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28th of June 2019
ATNF Colloquium
Galaxy evolution from a radio perspective: lesson learned from extra-galactic deep fields
Isabella Prandoni (INAF - Istituto di Radioastronomia)
Abstract: A wealth of new data from upgraded and new radio interferometers are rapidly improving and transforming our understanding of the faint extra-galactic radio sky. The unexpected detection of large numbers of RQ AGNs, traditionally studied at optical/IR or X-ray wavelengths, opens new exciting perspectives for deep radio-continuum surveys, providing a unique and powerful dust/gas-obscuration-free tool to get a global census of both star formation and AGN activity up to high redshifts; hence tracing the apparently simultaneous evolution of stellar populations and black hole growth in galaxies.

The mounting radio source statistics at sub-mJy and μJy flux levels is providing us with progressively more stringent observational constraints on the physical properties of the faint radio population, and on the modeling of its various components. In this talk I will provide a brief overview of the latest results, focusing on two extragalactic deep fields observed as part of ongoing legacy surveys: the Lockman Hole (LH), observed at 150 MHz and 1.4 GHz with LOFAR and WSRT, and the GOODS-N field, observed with eMERLIN and JVLA at 1.4 and 5 GHz .

The above two cases very well serve the purpose of illustrating a) the benefit of wide-area surveys to provide statistically robust constraints on radio source demography and evolution, and b) the added value of sub-arcsec resolution to get an unbiased census of star formation, and to address the role of AGN feedback in galaxy evolution. In addition, the WSRT 1.4 GHz mosaic of the LH provides an excellent test-bed for the EMU radio-continuum all-sky survey planned for ASKAP, as it shares same sensitivity (10 uJy) and resolution (~10 arcsec). I will conclude addressing the implications of such results for future radio surveys, including EMU, and highlighting the synergies with other opt/IR and X-ray facilities/surveys.

Caption: LOFAR HBA ~25 sq. degr pointing. Median rms ~35 uJy after ~100h observations. Overplotted: WSRT 1.4 GHz mosaic (16 pointings) covering the inner 6.6 sq. degr (11 uJy rms); radio source counts obtained from it, showing that models (blue and light blue bands) fall short of observations below ~500 uJy.

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