A deep survey of the AKARI north ecliptic pole field - I. WSRT 20 cm radio survey description, observations and data reduction

摘要

Aims. The Westerbork Radio Synthesis Telescope, ,has been used to make a deep radio survey of an 1.7degree2field coinciding with the AKARI north ecliptic pole deep field. Theobservations, data reduction and source count analysis are presented,along with a description of the overall scientific objectives. Methods. The survey consisted of10pointings, mosaiced with enough overlap to maintain asimilar sensitivity across the central region that reached as low as21Jybeam-1at1.4GHz. Results. A catalogue containing 462 sources detectedwith a resolution of17.015.5is presented. The differential source counts calculated from the datahave been compared with those from the shallow surveyof Kollgaard etal. 1994, and show a pronounced excess forsources fainter than 1mJy,consistent with the presence of a population of star forming galaxiesat sub-mJy flux levels. Conclusions. The AKARI north ecliptic pole deepfield is the focus of a major observing campaign conducted across theentire spectral region. The combination of these data sets, along withthe deep nature of the radio observations will allow unique studies ofa large range of topics including the redshift evolution of theluminosity function of radio sources, the clustering environment ofradio galaxies, the nature of obscured radio-loud active galacticnuclei, and the radio/far-infrared correlation for distant galaxies.This catalogue provides the basic data set for a future series of paperdealing with source identifications, morphologies, and the associatedproperties of the identified radio sources. Key words: galaxies: active - radiocontinuum: galaxies - surveys - catalogs - cosmology: observations