Deep JVLA Imaging of GOODS-N at 20cm

TL;DR

This paper presents deep 20cm radio imaging of the GOODS-N field with the VLA, cataloging 795 sources, analyzing their optical/NIR counterparts, and exploring their sizes, orientations, and star-formation activity across different redshifts.

Contribution

It provides the deepest wideband 20cm VLA observations of GOODS-N, with a detailed catalog and analysis linking radio sources to optical/NIR data and galaxy properties.

Findings

Most sources have correct optical/NIR identifications.

Radio sizes > 1" correlate with galaxy orientations for z<1.

High star-formation rates inferred for z>1 sources.

Abstract

New wideband continuum observations in the 1 - 2 GHz band of the GOODS-N field using NSF's Karl G. Jansky Very Large Array (VLA) are presented. The best image with an effective frequency of 1525 MHz reaches an rms noise in the field center of 2.2 uJy with 1.6" resolution. A catalog of 795 sources is presented covering a radius of nine arcminutes centered near the nominal center for the GOODS-N field, very near the nominal VLA pointing center for the observations. Optical/NIR identifications and redshift estimates both from ground-based and HST observations are discussed. Using these optical/NIR data, it is most likely that fewer than 2 per cent of the sources without confusion problems do not have a correct identification. A large subset of the detected sources have radio sizes > 1". It is shown that the radio orientations for such sources correlate well with the HST source orientations especially for z < 1. This suggests that a least a large subset of the 10kpc-scale disks of LIRG/ULIRG galaxies have strong star-formation, not just in the nucleus. For the half of the objects with z > 1, the sample must be some mixture of very high star-formation rates, typically 300 M_sun/yr assuming pure star-formation, and an AGN or a mixed AGN/star-formation population.