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Discovery of 24 radio-bright quasars at $4.9 \leq z \leq6.6$ using low-frequency radio observations
(2022-12-31)
High redshift quasars ($z>5$) that also shine brightly at radio wavelengths are unique signposts of supermassive black hole activity in the early universe. However, bright radio sources at $z\ge5$ are extremely rare and ...
Nearby galaxies in the LOFAR Two-metre Sky Survey : I. Insights into the non-linearity of the radio–SFR relation
(2022-08-08)
Context. Cosmic rays and magnetic fields are key ingredients in galaxy evolution, regulating both stellar feedback and star formation. Their properties can be studied with low-frequency radio continuum observations, free ...
The Planck clusters in the LOFAR sky. I. LoTSS-DR2 new detections and sample overview
(2022-04-30)
Context. Relativistic electrons and magnetic fields permeate the intra-cluster medium (ICM) and manifest themselves as diffuse sources of synchrotron emission observable at radio wavelengths, namely radio halos and radio ...
Sub-arcsecond imaging with the International LOFAR Telescope : I. Foundational calibration strategy and pipeline
(2022-02-28)
The International LOFAR Telescope is an interferometer with stations spread across Europe. With baselines of up to ∼2000 km, LOFAR has the unique capability of achieving sub-arcsecond resolution at frequencies below 200 ...
The LOFAR Two-metre Sky Survey -- V. Second data release
(2022-02-25)
In this data release from the ongoing LOw-Frequency ARray (LOFAR) Two-metre Sky Survey we present 120a 168 MHz images covering 27% of the northern sky. Our coverage is split into two regions centred at approximately 12h45m ...
Low frequency radio properties of the $z>5$ quasar population
(2021-12-31)
Optically luminous quasars at z > 5 are important probes of super-massive black hole (SMBH) formation. With new and future radio facilities, the discovery of the brightest low-frequency radio sources in this epoch would ...
The population of M dwarfs observed at low radio frequencies
(2021-10-11)
Coherent low-frequency (≲200 MHz) radio emission from stars encodes the conditions of the outer corona, mass-ejection events and space weather 1–5. Previous low-frequency searches for radio-emitting stellar systems have ...
The contribution of discrete sources to the sky temperature at 144 MHz
(2021-04-07)
In recent years, the level of the extragalactic radio background has become a point of considerable interest, with some lines of argument pointing to an entirely new cosmological synchrotron background. The contribution ...
The beautiful mess in Abell 2255
(2020-07-07)
We present LOFAR observations of one of the most spectacular objects in the radio sky: Abell 2255. This is a nearby ($z = 0.0806$) merging galaxy cluster hosting one of the first radio halos ever detected in the intra-cluster ...