The Low Frequency Array (LOFAR) is an ideal instrument to conduct deep extragalactic
surveys. It has a large field of view and is sensitive to large-scale and compact emission. It …

ABSTRACT A new upper limit on the 21 cm signal power spectrum at a redshift of z≈ 9.1 is
presented, based on 141 h of data obtained with the Low-Frequency Array (LOFAR). The …

The LOFAR Two-metre Sky Survey (LoTSS) is a deep 120–168 MHz imaging survey that will
eventually cover the entire northern sky. Each of the 3170 pointings will be observed for 8 h …

We present the first full release of a survey of the 150 MHz radio sky, observed with the Giant
Metrewave Radio Telescope (GMRT) between April 2010 and March 2012 as part of the …

Context. Relativistic electrons and magnetic fields permeate the intra-cluster medium (ICM)
and manifest themselves as diffuse sources of synchrotron emission observable at radio …

The new generation of radio interferometers is characterized by high sensitivity, wide fields
of view and large fractional bandwidth. To synthesize the deepest images enabled by the …

The hot plasma within merging galaxy clusters is predicted to be filled with shocks and
turbulence that may convert part of their kinetic energy into relativistic electrons and …

We describe a new multiscale deconvolution algorithm that can also be used in a
multifrequency mode. The algorithm only affects the minor clean loop. In single-frequency …

Diffuse cluster radio sources, in the form of radio halos and relics, reveal the presence of
cosmic rays and magnetic fields in the intracluster medium (ICM). These cosmic rays are …

Context. New generation low-frequency telescopes are exploring a new parameter space in
terms of depth and resolution. The data taken with these interferometers, for example with …