsars in our sample have not had their RM values previously published, whereas 104 pulsar RMs have been revised. We used a novel quadratic fitting algorithm to obtain an accurate RM from the calibrated polarisation profiles recorded across 256 MHz of receiver bandwidth. The new data are used in conjunction with previously known Dispersion Measures (DMs) and the NE2001 electron-density model to study models of the direction and magnitude of the Galactic magnetic field.

Abstract:

We describe a uniform all-sky survey of bright blazars, selected primarily by their flat radio spectra, that is designed to provide a large catalog of likely γ-ray active galactic nuclei (AGNs). The defined sample has 1625 targets with radio and X-ray properties similar to those of the EGRET blazars, spread uniformly across the |b| > 10° sky. We also report progress toward optical characterization of the sample; of objects with known R < 23, 85% have been classified and 81% have measured redshifts. One goal of this program is to focus attention on the most interesting (e.g., high-redshift, high-luminosity,...) sources for intensive multiwavelength study during the observations by the Large Area Telescope (LAT) on GLAST. © 2008. The American Astronomical Society. All rights reserved.