Predictions for Ultra-deep Radio Counts of Star-forming Galaxies

We have worked outty predictions for the radio counts of star-forming galaxies down to nJy levels, along with redshift distributions down to the detection limits of the phase 1 Square Kilometer Array MID telescope (SKA1-MID) and of its precursors. Such predictions were obtained by coupling epoch-dep...

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Bibliographic Details
Main Authors: Mancuso, Claudia, Lapi, Andrea, Cai, Zhen-Yi, Negrello, Mattia, DE ZOTTI, Gianfranco, BRESSAN, Alessandro, BONATO, MATTEO, Perrotta, Francesca, Danese, Luigi
Format: Article in Journal/Newspaper
Language:English
Published: 2015
Subjects:
South Pole
South pole
Online Access:https://hdl.handle.net/20.500.12386/30238
https://doi.org/10.1088/0004-637X/810/1/72
https://iopscience.iop.org/article/10.1088/0004-637X/810/1/72
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Summary:We have worked outty predictions for the radio counts of star-forming galaxies down to nJy levels, along with redshift distributions down to the detection limits of the phase 1 Square Kilometer Array MID telescope (SKA1-MID) and of its precursors. Such predictions were obtained by coupling epoch-dependent star formation rate (SFR) functions with relations between SFR and radio (synchrotron and free-free) emission. The SFR functions were derived taking into account both the dust-obscured and the unobscured star formation, by combining far-infrared, ultraviolet, and Hα luminosity functions up to high redshifts. We have also revisited the South Pole Telescope counts of dusty galaxies at 95 GHz, performing a detailed analysis of the Spectral Energy Distributions. Our results show that the deepest SKA1-MID surveys will detect high-z galaxies with SFRs two orders of magnitude lower compared to Herschel surveys. The highest redshift tails of the distributions at the detection limits of planned SKA1-MID surveys comprise a substantial fraction of strongly lensed galaxies. We predict that a survey down to 0.25 μJy at 1.4 GHz will detect about 1200 strongly lensed galaxies per square degree, at redshifts of up to 10. For about 30% of them the SKA1-MID will detect at least 2 images. The SKA1-MID will thus provide a comprehensive view of the star formation history throughout the re-ionization epoch, unaffected by dust extinction. We have also provided specific predictions for the EMU/ASKAP and MIGHTEE/MeerKAT surveys.

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