Browsing by Author "Harwood, J. J."

Now showing items 1-20 of 22

    • The intergalactic magnetic field probed by a giant radio galaxy 

      O'Sullivan, S. P.; Machalski, J.; Eck, C. L. Van; Heald, G.; Brueggen, M.; Fynbo, J. P. U.; Heintz, K. E.; Lara-Lopez, M. A.; Vacca, V.; Hardcastle, M. J.; Shimwell, T. W.; Tasse, C.; Vazza, F.; Andernach, H.; Birkinshaw, M.; Haverkorn, M.; Horellou, C.; Williams, W. L.; Harwood, J. J.; Brunetti, G.; Anderson, J. M.; Mao, S. A.; Nikiel-Wroczynski, B.; Takahashi, K.; Carretti, E.; Vernstrom, T.; Weeren, R. J. van; Orru, E.; Morabito, L. K.; Callingham, J. R. (2018-10-09)
      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 its origin (i.e. primordial or otherwise). ...

    • Investigating the spectra and physical nature of galaxy scale jets 

      Webster, B.; Croston, J. H.; Harwood, J. J.; Baldi, R. D.; Hardcastle, M. J.; Mingo, B.; Rottgering, H. J. A. (2021-10-13)
      Previous studies have shown that physically small, low-luminosity radio galaxies, which we refer to as galaxy scale jets (GSJ), could potentially have a significant effect upon the host galaxy's evolution. Using 6 arcsec ...

    • Investigating the Unification of LOFAR-detected powerful AGN in the Boötes Field 

      Morabito, Leah K.; Williams, W. L.; Duncan, Kenneth J.; Röttgering, H.~J.~A.; Miley, George; Saxena, Aayush; Barthel, Peter; Best, Philip N.; Bruggen, M.; Brunetti, G.; Chyży, K. T.; Engels, D.; Hardcastle, M. J.; Harwood, J. J.; Jarvis, Matt J.; Mahony, E. K.; Prandoni, I.; Shimwell, Timothy W.; Shulevski, Alexander; Tasse, C. (2017-08-01)
      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 will have different projected linear sizes. ...

    • The Lockman Hole project : LOFAR observations and spectral index properties of low-frequency radio sources 

      Mahony, E. K.; Morganti, R.; Prandoni, I.; Bemmel, I. M. van; Shimwell, T. W.; Brienza, M.; Best, P. N.; Brüggen, M.; Rivera, G. Calistro; Gasperin, F. de; Hardcastle, M. J.; Harwood, J. J.; Heald, G.; Jarvis, M. J.; Mandal, S.; Miley, G. K.; Retana-Montenegro, E.; Röttgering, H. J. A.; Sabater, J.; Tasse, C.; Velzen, S. van; Weeren, R. J. van; Williams, W. L.; White, G. J. (2016-12-11)
      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 evolutionary properties of the various source ...

    • LOFAR first look at the giant radio galaxy 3C 236 

      Shulevski, A.; Barthel, P. D.; Morganti, R.; Harwood, J. J.; Brienza, M.; Shimwell, T. W.; Röttgering, H. J. A.; White, G. J.; Callingham, J. R.; Mooney, S.; Rafferty, D. A. (2019-07-28)
      We have examined the giant radio galaxy 3C~236 using LOFAR at 143 MHz down to an angular resolution of 7", in combination with observations at higher frequencies. We have used the low frequency data to derive spectral index ...

    • LOFAR MSSS: Discovery of a 2.56 Mpc giant radio galaxy associated with a disturbed galaxy group 

      Clarke, A. O.; Heald, G.; Jarrett, T.; Bray, J. D.; Hardcastle, Martin; Cantwell, T. M.; Scaife, A. M. M.; Brienza, M.; Bonafede, A.; Breton, R. P.; Broderick, J. W.; Carbone, D.; Croston, J. H.; Farnes, J. S.; Harwood, J. J.; Heesen, V.; Horneffer, A.; Horst, A. J. van der; Iacobelli, M.; Jurusik, W.; Kokotanekov, G.; McKean, J. P.; Morabito, L. K.; Mulcahy, D. D.; Nikiel-Wroczynski, B. S.; Orru, E.; Paladino, R.; Pandey-Pommier, M.; Pietka, M.; Pizzo, R.; Pratley, L.; Riseley, C. J.; Rottgering, H. J. A.; Rowlinson, A.; Sabater, J.; Sendlinger, K.; Shulevski, A.; Sridhar, S. S.; Stewart, A. J.; Tasse, C.; Velzen, S. van; Weeren, R. J. van; Wise, M. W. (2017-05-01)
      We report on the discovery in the LOFAR Multifrequency Snapshot Sky Survey (MSSS) of a giant radio galaxy (GRG) with a projected size of $2.56 \pm 0.07$ Mpc projected on the sky. It is associated with the galaxy triplet ...

    • LOFAR MSSS: The Scaling Relation between AGN Cavity Power and Radio Luminosity at Low Radio Frequencies 

      Kokotanekov, G.; Wise, Michael; Heald, G. H.; McKean, J. P.; Bîrzan, L.; Rafferty, D. A.; Godfrey, L. E H; Vries, M. de; Intema, Huib T.; Broderick, J. W.; Hardcastle, M. J.; Bonafede, A.; Clarke, A. O.; Weeren, R. J. van; Röttgering, H.~J.~A.; Pizzo, R.; Iacobelli, M.; Orrú, E.; Shulevski, Alexander; Riseley, C. J.; Breton, R. P.; Nikiel-Wroczyński, B.; Sridhar, S. S.; Stewart, A. J.; Rowlinson, A.; Horst, A. J. van der; Harwood, J. J.; Gürkan, G.; Carbone, D.; Pandey-Pommier, M.; Tasse, C.; Scaife, A. M. M.; Pratley, L.; Ferrari, Chiara; Croston, J. H.; Pandey, V. N.; Jurusik, W.; Mulcahy, D. D. (2017-09-07)
      We present a new analysis of the widely used relation between cavity power and radio luminosity in clusters of galaxies with evidence for strong AGN feedback. We study the correlation at low radio frequencies using two new ...

    • LOFAR observations of the XMM-LSS field 

      Hale, C. L.; Williams, W.; Jarvis, M. J.; Hardcastle, M. J.; Morabito, Leah K.; Shimwell, T. W.; Tasse, C.; Best, P. N.; Harwood, J. J.; Heywood, I.; Prandoni, I.; Röttgering, H. J. A.; Sabater, J.; Smith, D. J. B.; Weeren, R. J. van (2018-11-19)
      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 $-4.5^{\circ}$, this is a challenging field to observe ...

    • LOFAR reveals the giant : A low-frequency radio continuum study of the outflow in the nearby FR I radio galaxy 3C 31 

      Heesen, V.; Croston, J. H.; Morganti, R.; Hardcastle, M. J.; Stewart, A. J.; Best, P. N.; Broderick, J. W.; Brüggen, M.; Brunetti, G.; Chyzy, K. T.; Harwood, J. J.; Haverkorn, M.; Hess, K. M.; Intema, H. T.; Jamrozy, M.; Kunert-Bajraszewska, M.; McKean, J. P.; Orrú, E.; Röttgering, H. J.A.; Shimwell, T. W.; Shulevski, A.; White, G. J.; Wilcots, E. M.; Williams, W. L. (2018-03-11)
      We present a deep, low-frequency radio continuum study of the nearby Fanaroff-Riley class I (FR I) radio galaxy 3C 31 using a combination of LOw Frequency ARray (LOFAR; 30-85 and 115-178 MHz), Very Large Array (VLA; 290-420 ...

    • The LOFAR Two-metre Sky Survey (LoTSS) III. First Data Release: optical/IR identifications and value-added catalogue 

      Williams, W. L.; Hardcastle, M. J.; Best, P. N.; Sabater, J.; Croston, J. H.; Duncan, K. J.; Shimwell, T. W.; Röttgering, H. J. A.; Nisbet, D.; Gürkan, G.; Alegre, L.; Cochrane, R. K.; Goyal, A.; Hale, C. L.; Jackson, N.; Jamrozy, M.; Kondapally, R.; Kunert-Bajraszewska, M.; Mahatma, V. H.; Mingo, B.; Morabito, L. K.; Prandoni, I.; Roskowinski, C.; Shulevski, A.; Smith, D. J. B.; Tasse, C.; Urquhart, S.; Webster, B.; White, G. J.; Beswick, R. J.; Callingham, J. R.; Chyży, K. T.; Gasperin, F. de; Harwood, J. J.; Hoeft, M.; Iacobelli, M.; McKean, J. P.; Mechev, A. P.; Miley, G. K.; Schwarz, D. J.; Weeren, R. J. van (2018-11-09)
      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 scientific objectives of LoTSS rely upon, or are ...

    • The LOFAR Two-metre Sky Survey - I. Survey Description and Preliminary Data Release 

      Shimwell, T. W.; Röttgering, H. J. A.; Best, P. N.; Williams, W. L.; Dijkema, T. J.; Gasperin, F. de; Hardcastle, M. J.; Heald, G. H.; Hoang, D. N.; Horneffer, A.; Intema, H.; Mahony, E. K.; Mandal, S.; Mechev, A. P.; Morabito, L.; Oonk, J. B. R.; Rafferty, D.; Retana-Montenegro, E.; Sabater, J.; Tasse, C.; Weeren, R. J. van; Brüggen, M.; Brunetti, G.; Chyży, K. T.; Conway, J. E.; Haverkorn, M.; Jackson, N.; Jarvis, M. J.; McKean, J. P.; Miley, G. K.; Morganti, R.; White, G. J.; Wise, M. W.; Bemmel, I. M. van; Beck, R.; Brienza, M.; Bonafede, A.; Rivera, G. Calistro; Cassano, R.; Clarke, A. O.; Cseh, D.; Deller, A.; Drabent, A.; Driel, W. van; Engels, D.; Falcke, H.; Ferrari, C.; Fröhlich, S.; Garrett, M. A.; Harwood, J. J.; Heesen, V.; Hoeft, M.; Horellou, C.; Israel, F. P.; Kapińska, A. D.; Kunert-Bajraszewska, M.; McKay, D. J.; Mohan, N. R.; Orrú, E.; Pizzo, R. F.; Prandoni, I.; Schwarz, D. J.; Shulevski, A.; Sipior, M.; Smith, D. J. B.; Sridhar, S. S.; Steinmetz, M.; Stroe, A.; Varenius, E.; Werf, P. P. van der; Zensus, J. A.; Zwart, J. T. L. (2017-02-09)
      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 hrs, which, at most declinations, is sufficient ...

    • The LOFAR Two-metre Sky Survey - II. First data release 

      Shimwell, T. W.; Tasse, C.; Hardcastle, M. J.; Mechev, A. P.; Williams, W. L.; Best, P. N.; Röttgering, H. J. A.; Callingham, J. R.; Dijkema, T. J.; Gasperin, F. de; Hoang, D. N.; Hugo, B.; Mirmont, M.; Oonk, J. B. R.; Prandoni, I.; Rafferty, D.; Sabater, J.; Smirnov, O.; Weeren, R. J. van; White, G. J.; Atemkeng, M.; Bester, L.; Bonnassieux, E.; Brüggen, M.; Brunetti, G.; Chyży, K. T.; Cochrane, R.; Conway, J. E.; Croston, J. H.; Danezi, A.; Duncan, K.; Haverkorn, M.; Heald, G. H.; Iacobelli, M.; Intema, H. T.; Jackson, N.; Jamrozy, M.; Jarvis, M. J.; Lakhoo, R.; Mevius, M.; Miley, G. K.; Morabito, L.; Morganti, R.; Nisbet, D.; Orrú, E.; Smith, D. J. B.; Harwood, J. J.; Heesen, V.; Mahatma, V.; Mingo, B. (2018-09-12)
      The LOFAR Two-metre Sky Survey (LoTSS) is an ongoing sensitive, high-resolution 120-168MHz survey of the entire northern sky for which observations are now 20% complete. We present our first full-quality public data release. ...

    • LoTSS DR1 : Double-double radio galaxies in the HETDEX field 

      Mahatma, V. H.; Hardcastle, M. J.; Williams, W. L.; Best, P. N.; Croston, J. H.; Duncan, K.; Mingo, B.; Morganti, R.; Brienza, M.; Cochrane, R. K.; Gürkan, G.; Harwood, J. J.; Jarvis, M. J.; Jamrozy, M.; Jurlin, N.; Morabito, Leah K.; Röttgering, H. J. A.; Sabater, J.; Shimwell, T. W.; Smith, D. J. B.; Shulevski, A.; Tasse, C. (2018-11-20)
      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 display large-scale remnant radio plasma in ...

    • The LoTSS view of radio AGN in the local Universe. The most massive galaxies are always switched on 

      Sabater, J.; Best, P.N.; Hardcastle, M. J.; Shimwell, T. W.; Tasse, C.; Williams, W. L.; Brüggen, M.; Cochrane, R. K.; Croston, J. H.; Gasperin, F. de; Duncan, K. J.; Gürkan, G.; Mechev, A. P.; Morabito, Leah K.; Prandoni, I.; Röttgering, H. J. A.; Smith, D. J. B.; Harwood, J. J.; Mingo, B.; Mooney, S.; Saxena, A. (2018-11-15)
      This paper presents a study of the local radio source population, by cross-comparing the data from the first data release (DR1) of the LOFAR Two-Metre Sky Survey (LoTSS) with the Sloan Digital Sky Survey (SDSS) DR7 main ...

    • Low-frequency observations of the Giant Radio Galaxy NGC 6251 

      Cantwell, T. M.; Bray, J. D.; Croston, J. H.; Scaife, A. M. M.; Mulcahy, D. D.; Best, P. N.; Bruggen, M.; Brunetti, G.; Callingham, J. R.; Clarke, A. O.; Hardcastle, M. J.; Harwood, J. J.; Heald, G.; Heesen, V.; Iacobelli, M.; Jamrozy, M.; Morganti, R.; Orru, E.; O'Sullivan, S. P.; Riseley, C. J.; Rottgering, H. J. A.; Shulevski, A.; Sridhar, S. S.; Tasse, C.; Eck, C. L. Van (2020-06-01)
      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 these frequencies to date, revealing for ...

    • Radiative age mapping of the remnant radio galaxy B2 0924+30 : The LOFAR perspective 

      Shulevski, A.; Morganti, R.; Harwood, J. J.; Barthel, P. D.; Jamrozy, M.; Brienza, M.; Brunetti, G.; Röttgering, H. J.A.; Murgia, M.; White, G. J.; Croston, J. H.; Brüggen, M. (2017-04-01)
      We have observed the steep spectrum radio source B2 0924+30 using the LOw Frequency ARray (LOFAR) telescope. Hosted by a z = 0.026 elliptical galaxy, it has a relatively large angular size of 12′ (corresponding to 360 kpc ...

    • Raining in MKW 3 s: a Chandra-MUSE analysis of X-ray cold filaments around 3CR 318.1 

      Jimenez-Gallardo, A.; Massaro, F.; Balmaverde, B.; Paggi, A.; Capetti, A.; Forman, W. R.; Kraft, R. P.; Baldi, R. D.; Mahatma, V. H.; Mazzucchelli, C.; Missaglia, V.; Ricci, F.; Venturi, G.; Bam, S. A.; Liuzzo, E.; O'Dea, C. P.; Prieto, M. A.; Röttgering, H. J. A.; Sani, E.; Sparks, W. B.; Tremblay, G. R.; Weeren, R. J. van; Wilkes, B. J.; Harwood, J. J.; Mazzotta, P.; Kuraszkiewicz, J. (2021-05-10)
      We present the analysis of X-ray and optical observations of gas filaments observed in the radio source 3CR 318.1, associated with NGC 5920, the Brightest Cluster Galaxy (BCG) of MKW 3s, a nearby cool core galaxy cluster. ...

    • Remnant radio-loud AGN in the Herschel-ATLAS field 

      Mahatma, V. H.; Hardcastle, M. J.; Williams, W. L.; Brienza, M.; Bruggen, M.; Croston, J. H.; Gurkan, G.; Harwood, J. J.; Kunert-Bajraszewska, M.; Morganti, R.; Rottgering, H. J. A.; Shimwell, T. W.; Tasse, C. (2018-04-21)
      Only a small fraction of observed active galactic nuclei (AGN) display large-scale radio emission associated with jets, yet these radio-loud AGN have become increasingly important in models of galaxy evolution. In determining ...

    • Revolutionizing Our Understanding of AGN Feedback and its Importance to Galaxy Evolution in the Era of the Next Generation Very Large Array 

      Nyland, K.; Harwood, J. J.; Mukherjee, D.; Jagannathan, P.; Rujopakarn, W.; Emonts, B.; Alatalo, K.; Bicknell, G. V.; Davis, T. A.; Greene, J. E.; Kimball, A.; Lacy, M.; Lonsdale, Carol; Lonsdale, Colin; Maksym, W. P.; Molnár, D. C.; Morabito, L.; Murphy, E. J.; Patil, P.; Prandoni, I.; Sargent, M.; Vlahakis, C. (2018-05-18)
      Energetic feedback by active galactic nuclei (AGNs) plays an important evolutionary role in the regulation of star formation on galactic scales. However, the effects of this feedback as a function of redshift and galaxy ...

    • Signatures from a merging galaxy cluster and its AGN population : LOFAR observations of Abell 1682 

      Clarke, A. O.; Scaife, Anna M.M.; Shimwell, T.; Weeren, R. J. van; Bonafede, A.; Heald, George; Brunetti, G.; Cantwell, T. M.; Gasperin, F. de; Brüggen, M.; Botteon, A.; Hoeft, M.; Horellou, C.; Cassano, R.; Harwood, J. J.; Röttgering, H. J. A. (2019-07-05)
      We present LOFAR data from 110-180 MHz of the merging galaxy cluster Abell 1682, alongside archival optical, radio, and X-ray data. Our images of 6 arcsec in resolution at low frequencies reveal new structures associated ...