On-The-Fly interferometric imaging with the MeerKLASS survey

Abstract

MeerKLAS, the MeerKAT Large Area Synoptic Survey, aims to survey large areas of the sky with MeerKAT in order to probe cosmology using the single dish HI intensity mapping (IM) technique. The MeerKLASS project provides an additional wide continuum survey capability alongside the single-dish HI IM survey by utilizing the ‘On-the-Fly’ (OTF) mapping technique. The target is to cover 10,000 sq. deg on the UHF band with 35 uJy rms and 15’’ resolution. This OTF interferometric imaging technique enables commensal observing for intensity mapping and interferometric imaging. The target sky area will cover most of the Southern sky, overlapping with several optical/NIR wide galaxy surveys and providing an invaluable legacy dataset. We have successfully implemented an end-to-end pipeline that produces continuum images from fast scanning MeerKLASS observations. In this presentation, I will focus on the development of the MeerKLASS OTF imaging pipeline. OTF imaging comes with its own set of challenges, such as flux errors due to smearing caused by the motion of the pointing centre on the sky. I shall discuss how we have mitigated the challenges in the OTF pipeline and the consequences. The final data product for the OTF-MeerKLASS survey consists of deep continuum images obtained by combining all the data from repeated scans of the same sky patch. Finally I shall discuss early science results for the survey such as source count, clustering and multi-wavelength analysis of the OTF catalog radio sources from L and UHF-band. In future, with many fold data acquisition by the MeerKLASS survey we expect to embark on the search for slow transients and I plan to briefly discuss the prospect of such analysis. Lessons from these techniques will be valuable for the upcoming SKA-mid observations.