Browsing by Author "Harwood, Jeremy"

Now showing items 1-8 of 8

    • Constraining AGN duty cycle in the cool-core cluster MS 0735.6+7421 with LOFAR data 

      Biava, Nadia; Brienza, Marisa; Bonafede, Annalisa; Gitti, Myriam; Bonnassieux, Etienne; Harwood, Jeremy; Edge, Alastair C.; Riseley, Christopher J.; Vantyghem, Adrian (2021-06-25)
      MS 0735.6+7421 is a galaxy cluster which hosts a central radio galaxy with a very steep spectrum, produced by one of the most powerful known jetted active galactic nuclei (AGN). The radio plasma, ejected at nearly light ...

    • High-resolution international LOFAR observations of 4C~43.15 -- Spectral ages and injection indices in a high-z radio galaxy 

      Sweijen, Frits; Morabito, Leah K.; Harwood, Jeremy; Weeren, Reinout J. van; Röttgering, Huub J. A.; Callingham, Joseph R.; Jackson, Neal; Miley, George; Moldon, Javier (2022-02-01)
      It has long been known that radio sources with the steepest spectra are preferentially associated with the most distant galaxies, the α - z relation, but the reason for this relation is an open question. The spatial ...

    • Investigating the spectral age problem with powerful radio galaxies 

      Mahatma, Vijay H.; Hardcastle, Martin J.; Croston, Judith H.; Harwood, Jeremy; Ineson, Judith; Moldon, Javier (2020-02-01)
      The 'spectral age problem' is our systematic inability to reconcile the maximum cooling time of radiating electrons in the lobes of a radio galaxy with its age as modelled by the dynamical evolution of the lobes. While ...

    • LOFAR view of NGC 3998, a sputtering AGN 

      Sridhar, Sarrvesh S.; Morganti, Raffaella; Nyland, Kristina; Frank, Bradley S.; Harwood, Jeremy; Oosterloo, Tom (2020-02-18)
      Low-power radio sources dominate the radio sky. They tend to be small in size and dominated by their cores, but the origin of their properties and the evolution of their radio plasma are not well constrained. Interestingly, ...

    • A low frequency study of linear polarization in radio galaxies 

      Mahatma, Vijay H.; Hardcastle, Martin J.; Harwood, Jeremy; O'Sullivan, Shane P.; Heald, George; Horellou, Cathy; Smith, Daniel J. B. (2020-12-26)
      Radio galaxies are linearly polarized -- an important property that allows us to infer the properties of the magnetic field of the source and its environment. However at low frequencies, Faraday rotation substantially ...

    • Spectral age modelling of the 'Sausage' cluster radio relic 

      Stroe, A.; Harwood, Jeremy; Hardcastle, M.J.; Rottgering, H.J.A. (2014-12-01)
      CIZA J2242.8+5301 is a post-core passage, binary merging cluster that hosts a large, thin, arc-like radio relic, nicknamed the 'Sausage', tracing a relatively strong shock front. We perform spatially resolved spectral ...

    • Spectral analysis of spatially-resolved 3C295 (sub-arcsecond resolution) with the International LOFAR Telescope 

      Bonnassieux, Etienne; Sweijen, Frits; Brienza, Marisa; Rajpurohit, Kamlesh; Riseley, Christopher John; Bonafede, Annalisa; Jackson, Neal; Morabito, Leah K.; Brunetti, Gianfranco; Harwood, Jeremy; Kappes, Alex; Rottgering, Huub J.; Tasse, Cyril; Weeren, Reinout van (2022-02-25)
      3C295 is a bright, compact steep spectrum source with a well-studied integrated radio spectral energy distribution (SED) from 132 MHz to 15 GHz. However, spatially resolved spectral studies have been limited due to a lack ...

    • Sub-arcsecond imaging with the International LOFAR Telescope. II. Completion of the LOFAR Long-Baseline Calibrator Survey 

      Jackson, Neal; Badole, Shruti; Chhetri, Rajan; Prusis, Kaspars; Nikolajevs, Atvars; Morabito, Leah; Brentjens, Michiel; Sweijen, Frits; Iacobelli, Marco; Orrù, Emanuela; Sluman, J.; Blaauw, R.; Mulder, H.; Dijk, P. van; Mooney, Sean; Deller, Adam; Moldon, Javier; Callingham, J. R.; Harwood, Jeremy; Hardcastle, Martin; Heald, George; Drabent, Alexander; McKean, J. P.; Asgekar, A.; Avruch, I. M.; Bentum, M. J.; Bonafede, A.; Brouw, W. N.; Brüggen, M.; Butcher, H. R.; Ciardi, B.; Coolen, A.; Corstanje, A.; Damstra, S.; Duscha, S.; Eislöffel, J.; Falcke, H.; Garrett, M.; Gasperin, F. de; Griessmeier, J. -M.; Gunst, A. W.; Haarlem, M. P. van; Hoeft, M.; Horst, A. J. van der; Jütte, E.; Koopmans, L. V. E.; Krankowski, A.; Maat, P.; Mann, G.; Miley, G. K.; Nelles, A.; Norden, M.; Paas, M.; Pandey, V. N.; Pandey-Pommier, M.; Pizzo, R. F.; Reich, W.; Rothkaehl, H.; Rowlinson, A.; Ruiter, M.; Shulevski, A.; Schwarz, D. J.; Smirnov, O.; Tagger, M.; Vocks, C.; Weeren, R. J. van; Wijers, R.; Wucknitz, O.; Zarka, P.; Zensus, J. A.; Zucca, P. (2022-02-01)
      The Low-Frequency Array (LOFAR) Long-Baseline Calibrator Survey (LBCS) was conducted between 2014 and 2019 in order to obtain a set of suitable calibrators for the LOFAR array. In this paper, we present the complete survey, ...