Magnetic History of the Universe
CHILES Con Pol will observe a dense grid of polarized radio sources and their Faraday rotation measures (>200/deg2). This will provide a unique opportunity to investigate the nature of intergalactic magnetic fields by searching for their statistical imprints throughout many closely-separated lines of sight. Observations of intergalactic magnetic fields are critically needed to chart the key epochs of cosmic web magnetization, with implications for primordial particle physics (e.g. baryon asymmetry), cosmology (e.g. small-scale matter power spectrum), and astrophysics (e.g. Pop III star formation, galaxy evolution).
The new parameter space opened by CHILES Con Pol will extend the utility of radio band studies beyond the usual radio quasar and radio galaxy populations, opening sensitivity to the starforming and radio-quiet AGN populations that form the bulk of extragalactic sources detected in the optical, X-ray, and infrared bands. CHILES Con Pol will be sensitive to star formation rates of 10 M☉/year at z=2, and to ultra-luminous infrared galaxies and sub-millimeter galaxies out to z=8 and beyond. Our primary interests include construction of number counts and luminosity functions to investigate the evolution of radio sources, clustering of radio selected galaxies, evolution of the far-infrared radio correlation, and galaxy polarization properties.
Weak Lensing Techniques
Weak gravitational lensing studies in the radio band encounter different systematics to those in the optical, e.g. the former has a more stable and better characterized observing beam. Radio weak lensing therefore offers great potential for reducing uncertainties on cosmological parameters to better study dark energy. The position angle of linear polarization is unaffected by weak lensing, making it a promising tool for distinguishing lensing distortions induced by the cosmic web from intrinsic source orientations, the latter being a chief systematic in optical lensing surveys. However, the polarization properties of sub-mJy radio sources are poorly understood. While CHILES Con Pol does not have sufficient angular resolution to observe weak lensing, it has the sensitivity and multi-wavelength resources to lay the groundwork for future lensing studies by carefully characterizing populations of faint polarized radio sources.
Variables and Transients
CHILES Con Pol produces calibrated and imaged data within 10 hours of observation (epochs are typically 4 or 6 hours in length). These data are provided to our partner team CHILES VERDES to perform the deepest search for radio variables and transients to date, opening new parameter space expected to contain tidal disruption events, radio supernovae, orphan gamma-ray bursts, and neutron star-neutron star mergers. CHILES VERDES is performing concurrent optical monitoring of our target field to an r-band magnitude of 20 with the Liverpool Telescope in La Palma.
CHILES Con Pol will deliver a 'gold standard' multi-wavelength cross-matched source catalog containing approximately 4000 sources, of legacy value to the worldwide astronomical community. The catalog will be useful for training machine learning algorithms to identify and classify radio sources in parts of the sky lacking deep multi-wavelength coverage, of relevance to upcoming wide-field surveys with the Square Kilometre Array and its pathfinders.