J/MNRAS/471/210 eMERGE Survey. I. VLA 5.5GHz sources (Guidetti+, 2017) ================================================================================ The eMERGE Survey. I: Very Large Array 5.5 GHz observations of the GOODS-North Field. Guidetti D., Bondi M., Prandoni I., Muxlow T.W.B., Beswick R., Wrigley N., Smail I., Mchardy I., Thomson A.P., Radcliffe J., Argo M.K. =2017MNRAS.471..210G (SIMBAD/NED BibCode) ================================================================================ ADC_Keywords: Active gal. nuclei ; Radio sources ; Redshifts ; Morphology Keywords: galaxies: active - galaxies: evolution - galaxies: starburst cosmology: observations - radio continuum: galaxies Abstract: We present new observations of the GOODS-N field obtained at 5.5GHz with the Karl G. Jansky Very Large Array. The central region of the field was imaged to a median rms of 3{mu}Jy/beam with a resolution of 0.5 arcsec. From a 14-arcmin diameter region, we extracted a sample of 94 radio sources with signal-to-noise ratio greater than 5. Near-IR identifications are available for about ~88 per cent of the radio sources. We used different multiband diagnostics to separate active galactic nuclei (AGNs), both radiatively efficient and inefficient, from star-forming galaxies. From our analysis, we find that about 80 per cent of our radio-selected sample is AGN dominated, with the fraction rising to 92 per cent when considering only the radio sources with redshift >1.5. This large fraction of AGN-dominated radio sources at very low flux densities (the median flux density at 5.5GHz is 42{mu}Jy), where star-forming galaxies are expected to dominate, is somewhat surprising and at odds with other results. Our interpretation is that both the frequency and angular resolution of our radio observations strongly select against radio sources whose brightness distribution is diffuse on a scale of several kpc. Indeed, we find that the median angular sizes of the AGN-dominated sources is around 0.2-0.3arcsec against 0.8 arcsec for star-forming galaxies. This highlights the key role that high frequency radio observations can play in pinpointing AGN-driven radio emission at {mu}Jy levels. This work is part of the eMERGE legacy project. Description: We obtained new VLA observations of the GOODS-N field at a central frequency of 5.5GHz with a 2GHz bandwidth in A- and B-configurations. The VLA A-configuration observations were taken over four nights in 2012 October (2012 October 6-8 and 20, project code 12B-181), for a total observing time of 14h. The B-configuration data were taken in one night (2013 September 27, project code 13B-152) for a total time of 2.5h. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table1.dat 95 94 The catalogue of source detected above 5 sigma at 5.5GHz table2.dat 34 8 Polarized sources table4.dat 44 77 Multiwavelength classification for the 5.5GHz sources with NIR identification -------------------------------------------------------------------------------- See also: J/ApJ/689/687 : GOODS-N spectroscopic survey (Barger+, 2008) J/ApJS/235/34 : Deep JVLA imaging of GOODS-N at 20cm (Owen, 2018) J/A+A/619/A48 : GOODS-N AGN VLBI detect. & radio properties (Radcliffe+, 2018) Byte-by-byte Description of file: table1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 14 A14 --- Name Source name (JHHMMSS+DDMMSS) 16- 17 I2 h RAh Right ascension (J2000) 19- 20 I2 min RAm Right ascension (J2000) 22- 26 F5.2 s RAs Right ascension (J2000) 28 A1 --- DE- Declination sign (J2000) 29- 30 I2 deg DEd Declination (J2000) 32- 33 I2 arcmin DEm Declination (J2000) 35- 39 F5.2 arcsec DEs Declination (J2000) 41- 44 F4.2 arcsec e_RAs Error on RA (arcsec) 46- 49 F4.2 arcsec e_DEs Error on DE (arcsec) 51- 55 F5.1 --- S/N Signal-to-noise ratio 57- 62 F6.1 uJy/beam Fpeak Peak brightness at 5GHz 64- 67 F4.1 uJy/beam e_Fpeak Error on peak brightness at 5GHz 69- 74 F6.1 uJy Ftot Total flux density at 5GHz 76- 79 F4.1 uJy e_Ftot Error on total flux density at 5GHz 81- 85 F5.2 arcsec Amaj ?=-9 Deconvolved sizes: major axis 87- 91 F5.2 arcsec Bmin ?=-9 Deconvolved sizes: minor axis 93- 95 I3 deg PA ?=-99 Deconvolved sizes: position angle -------------------------------------------------------------------------------- Byte-by-byte Description of file: table2.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 14 A14 --- Name Source name (JHHMMSS+DDMMSS) 16- 19 F4.1 uJy Ppeak Peak of polarized emission at 5GHz 21- 24 F4.1 --- SNRP SNR of the polarized emission 26- 29 F4.1 uJy Ptot Total polarized emission at 5GHz 31- 34 F4.1 % Pol Average fractional polarization at 5GHz -------------------------------------------------------------------------------- Byte-by-byte Description of file: table4.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 14 A14 --- Name Source name (JHHMMSS+DDMMSS) 16- 20 F5.3 --- z z Spectroscopic (s) or photometric (p) redshift 22 A1 --- n_z [s/p] Spectroscopic (s) or photometric (p) redshift 24- 31 A8 --- ClassIR Classification based on the four IR diagnotics 33 A1 --- X-ray [Y/N] X-ray AGN (Y) or not (N) 35 A1 --- Radio-exc [Y/N] Radio-excess AGN (Y) or not (N) 37 A1 --- VLBI [Y/N] VLBI detected sources (Y) or not (N) 39- 44 A6 --- Class Final classification combining all the multiwavelength diagnostics -------------------------------------------------------------------------------- History: From electronic version of the journal ================================================================================ (End) Patricia Vannier [CDS] 15-May-2020