A sharper view of the outer Galaxy at 1420 and 408 MHz from the Canadian Galactic Plane Survey - I. Revisiting the KR catalogue and new Gigahertz Peaked Spectrum Sources

TL;DR

This study uses high-resolution radio images from the Canadian Galactic Plane Survey to reexamine the Kallas and Reich catalogue, identifying the nature of sources and discovering new Gigahertz Peaked Spectrum sources.

Contribution

It provides a detailed reclassification of radio sources in the catalogue and identifies new candidate Gigahertz Peaked Spectrum sources using 408 and 1420 MHz data.

Findings

Reclassified sources as extended or compact, Galactic or extragalactic.

Highlighted large HII regions without optical counterparts.

Identified new Gigahertz Peaked Spectrum source candidates.

Abstract

Arcminute-resolution radio continuum images at 408 and 1420 MHz from the Canadian Galactic Plane Survey (CGPS) have been used to reexamine radio sources listed in the Kallas and Reich (1980) catalogue. This catalogue is of particular interest to Galactic studies as it lists both extended and compact radio sources found in the second Galactic quadrant. We have determined the nature (extended vs. compact, Galactic vs. extragalactic) of all of these bright radio sources. A number of large HII regions with no optical counterparts are highlighted along with a sample of large radio galaxies. Many sources previously thought to be extended Galactic objects are shown to be point sources. A sample of point sources with flat or rising spectra between 408 and 1420 MHz has been compiled, and within this sample likely Gigahertz Peaked Spectrum sources have been identified.