The VLA-COSMOS Survey - V. 324 MHz continuum observations (CROSBI ID 210235)
Prilog u časopisu | izvorni znanstveni rad | međunarodna recenzija
Podaci o odgovornosti
Smolčić, Vernesa ; Ciliegi, Paolo ; Jelić, Vibor ; Bondi, Marco ; Schinnerer, Eva ; Carilli, Chris L. ; Riechers, Dominik A. ; Salvato, Mara ; Brković, Alen ; Capak, Peter ; Ilbert, Olivier ; Karim, Alexander ; McCracken, Henry ; Scoville, Nick Z.
engleski
The VLA-COSMOS Survey - V. 324 MHz continuum observations
We present 90 cm Very Large Array imaging of the COSMOS field, comprising a circular area of 3.14 square degrees at 8.0arcsec × 6.0arcsec angular resolution with an average rms of 0.5 mJy beam-1. The extracted catalogue contains 182 sources (down to 5.5σ), 30 of which are multicomponent sources. Using Monte Carlo artificial source simulations, we derive the completeness of the catalogue, and we show that our 90 cm source counts agree very well with those from previous studies. Using X- ray, NUV- NIR and radio COSMOS data to investigate the population mix of our 90 cm radio sample, we find that our sample is dominated by active galactic nuclei. The average 90-20 cm spectral index (Sν ∝ να, where Sν is the flux density at frequency ν and α the spectral index) of our 90 cm selected sources is -0.70, with an interquartile range from -0.90 to -0.53. Only a few ultra-steep- spectrum sources are present in our sample, consistent with results in the literature for similar fields. Our data do not show clear steepening of the spectral index with redshift. Nevertheless, our sample suggests that sources with spectral indices steeper than -1 all lie at z ≳ 1, in agreement with the idea that ultra-steep- spectrum radio sources may trace intermediate- redshift galaxies (z ≳ 1).
radiation mechanisms: general ; surveys ; radio continuum: galaxies
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Podaci o izdanju
443 (3)
2014.
2590-2598
objavljeno
0035-8711
1365-2966
10.1093/mnras/stu1331