A Northern Sky Survey at 15GHz

Abstract

Due to the challenging nature of high frequency radio surveys, few have been performed, resulting in a poor knowledge of the high frequency radio source population. The Arcminute MicroKelvin Imager Small Array (AMI-SA) is now conducting a legacy survey of the complete Northern hemisphere at 15 GHz. This is the highest frequency survey conducted to date of the whole Northern hemisphere to a source detection level of 10 mJy. This project involved understanding of the calibration and imaging process of the AMI-SA drift scan data which were used to combine the different scans into a continuous map. The continuous maps were stitched together to generated larger maps of the Northern hemisphere and these maps were searched for sources and when the survey is completed a catalogue will be compiled. Modifications of the data pipeline were investigated with the aim to improved image quality through implementing self-calibration techniques to remove artefacts round bright sources. It was discovered that self-calibration significantly improved the image quality over what could be achieved with interleaved observations of a bright calibrator source, and the data reduction pipeline will be changed to include such a self-calibration step as standard. In future, identified sources will be followed up by observations with the AMI-LA to match NVSS resolution. A comparison of these results with NVSS will allow calculation of the radio spectral index distribution between 1.4 and 15 GHz and identification of any currently undiscovered inverted spectrum sources.

Date of Award	1 Aug 2022
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Keith Grainge (Supervisor) & Anna Scaife (Supervisor)