Publications (147)
Exploring the radio-loudness of SDSS quasars with spectral stacking
M. I. Arnaudova, D. J. B. Smith, M. J. Hardcastle +9
We use new 144 MHz observations over 5634 deg from the LOFAR Two-metre Sky Survey (LoTSS) to compile the largest sample of uniformly-selected, spectroscopically-confirmed quasa…
The LOFAR Two-metre Sky Survey Deep fields: The star formation rate - radio luminosity relation at low frequencies
D. J. B. Smith, P. Haskell, G. Gürkan +17
In this paper, we investigate the relationship between 150MHz luminosity and star formation rate (the SFR-L150 relation) using 150MHz measurements for a near-infrared selected samp…
Coherent radio emission from a quiescent red dwarf indicative of star-planet interaction
H. K. Vedantham, J. R. Callingham, T. W. Shimwell +11
Low frequency (MHz) stellar radio emission is expected to originate in the outer corona at heights comparable to and larger than the stellar radius. Such emission…
The contribution of discrete sources to the sky temperature at 144 MHz
M. J. Hardcastle, T. W. Shimwell, C. Tasse +7
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 s…
Radio fossils, relics, and haloes in Abell 3266: cluster archaeology with ASKAP-EMU and the ATCA
C. J. Riseley, E. Bonnassieux, T. Vernstrom +21
Abell 3266 is a massive and complex merging galaxy cluster that exhibits significant substructure. We present new, highly sensitive radio continuum observations of Abell 3266 perfo…
The LOFAR Two Metre Sky Survey: Deep Fields Data Release 1 -- III. Host-galaxy identifications and value added catalogues
R. Kondapally, P. N. Best, M. J. Hardcastle +40
We present the source associations, cross-identifications, and multi-wavelength properties of the faint radio source population detected in the deep tier of the LOFAR Two Metre Sky…
Remnant radio-loud AGN in the Herschel-ATLAS field
V. H. Mahatma, M. J. Hardcastle, W. L. Williams +10
Only a small fraction of observed Active Galactic Nuclei display large-scale radio emission associated with jets, yet these radio-loud AGN have become increasingly important in mod…
Low-frequency monitoring of flare star binary CR Draconis: Long-term electron-cyclotron maser emission
J. R. Callingham, B. J. S. Pope, A. D. Feinstein +12
Recently detected coherent low-frequency radio emission from M dwarf systems shares phenomenological similarities with emission produced by magnetospheric processes from the gas gi…
Ultra-low frequency LOFAR spectral indices of cluster radio halos
T. Pasini, F. de Gasperin, M. Brüggen +11
A fraction of galaxy clusters harbor diffuse radio sources known as radio halos. The currently adopted scenario for their formation is based on second-order Fermi re-acceleration o…
Deep sub-arcsecond widefield imaging of the Lockman Hole field at 144 MHz
F. Sweijen, R. J. van Weeren, H. J. A. Röttgering +11
High quality low-frequency radio surveys have the promise of advancing our understanding of many important topics in astrophysics, including the life cycle of active galactic nucle…
Sub-arcsecond imaging with the International LOFAR Telescope I. Foundational calibration strategy and pipeline
L. K. Morabito, N. J. Jackson, S. Mooney +71
[abridged] The International LOFAR Telescope is an interferometer with stations spread across Europe. With baselines of up to ~2,000 km, LOFAR has the unique capability of achievin…
Discovery of Carbon Radio Recombination Lines in absorption towards Cygnus~A
J. B. R. Oonk, R. J. van Weeren, F. Salgado +100
We present the first detection of carbon radio recombination line absorption along the line of sight to Cygnus A. The observations were carried out with the LOw Frequency ARray in…
The LOFAR Two-metre Sky Survey IV. First Data Release: Photometric redshifts and rest-frame magnitudes
Kenneth J Duncan, J. Sabater, H. J. A. Röttgering +24
The LOFAR Two-metre Sky Survey (LoTSS) is a sensitive, high-resolution 120-168 MHz survey of the Northern sky. The LoTSS First Data Release (DR1) presents 424 square degrees of rad…
First LOFAR observations at very low frequencies of cluster-scale non-thermal emission: the case of Abell 2256
R. J. van Weeren, H. J. A. Rottgering, D. A. Rafferty +79
Abell 2256 is one of the best known examples of a galaxy cluster hosting large-scale diffuse radio emission that is unrelated to individual galaxies. It contains both a giant radio…
Gravitational lensing in LoTSS DR2 -- Extremely faint 144-MHz radio emission from two highly magnified quasars
J. P. McKean, R. Luichies, A. Drabent +8
We report extremely faint 144 MHz radio emission from two gravitationally lensed quasars, SDSS J1004+4112 (z = 1.730) and SDSS J2222+2745 (z = 2.803), using the LOFAR Two Metre Sky…
Exploring the properties of low-frequency radio emission and magnetic fields in a sample of compact galaxy groups using the LOFAR Two-Metre Sky Survey (LoTSS)
B. Nikiel-WroczyÅski, A. Berger, N. Herrera Ruiz +14
We use the LOFAR Two-metre Sky Survey (LoTSS) Data Release I to identify the groups of galaxies (and individual galaxies) from the Hickson Compact Groups and Magnitude Limited Comp…
The 1.28 GHz MeerKAT Galactic Center Mosaic
I. Heywood, I. Rammala, F. Camilo +108
The inner 200 pc region of the Galaxy contains a 4 million M supermassive black hole (SMBH), significant quantities of molecular gas, and star formation and cosmic…
Origin of the ring structures in Hercules A -- Sub-arcsecond 144 MHz to 7 GHz observations
R. Timmerman, R. J. van Weeren, J. R. Callingham +18
The prominent radio source Hercules A features complex structures in its radio lobes. Although it is one of the most comprehensively studied sources in the radio sky, the origin of…
The 1.28 GHz MeerKAT DEEP2 Image
T. Mauch, W. D. Cotton, J. J. Condon +101
We present the confusion-limited 1.28 GHz MeerKAT DEEP2 image covering one FWHM primary beam area with FWHM resolution and Jy/beam rms noi…
Revived Fossil Plasma Sources in Galaxy Clusters
S. Mandal, H. T. Intema, R. J. van Weeren +10
It is well established that particle acceleration by shocks and turbulence in the intra-cluster medium can produce cluster-scale synchrotron emitting sources. However, the detailed…
Radio Burst from a Stellar Coronal Mass Ejection
J. R. Callingham, C. Tasse, R. Keers +15
Coronal mass ejections (CMEs) are massive expulsions of magnetised plasma from a star, and are the largest contributors to space weather in the Solar System. CMEs are theorized to…
Detection of coherent low-frequency radio bursts from weak-line TTauri stars
A. Feeney-Johansson, S. J. D. Purser, T. P. Ray +7
In recent years, thanks to new facilities such as LOFAR capable of sensitive observations, much work has been done on the detection of stellar radio emission at low frequencies. Su…
LOFAR 150-MHz observations of the Boötes field: Catalogue and Source Counts
W. L. Williams, R. J. van Weeren, H. J. A. Röttgering +32
We present the first wide area (19 deg), deep ( μJy beam), high resolution ( arcsec) LOFAR High Band Antenna image of the Boötes field…
M87 at metre wavelengths: the LOFAR picture
F. de Gasperin, E. Orru', M. Murgia +92
M87 is a giant elliptical galaxy located in the centre of the Virgo cluster, which harbours a supermassive black hole of mass 6.4x10^9 M_sun, whose activity is responsible for the…
The LOFAR Two-metre Sky Survey: Deep Fields Data Release 2. I. The ELAIS-N1 field
T. W. Shimwell, C. L. Hale, P. N. Best +29
We present the final 6'' resolution data release of the ELAIS-N1 field from the LOw-Frequency ARray (LOFAR) Two-metre Sky Survey Deep Fields project (LoTSS Deep). The 144MHz images…
Low-frequency observations of the Giant Radio Galaxy NGC 6251
T. M. Cantwell, J. D. Bray, J. H. Croston +22
We present LOFAR observations at 150 MHz of the borderline FRI/FRII giant radio galaxy NGC 6251. This paper presents the most sensitive and highest-resolution images of NGC 6251 at…
Wide-Band, Low-Frequency Pulse Profiles of 100 Radio Pulsars with LOFAR
M. Pilia, J. W. T. Hessels, B. W. Stappers +84
LOFAR offers the unique capability of observing pulsars across the 10-240 MHz frequency range with a fractional bandwidth of roughly 50%. This spectral range is well-suited for stu…
LOFAR tied-array imaging and spectroscopy of solar S bursts
D. E. Morosan, P. T. Gallagher, P. Zucca +50
Context. The Sun is an active source of radio emission that is often associated with energetic phenomena ranging from nanoflares to coronal mass ejections (CMEs). At low radio freq…
LOFAR tied-array imaging of Type III solar radio bursts
D. E. Morosan, P. T. Gallagher, P. Zucca +82
The Sun is an active source of radio emission which is often associated with energetic phenomena such as solar flares and coronal mass ejections (CMEs). At low radio frequencies (<…
The Planck clusters in the LOFAR sky. II. LoTSS-DR2: Recovering diffuse extended emission with LOFAR
L. Bruno, G. Brunetti, A. Botteon +12
Extended radio sources in the sky require a dense sampling of short baselines to be properly imaged by interferometers. This problem arises in many areas of radio astronomy, such a…
LoTSS jellyfish galaxies: I. Radio tails in low redshift clusters
I. D. Roberts, R. J. van Weeren, S. L. McGee +6
In this paper we present a large sample of jellyfish galaxies in low redshift clusters (z<0.05), identified through 120-168 MHz radio continuum from the LOFAR Two-metre Sky Survey…
LOFAR early-time search for coherent radio emission from GRB 180706A
A. Rowlinson, K. Gourdji, K. van der Meulen +12
The nature of the central engines of gamma-ray bursts (GRBs) and the composition of their relativistic jets are still under debate. If the jets are Poynting flux dominated rather t…
LOFAR 144-MHz follow-up observations of GW170817
J. W. Broderick, T. W. Shimwell, K. Gourdji +66
We present low-radio-frequency follow-up observations of AT 2017gfo, the electromagnetic counterpart of GW170817, which was the first binary neutron star merger to be detected by A…
The life cycle of radio galaxies in the LOFAR Lockman Hole field
N. Jurlin, R. Morganti, M. Brienza +13
Radio galaxies are known to go through cycles of activity, where phases of apparent quiescence can be followed by repeated activity of the central supermassive black hole. A better…
The LOFAR Two-metre Sky Survey: VII. Third Data Release
T. W. Shimwell, M. J. Hardcastle, C. Tasse +99
We present the third data release of the LOFAR Two-metre Sky Survey (LoTSS-DR3). The survey images cover 88% of the northern sky and were created from 12,950 hrs of data (18.6 PB)…
LOFAR MSSS: Discovery of a 2.56 Mpc giant radio galaxy associated with a disturbed galaxy group
A. O. Clarke, G. Heald, T. Jarrett +40
We report on the discovery in the LOFAR Multifrequency Snapshot Sky Survey (MSSS) of a giant radio galaxy (GRG) with a projected size of Mpc projected on the sky. I…
New constraints on the magnetization of the cosmic web using LOFAR Faraday rotation observations
S. P. O'Sullivan, M. Brüggen, F. Vazza +11
Measuring the properties of extragalactic magnetic fields through the effect of Faraday rotation provides a means to understand the origin and evolution of cosmic magnetism. Here w…
The brightness and spatial distributions of terrestrial radio sources
A. R. Offringa, A. G. de Bruyn, S. Zaroubi +75
Faint undetected sources of radio-frequency interference (RFI) might become visible in long radio observations when they are consistently present over time. Thereby, they might obs…
SKA Science Data Challenge 2: analysis and results
P. Hartley, A. Bonaldi, R. Braun +105
The Square Kilometre Array Observatory (SKAO) will explore the radio sky to new depths in order to conduct transformational science. SKAO data products made available to astronomer…
The LOFAR LBA Sky Survey I. survey description and preliminary data release
F. de Gasperin, W. L. Williams, P. Best +38
LOFAR is the only radio telescope that is presently capable of high-sensitivity, high-resolution (<1 mJy/b and <15") observations at ultra-low frequencies (<100 MHz). To utilise th…
Possible discovery of Calvera's supernova remnant
M. Arias, A. Botteon, C. G. Bassa +13
We report the discovery of a ring of low surface brightness radio emission around the Calvera pulsar, a high Galactic latitude, isolated neutron star, in the LOFAR Two-metre Sky Su…
A large light-mass component of cosmic rays at 10^{17} - 10^{17.5} eV from radio observations
S. Buitink, A. Corstanje, H. Falcke +101
Cosmic rays are the highest energy particles found in nature. Measurements of the mass composition of cosmic rays between 10^{17} eV and 10^{18} eV are essential to understand whet…
Applying full polarization A-Projection to very wide field of view instruments: An imager for LOFAR
C. Tasse, B. van der Tol, J. van Zwieten +2
The aimed high sensitivities and large fields of view of the new generation of interferometers impose to reach high dynamic range of order 1: to 1: in the case of…
Imaging Jupiter's radiation belts down to 127 MHz with LOFAR
J. N. Girard, P. Zarka, C. Tasse +71
Context. Observing Jupiter's synchrotron emission from the Earth remains today the sole method to scrutinize the distribution and dynamical behavior of the ultra energetic electron…
The Coma cluster at LOFAR frequencies II: the halo, relic, and a new accretion relic
A. Bonafede, G. Brunetti, L. Rudnick +26
We present LOw Frequency ARray observations of the Coma cluster field at 144\,MHz. The cluster hosts one of the most famous radio halos, a relic, and a low surface-brightness bridg…
LOFAR MSSS: Detection of a low-frequency radio transient in 400 hrs of monitoring of the North Celestial Pole
A. J. Stewart, R. P. Fender, J. W. Broderick +99
We present the results of a four-month campaign searching for low-frequency radio transients near the North Celestial Pole with the Low-Frequency Array (LOFAR), as part of the Mult…
The ultra-steep diffuse radio emission observed in the cool-core cluster RX J1720.1+2638 with LOFAR at 54 MHz
N. Biava, F. de Gasperin, A. Bonafede +17
Diffuse radio emission at the centre of galaxy clusters has been observed both in merging clusters on scales of Mpc, called giant radio haloes, and in relaxed systems with a cool-c…
Differential Frequency-dependent Delay from the Pulsar Magnetosphere
T. E. Hassall, B. W. Stappers, P. Weltevrede +60
Some radio pulsars show clear drifting subpulses, in which subpulses are seen to drift in pulse longitude in a systematic pattern. Here we examine how the drifting subpulses of PSR…
LOFAR observations of galaxy clusters in HETDEX
R. J. van Weeren, T. W. Shimwell, A. Botteon +20
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…
LOFAR Deep Fields: Probing a broader population of polarized radio galaxies in ELAIS-N1
N. Herrera Ruiz, S. P. O'Sullivan, V. Vacca +19
We present deep polarimetric observations of the European Large Area ISO Survey-North 1 (ELAIS-N1) field using the Low Frequency Array (LOFAR) at 114.9-177.4 MHz. The ELAIS-N1 fiel…
The LOFAR window on star-forming galaxies and AGN - curved radio SEDs and IR-radio correlation at
G. Calistro-Rivera, W. L. Williams, M. J. Hardcastle +20
We present a study of the low-frequency radio properties of star forming (SF) galaxies and active galactic nuclei (AGN) up to redshift . The new spectral window probed by th…
Initial deep LOFAR observations of Epoch of Reionization windows: I. The North Celestial Pole
S. Yatawatta, A. G. de Bruyn, M. A. Brentjens +86
The aim of the LOFAR Epoch of Reionization (EoR) project is to detect the spectral fluctuations of the redshifted HI 21cm signal. This signal is weaker by several orders of magnitu…
Initial LOFAR observations of Epoch of Reionization windows: II. Diffuse polarized emission in the ELAIS-N1 field
V. Jelic, A. G. de Bruyn, M. Mevius +106
This study aims to characterise the polarized foreground emission in the ELAIS-N1 field and to address its possible implications for the extraction of the cosmological 21-cm signal…
Wide-band Simultaneous Observations of Pulsars: Disentangling Dispersion Measure and Profile Variations
T. E. Hassall, B. W. Stappers, J. W. T. Hessels +91
Dispersion in the interstellar medium is a well known phenomenon that follows a simple relationship, which has been used to predict the time delay of dispersed radio pulses since t…
Inflation of 430-parsec bipolar radio bubbles in the Galactic Centre by an energetic event
I. Heywood, F. Camilo, W. D. Cotton +96
The Galactic Centre contains a supermassive black hole with a mass of 4 million suns within an environment that differs markedly from that of the Galactic disk. While the black hol…
LoTSS DR1: Double-double radio galaxies in the HETDEX field
V. H. Mahatma, M. J. Hardcastle, W. L. Williams +19
Double-double radio galaxies (DDRGs) represent a short but unique phase in the life-cycle of some of the most powerful radio-loud active galactic nuclei (RLAGN). These galaxies dis…
V-LoTSS: The Circularly-Polarised LOFAR Two-metre Sky Survey
J. R. Callingham, T. W. Shimwell, H. K. Vedantham +44
We present the detection of 68 sources from the most sensitive radio survey in circular polarisation conducted to date. We use the second data release of the 144 MHz LOFAR Two-metr…
Calibrating High-Precision Faraday Rotation Measurements for LOFAR and the Next Generation of Low-Frequency Radio Telescopes
C. Sotomayor-Beltran, C. Sobey, J. W. T. Hessels +77
Faraday rotation measurements using the current and next generation of low-frequency radio telescopes will provide a powerful probe of astronomical magnetic fields. However, achiev…
The MeerKAT Galaxy Cluster Legacy Survey I. Survey Overview and Highlights
K. Knowles, W. D. Cotton, L. Rudnick +148
MeerKAT's large number of antennas, spanning 8 km with a densely packed 1 km core, create a powerful instrument for wide-area surveys, with high sensitivity over a wide range of an…
French SKA White Book - The French Community towards the Square Kilometre Array
F. Acero, J. -T. Acquaviva, R. Adam +175
The "Square Kilometre Array" (SKA) is a large international radio telescope project characterised, as suggested by its name, by a total collecting area of approximately one square…
Lunar occultation of the diffuse radio sky: LOFAR measurements between 35 and 80 MHz
H. K. Vedantham, L. V. E. Koopmans, A. G. de Bruyn +91
We present radio observations of the Moon between and MHz to demonstrate a novel technique of interferometrically measuring large-scale diffuse emission extending far bey…
Revival of the magnetar PSR J1622-4950: observations with MeerKAT, Parkes, XMM-Newton, Swift, Chandra, and NuSTAR
F. Camilo, P. Scholz, M. Serylak +205
New radio (MeerKAT and Parkes) and X-ray (XMM-Newton, Swift, Chandra, and NuSTAR) observations of PSR J1622-4950 indicate that the magnetar, in a quiescent state since at least ear…
The LOFAR Two-metre Sky Survey Deep fields: A new analysis of low-frequency radio luminosity as a star-formation tracer in the Lockman Hole region
M. Bonato, I. Prandoni, G. De Zotti +14
We have exploited LOFAR deep observations of the Lockman Hole field at 150 MHz to investigate the relation between the radio luminosity of star-forming galaxies (SFGs) and their st…
The intergalactic magnetic field probed by a giant radio galaxy
S. P. O'Sullivan, J. Machalski, C. L. Van Eck +27
Cosmological simulations predict that an intergalactic magnetic field (IGMF) pervades the large scale structure (LSS) of the Universe. Measuring the IGMF is important to determine…
MIGHTEE: Are giant radio galaxies more common than we thought?
J. Delhaize, I. Heywood, M. Prescott +31
We report the discovery of two new giant radio galaxies (GRGs) using the MeerKAT International GHz Tiered Extragalactic Exploration (MIGHTEE) survey. Both GRGs were found within a…
First LOFAR results on galaxy clusters
C. Ferrari, I. van Bemmel, A. Bonafede +21
Deep radio observations of galaxy clusters have revealed the existence of diffuse radio sources related to the presence of relativistic electrons and weak magnetic fields in the in…
The Planck clusters in the LOFAR sky VI. LoTSS-DR2: Properties of radio relics
A. Jones, F. de Gasperin, V. Cuciti +19
Context. It is well-established that shock waves in the intracluster medium launched by galaxy cluster mergers can produce synchrotron emission, which is visible to us at radio fre…
The twisted jets of Circinus X-1
M. Coriat, R. Fender, C. Tasse +3
We present the results of millimetre (33 and 35 GHz) and centimetre (2.1, 5.5 and 9.0 GHz) wavelength observations of the neutron star X-ray binary Circinus X-1, using the Australi…
Mining Mini-Halos with MeerKAT I. Calibration and Imaging
K. S. Trehaeven, V. Parekh, N. Oozeer +7
Radio mini-halos are clouds of diffuse, low surface brightness synchrotron emission that surround the Brightest Cluster Galaxy (BCG) in massive cool-core galaxy clusters. In this p…
LoTSS/HETDEX: Disentangling star formation and AGN activity in gravitationally-lensed radio-quiet quasars
H. R. Stacey, J. P. McKean, N. J. Jackson +15
Determining the star-forming properties of radio-quiet quasars is important for understanding the co-evolution of star formation and black hole accretion. Here, we present the dete…
Faceting for direction-dependent spectral deconvolution
C. Tasse, B. Hugo, M. Mirmont +7
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 th…
Calibrating the absolute amplitude scale for air showers measured at LOFAR
A. Nelles, J. R. Hörandel, T. Karskens +74
Air showers induced by cosmic rays create nanosecond pulses detectable at radio frequencies. These pulses have been measured successfully in the past few years at the LOw Frequency…
The LOFAR long baseline snapshot calibrator survey
J. Moldón, A. T. Deller, O. Wucknitz +82
Aims. An efficient means of locating calibrator sources for International LOFAR is developed and used to determine the average density of usable calibrator sources on the sky for s…
The Faraday Rotation Measure Grid of the LOFAR Two-metre Sky Survey: Data Release 2
S. P. O'Sullivan, T. W. Shimwell, M. J. Hardcastle +24
A Faraday rotation measure (RM) catalogue, or RM Grid, is a valuable resource for the study of cosmic magnetism. Using the second data release (DR2) from the LOFAR Two-metre Sky Su…
The LOFAR Two-metre Sky Survey (LoTSS) III. First Data Release: optical/IR identifications and value-added catalogue
W. L. Williams, M. J. Hardcastle, P. N. Best +38
The LOFAR Two-metre Sky Survey (LoTSS) is an ongoing sensitive, high-resolution 120-168 MHz survey of the Northern sky with diverse and ambitious science goals. Many of the scienti…
Peculiar radioX-ray relationship in active stars
H. K. Vedantham, J. R. Callingham, T. W. Shimwell +5
The empirical relationship between the non-thermal 5GHz radio luminosity and the soft X-ray luminosity of active stellar coronae, canonically called the Güdel-Benz relationship (G…
Extremely deep 150 MHz source counts from the LoTSS Deep Fields
S. Mandal, I. Prandoni, M. J. Hardcastle +19
With the advent of new generation low-frequency telescopes, such as the LOw Frequency ARray (LOFAR), and improved calibration techniques, we have now started to unveil the sub GHz…
A population of galaxy-scale jets discovered using LOFAR
B. Webster, J. H. Croston, B. Mingo +10
The effects of feedback from high luminosity radio-loud AGN have been extensively discussed in the literature, but feedback from low-luminosity radio-loud AGN is less well understo…
Blazars in the LOFAR Two-Metre Sky Survey First Data Release
S. Mooney, J. Quinn, J. R. Callingham +13
Historically, the blazar population has been poorly understood at low frequencies because survey sensitivity and angular resolution limitations have made it difficult to identify m…
The Lockman Hole project: LOFAR observations and spectral index properties of low-frequency radio sources
E. K. Mahony, R. Morganti, I. Prandoni +21
The Lockman Hole is a well-studied extragalactic field with extensive multi-band ancillary data covering a wide range in frequency, essential for characterising the physical and ev…
LOFAR Sparse Image Reconstruction
H. Garsden, J. N. Girard, J. L. Starck +77
Context. The LOw Frequency ARray (LOFAR) radio telescope is a giant digital phased array interferometer with multiple antennas distributed in Europe. It provides discrete sets of F…
The LOFAR LBA Sky Survey: Deep Fields I. The Boötes Field
W. L. Williams, F. de Gasperin, M. J. H. Hardcastle +9
We present the first sub-mJy ( mJy beam) survey to be completed below 100 MHz, which is over an order of magnitude deeper than previously achieved for widefield…
The LOFAR radio environment
A. R. Offringa, A. G. de Bruyn, S. Zaroubi +93
Aims: This paper discusses the spectral occupancy for performing radio astronomy with the Low-Frequency Array (LOFAR), with a focus on imaging observations. Methods: We have analys…
First evidence of a connection between cluster-scale diffuse radio emission in cool-core galaxy clusters and sloshing features
N. Biava, A. Bonafede, F. Gastaldello +15
Radio observations of a few cool-core galaxy clusters have revealed the presence of diffuse emission on cluster scales, similar to what was found in merging clusters in the form of…
LOFAR/H-ATLAS: A deep low-frequency survey of the Herschel-ATLAS North Galactic Pole field
M. J. Hardcastle, G. Gürkan, R. J. van Weeren +25
We present LOFAR High-Band Array (HBA) observations of the Herschel-ATLAS North Galactic Pole survey area. The survey we have carried out, consisting of four pointings covering aro…
YOLO-CIANNA: Galaxy detection with deep learning in radio data: II. Winning the SKA SDC2 using a generalized 3D-YOLO network
D. Cornu, B. Semelin, P. Salomé +8
As the scientific exploitation of the Square Kilometre Array (SKA) approaches, there is a need for new advanced data analysis and visualization tools capable of processing large hi…
Detecting cosmic rays with the LOFAR radio telescope
P. Schellart, A. Nelles, S. Buitink +102
The low frequency array (LOFAR), is the first radio telescope designed with the capability to measure radio emission from cosmic-ray induced air showers in parallel with interferom…
Nearby galaxies in LoTSS-DR2: insights into the non-linearity of the radio-SFR relation
V. Heesen, M. Staffehl, A. Basu +24
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-freq…
Fast algorithms to approximate the position-dependent point spread function responses in radio interferometric wide-field imaging
M. Atemkeng, O. Smirnov, C. Tasse +2
The desire for wide-field of view, large fractional bandwidth, high sensitivity, high spectral and temporal resolution has driven radio interferometry to the point of big data revo…
Pulsars with NenuFAR: backend and pipelines
L. Bondonneau, J. -M. GrieÃmeier, G. Theureau +27
NenuFAR (New extension in Nançay upgrading LoFAR) is a new radio telescope developed and built on the site of the Nançay Radio Observatory. It is designed to observe the largely…
Studying Galactic interstellar turbulence through fluctuations in synchrotron emission: First LOFAR Galactic foreground detection
M. Iacobelli, M. Haverkorn, E. Orrú +85
The characteristic outer scale of turbulence and the ratio of the random to ordered components of the magnetic field are key parameters to characterise magnetic turbulence in the i…
Investigating the Unification of LOFAR-detected powerful AGN in the Boötes Field
Leah K. Morabito, W. L. Williams, Kenneth J. Duncan +17
Low radio frequency surveys are important for testing unified models of radio-loud quasars and radio galaxies. Intrinsically similar sources that are randomly oriented on the sky w…
1-arcsecond imaging of ELAIS-N1 field at 144MHz using the LoTSS survey with international LOFAR telescope
Haoyang Ye, Frits Sweijen, Reinout van Weeren +10
We present the first wide area (2.5 x 2.5 deg^2) LOFAR High Band Antenna image at a resolution of 1.2'' x 2'' with a median noise of approximately 80 microJy per beam. It was made…
LOFAR HBA Observations of the Euclid Deep Field North (EDFN)
M. Bondi, R. Scaramella, G. Zamorani +19
We present the first deep (72 hours of observations) radio image of the Euclid Deep Field North (EDFN) obtained with the LOw-Frequency ARray (LOFAR) High Band Antenna (HBA) at 144…
The MeerKAT International GHz Tiered Extragalactic Exploration (MIGHTEE) Survey
Matt J. Jarvis, A. R. Taylor, I. Agudo +54
The MIGHTEE large survey project will survey four of the most well-studied extragalactic deep fields, totalling 20 square degrees to Jy sensitivity at Giga-Hertz frequencies, a…
A deep study of A399-401: An application for wide-field facet calibration
J. M. G. H. J. de Jong, R. J. van Weeren, A. Botteon +6
We examine the particle acceleration mechanism in the Mpc-scale bridge between Abell 399 and Abell 401 and assess in particular if the synchrotron emission originates from first-or…
LOFAR discovery of a quiet emission mode in PSR B0823+26
C. Sobey, N. J. Young, J. W. T. Hessels +91
PSR B0823+26, a 0.53-s radio pulsar, displays a host of emission phenomena over timescales of seconds to (at least) hours, including nulling, subpulse drifting, and mode-changing.…
LOFAR observations of the XMM-LSS field
C. L. Hale, W. Williams, M. J. Jarvis +12
We present observations of the XMM Large-Scale Structure (XMM-LSS) field observed with the LOw Frequency ARray (LOFAR) at 120-168 MHz. Centred at a J2000 declination of $-4.5^{\cir…
Probing Atmospheric Electric Fields in Thunderstorms through Radio Emission from Cosmic-Ray-Induced Air Showers
P. Schellart, T. N. G. Trinh, S. Buitink +71
We present measurements of radio emission from cosmic ray air showers that took place during thunderstorms. The intensity and polarization patterns of these air showers are radical…
NGC 326: X-shaped no more
M. J. Hardcastle, J. H. Croston, T. W. Shimwell +7
We present new 144-MHz LOFAR observations of the prototypical `X-shaped' radio galaxy NGC 326, which show that the formerly known wings of the radio lobes extend smoothly into a la…