The LOFAR Two-metre Sky Survey. IV. First Data Release: Photometric redshifts and rest-frame magnitudes

Duncan, K. J.K. J.DuncanSabater, J.J.SabaterRöttgering, H. J. A.H. J. A.RöttgeringJarvis, M. J.M. J.JarvisSmith, D. J. B.D. J. B.SmithBest, P. N.P. N.BestCallingham, J. R.J. R.CallinghamCochrane, R.R.CochraneCroston, J. H.J. H.CrostonHardcastle, M. J.M. J.HardcastleMingo, B.B.MingoMorabito, L.L.MorabitoNisbet, D.D.NisbetPRANDONI, ISABELLAISABELLAPRANDONIShimwell, T. W.T. W.ShimwellTasse, C.C.TasseWhite, G. J.G. J.WhiteWilliams, W. L.W. L.WilliamsAlegre, L.L.AlegreChyży, K. T.K. T.ChyżyGürkan, G.G.GürkanHoeft, M.M.HoeftKondapally, R.R.KondapallyMechev, A. P.A. P.MechevMiley, G. K.G. K.MileySchwarz, D. J.D. J.Schwarzvan Weeren, R. J.R. J.van Weeren2020-12-182020-12-1820190004-6361http://hdl.handle.net/20.500.12386/28976The LOFAR Two-metre Sky Survey (LoTSS) is a sensitive, high-resolution 120-168 MHz survey of the Northern sky. The LoTSS First Data Release (DR1) presents 424 square degrees of radio continuum observations over the HETDEX Spring Field (10h45m00s < right ascension < 15h30m00s and 45°00'00″ < declination < 57°00'00″) with a median sensitivity of 71 μJy beam-1 and a resolution of 6″. In this paper we present photometric redshifts (photo-z) for 94.4% of optical sources over this region that are detected in the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) 3π steradian survey. Combining the Pan-STARRS optical data with mid-infrared photometry from the Wide-field Infrared Survey Explorer, we estimate photo-zs using a novel hybrid photometric redshift methodology optimised to produce the best possible performance for the diverse sample of radio continuum selected sources. For the radio-continuum detected population, we find an overall scatter in the photo-z of 3.9% and an outlier fraction (|zphot-zspec|/(1 + zspec) > 0.15) of 7.9%. We also find that, at a given redshift, there is no strong trend in photo-z quality as a function of radio luminosity. However there are strong trends as a function of redshift for a given radio luminosity, a result of selection effects in the spectroscopic sample and/or intrinsic evolution within the radio source population. Additionally, for the sample of sources in the LoTSS First Data Release with optical counterparts, we present rest-frame optical and mid-infrared magnitudes based on template fits to the consensus photometric (or spectroscopic when available) redshift. LoTSS.The catalogue is available at the CDS via anonymous ftp to <A href="http://cdsarc.u-strasbg.fr/">http://cdsarc.u-strasbg.fr</A> (ftp://130.79.128.5) or via <A href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/622/A1">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/622/A1</A>STAMPAenThe LOFAR Two-metre Sky Survey. IV. First Data Release: Photometric redshifts and rest-frame magnitudesArticle10.1051/0004-6361/2018335622-s2.0-85062000573000458945400003https://www.aanda.org/articles/aa/full_html/2019/02/aa33562-18/aa33562-18.html2019A&A...622A...3DFIS/05 - ASTRONOMIA E ASTROFISICAERC sectors::Physical Sciences and Engineering::PE9 Universe sciences: astro-physics/chemistry/biology; solar systems; stellar, galactic and extragalactic astronomy, planetary systems, cosmology, space science, instrumentation