Browsing by Author "Harwood, Jeremy J."

Now showing items 1-12 of 12

    • FR II radio galaxies at low frequencies I : morphology, magnetic field strength and energetics 

      Harwood, Jeremy J.; Croston, Judith H.; Intema, Huib T.; Stewart, Adam J.; Ineson, Judith; Hardcastle, Martin; Godfrey, Leith; Best, Philip; Brienza, Marisa; Heesen, Volker; Mahony, Elizabeth K.; Morganti, Raffaella; Murgia, Matteo; Orrú, Emanuela; Röttgering, Huub; Shulevski, Aleksandar; Wise, Michael W. (2016-06-01)
      Due to their steep spectra, low-frequency observations of FR II radio galaxies potentially provide key insights in to the morphology, energetics and spectrum of these powerful radio sources. However, limitations imposed ...

    • FR-II radio galaxies at low frequencies II: spectral ageing and source dynamics 

      Harwood, Jeremy J.; Hardcastle, Martin J.; Morganti, Raffaella; Croston, Judith H.; Brüggen, Marcus; Brunetti, Gianfranco; Röttgering, Huub J. A.; Shulevski, Aleksander; White, Glenn J. (2017-07-01)
      In this paper, the second in a series investigating FR II radio galaxies at low frequencies, we use LOFAR and VLA observations between 117 and 456 MHz in addition to archival data to determine the dynamics and energetics ...

    • High-resolution VLA Imaging of Obscured Quasars : Young Radio Jets Caught in a Dense ISM 

      Patil, Pallavi; Nyland, Kristina; Whittle, Mark; Lonsdale, Carol; Lacy, Mark; Lonsdale, Colin; Mukherjee, Dipanjan; Trapp, A. C.; Kimball, Amy E.; Lanz, Lauranne; Wilkes, Belinda J.; Blain, Andrew; Harwood, Jeremy J.; Efstathiou, Andreas; Vlahakis, Catherine (2020-06-10)
      We present new subarcsecond-resolution Karl G. Jansky Very Large Array (VLA) imaging at 10 GHz of 155 ultraluminous (L bol ∼ 1011.7-1014.2 L o˙) and heavily obscured quasars with redshifts z ∼ 0.4-3. The sample was selected ...

    • The highest frequency detection of a radio relic : 16 GHz AMI observations of the 'Sausage' cluster 

      Stroe, Andra; Rumsey, Clare; Harwood, Jeremy J.; Van weeren, Reinout J.; Röttgering, Huub J.A.; Saunders, Richard D.E.; Sobral, David; Perrott, Yvette C.; Schammel, Michel P. (2014-06-11)
      We observed the cluster CIZA J2242.8+5301 with the Arcminute Microkelvin Imager at 16 GHz and present the first high radio-frequency detection of diffuse, non-thermal cluster emission. This cluster hosts a variety of bright, ...

    • The Host Galaxies of Hybrid Morphology Radio Sources 

      Stroe, Andra; Catlett, Victoria; Harwood, Jeremy J.; Vernstrom, Tessa; Mingo, Beatriz (2022-12-16)
      Based on their differing radio morphologies, powerful radio galaxies can be separated into the Fanaroff-Riley I (FR I) and II (FR II) classes. Hybrid morphology radio sources (HyMoRS) contain morphologies consistent with ...

    • The impact of a young radio galaxy : Clues from the cosmic ray electron population 

      Heesen, V.; Croston, J.H.; Harwood, Jeremy J.; Hardcastle, M.J.; Hota, Ananda (2014-04-01)
      In the framework of hierarchical structure formation, active galactic nuclei (AGN) feedback shapes the galaxy luminosity function. Low luminosity, galaxy-scale double radio sources are ideal targets to investigate the ...

    • Investigating the cause of the $α\,$-$\,z$ relation 

      Morabito, Leah K.; Harwood, Jeremy J. (2018-10-01)
      The correlation between radio spectral index and redshift has long been used to identify high-redshift radio galaxies, but its cause is unknown. Traditional explanations invoke either intrinsic relations between spectral ...

    • The resolved jet of 3C 273 at 150 MHz : Sub-arcsecond imaging with the LOFAR international baselines 

      Harwood, Jeremy J.; Mooney, Sean; Morabito, Leah K.; Quinn, John; Sweijen, Frits; Groeneveld, Christian; Bonnassieux, Etienne; Kappes, Alexander; Moldon, Javier (2022-02-01)
      Context. Since its discovery in 1963, 3C 273 has become one of the most widely studied quasars with investigations spanning the electromagnetic spectrum. While much has therefore been discovered about this historically ...

    • Spectral ageing in the era of big data : Integrated versus resolved models 

      Harwood, Jeremy J. (2017-04-21)
      Continuous injection models of spectral ageing have long been used to determine the age of radio galaxies from their integrated spectrum; however, many questions about their reliability remain unanswered. With various large ...

    • Spectral ageing in the lobes of cluster-centre FR II radio galaxies 

      Harwood, Jeremy J.; Hardcastle, M.J.; Croston, J. H. (2015-12-21)
      Recent investigations have shown that many parameters and assumptions made in the application of spectral-ageing models to FR II radio galaxies (e.g. injection index, uniform magnetic field, non-negligible cross-lobe age ...

    • The systematic spectral analysis of radio surveys 

      Harwood, Jeremy J.; Morganti, Raffaella (2016-03-14)
      Current and future continuum surveys being undertaken by the new generation of radio telescopes are now poised to address many important science questions, ranging from the earliest galaxies, to the physics of nearby AGN, ...

    • Unveiling the cause of hybrid morphology radio sources (HyMoRS) 

      Harwood, Jeremy J.; Vernstrom, Tessa; Stroe, Andra (2020-01-01)
      Hybrid morphology radio sources (HyMoRS) are a rare group of radio galaxies in which differing Fanaroff & Riley morphologies (FR I/II) are observed for each of the two lobes. While they potentially provide insights into ...