Speaker
Description
In an rapidly approaching SKA era, the need to characterise radio sources and their host galaxies accurately has emerged as a non-trivial problem, especially for undetected host galaxies. For this population without clear hosts, overlapping with infrared-faint radio sources (IFRSs), the bottleneck in obtaining redshifts lies in dedicated follow-up at sub-mm or infrared wavelengths using over-subscribed instruments. Given the wealth of sensitive, all-sky observations in the radio, there has to be a better way of determining the redshifts for this IFRS-like population which include the elusive powerful radio galaxies at z>5. Previously using the GLEAM survey, efforts were made to select low-frequency turnover high-redshift radio galaxies by their spectral index and curvature within GLEAM and then filter out by other characteristics and verify with follow-up at optical to sub-mm wavelengths. Two z>=3 radio galaxies that were verified from that pilot study now have LOFAR Low Band Antenna data spanning ~35-65 MHz, complementing GLEAM and opening a window into the MHz-peaked turnovers previously hinted at. We compare the rest-frame turnovers and linear source sizes for these sources at very high redshift with known relations and investigate the MHz-peaked spectrum population of sources that are within the large LOFAR field of view. We explore these as potential candidate high-redshift radio galaxies that can be selected or inferred from broadband radio SEDs that extend to <50 MHz.
| Timeslot preferences | 10min |
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