The e-MERGE Survey (e-MERLIN Galaxy Evolution Survey): overview and survey description

Publication date: 
Main author: 
Muxlow, T. W. B.
IAA authors: 
Pérez-Torres, M. A.
Muxlow, T. W. B.;Thomson, A. P.;Radcliffe, J. F.;Wrigley, N. H.;Beswick, R. J.;Smail, Ian;McHardy, I. M.;Garrington, S. T.;Ivison, R. J.;Jarvis, M. J.;Prandoni, I.;Bondi, M.;Guidetti, D.;Argo, M. K.;Bacon, David;Best, P. N.;Biggs, A. D.;Chapman, S. C.;Coppin, K.;Chen, H.;Garratt, T. K.;Garrett, M. A.;Ibar, E.;Kneib, Jean-Paul;Knudsen, Kirsten K.;Koopmans, L. V. E.;Morabito, L. K.;Murphy, E. J.;Njeri, A.;Pearson, Chris;Pérez-Torres, M. A.;Richards, A. M. S.;Röttgering, H. J. A.;Sargent, M. T.;Serjeant, Stephen;Simpson, C.;Simpson, J. M.;Swinbank, A. M.;Varenius, E.;Venturi, T.
Monthly Notices of the Royal Astronomical Society
Publication type: 
We present an overview and description of the e-MERGE Survey (e-MERLIN Galaxy Evolution Survey) Data Release 1 (DR1), a large program of high-resolution 1.5-GHz radio observations of the GOODS-N field comprising ∼140 h of observations with enhanced-Multi-Element Remotely Linked Interferometer Network (e-MERLIN) and ∼40 h with the Very Large Array (VLA). We combine the long baselines of e-MERLIN (providing high angular resolution) with the relatively closely packed antennas of the VLA (providing excellent surface brightness sensitivity) to produce a deep 1.5-GHz radio survey with the sensitivity ( ${\sim}1.5\, \mu$ Jy beam<SUP>-1</SUP>), angular resolution (0.2-0.7 arcsec) and field-of-view (∼15 × 15 arcmin<SUP>2</SUP>) to detect and spatially resolve star-forming galaxies and active galactic nucleus (AGN) at $z$ ≳ 1. The goal of e-MERGE is to provide new constraints on the deep, sub-arcsecond radio sky which will be surveyed by SKA1-mid. In this initial publication, we discuss our data analysis techniques, including steps taken to model in-beam source variability over an ∼20-yr baseline and the development of new point spread function/primary beam models to seamlessly merge e-MERLIN and VLA data in the uv plane. We present early science results, including measurements of the luminosities and/or linear sizes of ∼500 galaxies selected at 1.5 GHz. In combination with deep Hubble Space Telescope observations, we measure a mean radio-to-optical size ratio of r<SUB>e-MERGE</SUB>/r<SUB>HST</SUB> ∼ 1.02 ± 0.03, suggesting that in most high-redshift galaxies, the ∼GHz continuum emission traces the stellar light seen in optical imaging. This is the first in a series of papers that will explore the ∼kpc-scale radio properties of star-forming galaxies and AGN in the GOODS-N field observed by e-MERGE DR1.
ADS Bibcode: 
Galaxies: evolution;Galaxies: high-redshift;radio continuum: galaxies;Astrophysics - Astrophysics of Galaxies