Browsing by Author "Horellou, C."

Now showing items 1-16 of 16

    • Calibrating the relation of low-frequency radio continuum to star formation rate at 1 kpc scale with LOFAR 

      Heesen, V.; E., Buie II; Huff, C. J.; Perez, L. A.; Woolsey, J. G.; Rafferty, D. A.; Basu, A.; Beck, R.; Brinks, E.; Horellou, C.; Scannapieco, E.; Brüggen, M.; Dettmar, R. -J.; Sendlinger, K.; Nikiel-Wroczyński, B.; Chyży, K. T.; Best, P.N.; Heald, George H.; Paladino, R. (2018-10-15)
      Radio continuum (RC) emission in galaxies allows us to measure star formation rates (SFRs) unaffected by extinction due to dust, of which the low-frequency part is uncontaminated from thermal (free-free) emission. We ...

    • Detection of magnetic fields in the circumgalactic medium of nearby galaxies using Faraday rotation 

      Heesen, V.; O'Sullivan, S. P.; Brüggen, M.; Basu, A.; Beck, R.; Seta, A.; Carretti, E.; Krause, M. G. H.; Haverkorn, M.; Hutschenreuter, S.; Bracco, A.; Stein, M.; Bomans, D. J.; Dettmar, R. -J.; Chyży, K. T.; Heald, G. H.; Paladino, R.; Horellou, C. (2023-02-24)
      Context. The existence of magnetic fields in the circumgalactic medium (CGM) is largely unconstrained. Their detection is important as magnetic fields can have a significant impact on the evolution of the CGM and, in turn, ...

    • Exploring the making of a galactic wind in the star-bursting dwarf irregular galaxy IC 10 with LOFAR 

      Heesen, V.; Rafferty, D. A.; Horneffer, A.; Beck, R.; Basu, A.; Westcott, J.; Hindson, L.; Brinks, E.; Chyży, K. T.; Scaife, A. M. M.; Brüggen, M.; Heald, George; Fletcher, A.; Horellou, C.; Tabatabaei, F. S.; Paladino, R.; Nikiel-Wroczyński, B.; Hoeft, M.; Dettmar, R. -J. (2018-05-11)
      Low-mass galaxies are subject to strong galactic outflows, in which cosmic rays may play an important role; they can be best traced with low-frequency radio continuum observations, which are less affected by spectral ageing. ...

    • The Faraday Rotation Measure Grid of the LOFAR Two-metre Sky Survey: Data Release 2 

      O'Sullivan, S. P.; Shimwell, T. W.; Hardcastle, M. J.; Tasse, C.; Heald, G.; Carretti, E.; Brüggen, M.; Vacca, V.; Sobey, C.; Eck, C. L. Van; Horellou, C.; Beck, R.; Bilicki, M.; Bourke, S.; Botteon, A.; Croston, J. H.; Drabent, A.; Duncan, K.; Heesen, V.; Ideguchi, S.; Kirwan, M.; Lawlor, L.; Mingo, B.; Nikiel-Wroczyński, B.; Piotrowska, J.; Scaife, A. M. M.; Weeren, R. J. van (2023-01-02)
      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 Survey (LoTSS), we have produced a catalogue ...

    • 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). ...

    • LOFAR Deep Fields : Probing a broader population of polarized radio galaxies in ELAIS-N1 

      Ruiz, N. Herrera; O'Sullivan, S. P.; Vacca, V.; Jelić, V.; Nikiel-Wroczyński, B.; Bourke, S.; Sabater, J.; Dettmar, R. -J.; Heald, G.; Horellou, C.; Piras, S.; Sobey, C.; Shimwell, T. W.; Tasse, C.; Hardcastle, M. J.; Kondapally, R.; Chyży, K. T.; Iacobelli, M.; Best, P. N.; Brüggen, M.; Carretti, E.; Prandoni, I. (2021-04-07)
      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 field is part of the LOFAR Two-metre Sky Survey ...

    • LOFAR facet calibration 

      Van Weeren, R. J.; Williams, W. L.; Hardcastle, M.J.; Shimwell, T. W.; Rafferty, D. A.; Sabater, J.; Heald, G.; Sridhar, S. S.; Dijkema, T. J.; Brunetti, G.; Brüggen, M.; Andrade-Santos, F.; Ogrean, G. A.; Röttgering, H. J. A.; Dawson, W. A.; Forman, W.R.; Gasperin, F. de; Jones, C.; Miley, G.K.; Rudnick, L.; Sarazin, C.L.; Bonafede, A.; Best, P. N.; Bîrzan, L.; Cassano, R.; Chyży, K. T.; Croston, J. H.; Ensslin, T.; Ferrari, C.; Hoeft, M.; Horellou, C.; Jarvis, M.J.; Kraft, R.P.; Mevius, M.; Intema, H. T.; Murray, S. S.; Orrú, E.; Pizzo, R.; Simionescu, A.; Stroe, A.; Tol, S. van der; White, G.J. (2016-03-07)
      LOFAR, the Low-Frequency Array, is a powerful new radio telescope operating between 10 and 240 MHz. LOFAR allows detailed sensitive high-resolution studies of the low-frequency radio sky. At the same time LOFAR also provides ...

    • Lofar low-band antenna observations of the 3C 295 and boötes fields : Source counts and ultra-steep spectrum sources 

      Van Weeren, R. J.; Williams, W. L.; Tasse, C.; Röttgering, H. J.A.; Rafferty, D. A.; Van Der Tol, S.; Heald, G.; White, G. J.; Shulevski, A.; Best, P.; Intema, H. T.; Bhatnagar, S.; Reich, W.; Steinmetz, M.; Van Velzen, S.; Enßlin, T. A.; Prandoni, I.; De Gasperin, F.; Jamrozy, M.; Brunetti, G.; Jarvis, M. J.; McKean, J. P.; Wise, M. W.; Ferrari, C.; Harwood, J.; Oonk, J. B.R.; Hoeft, M.; Kunert-Bajraszewska, M.; Horellou, C.; Wucknitz, O.; Bonafede, A.; Mohan, N. R.; Scaife, A. M.M.; Klöckner, H. R.; Van Bemmel, I. M.; Merloni, A.; Chyzy, K. T.; Engels, D.; Falcke, H.; Pandey-Pommier, M.; Alexov, A.; Anderson, J.; Avruch, I. M.; Beck, R.; Bell, M. E.; Bentum, M. J.; Bernardi, G.; Breitling, F.; Broderick, J.; De Vos, M. (2014-10-01)
      We present Low Frequency Array (LOFAR) Low Band observations of the Boötes and 3C 295 fields. Our images made at 34, 46, and 62 MHz reach noise levels of 12, 8, and 5 mJy beam-1, making them the deepest images ever obtained ...

    • 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 -- V. Second data release 

      Shimwell, T. W.; Hardcastle, M. J.; Tasse, C.; Best, P. N.; Röttgering, H. J. A.; Williams, W. L.; Botteon, A.; Drabent, A.; Mechev, A.; Shulevski, A.; Weeren, R. J. van; Bester, L.; Brüggen, M.; Brunetti, G.; Callingham, J. R.; Chyży, K. T.; Conway, J. E.; Dijkema, T. J.; Duncan, K.; Gasperin, F. de; Hale, C. L.; Haverkorn, M.; Hugo, B.; Jackson, N.; Mevius, M.; Miley, G. K.; Morabito, L. K.; Morganti, R.; Offringa, A.; Oonk, J. B. R.; Rafferty, D.; Sabater, J.; Smith, D. J. B.; Schwarz, D. J.; Smirnov, O.; O'Sullivan, S. P.; Vedantham, H.; White, G. J.; Albert, J. G.; Alegre, L.; Asabere, B.; Bacon, D. J.; Bonafede, A.; Bonnassieux, E.; Brienza, M.; Bilicki, M.; Bonato, M.; Rivera, G. Calistro; Cassano, R.; Cochrane, R.; Croston, J. H.; Cuciti, V.; Dallacasa, D.; Danezi, A.; Dettmar, R. J.; Gennaro, G. Di; Edler, H. W.; Enßlin, T. A.; Emig, K. L.; Franzen, T. M. O.; García-Vergara, C.; Grange, Y. G.; Gürkan, G.; Hajduk, M.; Heald, G.; Heesen, V.; Hoang, D. N.; Hoeft, M.; Horellou, C.; Iacobelli, M.; Jamrozy, M.; Jelić, V.; Kondapally, R.; Kukreti, P.; Kunert-Bajraszewska, M.; Magliocchetti, M.; Mahatma, V.; Małek, K.; Mandal, S.; Massaro, F.; Meyer-Zhao, Z.; Mingo, B.; Mostert, R. I. J.; Nair, D. G.; Nakoneczny, S. J.; Nikiel-Wroczyński, B.; Orrú, E.; Pajdosz-Śmierciak, U.; Pasini, T.; Prandoni, I.; Piggelen, H. E. van; Rajpurohit, K.; Retana-Montenegro, E.; Riseley, C. J.; Rowlinson, A.; Saxena, A.; Schrijvers, C.; Sweijen, F.; Siewert, T. M.; Timmerman, R.; Vaccari, M.; Vink, J.; West, J. L.; Wołowska, A.; Zhang, X.; Zheng, J. (2022-02-25)
      In this data release from the ongoing LOw-Frequency ARray (LOFAR) Two-metre Sky Survey we present 120a 168 MHz images covering 27% of the northern sky. Our coverage is split into two regions centred at approximately 12h45m ...

    • LOFAR, VLA, and Chandra observations of the Toothbrush galaxy cluster 

      Van Weeren, R. J.; Brunetti, G.; Brüggen, M.; Andrade-Santos, F.; Ogrean, G. A.; Williams, W. L.; Röttgering, H. J. A.; Dawson, W. A.; Forman, W.R.; Gasperin, F. de; Hardcastle, M.J.; Jones, C.; Miley, G.K.; Rafferty, D. A.; Rudnick, L.; Sabater, J.; Sarazin, C.L.; Shimwell, T. W.; Bonafede, A.; Best, P. N.; Bîrzan, L.; Cassano, R.; Chyży, K. T.; Croston, J. H.; Dijkema, T. J.; Ensslin, T.; Ferrari, C.; Heald, G.; Hoeft, M.; Horellou, C.; Jarvis, M.J.; Kraft, R.P.; Mevius, M.; Intema, H. T.; Murray, S. S.; Orrú, E.; Pizzo, R.; Sridhar, S. S.; Simionescu, A.; Stroe, A.; Tol, S. van der; White, G.J. (2016-02-22)
      We present deep LOFAR observations between 120-181 MHz of the "Toothbrush" (RX J0603.3+4214), a cluster that contains one of the brightest radio relic sources known. Our LOFAR observations exploit a new and novel calibration ...

    • Nearby galaxies in the LOFAR Two-metre Sky Survey : I. Insights into the non-linearity of the radio–SFR relation 

      Heesen, V.; Staffehl, M.; Basu, A.; Beck, R.; Stein, M.; Tabatabaei, F. S.; Hardcastle, M. J.; Chyży, K. T.; Shimwell, T. W.; Adebahr, B.; Beswick, R.; Bomans, D. J.; Botteon, A.; Brinks, E.; Brüggen, M.; Dettmar, R. -J.; Drabent, A.; Gasperin, F. de; Gürkan, G.; Heald, G. H.; Horellou, C.; Nikiel-Wroczynski, B.; Paladino, R.; Piotrowska, J.; Röttgering, H. J. A.; Smith, D. J. B.; Tasse, C. (2022-08-08)
      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-frequency radio continuum observations, free ...

    • A plethora of diffuse steep spectrum radio sources in Abell 2034 revealed by LOFAR 

      Shimwell, T. W.; Luckin, J.; Brüggen, M.; Brunetti, G.; Intema, H. T.; Owers, M. S.; Röttgering, H. J. A.; Stroe, A.; Weeren, R. J. van; Williams, W. L.; Cassano, R.; Gasperin, F. de; Heald, G. H.; Hoang, D. N.; Hardcastle, M.J.; Sridhar, S. S.; Sabater, J.; Best, P. N.; Bonafede, A.; Chyży, K. T.; Ensslin, T. A.; Ferrari, C.; Haverkorn, M.; Hoeft, M.; Horellou, C.; McKean, J. P.; Morabito, L. K.; Orrù, E.; Pizzo, R.; Retana-Montenegro, E.; White, G.J. (2016-06-11)
      With Low-Frequency Array (LOFAR) observations, we have discovered a diverse assembly of steep spectrum emission that is apparently associated with the intra cluster medium (ICM) of the merging galaxy cluster Abell 2034. ...

    • Polarized point sources in the LOFAR Two-meter Sky Survey: A preliminary catalog 

      Eck, C. L. Van; Haverkorn, M.; Alves, M. I. R.; Beck, R.; Best, P.; Carretti, E.; Chyży, K. T.; Farnes, J. S.; Ferrière, K.; Hardcastle, M. J.; Heald, G.; Horellou, C.; Iacobelli, M.; Jelić, V.; Mulcahy, D. D.; O'Sullivan, S. P.; Polderman, I. M.; Reich, W.; Riseley, C. J.; Röttgering, H.; Schnitzeler, D. H. F. M.; Shimwell, T. W.; Vacca, V.; Vink, J.; White, G. J. (2018-06-01)
      The polarization properties of radio sources at very low frequencies (<200 MHz) have not been widely measured, but the new generation of low-frequency radio telescopes, including the Low Frequency Array (LOFAR: a Square ...

    • 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 ...

    • Untangling cosmic magnetic fields: Faraday tomography at metre wavelengths with LOFAR 

      O'Sullivan, Shane P.; Brüggen, M.; Eck, C. L. Van; Hardcastle, M. J.; Haverkorn, M.; Shimwell, T. W.; Tasse, C.; Vacca, V.; Horellou, C.; Heald, G. (2018-11-29)
      The technique of Faraday tomography is a key tool for the study ofmagnetised plasmas in the new era of broadband radio-polarisation observations. In particular, observations at metre wavelengths provide significantly better ...