Publications (14)
Direction-dependent calibration with image-domain gridding
Sebastiaan van der Tol, Sarod Yatawatta, Bram Veenboer +1
Wide-field images made by radio interferometers are invariably affected by direction-dependent systematic effects such as the ionosphere or the beam pattern. Calibration along a se…
Constraining the Nature of X-ray Cavities in Clusters and Galaxies
Steven Diehl, Hui Li, Chris Fryer +1
We present results from an extensive survey of 64 cavities in the X-ray halos of clusters, groups and normal elliptical galaxies. We show that the evolution of the size of the cavi…
LOFAR and APERTIF surveys of the radio sky: probing shocks and magnetic fields in galaxy clusters
Huub Rottgering, Jose Afonso, Peter Barthel +32
At very low frequencies, the new pan-European radio telescope LOFAR is opening the last unexplored window of the electromagnetic spectrum for astrophysical studies. The revolutiona…
LOFAR: Recent imaging results & future prospects
George Heald, Michael R. Bell, Andreas Horneffer +27
The Low Frequency Array (LOFAR) is under construction in the Netherlands and in several surrounding European countries. In this contribution, we describe the layout and design of t…
The Regulation of Cooling and Star Formation in Luminous Galaxies by AGN Feedback and the Cooling-Time/Entropy Threshold for the Onset of Star Formation
David Rafferty, Brian McNamara, Paul Nulsen
Using broadband optical imaging and Chandra X-ray data for a sample of 46 cluster central dominant galaxies (CDGs), we investigate the connection between star formation, the intrac…
Progress with the LOFAR Imaging Pipeline
George Heald, John McKean, Roberto Pizzo +14
One of the science drivers of the new Low Frequency Array (LOFAR) is large-area surveys of the low-frequency radio sky. Realizing this goal requires automated processing of the int…
First evidence of diffuse ultra-steep-spectrum radio emission surrounding the cool core of a cluster
Federica Savini, Annalisa Bonafede, Marcus Brueggen +14
Diffuse synchrotron radio emission from cosmic-ray electrons is observed at the center of a number of galaxy clusters. These sources can be classified either as giant radio halos,…
LOFAR: Early imaging results from commissioning for Cygnus A
John McKean, Louise Ker, Reinout J. van Weeren +19
The Low Frequency Array (LOFAR) will operate between 10 and 250 MHz, and will observe the low frequency Universe to an unprecedented sensitivity and angular resolution. The constru…
A LOFAR study of non-merging massive galaxy clusters
Federica Savini, Annalisa Bonafede, Marcus Brueggen +15
Centrally located diffuse radio emission has been observed in both merging and non-merging galaxy clusters. Depending on their morphology and size, we distinguish between giant rad…
The Hot and Energetic Universe: A White Paper presenting the science theme motivating the Athena+ mission
Kirpal Nandra, Didier Barret, Xavier Barcons +237
This White Paper, submitted to the recent ESA call for science themes to define its future large missions, advocates the need for a transformational leap in our understanding of tw…
Search for low-frequency diffuse radio emission around a shock in the massive galaxy cluster MACS J0744.9+3927
Amanda Wilber, Marcus Brüggen, Annalisa Bonafede +11
Merging galaxy clusters produce low Mach number shocks in the intracluster medium. These shocks can accelerate electrons to relativistic energies that are detectable at radio frequ…
Studying the late evolution of a radio-loud AGN in a galaxy group with LOFAR
Federica Savini, Annalisa Bonafede, Marcus Brüggen +17
Feedback by radio-loud active galactic nuclei (AGN) in galaxy groups is not fully understood. Open questions include the duty cycle of the AGN, the spatial extent of the radio lobe…
Evolutionary phases of merging clusters as seen by LOFAR
Amanda Wilber, Marcus Brüggen, Annalisa Bonafede +13
Massive, merging galaxy clusters often host giant, diffuse radio sources that arise from shocks and turbulence; hence, radio observations can be useful for determining the merger s…
X-ray Observables of Magnetically Dominated Cavities in Clusters
Steven Diehl, Masanori Nakamura, Hui Li +1
We present results from magneto-hydrodynamic jet simulations in the magnetically dominated regime and find that they inflate cavities into the intracluster medium. Mock Chandra X-r…