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42 results on '"A., Horneffer"'

1. First detection of frequency-dependent, time-variable dispersion measures

Author: Donner, J. Y., primary, Verbiest, J. P. W., additional, Tiburzi, C., additional, Osłowski, S., additional, Michilli, D., additional, Serylak, M., additional, Anderson, J. M., additional, Horneffer, A., additional, Kramer, M., additional, Grießmeier, J.-M., additional, Künsemöller, J., additional, Hessels, J. W. T., additional, Hoeft, M., additional, and Miskolczi, A., additional
Published: 2019
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2. The nature and origin of ultra high-energy cosmic rays

Author: J. R. Hörandel, P. Abreu, M. Aglietta, M. Ahlers, E. J. Ahn, I. F. M. Albuquerque, D. Allard, I. Allekotte, J. Allen, P. Allison, A. Almela, J. Alvarez Castillo, J. Alvarez Muñiz, M. Ambrosio, A. Aminaei, L. Anchordoqui, S. Andringa, T. Antičić, C. Aramo, E. Arganda, F. Arqueros, H. Asorey, P. Assis, J. Aublin, M. Ave, M. Avenier, G. Avila, T. Bäcker, A. M. Badescu, M. Balzer, K. B. Barber, A. F. Barbosa, R. Bardenet, S. L. C. Barroso, B. Baughman f, J. Bäuml, J. J. Beatty, B. R. Becker, K. H. Becker, A. Bellétoile, J. A. Bellido, S. BenZvi, C. Berat, X. Bertou, P. L. Biermann, P. Billoir, F. Blanco, M. Blanco, C. Bleve, H. Blümer, M. Boháčová, D. Boncioli, C. Bonifazi, R. Bonino, N. Borodai, J. Brack, I. Brancus, P. Brogueira, W. C. Brown, R. Bruijn i, P. Buchholz, A. Bueno, R. E. Burton, K. S. Caballero Mora, B. Caccianiga, L. Caramete, R. Caruso, A. Castellina, O. Catalano, G. Cataldi, L. Cazon, R. Cester, J. Chauvin, S. H. Cheng, A. Chiavassa, J. A. Chinellato, J. Chirinos Diaz, J. Chudoba, M. Cilmo, R. W. Clay, R. Conceição, F. Contreras, H. Cook, M. J. Cooper, J. Coppens, A. Cordier, S. Coutu, C. E. Covault, A. Creusot, A. Criss, J. Cronin, A. Curutiu, S. Dagoret Campagne, R. Dallier, B. Daniel, S. Dasso, K. Daumiller, B. R. Dawson, R. M. de Almeida, M. De Domenico, C. De Donato, S. J. de Jong, G. De La Vega, W. J. M. de Mello Junior, J. R. T. de Mello Neto, V. de Souza, K. D. de Vries, L. del Peral, M. del Río, O. Deligny, H. Dembinski, N. Dhital, C. Di Giulio, M. L. Díaz Castro, P. N. Diep, F. Diogo, C. Dobrigkeit, W. Docters, J. C. D'Olivo, P. N. Dong, A. Dorofeev, J. C. dos Anjos, M. T. Dova, D. D'Urso, I. Dutan, J. Ebr, R. Engel, M. Erdmann, C. O. Escobar, J. Espadanal, A. Etchegoyen, P. Facal San Luis, I. Fajardo Tapia, H. Falcke, G. Farrar, A. C. Fauth, N. Fazzini, A. P. Ferguson, B. Fick, A. Filevich, A. Filipčič, S. Fliescher, C. E. Fracchiolla, E. D. Fraenkel, O. Fratu, U. Fröhlich, B. Fuchs, R. Gaior, R. F. Gamarra, S. Gambetta, B. García, S. T. Garcia Roca, D. Garcia Gamez, D. Garcia Pinto, A. Gascon, H. Gemmeke, P. L. Ghia, U. Giaccari, M. Giller, H. Glass, M. S. Gold, G. Golup, F. Gomez Albarracin, M. Gómez Berisso, P. F. Gómez Vitale, P. Gonçalves, D. Gonzalez, J. G. Gonzalez, B. Gookin, A. Gorgi, P. Gouffon, E. Grashorn, S. Grebe, N. Griffith, M. Grigat, A. F. Grillo, Y. Guardincerri, F. Guarino, G. P. Guedes, A. Guzman, P. Hansen, D. Harari, T. A. Harrison, J. L. Harton, A. Haungs, T. Hebbeker, D. Heck, A. E. Herve, C. Hojvat, N. Hollon, V. C. Holmes, P. Homola, A. Horneffer, P. Horvath, M. Hrabovský, D. Huber, T. Huege, A. Insolia, F. Ionita, A. Italiano, C. Jarne, S. Jiraskova, M. Josebachuili, K. Kadija, K. H. Kampert, P. Karhan, P. Kasper, B. Kégl, B. Keilhauer, A. Keivani, J. L. Kelley, E. Kemp, R. M. Kieckhafer, H. O. Klages, M. Kleifges, J. Kleinfeller, J. Knapp, D. H. Koang, K. Kotera, N. Krohm, O. Krömer, D. Kruppke Hansen, F. Kuehn, D. Kuempel, J. K. Kulbartz, N. Kunka, G. La Rosa, C. Lachaud, D. LaHurd, L. Latronico, R. Lauer, P. Lautridou, S. Le Coz, M. S. A. B. Leão, D. Lebrun, P. Lebrun, M. A. Leigui de Oliveira, A. Letessier Selvon, I. Lhenry Yvon, K. Link, R. López, A. Lopez Agüera, K. Louedec, J. Lozano Bahilo, L. Lu, A. Lucero, M. Ludwig, H. Lyberis, M. C. Maccarone, C. Macolino, S. Maldera, D. Mandat, P. Mantsch, A. G. Mariazzi, J. Marin, V. Marin, I. C. Maris, H. R. Marquez Falcon, L. Martin, H. Martinez, O. Martínez Bravo, H. J. Mathes, J. Matthews, J. A. J. Matthews, G. Matthiae, D. Maurel, D. Maurizio, P. O. Mazur, G. Medina Tanco, M. Melissas, D. Melo, E. Menichetti, A. Menshikov, P. Mertsch, C. Meurer, S. Mićanović, M. I. Micheletti, I. A. Minaya, L. Miramonti, L. Molina Bueno, S. Mollerach, M. Monasor, D. Monnier Ragaigne, F. Montanet, B. Morales, C. Morello, E. Moreno, J. C. Moreno, M. Mostafá, C. A. Moura, M. A. Muller, G. Müller, M. Münchmeyer, R. Mussa, G. Navarra ‡, J. L. Navarro, S. Navas, P. Necesal, L. Nellen, A. Nelles, J. Neuser, P. T. Nhung, M. Niechciol, L. Niemietz, N. Nierstenhoefer, D. Nitz, D. Nosek, L. Nožka, J. Oehlschläger, A. Olinto, M. Ortiz, N. Pacheco, D. Pakk Selmi Dei, M. Palatka, J. Pallotta, N. Palmieri, G. Parente, E. Parizot, A. Parra, S. Pastor, T. Paul, M. Pech, J. Pękala, R. Pelayo, I. M. Pepe, R. Pesce, E. Petermann, S. Petrera, P. Petrinca, A. Petrolini, Y. Petrov, C. Pfendner, R. Piegaia, T. Pierog, P. Pieroni, M. Pimenta, V. Pirronello, M. Platino, M. Plum, V. H. Ponce, M. Pontz, A. Porcelli, P. Privitera, M. Prouza, E. J. Quel, S. Querchfeld, J. Rautenberg, O. Ravel, D. Ravignani, B. Revenu, J. Ridky, S. Riggi, M. Risse, P. Ristori, H. Rivera, V. Rizi, J. Roberts, W. Rodrigues de Carvalho, G. Rodriguez, J. Rodriguez Martino, J. Rodriguez Rojo, I. Rodriguez Cabo, M. D. Rodríguez Frías, G. Ros, J. Rosado, T. Rossler, M. Roth, B. Rouillé d'Orfeuil, E. Roulet, A. C. Rovero, C. Rühle, A. Saftoiu, F. Salamida, H. Salazar, F. Salesa Greus, G. Salina, F. Sánchez, C. E. Santo, E. Santos, E. M. Santos, F. Sarazin, B. Sarkar, S. Sarkar, R. Sato, N. Scharf, V. Scherini, H. Schieler, P. Schiffer, A. Schmidt, O. Scholten, H. Schoorlemmer, J. Schovancova, P. Schovánek, F. Schröder, S. Schulte, D. Schuster, S. J. Sciutto, M. Scuderi, A. Segreto, M. Settimo, A. Shadkam, R. C. Shellard, I. Sidelnik, G. Sigl, H. H. Silva Lopez, O. Sima, A. Śmiałkowski, R. Šmída, G. R. Snow, P. Sommers, J. Sorokin, H. Spinka, R. Squartini, Y. N. Srivastava, S. Stanic, J. Stapleton, J. Stasielak, M. Stephan, A. Stutz, F. Suarez, T. Suomijärvi, A. D. Supanitsky, T. Šuša, M. S. Sutherland, J. Swain, Z. Szadkowski, M. Szuba, A. Tapia, M. Tartare, O. Taşcău, C. G. Tavera Ruiz, R. Tcaciuc, N. T. Thao, D. Thomas, J. Tiffenberg, C. Timmermans, W. Tkaczyk, C. J. Todero Peixoto, G. Toma, L. Tomankova, B. Tomé, A. Tonachini, P. Travnicek, D. B. Tridapalli, G. Tristram, E. Trovato, M. Tueros, R. Ulrich, M. Unger, M. Urban, J. F. Valdés Galicia, I. Valiño, L. Valore, A. M. van den Berg, E. Varela, B. Vargas Cárdenas, J. R. Vázquez, R. A. Vázquez, D. Veberič, V. Verzi, J. Vicha, M. Videla, L. Villaseñor, H. Wahlberg, P. Wahrlich, O. Wainberg, D. Walz, A. A. Watson, M. Weber, K. Weidenhaupt, A. Weindl, F. Werner, S. Westerhoff, B. J. Whelan, A. Widom, G. Wieczorek, L. Wiencke, B. Wilczyńska, H. Wilczyński, M. Will, C. Williams, T. Winchen, M. Wommer, B. Wundheiler, T. Yamamoto a, T. Yapici, P. Younk, G. Yuan, A. Yushkov, B. Zamorano, E. Zas, D. Zavrtanik, M. Zavrtanik, I. Zaw h, A. Zepeda, Y. Zhu, M. Zimbres Silva, M. Ziolkowski, COLUCCIA, MARIA RITA, DE MITRI, Ivan, MARSELLA, GIOVANNI, MARTELLO, Daniele, PERRONE, Lorenzo, J. R., Hörandel for the Auger Collaboration, M., Ambrosio, Aramo, Carla, M., Cilmo, D'Urso, Domenico, Guarino, Fausto, Valore, Laura, J. R., Hörandel, P., Abreu, M., Aglietta, M., Ahler, E. J., Ahn, I. F. M., Albuquerque, D., Allard, I., Allekotte, J., Allen, P., Allison, A., Almela, J., Alvarez Castillo, J., Alvarez Muñiz, A., Aminaei, L., Anchordoqui, S., Andringa, T., Antičić, C., Aramo, E., Arganda, F., Arquero, H., Asorey, P., Assi, J., Aublin, M., Ave, M., Avenier, G., Avila, T., Bäcker, A. M., Badescu, M., Balzer, K. B., Barber, A. F., Barbosa, R., Bardenet, S. L. C., Barroso, B., Baughman f, J., Bäuml, J. J., Beatty, B. R., Becker, K. H., Becker, A., Bellétoile, J. A., Bellido, S., Benzvi, C., Berat, X., Bertou, P. L., Biermann, P., Billoir, F., Blanco, M., Blanco, C., Bleve, H., Blümer, M., Boháčová, D., Boncioli, C., Bonifazi, R., Bonino, N., Borodai, J., Brack, I., Brancu, P., Brogueira, W. C., Brown, R., Bruijn i, P., Buchholz, A., Bueno, R. E., Burton, K. S., Caballero Mora, B., Caccianiga, L., Caramete, R., Caruso, A., Castellina, O., Catalano, G., Cataldi, L., Cazon, R., Cester, J., Chauvin, S. H., Cheng, A., Chiavassa, J. A., Chinellato, J., Chirinos Diaz, J., Chudoba, R. W., Clay, Coluccia, MARIA RITA, R., Conceição, F., Contrera, H., Cook, M. J., Cooper, J., Coppen, A., Cordier, S., Coutu, C. E., Covault, A., Creusot, A., Cri, J., Cronin, A., Curutiu, S., Dagoret Campagne, R., Dallier, B., Daniel, S., Dasso, K., Daumiller, B. R., Dawson, R. M., de Almeida, M., De Domenico, C., De Donato, S. J., de Jong, G., De La Vega, W. J. M., de Mello Junior, J. R. T., de Mello Neto, DE MITRI, Ivan, V., de Souza, K. D., de Vrie, L., del Peral, M., del Río, O., Deligny, H., Dembinski, N., Dhital, C., Di Giulio, M. L., Díaz Castro, P. N., Diep, F., Diogo, C., Dobrigkeit, W., Docter, J. C., D'Olivo, P. N., Dong, A., Dorofeev, J. C., dos Anjo, M. T., Dova, D., D'Urso, I., Dutan, J., Ebr, R., Engel, M., Erdmann, C. O., Escobar, J., Espadanal, A., Etchegoyen, P., Facal San Lui, I., Fajardo Tapia, H., Falcke, G., Farrar, A. C., Fauth, N., Fazzini, A. P., Ferguson, B., Fick, A., Filevich, A., Filipčič, S., Fliescher, C. E., Fracchiolla, E. D., Fraenkel, O., Fratu, U., Fröhlich, B., Fuch, R., Gaior, R. F., Gamarra, S., Gambetta, B., García, S. T., Garcia Roca, D., Garcia Gamez, D., Garcia Pinto, A., Gascon, H., Gemmeke, P. L., Ghia, U., Giaccari, M., Giller, H., Gla, M. S., Gold, G., Golup, F., Gomez Albarracin, M., Gómez Berisso, P. F., Gómez Vitale, P., Gonçalve, D., Gonzalez, J. G., Gonzalez, B., Gookin, A., Gorgi, P., Gouffon, E., Grashorn, S., Grebe, N., Griffith, M., Grigat, A. F., Grillo, Y., Guardincerri, F., Guarino, G. P., Guede, A., Guzman, P., Hansen, D., Harari, T. A., Harrison, J. L., Harton, A., Haung, T., Hebbeker, D., Heck, A. E., Herve, C., Hojvat, N., Hollon, V. C., Holme, P., Homola, A., Horneffer, P., Horvath, M., Hrabovský, D., Huber, T., Huege, A., Insolia, F., Ionita, A., Italiano, C., Jarne, S., Jiraskova, M., Josebachuili, K., Kadija, K. H., Kampert, P., Karhan, P., Kasper, B., Kégl, B., Keilhauer, A., Keivani, J. L., Kelley, E., Kemp, R. M., Kieckhafer, H. O., Klage, M., Kleifge, J., Kleinfeller, J., Knapp, D. H., Koang, K., Kotera, N., Krohm, O., Krömer, D., Kruppke Hansen, F., Kuehn, D., Kuempel, J. K., Kulbartz, N., Kunka, G., La Rosa, C., Lachaud, D., Lahurd, L., Latronico, R., Lauer, P., Lautridou, S., Le Coz, M. S. A. B., Leão, D., Lebrun, P., Lebrun, M. A., Leigui de Oliveira, A., Letessier Selvon, I., Lhenry Yvon, K., Link, R., López, A., Lopez Agüera, K., Louedec, J., Lozano Bahilo, L., Lu, A., Lucero, M., Ludwig, H., Lyberi, M. C., Maccarone, C., Macolino, S., Maldera, D., Mandat, P., Mantsch, A. G., Mariazzi, J., Marin, V., Marin, I. C., Mari, H. R., Marquez Falcon, Marsella, Giovanni, Martello, Daniele, L., Martin, H., Martinez, O., Martínez Bravo, H. J., Mathe, J., Matthew, J. A. J., Matthew, G., Matthiae, D., Maurel, D., Maurizio, P. O., Mazur, G., Medina Tanco, M., Melissa, D., Melo, E., Menichetti, A., Menshikov, P., Mertsch, C., Meurer, S., Mićanović, M. I., Micheletti, I. A., Minaya, L., Miramonti, L., Molina Bueno, S., Mollerach, M., Monasor, D., Monnier Ragaigne, F., Montanet, B., Morale, C., Morello, E., Moreno, J. C., Moreno, M., Mostafá, C. A., Moura, M. A., Muller, G., Müller, M., Münchmeyer, R., Mussa, G., Navarra ‡, J. L., Navarro, S., Nava, P., Necesal, L., Nellen, A., Nelle, J., Neuser, P. T., Nhung, M., Niechciol, L., Niemietz, N., Nierstenhoefer, D., Nitz, D., Nosek, L., Nožka, J., Oehlschläger, A., Olinto, M., Ortiz, N., Pacheco, D., Pakk Selmi Dei, M., Palatka, J., Pallotta, N., Palmieri, G., Parente, E., Parizot, A., Parra, S., Pastor, T., Paul, M., Pech, J., Pękala, R., Pelayo, I. M., Pepe, Perrone, Lorenzo, R., Pesce, E., Petermann, S., Petrera, P., Petrinca, A., Petrolini, Y., Petrov, C., Pfendner, R., Piegaia, T., Pierog, P., Pieroni, M., Pimenta, V., Pirronello, M., Platino, M., Plum, V. H., Ponce, M., Pontz, A., Porcelli, P., Privitera, M., Prouza, E. J., Quel, S., Querchfeld, J., Rautenberg, O., Ravel, D., Ravignani, B., Revenu, J., Ridky, S., Riggi, M., Risse, P., Ristori, H., Rivera, V., Rizi, J., Robert, W., Rodrigues de Carvalho, G., Rodriguez, J., Rodriguez Martino, J., Rodriguez Rojo, I., Rodriguez Cabo, M. D., Rodríguez Fría, G., Ro, J., Rosado, T., Rossler, M., Roth, B., Rouillé d'Orfeuil, E., Roulet, A. C., Rovero, C., Rühle, A., Saftoiu, F., Salamida, H., Salazar, F., Salesa Greu, G., Salina, F., Sánchez, C. E., Santo, E., Santo, E. M., Santo, F., Sarazin, B., Sarkar, S., Sarkar, R., Sato, N., Scharf, V., Scherini, H., Schieler, P., Schiffer, A., Schmidt, O., Scholten, H., Schoorlemmer, J., Schovancova, P., Schovánek, F., Schröder, S., Schulte, D., Schuster, S. J., Sciutto, M., Scuderi, A., Segreto, M., Settimo, A., Shadkam, R. C., Shellard, I., Sidelnik, G., Sigl, H. H., Silva Lopez, O., Sima, A., Śmiałkowski, R., Šmída, G. R., Snow, P., Sommer, J., Sorokin, H., Spinka, R., Squartini, Y. N., Srivastava, S., Stanic, J., Stapleton, J., Stasielak, M., Stephan, A., Stutz, F., Suarez, T., Suomijärvi, A. D., Supanitsky, T., Šuša, M. S., Sutherland, J., Swain, Z., Szadkowski, M., Szuba, A., Tapia, M., Tartare, O., Taşcău, C. G., Tavera Ruiz, R., Tcaciuc, N. T., Thao, D., Thoma, J., Tiffenberg, C., Timmerman, W., Tkaczyk, C. J., Todero Peixoto, G., Toma, L., Tomankova, B., Tomé, A., Tonachini, P., Travnicek, D. B., Tridapalli, G., Tristram, E., Trovato, M., Tuero, R., Ulrich, M., Unger, M., Urban, J. F., Valdés Galicia, I., Valiño, L., Valore, A. M., van den Berg, E., Varela, B., Vargas Cárdena, J. R., Vázquez, R. A., Vázquez, D., Veberič, V., Verzi, J., Vicha, M., Videla, L., Villaseñor, H., Wahlberg, P., Wahrlich, O., Wainberg, D., Walz, A. A., Watson, M., Weber, K., Weidenhaupt, A., Weindl, F., Werner, S., Westerhoff, B. J., Whelan, A., Widom, G., Wieczorek, L., Wiencke, B., Wilczyńska, H., Wilczyński, M., Will, C., William, T., Winchen, M., Wommer, B., Wundheiler, T., Yamamoto a, T., Yapici, P., Younk, G., Yuan, A., Yushkov, B., Zamorano, E., Za, D., Zavrtanik, M., Zavrtanik, I., Zaw h, A., Zepeda, Y., Zhu, M., Zimbres Silva, and M., Ziolkowski
Subjects: Physics, business.industry, Astronomy, Astrophysical source, General Physics and Astronomy, Pierre Auger Observatory, Cosmic Ray, Particle detector, Cosmology, Radiation flux, Optics, Measuring instrument, Ultra-high-energy cosmic ray, business
Abstract: The Earth is exposed to a permanent rain of cosmic particles from outer space [1]. Most of the particles are fully ionised atomic nuclei, moving with relativistic energies. The bulk of them with energies up to 1017 eV originate within our Milky Way. They are most likely accel- erated in supernova remnants. Some particles have a thousand times higher energies, i.e., around 1020 eV. This corresponds to the kinetic energy of a tennis ball with a mass of 50 g and a velocity of 90 km/h
Published: 2012

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

Author: Michael W. Wise, Leah K. Morabito, Jeremy J. Harwood, D. Carbone, Emanuela Orru, T. M. Cantwell, Judith H. Croston, Marisa Brienza, G. Kokotanekov, Rosita Paladino, George Heald, D. D. Mulcahy, A. O. Clarke, Annalisa Bonafede, A. Horneffer, Luke Pratley, Huub Röttgering, Martin J. Hardcastle, Adam Stewart, S. S. Sridhar, Cyril Tasse, Marco Iacobelli, R. Pizzo, J. W. Broderick, Jamie Farnes, A. J. van der Horst, K. Sendlinger, Anna M. M. Scaife, Rene P. Breton, J. Sabater, Volker Heesen, Thomas H. Jarrett, W. Jurusik, M. Pietka, Justin D. Bray, S. van Velzen, Błażej Nikiel-Wroczyński, John McKean, M. Pandey-Pommier, Antonia Rowlinson, R. J. van Weeren, C. J. Riseley, Aleksandar Shulevski, Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche Astrophysique de Lyon ( CRAL ), École normale supérieure - Lyon ( ENS Lyon ) -Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Galaxies, Etoiles, Physique, Instrumentation ( GEPI ), Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), Astronomy, Kapteyn Astronomical Institute, Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), and High Energy Astrophys. & Astropart. Phys (API, FNWI)
Subjects: SELECTION, Active galactic nucleus, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Stellar mass, Radio galaxy, Astronomy, [ PHYS.ASTR ] Physics [physics]/Astrophysics [astro-ph], Astrophysics::High Energy Astrophysical Phenomena, UNIVERSE, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, galaxies [infrared], infrared: galaxies, surveys, galaxies: groups: general, Galaxy group, 0103 physical sciences, WISE, galaxies: interactions, FIELD, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, radio continuum: galaxies, 010308 nuclear & particles physics, Star formation, groups: general [galaxies], interactions [galaxies], supermassive black holes [quasars], quasars: supermassive black holes, Velocity dispersion, Astronomy and Astrophysics, LOFAR, ATLAS, Astrophysics - Astrophysics of Galaxies, Galaxy, galaxies [radio continuum], EVOLUTION, I. SURVEY DESCRIPTION, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), ALL-SKY SURVEY, SDSS-III, ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, CLUSTERS, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: 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 UGC 9555, within which one is identified as a broad-line galaxy in the Sloan Digital Sky Survey (SDSS) at a redshift of $0.05453 \pm 1 \times 10^{-5} $, and with a velocity dispersion of $215.86 \pm 6.34$ km/s. From archival radio observations we see that this galaxy hosts a compact flat-spectrum radio source, and we conclude that it is the active galactic nucleus (AGN) responsible for generating the radio lobes. The radio luminosity distribution of the jets, and the broad-line classification of the host AGN, indicate this GRG is orientated well out of the plane of the sky, making its physical size one of the largest known for any GRG. Analysis of the infrared data suggests that the host is a lenticular type galaxy with a large stellar mass ($\log~\mathrm{M}/\mathrm{M}_\odot = 11.56 \pm 0.12$), and a moderate star formation rate ($1.2 \pm 0.3~\mathrm{M}_\odot/\mathrm{year}$). Spatially smoothing the SDSS images shows the system around UGC 9555 to be significantly disturbed, with a prominent extension to the south-east. Overall, the evidence suggests this host galaxy has undergone one or more recent moderate merger events and is also experiencing tidal interactions with surrounding galaxies, which have caused the star formation and provided the supply of gas to trigger and fuel the Mpc-scale radio lobes., Compressed for arXiv, see journal for full resolution images
Published: 2017

4. Reliable detection and characterization of low-frequency polarized sources in the LOFAR M51 field

Author: Neld, A., primary, Horellou, C., additional, Mulcahy, D. D., additional, Beck, R., additional, Bourke, S., additional, Carozzi, T. D., additional, Chyży, K. T., additional, Conway, J. E., additional, Farnes, J. S., additional, Fletcher, A., additional, Haverkorn, M., additional, Heald, G., additional, Horneffer, A., additional, Nikiel-Wroczyński, B., additional, Paladino, R., additional, Sridhar, S. S., additional, and Van Eck, C. L., additional
Published: 2018
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5. Investigation of the cosmic ray population and magnetic field strength in the halo of NGC 891

Author: Mulcahy, D. D., primary, Horneffer, A., additional, Beck, R., additional, Krause, M., additional, Schmidt, P., additional, Basu, A., additional, Chyży, K. T., additional, Dettmar, R.-J., additional, Haverkorn, M., additional, Heald, G., additional, Heesen, V., additional, Horellou, C., additional, Iacobelli, M., additional, Nikiel-Wroczyński, B., additional, Paladino, R., additional, Scaife, A. M. M., additional, Sridhar, Sarrvesh S., additional, Strom, R. G., additional, Tabatabaei, F. S., additional, Cantwell, T., additional, Carey, S. H., additional, Grainge, K., additional, Hickish, J., additional, Perrot, Y., additional, Razavi-Ghods, N., additional, Scott, P., additional, and Titterington, D., additional
Published: 2018
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6. Tracking of an electron beam through the solar corona with LOFAR

Author: Mann, G., primary, Breitling, F., additional, Vocks, C., additional, Aurass, H., additional, Steinmetz, M., additional, Strassmeier, K. G., additional, Bisi, M. M., additional, Fallows, R. A., additional, Gallagher, P., additional, Kerdraon, A., additional, Mackinnon, A., additional, Magdalenic, J., additional, Rucker, H., additional, Anderson, J., additional, Asgekar, A., additional, Avruch, I. M., additional, Bell, M. E., additional, Bentum, M. J., additional, Bernardi, G., additional, Best, P., additional, Bîrzan, L., additional, Bonafede, A., additional, Broderick, J. W., additional, Brüggen, M., additional, Butcher, H. R., additional, Ciardi, B., additional, Corstanje, A., additional, de Gasperin, F., additional, de Geus, E., additional, Deller, A., additional, Duscha, S., additional, Eislöffel, J., additional, Engels, D., additional, Falcke, H., additional, Fender, R., additional, Ferrari, C., additional, Frieswijk, W., additional, Garrett, M. A., additional, Grießmeier, J., additional, Gunst, A. W., additional, van Haarlem, M., additional, Hassall, T. E., additional, Heald, G., additional, Hessels, J. W. T., additional, Hoeft, M., additional, Hörandel, J., additional, Horneffer, A., additional, Juette, E., additional, Karastergiou, A., additional, Klijn, W. F. A., additional, Kondratiev, V. I., additional, Kramer, M., additional, Kuniyoshi, M., additional, Kuper, G., additional, Maat, P., additional, Markoff, S., additional, McFadden, R., additional, McKay-Bukowski, D., additional, McKean, J. P., additional, Mulcahy, D. D., additional, Munk, H., additional, Nelles, A., additional, Norden, M. J., additional, Orru, E., additional, Paas, H., additional, Pandey-Pommier, M., additional, Pandey, V. N., additional, Pizzo, R., additional, Polatidis, A. G., additional, Rafferty, D., additional, Reich, W., additional, Röttgering, H., additional, Scaife, A. M. M., additional, Schwarz, D. J., additional, Serylak, M., additional, Sluman, J., additional, Smirnov, O., additional, Stappers, B. W., additional, Tagger, M., additional, Tang, Y., additional, Tasse, C., additional, ter Veen, S., additional, Thoudam, S., additional, Toribio, M. C., additional, Vermeulen, R., additional, van Weeren, R. J., additional, Wise, M. W., additional, Wucknitz, O., additional, Yatawatta, S., additional, Zarka, P., additional, and Zensus, J. A., additional
Published: 2018
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7. The LOFAR Two-metre Sky Survey:I. Survey description and preliminary data release

Author: Shimwell, T. W. (T. W.), Rottgering, H. J. (H. J. A.), Best, P. N. (P. N.), Williams, W. L. (W. L.), Dijkema, T. J. (T. J.), de Gasperin, F. (F.), Hardcastle, M. J. (M. J.), Heald, G. H. (G. H.), Hoang, D. N. (D. N.), Horneffer, A. (A.), Intema, H. (H.), Mahony, E. K. (E. K.), Mandal, S. (S.), Mechev, A. P. (A. P.), Morabito, L. (L.), Oonk, J. B. (J. B. R.), Rafferty, D. (D.), Retana-Montenegro, E. (E.), Sabater, J. (J.), Tasse, C. (C.), van Weeren, R. J. (R. J.), Brueggen, M. (M.), Brunetti, G. (G.), Chyzy, K. T. (K. T.), Conway, J. E. (J. E.), Haverkorn, M. (M.), Jackson, N. (N.), Jarvis, M. J. (M. J.), McKean, J. P. (J. P.), Miley, G. K. (G. K.), Morganti, R. (R.), White, G. J. (G. J.), Wise, M. W. (M. W.), van Bemmel, I. M. (I. M.), Beck, R. (R.), Brienza, M. (M.), Bonafede, A. (A.), Rivera, G. C. (G. Calistro), Cassano, R. (R.), Clarke, A. O. (A. O.), Cseh, D. (D.), Deller, A. (A.), Drabent, A. (A.), van Driel, W. (W.), Engels, D. (D.), Falcke, H. (H.), Ferrari, C. (C.), Froehlich, S. (S.), Garrett, M. A. (M. A.), Harwood, J. J. (J. J.), Heesen, V. (V.), Hoeft, M. (M.), Horellou, C. (C.), Israel, F. P. (F. P.), Kapinska, A. D. (A. D.), Kunert-Bajraszewska, M. (M.), McKay, D. J. (D. J.), Mohan, N. R. (N. R.), Orru, E. (E.), Pizzo, R. F. (R. F.), Prandoni, I. (I.), Schwarz, D. J. (D. J.), Shulevski, A. (A.), Sipior, M. (M.), Smith, D. J. (D. J. B.), Sridhar, S. S. (S. S.), Steinmetz, M. (M.), Stroe, A. (A.), Varenius, E. (E.), van der Werf, P. P. (P. P.), Zensus, J. A. (J. A.), Zwart, J. T. (J. T. L.), Shimwell, T. W. (T. W.), Rottgering, H. J. (H. J. A.), Best, P. N. (P. N.), Williams, W. L. (W. L.), Dijkema, T. J. (T. J.), de Gasperin, F. (F.), Hardcastle, M. J. (M. J.), Heald, G. H. (G. H.), Hoang, D. N. (D. N.), Horneffer, A. (A.), Intema, H. (H.), Mahony, E. K. (E. K.), Mandal, S. (S.), Mechev, A. P. (A. P.), Morabito, L. (L.), Oonk, J. B. (J. B. R.), Rafferty, D. (D.), Retana-Montenegro, E. (E.), Sabater, J. (J.), Tasse, C. (C.), van Weeren, R. J. (R. J.), Brueggen, M. (M.), Brunetti, G. (G.), Chyzy, K. T. (K. T.), Conway, J. E. (J. E.), Haverkorn, M. (M.), Jackson, N. (N.), Jarvis, M. J. (M. J.), McKean, J. P. (J. P.), Miley, G. K. (G. K.), Morganti, R. (R.), White, G. J. (G. J.), Wise, M. W. (M. W.), van Bemmel, I. M. (I. M.), Beck, R. (R.), Brienza, M. (M.), Bonafede, A. (A.), Rivera, G. C. (G. Calistro), Cassano, R. (R.), Clarke, A. O. (A. O.), Cseh, D. (D.), Deller, A. (A.), Drabent, A. (A.), van Driel, W. (W.), Engels, D. (D.), Falcke, H. (H.), Ferrari, C. (C.), Froehlich, S. (S.), Garrett, M. A. (M. A.), Harwood, J. J. (J. J.), Heesen, V. (V.), Hoeft, M. (M.), Horellou, C. (C.), Israel, F. P. (F. P.), Kapinska, A. D. (A. D.), Kunert-Bajraszewska, M. (M.), McKay, D. J. (D. J.), Mohan, N. R. (N. R.), Orru, E. (E.), Pizzo, R. F. (R. F.), Prandoni, I. (I.), Schwarz, D. J. (D. J.), Shulevski, A. (A.), Sipior, M. (M.), Smith, D. J. (D. J. B.), Sridhar, S. S. (S. S.), Steinmetz, M. (M.), Stroe, A. (A.), Varenius, E. (E.), van der Werf, P. P. (P. P.), Zensus, J. A. (J. A.), and Zwart, J. T. (J. T. L.)
Abstract: 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 h, which, at most declinations, is sufficient to produce ~5″ resolution images with a sensitivity of ~100 μJy/beam and accomplish the main scientific aims of the survey, which are to explore the formation and evolution of massive black holes, galaxies, clusters of galaxies and large-scale structure. Owing to the compact core and long baselines of LOFAR, the images provide excellent sensitivity to both highly extended and compact emission. For legacy value, the data are archived at high spectral and time resolution to facilitate subarcsecond imaging and spectral line studies. In this paper we provide an overview of the LoTSS. We outline the survey strategy, the observational status, the current calibration techniques, a preliminary data release, and the anticipated scientific impact. The preliminary images that we have released were created using a fully automated but direction-independent calibration strategy and are significantly more sensitive than those produced by any existing large-area low-frequency survey. In excess of 44 000 sources are detected in the images that have a resolution of 25″, typical noise levels of less than 0.5 mJy/beam, and cover an area of over 350 square degrees in the region of the HETDEX Spring Field (right ascension 10h45m00s to 15h30m00s and declination 45°00′00″ to 57°00′00″).
Published: 2017

8. The LOFAR Two-metre Sky Survey: I. Survey description and preliminary data release

Author: Shimwell, T., Röttgering, H., Best, P., Williams, W., Dijkema, T., De Gasperin, F., Hardcastle, M., Heald, G., Hoang, D., Horneffer, A., Intema, Hubertus, Mahony, E., Mandal, S., Mechev, A., Morabito, L., Oonk, J., Rafferty, D., Retana-Montenegro, E., Sabater, J., Tasse, C., Van Weeren, R., Brüggen, M., Brunetti, G., Chy, K., Conway, J., Haverkorn, M., Jackson, N., Jarvis, M., McKean, J., Miley, G., Morganti, R., White, G., Wise, M., Van Bemmel, I., Beck, R., Brienza, M., Bonafede, A., Calistro Rivera, G., Cassano, R., Clarke, A., Cseh, D., Deller, A., Drabent, A., Van Driel, W., Engels, D., Falcke, H., Ferrari, C., Fröhlich, S., Garrett, M., Harwood, J., Heesen, V., Hoeft, M., Horellou, C., Israel, F., Kapinska, A., Kunert-Bajraszewska, M., McKay, D., Mohan, N., Orrú, E., Pizzo, R., Prandoni, I., Schwarz, D., Shulevski, A., Sipior, M., Smith, D., Sridhar, S., Steinmetz, M., Stroe, A., Varenius, E., Van Der Werf, P., Zensus, J., Zwart, J., Shimwell, T., Röttgering, H., Best, P., Williams, W., Dijkema, T., De Gasperin, F., Hardcastle, M., Heald, G., Hoang, D., Horneffer, A., Intema, Hubertus, Mahony, E., Mandal, S., Mechev, A., Morabito, L., Oonk, J., Rafferty, D., Retana-Montenegro, E., Sabater, J., Tasse, C., Van Weeren, R., Brüggen, M., Brunetti, G., Chy, K., Conway, J., Haverkorn, M., Jackson, N., Jarvis, M., McKean, J., Miley, G., Morganti, R., White, G., Wise, M., Van Bemmel, I., Beck, R., Brienza, M., Bonafede, A., Calistro Rivera, G., Cassano, R., Clarke, A., Cseh, D., Deller, A., Drabent, A., Van Driel, W., Engels, D., Falcke, H., Ferrari, C., Fröhlich, S., Garrett, M., Harwood, J., Heesen, V., Hoeft, M., Horellou, C., Israel, F., Kapinska, A., Kunert-Bajraszewska, M., McKay, D., Mohan, N., Orrú, E., Pizzo, R., Prandoni, I., Schwarz, D., Shulevski, A., Sipior, M., Smith, D., Sridhar, S., Steinmetz, M., Stroe, A., Varenius, E., Van Der Werf, P., Zensus, J., and Zwart, J.
Abstract: 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 h, which, at most declinations, is sufficient to produce ~5″ resolution images with a sensitivity of ~100 μJy/beam and accomplish the main scientific aims of the survey, which are to explore the formation and evolution of massive black holes, galaxies, clusters of galaxies and large-scale structure. Owing to the compact core and long baselines of LOFAR, the images provide excellent sensitivity to both highly extended and compact emission. For legacy value, the data are archived at high spectral and time resolution to facilitate subarcsecond imaging and spectral line studies. In this paper we provide an overview of the LoTSS. We outline the survey strategy, the observational status, the current calibration techniques, a preliminary data release, and the anticipated scientific impact. The preliminary images that we have released were created using a fully automated but direction-independent calibration strategy and are significantly more sensitive than those produced by any existing large-area low-frequency survey. In excess of 44 000 sources are detected in the images that have a resolution of 25″, typical noise levels of less than 0.5 mJy/beam, and cover an area of over 350 square degrees in the region of the HETDEX Spring Field (right ascension 10h45m00s to 15h30m00s and declination 45°00′00″ to 57°00′00″).
Published: 2017

9. Faraday tomography of the local interstellar medium with LOFAR: Galactic foregrounds towards IC 342*

Author: Van Eck, C., Haverkorn, M., Alves, M., Beck, R., De Bruyn, A., Enßlin, T., Farnes, J., Ferrière, K., Heald, G., Horellou, C., Horneffer, A., Iacobelli, M., Jelic, V., Martí-Vidal, I., Mulcahy, D., Reich, W., Röttgering, H., Scaife, A., Schnitzeler, D., Sobey, Charlotte, Sridhar, S., Van Eck, C., Haverkorn, M., Alves, M., Beck, R., De Bruyn, A., Enßlin, T., Farnes, J., Ferrière, K., Heald, G., Horellou, C., Horneffer, A., Iacobelli, M., Jelic, V., Martí-Vidal, I., Mulcahy, D., Reich, W., Röttgering, H., Scaife, A., Schnitzeler, D., Sobey, Charlotte, and Sridhar, S.
Abstract: Â© 2017 ESO. Magnetic fields pervade the interstellar medium (ISM), but are difficult to detect and characterize. The new generation of low-frequency radio telescopes, such as the Low Frequency Array (LOFAR: a Square Kilometre Array-low pathfinder), provides advancements in our capability of probing Galactic magnetism through low-frequency polarimetry. Maps of diffuse polarized radio emission and the associated Faraday rotation can be used to infer properties of, and trace structure in, the magnetic fields in the ISM. However, to date very little of the sky has been probed at high angular and Faraday depth resolution. We observed a 5Â° by 5Â° region centred on the nearby galaxy IC 342 (â„“ = 138.2Â°,b = + 10.6Â°) using the LOFAR high-band antennae in the frequency range 115-178 MHz. We imaged this region at 4â€².5x3â€².84.5 Ã— 3.8 resolution and performed Faraday tomography to detect foreground Galactic polarized synchrotron emission separated by Faraday depth (different amounts of Faraday rotation). Our Faraday depth cube shows a rich polarized structure, with up to 30 K of polarized emission at 150 MHz. We clearly detect two polarized features that extend over most of the field, but are clearly separated in Faraday depth. Simulations of the behaviour of the depolarization of Faraday-thick structures at such low frequencies show that such structures would be too strongly depolarized to explain the observations. These structures are therefore rejected as the source of the observed polarized features. Only Faraday thin structures will not be strongly depolarized at low frequencies; producing such structures requires localized variations in the ratio of synchrotron emissivity to Faraday depth per unit distance. Such variations can arise from several physical phenomena, such as a transition between regions of ionized and (mostly) neutral gas. We conclude that the observed polarized emission is Faraday thin, and propose that the emission originates from two mostly neutr
Published: 2017

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

Author: Clarke, A. O., primary, Heald, G., additional, Jarrett, T., additional, Bray, J. D., additional, Hardcastle, M. J., additional, Cantwell, T. M., additional, Scaife, A. M. M., additional, Brienza, M., additional, Bonafede, A., additional, Breton, R. P., additional, Broderick, J. W., additional, Carbone, D., additional, Croston, J. H., additional, Farnes, J. S., additional, Harwood, J. J., additional, Heesen, V., additional, Horneffer, A., additional, van der Horst, A. J., additional, Iacobelli, M., additional, Jurusik, W., additional, Kokotanekov, G., additional, McKean, J. P., additional, Morabito, L. K., additional, Mulcahy, D. D., additional, Nikiel-Wroczyñski, B. S., additional, Orrú, E., additional, Paladino, R., additional, Pandey-Pommier, M., additional, Pietka, M., additional, Pizzo, R., additional, Pratley, L., additional, Riseley, C. J., additional, Rottgering, H. J. A., additional, Rowlinson, A., additional, Sabater, J., additional, Sendlinger, K., additional, Shulevski, A., additional, Sridhar, S. S., additional, Stewart, A. J., additional, Tasse, C., additional, van Velzen, S., additional, van Weeren, R. J., additional, and Wise, M. W., additional
Published: 2017
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11. The LOFAR Two-metre Sky Survey

Author: Shimwell, T. W., primary, Röttgering, H. J. A., additional, Best, P. N., additional, Williams, W. L., additional, Dijkema, T. J., additional, de Gasperin, F., additional, Hardcastle, M. J., additional, Heald, G. H., additional, Hoang, D. N., additional, Horneffer, A., additional, Intema, H., additional, Mahony, E. K., additional, Mandal, S., additional, Mechev, A. P., additional, Morabito, L., additional, Oonk, J. B. R., additional, Rafferty, D., additional, Retana-Montenegro, E., additional, Sabater, J., additional, Tasse, C., additional, van Weeren, R. J., additional, Brüggen, M., additional, Brunetti, G., additional, Chyży, K. T., additional, Conway, J. E., additional, Haverkorn, M., additional, Jackson, N., additional, Jarvis, M. J., additional, McKean, J. P., additional, Miley, G. K., additional, Morganti, R., additional, White, G. J., additional, Wise, M. W., additional, van Bemmel, I. M., additional, Beck, R., additional, Brienza, M., additional, Bonafede, A., additional, Calistro Rivera, G., additional, Cassano, R., additional, Clarke, A. O., additional, Cseh, D., additional, Deller, A., additional, Drabent, A., additional, van Driel, W., additional, Engels, D., additional, Falcke, H., additional, Ferrari, C., additional, Fröhlich, S., additional, Garrett, M. A., additional, Harwood, J. J., additional, Heesen, V., additional, Hoeft, M., additional, Horellou, C., additional, Israel, F. P., additional, Kapińska, A. D., additional, Kunert-Bajraszewska, M., additional, McKay, D. J., additional, Mohan, N. R., additional, Orrú, E., additional, Pizzo, R. F., additional, Prandoni, I., additional, Schwarz, D. J., additional, Shulevski, A., additional, Sipior, M., additional, Smith, D. J. B., additional, Sridhar, S. S., additional, Steinmetz, M., additional, Stroe, A., additional, Varenius, E., additional, van der Werf, P. P., additional, Zensus, J. A., additional, and Zwart, J. T. L., additional
Published: 2017
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12. Faraday tomography of the local interstellar medium with LOFAR: Galactic foregrounds towards IC 342

Author: Van Eck, C. L., primary, Haverkorn, M., additional, Alves, M. I. R., additional, Beck, R., additional, de Bruyn, A. G., additional, Enßlin, T., additional, Farnes, J. S., additional, Ferrière, K., additional, Heald, G., additional, Horellou, C., additional, Horneffer, A., additional, Iacobelli, M., additional, Jelić, V., additional, Martí-Vidal, I., additional, Mulcahy, D. D., additional, Reich, W., additional, Röttgering, H. J. A., additional, Scaife, A. M. M., additional, Schnitzeler, D. H. F. M., additional, Sobey, C., additional, and Sridhar, S. S., additional
Published: 2017
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13. Cosmic rays studied with a hybrid high school detector array

Author: Y. Koopman, G. Schoonderbeek, C. J.W.P. Timmermans, Heino Falcke, A. Horneffer, A. Nigl, Pim Schellart, H. J. Pepping, C. M. de Vos, and Jan Kuijpers
Subjects: Physics, Field (physics), business.industry, Astronomy, Astrophysics (astro-ph), Detector, Digital data, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, General Physics and Astronomy, Cosmic ray, Astrophysics, Coincidence, Particle detector, Optics, Pathfinder, Experimental High Energy Physics, Detector array, business
Abstract: The LORUN/NAHSA system is a pathfinder for hybrid cosmic ray research combined with education and outreach in the field of astro-particle physics. Particle detectors and radio antennae were mainly setup by students and placed on public buildings. After fully digital data acquisition, coincidence detections were selected. Three candidate events confirmed a working prototype, which can be multiplied to extend further particle detector arrays on high schools., Comment: 10 pages, 6 figures. Nigl, A., Timmermans, C., Schellart, P., Kuijpers, J., Falcke, H., Horneffer, A., de Vos, C. M., Koopman, Y., Pepping, H. J., Schoonderbeek, G., Cosmic rays studied with a hybrid high school detector array, Europhysics News (EPN), Vol. 38, No. 5, accepted on 22/08/2007
Published: 2007

14. LBCS: The LOFAR Long-Baseline Calibrator Survey

Author: Jackson, N., Tagore, A., Deller, A., Moldón, J., Varenius, E., Morabito, L., Wucknitz, O., Carozzi, T., Conway, J., Drabent, A., Kapinska, A., Orrù, E., Brentjens, M., Blaauw, R., Kuper, G., Sluman, J., Schaap, J., Vermaas, N., Iacobelli, M., Cerrigone, L., Shulevski, A., Ter Veen, S., Fallows, R., Pizzo, R., Sipior, M., Anderson, J., Avruch, I., Bell, M., Van Bemmel, I., Bentum, M., Best, P., Bonafede, A., Breitling, F., Broderick, J., Brouw, W., Brüggen, M., Ciardi, B., Corstanje, A., De Gasperin, F., De Geus, E., Eislöffel, J., Engels, D., Falcke, H., Garrett, M., Grießmeier, J., Gunst, A., Van Haarlem, M., Heald, G., Hoeft, M., Hörandel, J., Horneffer, A., Intema, Hubertus, Juette, E., Kuniyoshi, M., Van Leeuwen, J., Loose, G., Maat, P., McFadden, R., McKay-Bukowski, D., McKean, J., Mulcahy, D., Munk, H., Pandey-Pommier, M., Polatidis, A., Reich, W., Röttgering, H., Rowlinson, A., Scaife, A., Schwarz, D., Steinmetz, M., Swinbank, J., Thoudam, S., Toribio, M., Vermeulen, R., Vocks, C., Van Weeren, R., Wise, M., Yatawatta, S., Zarka, P., Jackson, N., Tagore, A., Deller, A., Moldón, J., Varenius, E., Morabito, L., Wucknitz, O., Carozzi, T., Conway, J., Drabent, A., Kapinska, A., Orrù, E., Brentjens, M., Blaauw, R., Kuper, G., Sluman, J., Schaap, J., Vermaas, N., Iacobelli, M., Cerrigone, L., Shulevski, A., Ter Veen, S., Fallows, R., Pizzo, R., Sipior, M., Anderson, J., Avruch, I., Bell, M., Van Bemmel, I., Bentum, M., Best, P., Bonafede, A., Breitling, F., Broderick, J., Brouw, W., Brüggen, M., Ciardi, B., Corstanje, A., De Gasperin, F., De Geus, E., Eislöffel, J., Engels, D., Falcke, H., Garrett, M., Grießmeier, J., Gunst, A., Van Haarlem, M., Heald, G., Hoeft, M., Hörandel, J., Horneffer, A., Intema, Hubertus, Juette, E., Kuniyoshi, M., Van Leeuwen, J., Loose, G., Maat, P., McFadden, R., McKay-Bukowski, D., McKean, J., Mulcahy, D., Munk, H., Pandey-Pommier, M., Polatidis, A., Reich, W., Röttgering, H., Rowlinson, A., Scaife, A., Schwarz, D., Steinmetz, M., Swinbank, J., Thoudam, S., Toribio, M., Vermeulen, R., Vocks, C., Van Weeren, R., Wise, M., Yatawatta, S., and Zarka, P.
Abstract: We outline the LOFAR Long-Baseline Calibrator Survey (LBCS), whose aim is to identify sources suitable for calibrating the highest-resolution observations made with the International LOFAR Telescope, which include baselines >1000 km. Suitable sources must contain significant correlated flux density (50 - 100 mJy) at frequencies around 110-190 MHz on scales of a few hundred milliarcseconds. At least for the 200-300-km international baselines, we find around 1 suitable calibrator source per square degree over a large part of the northern sky, in agreement with previous work. This should allow a randomly selected target to be successfully phase calibrated on the international baselines in over 50% of cases. Products of the survey include calibrator source lists and fringe-rate and delay maps of wide areas - typically a few degrees - around each source. The density of sources with significant correlated flux declines noticeably with baseline length over the range 200-600 km, with good calibrators on the longest baselines appearing only at the rate of 0.5 per sq. deg. Coherence times decrease from 1-3 min on 200-km baselines to about 1 min on 600-km baselines, suggesting that ionospheric phase variations contain components with scales of a few hundred kilometres. The longest median coherence time, at just over 3 min, is seen on the DE609 baseline, which at 227 km is close to being the shortest. We see median coherence times of between 80 and 110 s on the four longest baselines (580-600 km), and about 2 min for the other baselines. The success of phase transfer from calibrator to target is shown to be influenced by distance, in a manner that suggests a coherence patch at 150-MHz of the order of 1 deg. Although source structures cannot be measured in these observations, we deduce that phase transfer is affected if the calibrator source structure is not known. We give suggestions for calibration strategies and choice of calibrator sources, and describe the access to the
Published: 2016

15. LBCS: The LOFAR Long-Baseline Calibrator Survey

Author: Jackson, N., primary, Tagore, A., additional, Deller, A., additional, Moldón, J., additional, Varenius, E., additional, Morabito, L., additional, Wucknitz, O., additional, Carozzi, T., additional, Conway, J., additional, Drabent, A., additional, Kapinska, A., additional, Orrù, E., additional, Brentjens, M., additional, Blaauw, R., additional, Kuper, G., additional, Sluman, J., additional, Schaap, J., additional, Vermaas, N., additional, Iacobelli, M., additional, Cerrigone, L., additional, Shulevski, A., additional, ter Veen, S., additional, Fallows, R., additional, Pizzo, R., additional, Sipior, M., additional, Anderson, J., additional, Avruch, I. M., additional, Bell, M. E., additional, van Bemmel, I., additional, Bentum, M. J., additional, Best, P., additional, Bonafede, A., additional, Breitling, F., additional, Broderick, J. W., additional, Brouw, W. N., additional, Brüggen, M., additional, Ciardi, B., additional, Corstanje, A., additional, de Gasperin, F., additional, de Geus, E., additional, Eislöffel, J., additional, Engels, D., additional, Falcke, H., additional, Garrett, M. A., additional, Grießmeier, J. M., additional, Gunst, A. W., additional, van Haarlem, M. P., additional, Heald, G., additional, Hoeft, M., additional, Hörandel, J., additional, Horneffer, A., additional, Intema, H., additional, Juette, E., additional, Kuniyoshi, M., additional, van Leeuwen, J., additional, Loose, G. M., additional, Maat, P., additional, McFadden, R., additional, McKay-Bukowski, D., additional, McKean, J. P., additional, Mulcahy, D. D., additional, Munk, H., additional, Pandey-Pommier, M., additional, Polatidis, A. G., additional, Reich, W., additional, Röttgering, H. J. A., additional, Rowlinson, A., additional, Scaife, A. M. M., additional, Schwarz, D. J., additional, Steinmetz, M., additional, Swinbank, J., additional, Thoudam, S., additional, Toribio, M. C., additional, Vermeulen, R., additional, Vocks, C., additional, van Weeren, R. J., additional, Wise, M. W., additional, Yatawatta, S., additional, and Zarka, P., additional
Published: 2016
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16. Wide-band, low-frequency pulse profiles of 100 radio pulsars with LOFAR

Author: Pilia, M., primary, Hessels, J. W. T., additional, Stappers, B. W., additional, Kondratiev, V. I., additional, Kramer, M., additional, van Leeuwen, J., additional, Weltevrede, P., additional, Lyne, A. G., additional, Zagkouris, K., additional, Hassall, T. E., additional, Bilous, A. V., additional, Breton, R. P., additional, Falcke, H., additional, Grießmeier, J.-M., additional, Keane, E., additional, Karastergiou, A., additional, Kuniyoshi, M., additional, Noutsos, A., additional, Osłowski, S., additional, Serylak, M., additional, Sobey, C., additional, ter Veen, S., additional, Alexov, A., additional, Anderson, J., additional, Asgekar, A., additional, Avruch, I. M., additional, Bell, M. E., additional, Bentum, M. J., additional, Bernardi, G., additional, Bîrzan, L., additional, Bonafede, A., additional, Breitling, F., additional, Broderick, J. W., additional, Brüggen, M., additional, Ciardi, B., additional, Corbel, S., additional, de Geus, E., additional, de Jong, A., additional, Deller, A., additional, Duscha, S., additional, Eislöffel, J., additional, Fallows, R. A., additional, Fender, R., additional, Ferrari, C., additional, Frieswijk, W., additional, Garrett, M. A., additional, Gunst, A. W., additional, Hamaker, J. P., additional, Heald, G., additional, Horneffer, A., additional, Jonker, P., additional, Juette, E., additional, Kuper, G., additional, Maat, P., additional, Mann, G., additional, Markoff, S., additional, McFadden, R., additional, McKay-Bukowski, D., additional, Miller-Jones, J. C. A., additional, Nelles, A., additional, Paas, H., additional, Pandey-Pommier, M., additional, Pietka, M., additional, Pizzo, R., additional, Polatidis, A. G., additional, Reich, W., additional, Röttgering, H., additional, Rowlinson, A., additional, Schwarz, D., additional, Smirnov, O., additional, Steinmetz, M., additional, Stewart, A., additional, Swinbank, J. D., additional, Tagger, M., additional, Tang, Y., additional, Tasse, C., additional, Thoudam, S., additional, Toribio, M. C., additional, van der Horst, A. J., additional, Vermeulen, R., additional, Vocks, C., additional, van Weeren, R. J., additional, Wijers, R. A. M. J., additional, Wijnands, R., additional, Wijnholds, S. J., additional, Wucknitz, O., additional, and Zarka, P., additional
Published: 2016
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17. The peculiar radio galaxy 4C 35.06: A case for recurrent AGN activity?

Author: Shulevski, A., Morganti, R., Barthel, P., Murgia, M., Van Weeren, R., White, G., Brüggen, M., Kunert-Bajraszewska, M., Jamrozy, M., Best, P., Röttgering, H., Chyzy, K., De Gasperin, F., Bîrzan, L., Brunetti, G., Brienza, M., Rafferty, D., Anderson, J., Beck, R., Deller, A., Zarka, P., Schwarz, D., Mahony, E., Orru, E., Bell, M., Bentum, M., Bernardi, G., Bonafede, A., Breitling, F., Broderick, J., Butcher, H., Carbone, D., Ciardi, B., De Geus, E., Duscha, S., Eislöffel, J., Engels, D., Falcke, H., Fallows, R., Fender, R., Ferrari, C., Frieswijk, W., Garrett, M., Grießmeier, J., Gunst, A., Heald, G., Hoeft, M., Hörandel, J., Horneffer, A., Van Der Horst, A., Intema, Hubertus, Juette, E., Karastergiou, A., Kondratiev, V., Kramer, M., Kuniyoshi, M., Kuper, G., Maat, P., Mann, G., McFadden, R., McKay-Bukowski, D., McKean, J., Meulman, H., Mulcahy, D., Munk, H., Norden, M., Paas, H., Pandey-Pommier, M., Pizzo, R., Polatidis, A., Reich, W., Rowlinson, A., Scaife, A., Serylak, M., Sluman, J., Smirnov, O., Steinmetz, M., Swinbank, J., Tagger, M., Tang, Y., Tasse, C., Thoudam, S., Toribio, M., Shulevski, A., Morganti, R., Barthel, P., Murgia, M., Van Weeren, R., White, G., Brüggen, M., Kunert-Bajraszewska, M., Jamrozy, M., Best, P., Röttgering, H., Chyzy, K., De Gasperin, F., Bîrzan, L., Brunetti, G., Brienza, M., Rafferty, D., Anderson, J., Beck, R., Deller, A., Zarka, P., Schwarz, D., Mahony, E., Orru, E., Bell, M., Bentum, M., Bernardi, G., Bonafede, A., Breitling, F., Broderick, J., Butcher, H., Carbone, D., Ciardi, B., De Geus, E., Duscha, S., Eislöffel, J., Engels, D., Falcke, H., Fallows, R., Fender, R., Ferrari, C., Frieswijk, W., Garrett, M., Grießmeier, J., Gunst, A., Heald, G., Hoeft, M., Hörandel, J., Horneffer, A., Van Der Horst, A., Intema, Hubertus, Juette, E., Karastergiou, A., Kondratiev, V., Kramer, M., Kuniyoshi, M., Kuper, G., Maat, P., Mann, G., McFadden, R., McKay-Bukowski, D., McKean, J., Meulman, H., Mulcahy, D., Munk, H., Norden, M., Paas, H., Pandey-Pommier, M., Pizzo, R., Polatidis, A., Reich, W., Rowlinson, A., Scaife, A., Serylak, M., Sluman, J., Smirnov, O., Steinmetz, M., Swinbank, J., Tagger, M., Tang, Y., Tasse, C., Thoudam, S., and Toribio, M.
Abstract: Using observations obtained with the LOw Fequency ARray (LOFAR), the Westerbork Synthesis Radio Telescope (WSRT) and archival Very Large Array (VLA) data, we have traced the radio emission to large scales in the complex source 4C 35.06 located in the core of the galaxy cluster Abell 407. At higher spatial resolution (~ 4?), the source was known to have two inner radio lobes spanning 31 kpc and a diffuse, low-brightness extension running parallel to them, offset by about 11 kpc (in projection). At 62 MHz, we detect the radio emission of this structure extending out to 210 kpc. At 1.4 GHz and intermediate spatial resolution (~ 30?), the structure appears to have a helical morphology. We have derived the characteristics of the radio spectral index across the source. We show that the source morphology is most likely the result of at least two episodes of AGN activity separated by a dormant period of around 35 Myr. The outermost regions of radio emission have a steep spectral index (a<-1), indicative of old plasma. We connect the spectral index properties of the resolved source structure with the integrated fluxdensity spectral index of 4C 35.06 and suggest an explanation for its unusual integrated flux density spectral shape (a moderately steep power law with no discernible spectral break), possibly providing a proxy for future studies of more distant radio sources through inferring their detailed spectral index properties and activity history from their integrated spectral indices. The AGN is hosted by one of the galaxies located in the cluster core of Abell 407. We propose that it is intermittently active as it moves in the dense environment in the cluster core. In this scenario, the AGN turned on sometime in the past, and has produced the helical pattern of emission, possibly a sign of jet precession/merger during that episode of activity. Using LOFAR, we can trace the relic plasma from that episode of activity out to greater distances from the core than ever befo
Published: 2015

18. Studying Galactic interstellar turbulence through fluctuations in synchrotron emission

Author: Iacobelli, M., Haverkorn, M., Orrú, E., Pizzo, R. F., Anderson, J., Beck, R., Bell, M. R., Bonafede, A., Chyzy, K., Dettmar, R.-J., Enßlin, T. A., Heald, G., Horellou, C., Horneffer, A., Jurusik, W., Junklewitz, H., Kuniyoshi, M., Mulcahy, D. D., Paladino, R., Reich, W., Scaife, A., Sobey, C., Sotomayor-Beltran, C., Alexov, A., Asgekar, A., Avruch, I. M., Bell, M. E., van Bemmel, I., Bentum, M. J., Bernardi, G., Best, P., Bırzan, L., Breitling, F., Broderick, J., Brouw, W. N., Brüggen, M., Butcher, H. R., Ciardi, B., Conway, J. E., de Gasperin, F., de Geus, E., Duscha, S., Eislöffel, J., Engels, D., Falcke, H., Fallows, R. A., Ferrari, C., Frieswijk, W., Garrett, M. A., Grießmeier, J., Gunst, A. W., Hamaker, J. P., Hassall, T. E., Hessels, J. W. T., Hoeft, M., Hörandel, J., Jelic, V., Karastergiou, A., Kondratiev, V. I., Koopmans, L. V. E., Kramer, M., Kuper, G., van Leeuwen, J., Macario, G., Mann, G., McKean, J. P., Munk, H., Pandey-Pommier, M., Polatidis, A. G., Röttgering, H., Schwarz, Dominik, Sluman, J., Smirnov, O., Stappers, B. W., Steinmetz, M., Tagger, M., Tang, Y., Tasse, C., Toribio, C., Vermeulen, R., Vocks, C., Vogt, C., van Weeren, R. J., Wise, M. W., Wucknitz, O., Yatawatta, S., Zarka, P., Zensus, A., Leiden Observatory [Leiden], Universiteit Leiden, Netherlands Institute for Radio Astronomy (ASTRON), Radboud University [Nijmegen], Max-Planck-Institut für Radioastronomie (MPIFR), Max Planck Institute for Astrophysics, Max-Planck-Gesellschaft, Jacobs University [Bremen], Uniwersytet Jagielloński w Krakowie = Jagiellonian University (UJ), Astronomisches Institut der Ruhr-Universität Bochum, Ruhr-Universität Bochum [Bochum], Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), School of Physics and Astronomy [Southampton], University of Southampton, Sydney Institute for Astronomy (SIfA), The University of Sydney, SRON Netherlands Institute for Space Research (SRON), Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University-Smithsonian Institution, University of Edinburgh, Leibniz-Institut für Astrophysik Potsdam (AIP), Kapteyn Astronomical Institute [Groningen], University of Groningen [Groningen], Onsala Space Observatory (OSO), Chalmers University of Technology [Göteborg], Medstar Research Institute, Thüringer Landessternwarte Tautenburg (TLS), Hamburger Sternwarte/Hamburg Observatory, Universität Hamburg (UHH), Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Jodrell Bank Centre for Astrophysics, University of Manchester [Manchester], University of Amsterdam [Amsterdam] (UvA), Oxford Astrophysics, University of Oxford, Université de Nice Sophia-Antipolis (UNSA), Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Universität Bielefeld, Rhodes University, Grahamstown, SKA South Africa, Ska South Africa, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Astronomical Institute Anton Pannekoek (AI PANNEKOEK), Argelander-Institut für Astronomie (AlfA), Rheinische Friedrich-Wilhelms-Universität Bonn, Observatoire de Paris - Site de Paris (OP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), This work is part of the research programme 639.042.915, which is (partly) financed by the Netherlands Organisation for Scientific Research (NWO)., European Project: 239490,EC:FP7:PEOPLE,FP7-PEOPLE-IRG-2008,MAGNETIC_MILKYWAY(2009), Universiteit Leiden [Leiden], Radboud university [Nijmegen], Harvard University [Cambridge]-Smithsonian Institution, Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University of Oxford [Oxford], École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: Galaxy, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], astronomical techniques, synchrotron radiation, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Cosmology and Extragalactic Astrophysics, interstellar matter, cosmic ray propagation, [PHYS.PHYS.PHYS-SPACE-PH]Physics [physics]/Physics [physics]/Space Physics [physics.space-ph], Astrophysics::Galaxy Astrophysics
Abstract: International audience; Aims: The characteristic outer scale of turbulence (i.e. the scale at which the dominant source of turbulence injects energy to the interstellar medium) and the ratio of the random to ordered components of the magnetic field are key parameters to characterise magnetic turbulence in the interstellar gas, which affects the propagation of cosmic rays within the Galaxy. We provide new constraints to those two parameters.Methods: We use the LOw Frequency ARray (LOFAR) to image the diffuse continuum emission in the Fan region at (l,b) ~ (137.0°, +7.0°) at 80' × 70' resolution in the range [146, 174] MHz. We detect multi-scale fluctuations in the Galactic synchrotron emission and compute their power spectrum. Applying theoretical estimates and derivations from the literature for the first time, we derive the outer scale of turbulence and the ratio of random to ordered magnetic field from the characteristics of these fluctuations.Results: We obtain the deepest image of the Fan region to date and find diffuse continuum emission within the primary beam. The power spectrum displays a power law behaviour for scales between 100 and 8 arcmin with a slope α = -1.84 ± 0.19. We find an upper limit of ~20 pc for the outer scale of the magnetic interstellar turbulence toward the Fan region, which is in agreement with previous estimates in literature. We also find a variation of the ratio of random to ordered field as a function of Galactic coordinates, supporting different turbulent regimes.Conclusions. We present the first LOFAR detection and imaging of the Galactic diffuse synchrotron emission around 160 MHz from the highly polarized Fan region. The power spectrum of the foreground synchrotron fluctuations is approximately a power law with a slope α ≈ -1.84 up to angular multipoles of ≤1300, corresponding to an angular scale of ~8 arcmin. We use power spectra fluctuations from LOFAR as well as earlier GMRT and WSRT observations to constrain the outer scale of turbulence (Lout) of the Galactic synchrotron foreground, finding a range of plausible values of 10-20 pc. Then, we use this information to deduce lower limits of the ratio of ordered to random magnetic field strength. These are found to be 0.3, 0.3, and 0.5 for the LOFAR, WSRT and GMRT fields considered respectively. Both these constraints are in agreement with previous estimates.
Published: 2013

19. The LOFAR Multifrequency Snapshot Sky Survey (MSSS)

Author: Heald, G. H., primary, Pizzo, R. F., additional, Orrú, E., additional, Breton, R. P., additional, Carbone, D., additional, Ferrari, C., additional, Hardcastle, M. J., additional, Jurusik, W., additional, Macario, G., additional, Mulcahy, D., additional, Rafferty, D., additional, Asgekar, A., additional, Brentjens, M., additional, Fallows, R. A., additional, Frieswijk, W., additional, Toribio, M. C., additional, Adebahr, B., additional, Arts, M., additional, Bell, M. R., additional, Bonafede, A., additional, Bray, J., additional, Broderick, J., additional, Cantwell, T., additional, Carroll, P., additional, Cendes, Y., additional, Clarke, A. O., additional, Croston, J., additional, Daiboo, S., additional, de Gasperin, F., additional, Gregson, J., additional, Harwood, J., additional, Hassall, T., additional, Heesen, V., additional, Horneffer, A., additional, van der Horst, A. J., additional, Iacobelli, M., additional, Jelić, V., additional, Jones, D., additional, Kant, D., additional, Kokotanekov, G., additional, Martin, P., additional, McKean, J. P., additional, Morabito, L. K., additional, Nikiel-Wroczyński, B., additional, Offringa, A., additional, Pandey, V. N., additional, Pandey-Pommier, M., additional, Pietka, M., additional, Pratley, L., additional, Riseley, C., additional, Rowlinson, A., additional, Sabater, J., additional, Scaife, A. M. M., additional, Scheers, L. H. A., additional, Sendlinger, K., additional, Shulevski, A., additional, Sipior, M., additional, Sobey, C., additional, Stewart, A. J., additional, Stroe, A., additional, Swinbank, J., additional, Tasse, C., additional, Trüstedt, J., additional, Varenius, E., additional, van Velzen, S., additional, Vilchez, N., additional, van Weeren, R. J., additional, Wijnholds, S., additional, Williams, W. L., additional, de Bruyn, A. G., additional, Nijboer, R., additional, Wise, M., additional, Alexov, A., additional, Anderson, J., additional, Avruch, I. M., additional, Beck, R., additional, Bell, M. E., additional, van Bemmel, I., additional, Bentum, M. J., additional, Bernardi, G., additional, Best, P., additional, Breitling, F., additional, Brouw, W. N., additional, Brüggen, M., additional, Butcher, H. R., additional, Ciardi, B., additional, Conway, J. E., additional, de Geus, E., additional, de Jong, A., additional, de Vos, M., additional, Deller, A., additional, Dettmar, R.-J., additional, Duscha, S., additional, Eislöffel, J., additional, Engels, D., additional, Falcke, H., additional, Fender, R., additional, Garrett, M. A., additional, Grießmeier, J., additional, Gunst, A. W., additional, Hamaker, J. P., additional, Hessels, J. W. T., additional, Hoeft, M., additional, Hörandel, J., additional, Holties, H. A., additional, Intema, H., additional, Jackson, N. J., additional, Jütte, E., additional, Karastergiou, A., additional, Klijn, W. F. A., additional, Kondratiev, V. I., additional, Koopmans, L. V. E., additional, Kuniyoshi, M., additional, Kuper, G., additional, Law, C., additional, van Leeuwen, J., additional, Loose, M., additional, Maat, P., additional, Markoff, S., additional, McFadden, R., additional, McKay-Bukowski, D., additional, Mevius, M., additional, Miller-Jones, J. C. A., additional, Morganti, R., additional, Munk, H., additional, Nelles, A., additional, Noordam, J. E., additional, Norden, M. J., additional, Paas, H., additional, Polatidis, A. G., additional, Reich, W., additional, Renting, A., additional, Röttgering, H., additional, Schoenmakers, A., additional, Schwarz, D., additional, Sluman, J., additional, Smirnov, O., additional, Stappers, B. W., additional, Steinmetz, M., additional, Tagger, M., additional, Tang, Y., additional, ter Veen, S., additional, Thoudam, S., additional, Vermeulen, R., additional, Vocks, C., additional, Vogt, C., additional, Wijers, R. A. M. J., additional, Wucknitz, O., additional, Yatawatta, S., additional, and Zarka, P., additional
Published: 2015
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20. Calibrating high-precision Faraday rotation measurements for LOFAR and the next generation of low-frequency radio telescopes (Corrigendum)

Author: Sotomayor-Beltran, C., primary, Sobey, C., additional, Hessels, J. W. T., additional, de Bruyn, G., additional, Noutsos, A., additional, Alexov, A., additional, Anderson, J., additional, Asgekar, A., additional, Avruch, I. M., additional, Beck, R., additional, Bell, M. E., additional, Bell, M. R., additional, Bentum, M. J., additional, Bernardi, G., additional, Best, P., additional, Birzan, L., additional, Bonafede, A., additional, Breitling, F., additional, Broderick, J., additional, Brouw, W. N., additional, Brüggen, M., additional, Ciardi, B., additional, de Gasperin, F., additional, Dettmar, R.-J., additional, van Duin, A., additional, Duscha, S., additional, Eislöffel, J., additional, Falcke, H., additional, Fallows, R. A., additional, Fender, R., additional, Ferrari, C., additional, Frieswijk, W., additional, Garrett, M. A., additional, Grießmeier, J., additional, Grit, T., additional, Gunst, A. W., additional, Hassall, T. E., additional, Heald, G., additional, Hoeft, M., additional, Horneffer, A., additional, Iacobelli, M., additional, Juette, E., additional, Karastergiou, A., additional, Keane, E., additional, Kohler, J., additional, Kramer, M., additional, Kondratiev, V. I., additional, Koopmans, L. V. E., additional, Kuniyoshi, M., additional, Kuper, G., additional, van Leeuwen, J., additional, Maat, P., additional, Macario, G., additional, Markoff, S., additional, McKean, J. P., additional, Mulcahy, D. D., additional, Munk, H., additional, Orru, E., additional, Paas, H., additional, Pandey-Pommier, M., additional, Pilia, M., additional, Pizzo, R., additional, Polatidis, A. G., additional, Reich, W., additional, Röttgering, H., additional, Serylak, M., additional, Sluman, J., additional, Stappers, B. W., additional, Tagger, M., additional, Tang, Y., additional, Tasse, C., additional, ter Veen, S., additional, Vermeulen, R., additional, van Weeren, R. J., additional, Wijers, R. A. M. J., additional, Wijnholds, S. J., additional, Wise, M. W., additional, Wucknitz, O., additional, Yatawatta, S., additional, and Zarka, P., additional
Published: 2015
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21. The peculiar radio galaxy 4C 35.06: a case for recurrent AGN activity?

Author: Shulevski, A., primary, Morganti, R., additional, Barthel, P. D., additional, Murgia, M., additional, van Weeren, R. J., additional, White, G. J., additional, Brüggen, M., additional, Kunert-Bajraszewska, M., additional, Jamrozy, M., additional, Best, P. N., additional, Röttgering, H. J. A., additional, Chyzy, K. T., additional, de Gasperin, F., additional, Bîrzan, L., additional, Brunetti, G., additional, Brienza, M., additional, Rafferty, D. A., additional, Anderson, J., additional, Beck, R., additional, Deller, A., additional, Zarka, P., additional, Schwarz, D., additional, Mahony, E., additional, Orrú, E., additional, Bell, M. E., additional, Bentum, M. J., additional, Bernardi, G., additional, Bonafede, A., additional, Breitling, F., additional, Broderick, J. W., additional, Butcher, H. R., additional, Carbone, D., additional, Ciardi, B., additional, de Geus, E., additional, Duscha, S., additional, Eislöffel, J., additional, Engels, D., additional, Falcke, H., additional, Fallows, R. A., additional, Fender, R., additional, Ferrari, C., additional, Frieswijk, W., additional, Garrett, M. A., additional, Grießmeier, J., additional, Gunst, A. W., additional, Heald, G., additional, Hoeft, M., additional, Hörandel, J., additional, Horneffer, A., additional, van der Horst, A. J., additional, Intema, H., additional, Juette, E., additional, Karastergiou, A., additional, Kondratiev, V. I., additional, Kramer, M., additional, Kuniyoshi, M., additional, Kuper, G., additional, Maat, P., additional, Mann, G., additional, McFadden, R., additional, McKay-Bukowski, D., additional, McKean, J. P., additional, Meulman, H., additional, Mulcahy, D. D., additional, Munk, H., additional, Norden, M. J., additional, Paas, H., additional, Pandey-Pommier, M., additional, Pizzo, R., additional, Polatidis, A. G., additional, Reich, W., additional, Rowlinson, A., additional, Scaife, A. M. M., additional, Serylak, M., additional, Sluman, J., additional, Smirnov, O., additional, Steinmetz, M., additional, Swinbank, J., additional, Tagger, M., additional, Tang, Y., additional, Tasse, C., additional, Thoudam, S., additional, Toribio, M. C., additional, Vermeulen, R., additional, Vocks, C., additional, Wijers, R. A. M. J., additional, Wise, M. W., additional, and Wucknitz, O., additional
Published: 2015
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22. The nature of the low-frequency emission of M 51

Author: Mulcahy, D. D., primary, Horneffer, A., additional, Beck, R., additional, Heald, G., additional, Fletcher, A., additional, Scaife, A., additional, Adebahr, B., additional, Anderson, J. M., additional, Bonafede, A., additional, Brüggen, M., additional, Brunetti, G., additional, Chyży, K. T., additional, Conway, J., additional, Dettmar, R.-J., additional, Enßlin, T., additional, Haverkorn, M., additional, Horellou, C., additional, Iacobelli, M., additional, Israel, F. P., additional, Junklewitz, H., additional, Jurusik, W., additional, Köhler, J., additional, Kuniyoshi, M., additional, Orrú, E., additional, Paladino, R., additional, Pizzo, R., additional, Reich, W., additional, and Röttgering, H. J. A., additional
Published: 2014
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23. LOFAR tied-array imaging of Type III solar radio bursts

Author: Morosan, D. E., primary, Gallagher, P. T., additional, Zucca, P., additional, Fallows, R., additional, Carley, E. P., additional, Mann, G., additional, Bisi, M. M., additional, Kerdraon, A., additional, Konovalenko, A. A., additional, MacKinnon, A. L., additional, Rucker, H. O., additional, Thidé, B., additional, Magdalenić, J., additional, Vocks, C., additional, Reid, H., additional, Anderson, J., additional, Asgekar, A., additional, Avruch, I. M., additional, Bentum, M. J., additional, Bernardi, G., additional, Best, P., additional, Bonafede, A., additional, Bregman, J., additional, Breitling, F., additional, Broderick, J., additional, Brüggen, M., additional, Butcher, H. R., additional, Ciardi, B., additional, Conway, J. E., additional, de Gasperin, F., additional, de Geus, E., additional, Deller, A., additional, Duscha, S., additional, Eislöffel, J., additional, Engels, D., additional, Falcke, H., additional, Ferrari, C., additional, Frieswijk, W., additional, Garrett, M. A., additional, Grießmeier, J., additional, Gunst, A. W., additional, Hassall, T. E., additional, Hessels, J. W. T., additional, Hoeft, M., additional, Hörandel, J., additional, Horneffer, A., additional, Iacobelli, M., additional, Juette, E., additional, Karastergiou, A., additional, Kondratiev, V. I., additional, Kramer, M., additional, Kuniyoshi, M., additional, Kuper, G., additional, Maat, P., additional, Markoff, S., additional, McKean, J. P., additional, Mulcahy, D. D., additional, Munk, H., additional, Nelles, A., additional, Norden, M. J., additional, Orru, E., additional, Paas, H., additional, Pandey-Pommier, M., additional, Pandey, V. N., additional, Pietka, G., additional, Pizzo, R., additional, Polatidis, A. G., additional, Reich, W., additional, Röttgering, H., additional, Scaife, A. M. M., additional, Schwarz, D., additional, Serylak, M., additional, Smirnov, O., additional, Stappers, B. W., additional, Stewart, A., additional, Tagger, M., additional, Tang, Y., additional, Tasse, C., additional, Thoudam, S., additional, Toribio, C., additional, Vermeulen, R., additional, van Weeren, R. J., additional, Wucknitz, O., additional, Yatawatta, S., additional, and Zarka, P., additional
Published: 2014
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24. Initial LOFAR observations of epoch of reionization windows

Author: Jelić, V., primary, de Bruyn, A. G., additional, Mevius, M., additional, Abdalla, F. B., additional, Asad, K. M. B., additional, Bernardi, G., additional, Brentjens, M. A., additional, Bus, S., additional, Chapman, E., additional, Ciardi, B., additional, Daiboo, S., additional, Fernandez, E. R., additional, Ghosh, A., additional, Harker, G., additional, Jensen, H., additional, Kazemi, S., additional, Koopmans, L. V. E., additional, Labropoulos, P., additional, Martinez-Rubi, O., additional, Mellema, G., additional, Offringa, A. R., additional, Pandey, V. N., additional, Patil, A. H., additional, Thomas, R. M., additional, Vedantham, H. K., additional, Veligatla, V., additional, Yatawatta, S., additional, Zaroubi, S., additional, Alexov, A., additional, Anderson, J., additional, Avruch, I. M., additional, Beck, R., additional, Bell, M. E., additional, Bentum, M. J., additional, Best, P., additional, Bonafede, A., additional, Bregman, J., additional, Breitling, F., additional, Broderick, J., additional, Brouw, W. N., additional, Brüggen, M., additional, Butcher, H. R., additional, Conway, J. E., additional, de Gasperin, F., additional, de Geus, E., additional, Deller, A., additional, Dettmar, R.-J., additional, Duscha, S., additional, Eislöffel, J., additional, Engels, D., additional, Falcke, H., additional, Fallows, R. A., additional, Fender, R., additional, Ferrari, C., additional, Frieswijk, W., additional, Garrett, M. A., additional, Grießmeier, J., additional, Gunst, A. W., additional, Hamaker, J. P., additional, Hassall, T. E., additional, Haverkorn, M., additional, Heald, G., additional, Hessels, J. W. T., additional, Hoeft, M., additional, Hörandel, J., additional, Horneffer, A., additional, van der Horst, A., additional, Iacobelli, M., additional, Juette, E., additional, Karastergiou, A., additional, Kondratiev, V. I., additional, Kramer, M., additional, Kuniyoshi, M., additional, Kuper, G., additional, van Leeuwen, J., additional, Maat, P., additional, Mann, G., additional, McKay-Bukowski, D., additional, McKean, J. P., additional, Munk, H., additional, Nelles, A., additional, Norden, M. J., additional, Paas, H., additional, Pandey-Pommier, M., additional, Pietka, G., additional, Pizzo, R., additional, Polatidis, A. G., additional, Reich, W., additional, Röttgering, H., additional, Rowlinson, A., additional, Scaife, A. M. M., additional, Schwarz, D., additional, Serylak, M., additional, Smirnov, O., additional, Steinmetz, M., additional, Stewart, A., additional, Tagger, M., additional, Tang, Y., additional, Tasse, C., additional, ter Veen, S., additional, Thoudam, S., additional, Toribio, C., additional, Vermeulen, R., additional, Vocks, C., additional, van Weeren, R. J., additional, Wijers, R. A. M. J., additional, Wijnholds, S. J., additional, Wucknitz, O., additional, and Zarka, P., additional
Published: 2014
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25. Calibrating high-precision Faraday rotation measurements for LOFAR and the next generation of low-frequency radio telescopes

Author: Sotomayor-Beltran, C., Sobey, Charlotte, Hessels, J., De Bruyn, G., Noutsos, A., Alexov, A., Anderson, J., Asgekar, A., Avruch, I., Beck, R., Bell, M., Bentum, M., Bernardi, G., Best, P., Birzan, L., Bonafede, A., Breitling, F., Broderick, J., Brouw, W., Brüggen, M., Ciardi, B., De Gasperin, F., Dettmar, R., Van Duin, A., Duscha, S., Eislöffel, J., Falcke, H., Fallows, R., Fender, R., Ferrari, C., Frieswijk, W., Garrett, M., Grießmeier, J., Grit, T., Gunst, A., Hassall, T., Heald, G., Hoeft, M., Horneffer, A., Iacobelli, M., Juette, E., Karastergiou, A., Keane, E., Kohler, J., Kramer, M., Kondratiev, V., Koopmans, L., Kuniyoshi, M., Kuper, G., Van Leeuwen, J., Maat, P., MacArio, G., Markoff, S., McKean, J., Mulcahy, D., Munk, H., Orru, E., Paas, H., Pandey-Pommier, M., Pilia, M., Pizzo, R., Polatidis, A., Reich, W., Röttgering, H., Serylak, M., Sluman, J., Stappers, B., Tagger, M., Tang, Y., Tasse, C., Ter Veen, S., Vermeulen, R., Van Weeren, R., Wijers, R., Wijnholds, S., Wise, M., Wucknitz, O., Sotomayor-Beltran, C., Sobey, Charlotte, Hessels, J., De Bruyn, G., Noutsos, A., Alexov, A., Anderson, J., Asgekar, A., Avruch, I., Beck, R., Bell, M., Bentum, M., Bernardi, G., Best, P., Birzan, L., Bonafede, A., Breitling, F., Broderick, J., Brouw, W., Brüggen, M., Ciardi, B., De Gasperin, F., Dettmar, R., Van Duin, A., Duscha, S., Eislöffel, J., Falcke, H., Fallows, R., Fender, R., Ferrari, C., Frieswijk, W., Garrett, M., Grießmeier, J., Grit, T., Gunst, A., Hassall, T., Heald, G., Hoeft, M., Horneffer, A., Iacobelli, M., Juette, E., Karastergiou, A., Keane, E., Kohler, J., Kramer, M., Kondratiev, V., Koopmans, L., Kuniyoshi, M., Kuper, G., Van Leeuwen, J., Maat, P., MacArio, G., Markoff, S., McKean, J., Mulcahy, D., Munk, H., Orru, E., Paas, H., Pandey-Pommier, M., Pilia, M., Pizzo, R., Polatidis, A., Reich, W., Röttgering, H., Serylak, M., Sluman, J., Stappers, B., Tagger, M., Tang, Y., Tasse, C., Ter Veen, S., Vermeulen, R., Van Weeren, R., Wijers, R., Wijnholds, S., Wise, M., and Wucknitz, O.
Abstract: Faraday rotation measurements using the current and next generation of low-frequency radio telescopes will provide a powerful probe of astronomical magnetic fields. However, achieving the full potential of these measurements requires accurate removal of the time-variable ionospheric Faraday rotation contribution. We present ionFR, a code that calculates the amount of ionospheric Faraday rotation for a specific epoch, geographic location, and line-of-sight. ionFR uses a number of publicly available, GPS-derived total electron content maps and the most recent release of the International Geomagnetic Reference Field. We describe applications of this code for the calibration of radio polarimetric observations, and demonstrate the high accuracy of its modeled ionospheric Faraday rotations using LOFAR pulsar observations. These show that we can accurately determine some of the highest-precision pulsar rotation measures ever achieved. Precision rotation measures can be used to monitor rotation measure variations-either intrinsic or due to the changing line-of-sight through the interstellar medium. This calibration is particularly important for nearby sources, where the ionosphere can contribute a significant fraction of the observed rotation measure. We also discuss planned improvements to ionFR, as well as the importance of ionospheric Faraday rotation calibration for the emerging generation of low-frequency radio telescopes, such as the SKA and its pathfinders. © 2013 ESO.
Published: 2013

26. Studying Galactic interstellar turbulence through fluctuations in synchrotron emission: First LOFAR Galactic foreground detection

Author: Iacobelli, M., Haverkorn, M., Orrú, E., Pizzo, R., Anderson, J., Beck, R., Bell, M., Bonafede, A., Chyzy, K., Dettmar, R., Enßlin, T., Heald, G., Horellou, C., Horneffer, A., Jurusik, W., Junklewitz, H., Kuniyoshi, M., Mulcahy, D., Paladino, R., Reich, W., Scaife, A., Sobey, Charlotte, Sotomayor-Beltran, C., Alexov, A., Asgekar, A., Avruch, I., Van Bemmel, I., Bentum, M., Bernardi, G., Best, P., Birzan, L., Breitling, F., Broderick, J., Brouw, W., Brüggen, M., Butcher, H., Ciardi, B., Conway, J., De Gasperin, F., De Geus, E., Duscha, S., Eislöffel, J., Engels, D., Falcke, H., Fallows, R., Ferrari, C., Frieswijk, W., Garrett, M., Grießmeier, J., Gunst, A., Hamaker, J., Hassall, T., Hessels, J., Hoeft, M., Hörandel, J., Jelic, V., Karastergiou, A., Kondratiev, V., Koopmans, L., Kramer, M., Kuper, G., Van Leeuwen, J., MacArio, G., Mann, G., McKean, J., Munk, H., Pandey-Pommier, M., Polatidis, A., Röttgering, H., Schwarz, D., Sluman, J., Smirnov, O., Stappers, B., Steinmetz, M., Tagger, M., Tang, Y., Tasse, C., Toribio, C., Vermeulen, R., Vocks, C., Vogt, C., Van Weeren, R., Wise, M., Wucknitz, O., Yatawatta, S., Zarka, P., Zensus, A., Iacobelli, M., Haverkorn, M., Orrú, E., Pizzo, R., Anderson, J., Beck, R., Bell, M., Bonafede, A., Chyzy, K., Dettmar, R., Enßlin, T., Heald, G., Horellou, C., Horneffer, A., Jurusik, W., Junklewitz, H., Kuniyoshi, M., Mulcahy, D., Paladino, R., Reich, W., Scaife, A., Sobey, Charlotte, Sotomayor-Beltran, C., Alexov, A., Asgekar, A., Avruch, I., Van Bemmel, I., Bentum, M., Bernardi, G., Best, P., Birzan, L., Breitling, F., Broderick, J., Brouw, W., Brüggen, M., Butcher, H., Ciardi, B., Conway, J., De Gasperin, F., De Geus, E., Duscha, S., Eislöffel, J., Engels, D., Falcke, H., Fallows, R., Ferrari, C., Frieswijk, W., Garrett, M., Grießmeier, J., Gunst, A., Hamaker, J., Hassall, T., Hessels, J., Hoeft, M., Hörandel, J., Jelic, V., Karastergiou, A., Kondratiev, V., Koopmans, L., Kramer, M., Kuper, G., Van Leeuwen, J., MacArio, G., Mann, G., McKean, J., Munk, H., Pandey-Pommier, M., Polatidis, A., Röttgering, H., Schwarz, D., Sluman, J., Smirnov, O., Stappers, B., Steinmetz, M., Tagger, M., Tang, Y., Tasse, C., Toribio, C., Vermeulen, R., Vocks, C., Vogt, C., Van Weeren, R., Wise, M., Wucknitz, O., Yatawatta, S., Zarka, P., and Zensus, A.
Abstract: Aims. The characteristic outer scale of turbulence (i.e. the scale at which the dominant source of turbulence injects energy to the interstellar medium) and the ratio of the random to ordered components of the magnetic field are key parameters to characterise magnetic turbulence in the interstellar gas, which affects the propagation of cosmic rays within the Galaxy. We provide new constraints to those two parameters. Methods. We use the LOw Frequency ARray (LOFAR) to image the diffuse continuum emission in the Fan region at (l,b) ~ (137.0, +7.0) at 80'' × 70'' resolution in the range [146, 174] MHz. We detect multi-scale fluctuations in the Galactic synchrotron emission and compute their power spectrum. Applying theoretical estimates and derivations from the literature for the first time, we derive the outer scale of turbulence and the ratio of random to ordered magnetic field from the characteristics of these fluctuations. Results. We obtain the deepest image of the Fan region to date and find diffuse continuum emission within the primary beam. The power spectrum displays a power law behaviour for scales between 100 and 8 arcmin with a slope a =-1.84 ± 0.19. We find an upper limit of ~20 pc for the outer scale of the magnetic interstellar turbulence toward the Fan region, which is in agreement with previous estimates in literature. We also find a variation of the ratio of random to ordered field as a function of Galactic coordinates, supporting different turbulent regimes. Conclusions. We present the first LOFAR detection and imaging of the Galactic diffuse synchrotron emission around 160 MHz from the highly polarized Fan region. The power spectrum of the foreground synchrotron fluctuations is approximately a power law with a slope a ˜-1.84 up to angular multipoles of =1300, corresponding to an angular scale of ~8 arcmin. We use power spectra fluctuations from LOFAR as well as earlier GMRT and WSRT observations to constrain the outer scale of turbulence (Lout) of t
Published: 2013

27. Detecting cosmic rays with the LOFAR radio telescope

Author: Schellart, P., Nelles, A., Buitink, S., Corstanje, A., Enriquez, J., Falcke, H., Frieswijk, W., Horandel, J., Horneffer, A., James, C., Krause, M., Mevius, M., Scholten, O., ter Veen, S., Thoudam, S., Van den Akker, M., Alexov, A., Anderson, J., Avruch, I., Bahren, L., Beck, R., Bell, M., Bennema, P., Bentum, M., BERNARDI, G., Best, P., Bregman, J., Breitling, F., Brentjens, M., Broderick, J., Bruggen, M., Ciardi, B., Coolen, A., de Gasperin, F., de Geus, E., de Jong, A., de Vos, M., Duscha, S., Eisloffel, J., Fallows, R., Ferrari, C., Garrett, M., Grießmeier, J., Grit, T., Hamaker, J., Hassall, T., Heald, G., Hessels, J., Hoeft, M., Holties, H., Iacobelli, M., Juette, E., Karastergiou, A., Klijn, W., Kohler, J., Kondratiev, V., Kramer, M., Kuniyoshi, M., Kuper, G., Maat, P., Macario, G., Mann, G., Markoff, S., McKay-Bukowski, D., McKean, J., Miller-Jones, James, Mol, J., Mulcahy, D., Munk, H., Nijboer, R., Norden, M., Orru, E., Overeem, R., Paas, H., Pandey-Pommier, M., Pizzo, R., Polatidis, A., Renting, G., Romein, J., Rottgering, H., Schoenmakers, A., Schwarz, D., Sluman, J., Smirnov, O., Sobey, C., Stappers, B., Steinmetz, M., Swinbank, J., Tang, Y., Tasse, C., Toribio, M., van Leeuwen, J., Wijnholds, S., Wise, M., Wucknitz, O., Yatawatta, S., Zarka, P., Zensus, J., Schellart, P., Nelles, A., Buitink, S., Corstanje, A., Enriquez, J., Falcke, H., Frieswijk, W., Horandel, J., Horneffer, A., James, C., Krause, M., Mevius, M., Scholten, O., ter Veen, S., Thoudam, S., Van den Akker, M., Alexov, A., Anderson, J., Avruch, I., Bahren, L., Beck, R., Bell, M., Bennema, P., Bentum, M., BERNARDI, G., Best, P., Bregman, J., Breitling, F., Brentjens, M., Broderick, J., Bruggen, M., Ciardi, B., Coolen, A., de Gasperin, F., de Geus, E., de Jong, A., de Vos, M., Duscha, S., Eisloffel, J., Fallows, R., Ferrari, C., Garrett, M., Grießmeier, J., Grit, T., Hamaker, J., Hassall, T., Heald, G., Hessels, J., Hoeft, M., Holties, H., Iacobelli, M., Juette, E., Karastergiou, A., Klijn, W., Kohler, J., Kondratiev, V., Kramer, M., Kuniyoshi, M., Kuper, G., Maat, P., Macario, G., Mann, G., Markoff, S., McKay-Bukowski, D., McKean, J., Miller-Jones, James, Mol, J., Mulcahy, D., Munk, H., Nijboer, R., Norden, M., Orru, E., Overeem, R., Paas, H., Pandey-Pommier, M., Pizzo, R., Polatidis, A., Renting, G., Romein, J., Rottgering, H., Schoenmakers, A., Schwarz, D., Sluman, J., Smirnov, O., Sobey, C., Stappers, B., Steinmetz, M., Swinbank, J., Tang, Y., Tasse, C., Toribio, M., van Leeuwen, J., Wijnholds, S., Wise, M., Wucknitz, O., Yatawatta, S., Zarka, P., and Zensus, J.
Abstract: The low frequency array (LOFAR), is the first radio telescope designed with the capability to measure radio emission from cosmic-ray induced air showers in parallel with interferometric observations. In the first 2 years of observing, 405 cosmic-ray events in the energy range of 1016??1018 eV have been detected in the band from 30??80 MHz. Each of these air showers is registered with up to 1000 independent antennas resulting in measurements of the radio emission with unprecedented detail. This article describes the dataset, as well as the analysis pipeline, and serves as a reference for future papers based on these data. All steps necessary to achieve a full reconstruction of the electric field at every antenna position are explained, including removal of radio frequency interference, correcting for the antenna response and identification of the pulsed signal.
Published: 2013

28. Detecting cosmic rays with the LOFAR radio telescope

Author: Schellart, P., primary, Nelles, A., additional, Buitink, S., additional, Corstanje, A., additional, Enriquez, J. E., additional, Falcke, H., additional, Frieswijk, W., additional, Hörandel, J. R., additional, Horneffer, A., additional, James, C. W., additional, Krause, M., additional, Mevius, M., additional, Scholten, O., additional, ter Veen, S., additional, Thoudam, S., additional, van den Akker, M., additional, Alexov, A., additional, Anderson, J., additional, Avruch, I. M., additional, Bähren, L., additional, Beck, R., additional, Bell, M. E., additional, Bennema, P., additional, Bentum, M. J., additional, Bernardi, G., additional, Best, P., additional, Bregman, J., additional, Breitling, F., additional, Brentjens, M., additional, Broderick, J., additional, Brüggen, M., additional, Ciardi, B., additional, Coolen, A., additional, de Gasperin, F., additional, de Geus, E., additional, de Jong, A., additional, de Vos, M., additional, Duscha, S., additional, Eislöffel, J., additional, Fallows, R. A., additional, Ferrari, C., additional, Garrett, M. A., additional, Grießmeier, J., additional, Grit, T., additional, Hamaker, J. P., additional, Hassall, T. E., additional, Heald, G., additional, Hessels, J. W. T., additional, Hoeft, M., additional, Holties, H. A., additional, Iacobelli, M., additional, Juette, E., additional, Karastergiou, A., additional, Klijn, W., additional, Kohler, J., additional, Kondratiev, V. I., additional, Kramer, M., additional, Kuniyoshi, M., additional, Kuper, G., additional, Maat, P., additional, Macario, G., additional, Mann, G., additional, Markoff, S., additional, McKay-Bukowski, D., additional, McKean, J. P., additional, Miller-Jones, J. C. A., additional, Mol, J. D., additional, Mulcahy, D. D., additional, Munk, H., additional, Nijboer, R., additional, Norden, M. J., additional, Orru, E., additional, Overeem, R., additional, Paas, H., additional, Pandey-Pommier, M., additional, Pizzo, R., additional, Polatidis, A. G., additional, Renting, A., additional, Romein, J. W., additional, Röttgering, H., additional, Schoenmakers, A., additional, Schwarz, D., additional, Sluman, J., additional, Smirnov, O., additional, Sobey, C., additional, Stappers, B. W., additional, Steinmetz, M., additional, Swinbank, J., additional, Tang, Y., additional, Tasse, C., additional, Toribio, C., additional, van Leeuwen, J., additional, van Nieuwpoort, R., additional, van Weeren, R. J., additional, Vermaas, N., additional, Vermeulen, R., additional, Vocks, C., additional, Vogt, C., additional, Wijers, R. A. M. J., additional, Wijnholds, S. J., additional, Wise, M. W., additional, Wucknitz, O., additional, Yatawatta, S., additional, Zarka, P., additional, and Zensus, A., additional
Published: 2013
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29. M 87 at metre wavelengths: The LOFAR picture

Author: De Gasperin, F., Orrú, E., Murgia, M., Merloni, A., Falcke, H., Beck, R., Beswick, R., Bîrzan, L., Bonafede, A., Brüggen, M., Brunetti, G., Chyz°y, K., Conway, J., Croston, J., Enßlin, T., Ferrari, C., Heald, G., Heidenreich, S., Jackson, N., MacArio, G., McKean, J., Miley, G., Morganti, R., Offringa, A., Pizzo, R., Rafferty, D., Röttgering, H., Shulevski, A., Steinmetz, M., Tasse, C., Van Der Tol, S., Van Driel, W., Van Weeren, R., Van Zwieten, J., Alexov, A., Anderson, J., Asgekar, A., Avruch, M., Bell, M., Bentum, M., Bernardi, G., Best, P., Breitling, F., Broderick, J., Butcher, A., Ciardi, B., Dettmar, R., Eisloeffel, J., Frieswijk, W., Gankema, H., Garrett, M., Gerbers, M., Griessmeier, J., Gunst, A., Hassall, T., Hessels, J., Hoeft, M., Horneffer, A., Karastergiou, A., Köhler, J., Koopman, Y., Kuniyoshi, M., Kuper, G., Maat, P., Mann, G., Mevius, M., Mulcahy, D., Munk, H., Nijboer, R., Noordam, J., Paas, H., Pandey, M., Pandey, V., Polatidis, A., Reich, W., Schoenmakers, A., Sluman, J., Smirnov, O., Sobey, Charlotte, Stappers, B., Swinbank, J., De Gasperin, F., Orrú, E., Murgia, M., Merloni, A., Falcke, H., Beck, R., Beswick, R., Bîrzan, L., Bonafede, A., Brüggen, M., Brunetti, G., Chyz°y, K., Conway, J., Croston, J., Enßlin, T., Ferrari, C., Heald, G., Heidenreich, S., Jackson, N., MacArio, G., McKean, J., Miley, G., Morganti, R., Offringa, A., Pizzo, R., Rafferty, D., Röttgering, H., Shulevski, A., Steinmetz, M., Tasse, C., Van Der Tol, S., Van Driel, W., Van Weeren, R., Van Zwieten, J., Alexov, A., Anderson, J., Asgekar, A., Avruch, M., Bell, M., Bentum, M., Bernardi, G., Best, P., Breitling, F., Broderick, J., Butcher, A., Ciardi, B., Dettmar, R., Eisloeffel, J., Frieswijk, W., Gankema, H., Garrett, M., Gerbers, M., Griessmeier, J., Gunst, A., Hassall, T., Hessels, J., Hoeft, M., Horneffer, A., Karastergiou, A., Köhler, J., Koopman, Y., Kuniyoshi, M., Kuper, G., Maat, P., Mann, G., Mevius, M., Mulcahy, D., Munk, H., Nijboer, R., Noordam, J., Paas, H., Pandey, M., Pandey, V., Polatidis, A., Reich, W., Schoenmakers, A., Sluman, J., Smirnov, O., Sobey, Charlotte, Stappers, B., and Swinbank, J.
Abstract: Context.M 87 is a giant elliptical galaxy located in the centre of the Virgo cluster, which harbours a supermassive black hole of mass 6.4 × 109 M·, whose activity is responsible for the extended (80 kpc) radio lobes that surround the galaxy. The energy generated by matter falling onto the central black hole is ejected and transferred to the intra-cluster medium via a relativistic jet and morphologically complex systems of buoyant bubbles, which rise towards the edges of the extended halo. Aims. To place constraints on past activity cycles of the active nucleus, images of M 87 were produced at low radio frequencies never explored before at these high spatial resolution and dynamic range. To disentangle different synchrotron models and place constraints on source magnetic field, age and energetics, we also performed a detailed spectral analysis of M 87 extended radio-halo. Methods. We present the first observations made with the new Low-Frequency Array (LOFAR) of M 87 at frequencies down to 20 MHz. Three observations were conducted, at 15-30 MHz, 30-77 MHz and 116-162 MHz. We used these observations together with archival data to produce a low-frequency spectral index map and to perform a spectral analysis in the wide frequency range 30 MHz-10 GHz. Results. We do not find any sign of new extended emissions; on the contrary the source appears well confined by the high pressure of the intra-cluster medium. A continuous injection of relativistic electrons is the model that best fits our data, and provides a scenario in which the lobes are still supplied by fresh relativistic particles from the active galactic nuclei. We suggest that the discrepancy between the low-frequency radio-spectral slope in the core and in the halo implies a strong adiabatic expansion of the plasma as soon as it leaves the core area. The extended halo has an equipartition magnetic field strength of ? 10 µG, which increases to ? 13 µG in the zones where the particle flows are more active. The cont
Published: 2012

30. The LOFAR radio environment

Author: Offringa, A., De Bruyn, A., Zaroubi, S., Van Diepen, G., Martinez-Ruby, O., Labropoulos, P., Brentjens, M., Ciardi, B., Daiboo, S., Harker, G., Jelic, V., Kazemi, S., Koopmans, L., Mellema, G., Pandey, V., Pizzo, R., Schaye, J., Vedantham, H., Veligatla, V., Wijnholds, S., Yatawatta, S., Zarka, P., Alexov, A., Anderson, J., Asgekar, A., Avruch, M., Beck, R., Bell, M., Bentum, M., Bernardi, G., Best, P., Birzan, L., Bonafede, A., Breitling, F., Broderick, J., Brüggen, M., Butcher, H., Conway, J., De Vos, M., Dettmar, R., Eisloeffel, J., Falcke, H., Fender, R., Frieswijk, W., Gerbers, M., Griessmeier, J., Gunst, A., Hassall, T., Heald, G., Hessels, J., Hoeft, M., Horneffer, A., Karastergiou, A., Kondratiev, V., Koopman, Y., Kuniyoshi, M., Kuper, G., Maat, P., Mann, G., McKean, J., Meulman, H., Mevius, M., Mol, J., Nijboer, R., Noordam, J., Norden, M., Paas, H., Pandey, M., Polatidis, A., Rafferty, D., Rawlings, S., Reich, W., Röttgering, H., Schoenmakers, A., Sluman, J., Smirnov, O., Sobey, Charlotte, Stappers, B., Steinmetz, M., Swinbank, J., Tagger, M., Tang, Y., Tasse, C., Van Ardenne, A., Van Cappellen, W., Van Duin, A., Offringa, A., De Bruyn, A., Zaroubi, S., Van Diepen, G., Martinez-Ruby, O., Labropoulos, P., Brentjens, M., Ciardi, B., Daiboo, S., Harker, G., Jelic, V., Kazemi, S., Koopmans, L., Mellema, G., Pandey, V., Pizzo, R., Schaye, J., Vedantham, H., Veligatla, V., Wijnholds, S., Yatawatta, S., Zarka, P., Alexov, A., Anderson, J., Asgekar, A., Avruch, M., Beck, R., Bell, M., Bentum, M., Bernardi, G., Best, P., Birzan, L., Bonafede, A., Breitling, F., Broderick, J., Brüggen, M., Butcher, H., Conway, J., De Vos, M., Dettmar, R., Eisloeffel, J., Falcke, H., Fender, R., Frieswijk, W., Gerbers, M., Griessmeier, J., Gunst, A., Hassall, T., Heald, G., Hessels, J., Hoeft, M., Horneffer, A., Karastergiou, A., Kondratiev, V., Koopman, Y., Kuniyoshi, M., Kuper, G., Maat, P., Mann, G., McKean, J., Meulman, H., Mevius, M., Mol, J., Nijboer, R., Noordam, J., Norden, M., Paas, H., Pandey, M., Polatidis, A., Rafferty, D., Rawlings, S., Reich, W., Röttgering, H., Schoenmakers, A., Sluman, J., Smirnov, O., Sobey, Charlotte, Stappers, B., Steinmetz, M., Swinbank, J., Tagger, M., Tang, Y., Tasse, C., Van Ardenne, A., Van Cappellen, W., and Van Duin, A.
Abstract: Aims. This paper discusses the spectral occupancy for performing radio astronomy with the Low-Frequency Array (LOFAR), with a focus on imaging observations. Methods. We have analysed the radio-frequency interference (RFI) situation in two 24-h surveys with Dutch LOFAR stations, covering 30-78 MHz with low-band antennas and 115-163 MHz with high-band antennas. This is a subset of the full frequency range of LOFAR. The surveys have been observed with a 0.76 kHz/1 s resolution. Results. We measured the RFI occupancy in the low and high frequency sets to be 1.8% and 3.2% respectively. These values are found to be representative values for the LOFAR radio environment. Between day and night, there is no significant difference in the radio environment. We find that lowering the current observational time and frequency resolutions of LOFAR results in a slight loss of flagging accuracy. At LOFAR's nominal resolution of 0.76 kHz and 1 s, the false-positives rate is about 0.5%. This rate increases approximately linearly when decreasing the data frequency resolution. Conclusions. Currently, by using an automated RFI detection strategy, the LOFAR radio environment poses no perceivable problems for sensitive observing. It remains to be seen if this is still true for very deep observations that integrate over tens of nights, but the situation looks promising. Reasons for the low impact of RFI are the high spectral and time resolution of LOFAR; accurate detection methods; strong filters and high receiver linearity; and the proximity of the antennas to the ground. We discuss some strategies that can be used once low-level RFI starts to become apparent. It is important that the frequency range of LOFAR remains free of broadband interference, such as DAB stations and windmills. © 2012 ESO.
Published: 2012

31. Observing pulsars and fast transients with LOFAR

Author: Stappers, B., Hessels, J., Alexov, A., Anderson, K., Coenen, T., Hassall, T., Karastergiou, A., Kondratiev, V., Kramer, M., van Leeuwen, J., Mol, J., Noutsos, A., Romein, J., Weltevrede, P., Fender, R., Wijers, R., Baehren, L., Bell, M., Broderick, J., Daw, E., Dhillon, V., Eisloeffel, J., Falcke, H., Griessmeier, J., Law, C., Markoff, S., Miller-Jones, James, Scheers, B., Spreeuw, H., Swinbank, J., ter Veen, S., Wise, M., Wucknitz, O., Zarka, P., Anderson, J., Asgekar, A., Avruch, I., Beck, R., Bennema, P., Bentum, M., Best, P., Bregman, J., Brentjens, M., van de Brink, R., Broekema, P., Brouw, W., Brueggen, M., de Bruyn, A., Butcher, H., Ciardi, B., Conway, J., Dettmar, R., van Duin, A., van Enst, J., Garrett, M., Gerbers, M., Grit, T., Gunst, A., van Haarlem, M., Hamaker, J., Heald, G., Hoeft, M., Holties, H., Horneffer, A., Koopmans, L., Kuper, G., Loose, M., Maat, P., McKay-Bukowski, D., McKean, J., Miley, G., Morganti, R., Nijboer, R., Noordam, J., Norden, M., Olofsson, H., Pandey-Pommier, M., Polatidis, A., Reich, W., Roettgering, H., Schoenmakers, A., Sluman, J., Smirnov, O., Steinmetz, M., Sterks, C., Tagger, M., Tang, Y., Vermeulen, R., Vermaas, N., Vogt, C., de Vos, M., Wijnholds, S., Yatawatta, S., Zensus, J., Stappers, B., Hessels, J., Alexov, A., Anderson, K., Coenen, T., Hassall, T., Karastergiou, A., Kondratiev, V., Kramer, M., van Leeuwen, J., Mol, J., Noutsos, A., Romein, J., Weltevrede, P., Fender, R., Wijers, R., Baehren, L., Bell, M., Broderick, J., Daw, E., Dhillon, V., Eisloeffel, J., Falcke, H., Griessmeier, J., Law, C., Markoff, S., Miller-Jones, James, Scheers, B., Spreeuw, H., Swinbank, J., ter Veen, S., Wise, M., Wucknitz, O., Zarka, P., Anderson, J., Asgekar, A., Avruch, I., Beck, R., Bennema, P., Bentum, M., Best, P., Bregman, J., Brentjens, M., van de Brink, R., Broekema, P., Brouw, W., Brueggen, M., de Bruyn, A., Butcher, H., Ciardi, B., Conway, J., Dettmar, R., van Duin, A., van Enst, J., Garrett, M., Gerbers, M., Grit, T., Gunst, A., van Haarlem, M., Hamaker, J., Heald, G., Hoeft, M., Holties, H., Horneffer, A., Koopmans, L., Kuper, G., Loose, M., Maat, P., McKay-Bukowski, D., McKean, J., Miley, G., Morganti, R., Nijboer, R., Noordam, J., Norden, M., Olofsson, H., Pandey-Pommier, M., Polatidis, A., Reich, W., Roettgering, H., Schoenmakers, A., Sluman, J., Smirnov, O., Steinmetz, M., Sterks, C., Tagger, M., Tang, Y., Vermeulen, R., Vermaas, N., Vogt, C., de Vos, M., Wijnholds, S., Yatawatta, S., and Zensus, J.
Abstract: Low frequency radio waves, while challenging to observe, are a rich source of information about pulsars. The LOw Frequency ARray (LOFAR) is a new radio interferometer operating in the lowest 4 octaves of the ionospheric "radio window": 10-240 MHz, that will greatly facilitate observing pulsars at low radio frequencies. Through the huge collecting area, long baselines, and flexible digital hardware, it is expected that LOFAR will revolutionize radio astronomy at the lowest frequencies visible from Earth. LOFAR is a next-generation radio telescope and a pathfinder to the Square Kilometre Array (SKA), in that it incorporates advanced multi-beaming techniques between thousands of individual elements. We discuss the motivation for low-frequency pulsar observations in general and the potential of LOFAR in addressing these science goals. We present LOFAR as it is designed to perform high-time-resolution observations of pulsars and other fast transients, and outline the various relevant observing modes and data reduction pipelines that are already or will soon be implemented to facilitate these observations. A number of results obtained from commissioning observations are presented to demonstrate the exciting potential of the telescope. This paper outlines the case for low frequency pulsar observations and is also intended to serve as a reference for upcoming pulsar/fast transient science papers with LOFAR.
Published: 2011

32. LOFAR: The LOw-Frequency ARray

Author: van Haarlem, M. P., primary, Wise, M. W., additional, Gunst, A. W., additional, Heald, G., additional, McKean, J. P., additional, Hessels, J. W. T., additional, de Bruyn, A. G., additional, Nijboer, R., additional, Swinbank, J., additional, Fallows, R., additional, Brentjens, M., additional, Nelles, A., additional, Beck, R., additional, Falcke, H., additional, Fender, R., additional, Hörandel, J., additional, Koopmans, L. V. E., additional, Mann, G., additional, Miley, G., additional, Röttgering, H., additional, Stappers, B. W., additional, Wijers, R. A. M. J., additional, Zaroubi, S., additional, van den Akker, M., additional, Alexov, A., additional, Anderson, J., additional, Anderson, K., additional, van Ardenne, A., additional, Arts, M., additional, Asgekar, A., additional, Avruch, I. M., additional, Batejat, F., additional, Bähren, L., additional, Bell, M. E., additional, Bell, M. R., additional, van Bemmel, I., additional, Bennema, P., additional, Bentum, M. J., additional, Bernardi, G., additional, Best, P., additional, Bîrzan, L., additional, Bonafede, A., additional, Boonstra, A.-J., additional, Braun, R., additional, Bregman, J., additional, Breitling, F., additional, van de Brink, R. H., additional, Broderick, J., additional, Broekema, P. C., additional, Brouw, W. N., additional, Brüggen, M., additional, Butcher, H. R., additional, van Cappellen, W., additional, Ciardi, B., additional, Coenen, T., additional, Conway, J., additional, Coolen, A., additional, Corstanje, A., additional, Damstra, S., additional, Davies, O., additional, Deller, A. T., additional, Dettmar, R.-J., additional, van Diepen, G., additional, Dijkstra, K., additional, Donker, P., additional, Doorduin, A., additional, Dromer, J., additional, Drost, M., additional, van Duin, A., additional, Eislöffel, J., additional, van Enst, J., additional, Ferrari, C., additional, Frieswijk, W., additional, Gankema, H., additional, Garrett, M. A., additional, de Gasperin, F., additional, Gerbers, M., additional, de Geus, E., additional, Grießmeier, J.-M., additional, Grit, T., additional, Gruppen, P., additional, Hamaker, J. P., additional, Hassall, T., additional, Hoeft, M., additional, Holties, H. A., additional, Horneffer, A., additional, van der Horst, A., additional, van Houwelingen, A., additional, Huijgen, A., additional, Iacobelli, M., additional, Intema, H., additional, Jackson, N., additional, Jelic, V., additional, de Jong, A., additional, Juette, E., additional, Kant, D., additional, Karastergiou, A., additional, Koers, A., additional, Kollen, H., additional, Kondratiev, V. I., additional, Kooistra, E., additional, Koopman, Y., additional, Koster, A., additional, Kuniyoshi, M., additional, Kramer, M., additional, Kuper, G., additional, Lambropoulos, P., additional, Law, C., additional, van Leeuwen, J., additional, Lemaitre, J., additional, Loose, M., additional, Maat, P., additional, Macario, G., additional, Markoff, S., additional, Masters, J., additional, McFadden, R. A., additional, McKay-Bukowski, D., additional, Meijering, H., additional, Meulman, H., additional, Mevius, M., additional, Middelberg, E., additional, Millenaar, R., additional, Miller-Jones, J. C. A., additional, Mohan, R. N., additional, Mol, J. D., additional, Morawietz, J., additional, Morganti, R., additional, Mulcahy, D. D., additional, Mulder, E., additional, Munk, H., additional, Nieuwenhuis, L., additional, van Nieuwpoort, R., additional, Noordam, J. E., additional, Norden, M., additional, Noutsos, A., additional, Offringa, A. R., additional, Olofsson, H., additional, Omar, A., additional, Orrú, E., additional, Overeem, R., additional, Paas, H., additional, Pandey-Pommier, M., additional, Pandey, V. N., additional, Pizzo, R., additional, Polatidis, A., additional, Rafferty, D., additional, Rawlings, S., additional, Reich, W., additional, de Reijer, J.-P., additional, Reitsma, J., additional, Renting, G. A., additional, Riemers, P., additional, Rol, E., additional, Romein, J. W., additional, Roosjen, J., additional, Ruiter, M., additional, Scaife, A., additional, van der Schaaf, K., additional, Scheers, B., additional, Schellart, P., additional, Schoenmakers, A., additional, Schoonderbeek, G., additional, Serylak, M., additional, Shulevski, A., additional, Sluman, J., additional, Smirnov, O., additional, Sobey, C., additional, Spreeuw, H., additional, Steinmetz, M., additional, Sterks, C. G. M., additional, Stiepel, H.-J., additional, Stuurwold, K., additional, Tagger, M., additional, Tang, Y., additional, Tasse, C., additional, Thomas, I., additional, Thoudam, S., additional, Toribio, M. C., additional, van der Tol, B., additional, Usov, O., additional, van Veelen, M., additional, van der Veen, A.-J., additional, ter Veen, S., additional, Verbiest, J. P. W., additional, Vermeulen, R., additional, Vermaas, N., additional, Vocks, C., additional, Vogt, C., additional, de Vos, M., additional, van der Wal, E., additional, van Weeren, R., additional, Weggemans, H., additional, Weltevrede, P., additional, White, S., additional, Wijnholds, S. J., additional, Wilhelmsson, T., additional, Wucknitz, O., additional, Yatawatta, S., additional, Zarka, P., additional, Zensus, A., additional, and van Zwieten, J., additional
Published: 2013
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33. Calibrating high-precision Faraday rotation measurements for LOFAR and the next generation of low-frequency radio telescopes

Author: Sotomayor-Beltran, C., primary, Sobey, C., additional, Hessels, J. W. T., additional, de Bruyn, G., additional, Noutsos, A., additional, Alexov, A., additional, Anderson, J., additional, Asgekar, A., additional, Avruch, I. M., additional, Beck, R., additional, Bell, M. E., additional, Bell, M. R., additional, Bentum, M. J., additional, Bernardi, G., additional, Best, P., additional, Birzan, L., additional, Bonafede, A., additional, Breitling, F., additional, Broderick, J., additional, Brouw, W. N., additional, Brüggen, M., additional, Ciardi, B., additional, de Gasperin, F., additional, Dettmar, R.-J., additional, van Duin, A., additional, Duscha, S., additional, Eislöffel, J., additional, Falcke, H., additional, Fallows, R. A., additional, Fender, R., additional, Ferrari, C., additional, Frieswijk, W., additional, Garrett, M. A., additional, Grießmeier, J., additional, Grit, T., additional, Gunst, A. W., additional, Hassall, T. E., additional, Heald, G., additional, Hoeft, M., additional, Horneffer, A., additional, Iacobelli, M., additional, Juette, E., additional, Karastergiou, A., additional, Keane, E., additional, Kohler, J., additional, Kramer, M., additional, Kondratiev, V. I., additional, Koopmans, L. V. E., additional, Kuniyoshi, M., additional, Kuper, G., additional, van Leeuwen, J., additional, Maat, P., additional, Macario, G., additional, Markoff, S., additional, McKean, J. P., additional, Mulcahy, D. D., additional, Munk, H., additional, Orru, E., additional, Paas, H., additional, Pandey-Pommier, M., additional, Pilia, M., additional, Pizzo, R., additional, Polatidis, A. G., additional, Reich, W., additional, Röttgering, H., additional, Serylak, M., additional, Sluman, J., additional, Stappers, B. W., additional, Tagger, M., additional, Tang, Y., additional, Tasse, C., additional, ter Veen, S., additional, Vermeulen, R., additional, van Weeren, R. J., additional, Wijers, R. A. M. J., additional, Wijnholds, S. J., additional, Wise, M. W., additional, Wucknitz, O., additional, Yatawatta, S., additional, and Zarka, P., additional
Published: 2013
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34. The LOFAR radio environment

Author: Offringa, A. R., primary, de Bruyn, A. G., additional, Zaroubi, S., additional, van Diepen, G., additional, Martinez-Ruby, O., additional, Labropoulos, P., additional, Brentjens, M. A., additional, Ciardi, B., additional, Daiboo, S., additional, Harker, G., additional, Jelić, V., additional, Kazemi, S., additional, Koopmans, L. V. E., additional, Mellema, G., additional, Pandey, V. N., additional, Pizzo, R. F., additional, Schaye, J., additional, Vedantham, H., additional, Veligatla, V., additional, Wijnholds, S. J., additional, Yatawatta, S., additional, Zarka, P., additional, Alexov, A., additional, Anderson, J., additional, Asgekar, A., additional, Avruch, M., additional, Beck, R., additional, Bell, M., additional, Bell, M. R., additional, Bentum, M., additional, Bernardi, G., additional, Best, P., additional, Birzan, L., additional, Bonafede, A., additional, Breitling, F., additional, Broderick, J. W., additional, Brüggen, M., additional, Butcher, H., additional, Conway, J., additional, de Vos, M., additional, Dettmar, R. J., additional, Eisloeffel, J., additional, Falcke, H., additional, Fender, R., additional, Frieswijk, W., additional, Gerbers, M., additional, Griessmeier, J. M., additional, Gunst, A. W., additional, Hassall, T. E., additional, Heald, G., additional, Hessels, J., additional, Hoeft, M., additional, Horneffer, A., additional, Karastergiou, A., additional, Kondratiev, V., additional, Koopman, Y., additional, Kuniyoshi, M., additional, Kuper, G., additional, Maat, P., additional, Mann, G., additional, McKean, J., additional, Meulman, H., additional, Mevius, M., additional, Mol, J. D., additional, Nijboer, R., additional, Noordam, J., additional, Norden, M., additional, Paas, H., additional, Pandey, M., additional, Pizzo, R., additional, Polatidis, A., additional, Rafferty, D., additional, Rawlings, S., additional, Reich, W., additional, Röttgering, H. J. A., additional, Schoenmakers, A. P., additional, Sluman, J., additional, Smirnov, O., additional, Sobey, C., additional, Stappers, B., additional, Steinmetz, M., additional, Swinbank, J., additional, Tagger, M., additional, Tang, Y., additional, Tasse, C., additional, van Ardenne, A., additional, van Cappellen, W., additional, van Duin, A. P., additional, van Haarlem, M., additional, van Leeuwen, J., additional, van Weeren, R. J., additional, Vermeulen, R., additional, Vocks, C., additional, Wijers, R. A. M. J., additional, Wise, M., additional, and Wucknitz, O., additional
Published: 2012
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35. M 87 at metre wavelengths: the LOFAR picture

Author: de Gasperin, F., primary, Orrú, E., additional, Murgia, M., additional, Merloni, A., additional, Falcke, H., additional, Beck, R., additional, Beswick, R., additional, Bîrzan, L., additional, Bonafede, A., additional, Brüggen, M., additional, Brunetti, G., additional, Chyży, K., additional, Conway, J., additional, Croston, J. H., additional, Enßlin, T., additional, Ferrari, C., additional, Heald, G., additional, Heidenreich, S., additional, Jackson, N., additional, Macario, G., additional, McKean, J., additional, Miley, G., additional, Morganti, R., additional, Offringa, A., additional, Pizzo, R., additional, Rafferty, D., additional, Röttgering, H., additional, Shulevski, A., additional, Steinmetz, M., additional, Tasse, C., additional, van der Tol, S., additional, van Driel, W., additional, van Weeren, R. J., additional, van Zwieten, J. E., additional, Alexov, A., additional, Anderson, J., additional, Asgekar, A., additional, Avruch, M., additional, Bell, M., additional, Bell, M. R., additional, Bentum, M., additional, Bernardi, G., additional, Best, P., additional, Breitling, F., additional, Broderick, J. W., additional, Butcher, A., additional, Ciardi, B., additional, Dettmar, R. J., additional, Eisloeffel, J., additional, Frieswijk, W., additional, Gankema, H., additional, Garrett, M., additional, Gerbers, M., additional, Griessmeier, J. M., additional, Gunst, A. W., additional, Hassall, T. E., additional, Hessels, J., additional, Hoeft, M., additional, Horneffer, A., additional, Karastergiou, A., additional, Köhler, J., additional, Koopman, Y., additional, Kuniyoshi, M., additional, Kuper, G., additional, Maat, P., additional, Mann, G., additional, Mevius, M., additional, Mulcahy, D. D., additional, Munk, H., additional, Nijboer, R., additional, Noordam, J., additional, Paas, H., additional, Pandey, M., additional, Pandey, V. N., additional, Polatidis, A., additional, Reich, W., additional, Schoenmakers, A. P., additional, Sluman, J., additional, Smirnov, O., additional, Sobey, C., additional, Stappers, B., additional, Swinbank, J., additional, Tagger, M., additional, Tang, Y., additional, van Bemmel, I., additional, van Cappellen, W., additional, van Duin, A. P., additional, van Haarlem, M., additional, van Leeuwen, J., additional, Vermeulen, R., additional, Vocks, C., additional, White, S., additional, Wise, M., additional, Wucknitz, O., additional, and Zarka, P., additional
Published: 2012
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36. Observing pulsars and fast transients with LOFAR

Author: Stappers, B. W., primary, Hessels, J. W. T., additional, Alexov, A., additional, Anderson, K., additional, Coenen, T., additional, Hassall, T., additional, Karastergiou, A., additional, Kondratiev, V. I., additional, Kramer, M., additional, van Leeuwen, J., additional, Mol, J. D., additional, Noutsos, A., additional, Romein, J. W., additional, Weltevrede, P., additional, Fender, R., additional, Wijers, R. A. M. J., additional, Bähren, L., additional, Bell, M. E., additional, Broderick, J., additional, Daw, E. J., additional, Dhillon, V. S., additional, Eislöffel, J., additional, Falcke, H., additional, Griessmeier, J., additional, Law, C., additional, Markoff, S., additional, Miller-Jones, J. C. A., additional, Scheers, B., additional, Spreeuw, H., additional, Swinbank, J., additional, ter Veen, S., additional, Wise, M. W., additional, Wucknitz, O., additional, Zarka, P., additional, Anderson, J., additional, Asgekar, A., additional, Avruch, I. M., additional, Beck, R., additional, Bennema, P., additional, Bentum, M. J., additional, Best, P., additional, Bregman, J., additional, Brentjens, M., additional, van de Brink, R. H., additional, Broekema, P. C., additional, Brouw, W. N., additional, Brüggen, M., additional, de Bruyn, A. G., additional, Butcher, H. R., additional, Ciardi, B., additional, Conway, J., additional, Dettmar, R.-J., additional, van Duin, A., additional, van Enst, J., additional, Garrett, M., additional, Gerbers, M., additional, Grit, T., additional, Gunst, A., additional, van Haarlem, M. P., additional, Hamaker, J. P., additional, Heald, G., additional, Hoeft, M., additional, Holties, H., additional, Horneffer, A., additional, Koopmans, L. V. E., additional, Kuper, G., additional, Loose, M., additional, Maat, P., additional, McKay-Bukowski, D., additional, McKean, J. P., additional, Miley, G., additional, Morganti, R., additional, Nijboer, R., additional, Noordam, J. E., additional, Norden, M., additional, Olofsson, H., additional, Pandey-Pommier, M., additional, Polatidis, A., additional, Reich, W., additional, Röttgering, H., additional, Schoenmakers, A., additional, Sluman, J., additional, Smirnov, O., additional, Steinmetz, M., additional, Sterks, C. G. M., additional, Tagger, M., additional, Tang, Y., additional, Vermeulen, R., additional, Vermaas, N., additional, Vogt, C., additional, de Vos, M., additional, Wijnholds, S. J., additional, Yatawatta, S., additional, and Zensus, A., additional
Published: 2011
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37. Frequency spectra of cosmic ray air shower radio emission measured with LOPES

Author: Nigl, A., primary, Apel, W. D., additional, Arteaga, J. C., additional, Asch, T., additional, Auffenberg, J., additional, Badea, F., additional, Bähren, L., additional, Bekk, K., additional, Bertaina, M., additional, Biermann, P. L., additional, Blümer, J., additional, Bozdog, H., additional, Brancus, I. M., additional, Brüggemann, M., additional, Buchholz, P., additional, Buitink, S., additional, Butcher, H., additional, Cantoni, E., additional, Chiavassa, A., additional, Cossavella, F., additional, Daumiller, K., additional, de Souza, V., additional, Di Pierro, F., additional, Doll, P., additional, Engel, R., additional, Falcke, H., additional, Gemmeke, H., additional, Ghia, P. L., additional, Glasstetter, R., additional, Grupen, C., additional, Haungs, A., additional, Heck, D., additional, Hörandel, J. R., additional, Horneffer, A., additional, Huege, T., additional, Isar, P. G., additional, Kampert, K.-H., additional, Kickelbick, D., additional, Kolotaev, Y., additional, Krömer, O., additional, Kuijpers, J., additional, Lafebre, S., additional, Łuczak, P., additional, Manewald, M., additional, Mathes, H. J., additional, Mayer, H. J., additional, Meurer, C., additional, Mitrica, B., additional, Morello, C., additional, Navarra, G., additional, Nehls, S., additional, Oehlschläger, J., additional, Ostapchenko, S., additional, Over, S., additional, Petcu, M., additional, Pierog, T., additional, Rautenberg, J., additional, Rebel, H., additional, Roth, M., additional, Saftoiu, A., additional, Schieler, H., additional, Schmidt, A., additional, Schröder, F., additional, Sima, O., additional, Singh, K., additional, Stümpert, M., additional, Toma, G., additional, Trinchero, G. C., additional, Ulrich, H., additional, van Buren, J., additional, Walkowiak, W., additional, Weindl, A., additional, Wochele, J., additional, Zabierowski, J., additional, and Zensus, J. A., additional
Published: 2008
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38. Direction identification in radio images of cosmic-ray air showers detected with LOPES and KASCADE

Author: Nigl, A., primary, Apel, W. D., additional, Arteaga, J. C., additional, Asch, T., additional, Auffenberg, J., additional, Badea, F., additional, Bähren, L., additional, Bekk, K., additional, Bertaina, M., additional, Biermann, P. L., additional, Blümer, J., additional, Bozdog, H., additional, Brancus, I. M., additional, Brüggemann, M., additional, Buchholz, P., additional, Buitink, S., additional, Butcher, H., additional, Cantoni, E., additional, Chiavassa, A., additional, Cossavella, F., additional, Daumiller, K., additional, de Souza, V., additional, Di Pierro, F., additional, Doll, P., additional, Engel, R., additional, Falcke, H., additional, Gemmeke, H., additional, Ghia, P. L., additional, Glasstetter, R., additional, Grupen, C., additional, Haungs, A., additional, Heck, D., additional, Hörandel, J. R., additional, Horneffer, A., additional, Huege, T., additional, Isar, P. G., additional, Kampert, K.-H., additional, Kickelbick, D., additional, Kolotaev, Y., additional, Krömer, O., additional, Kuijpers, J., additional, Lafebre, S., additional, Łuczak, P., additional, Manewald, M., additional, Mathes, H. J., additional, Mayer, H. J., additional, Meurer, C., additional, Mitrica, B., additional, Morello, C., additional, Navarra, G., additional, Nehls, S., additional, Oehlschläger, J., additional, Ostapchenko, S., additional, Over, S., additional, Petcu, M., additional, Pierog, T., additional, Rautenberg, J., additional, Rebel, H., additional, Roth, M., additional, Saftoiu, A., additional, Schieler, H., additional, Schmidt, A., additional, Schröder, F., additional, Sima, O., additional, Singh, K., additional, Stümpert, M., additional, Toma, G., additional, Trinchero, G. C., additional, Ulrich, H., additional, van Buren, J., additional, Walkowiak, W., additional, Weindl, A., additional, Wochele, J., additional, Zabierowski, J., additional, and Zensus, J. A., additional
Published: 2008
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39. Cosmic rays studied with a hybrid high school detector array

Author: Nigl, A., primary, Timmermans, C., additional, Schellart, P., additional, Kuijpers, J., additional, Falcke, H., additional, Horneffer, A., additional, de Vos, C. M., additional, Koopman, Y., additional, Pepping, H. J., additional, and Schoonderbeek, G., additional
Published: 2007
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40. Amplified radio emission from cosmic ray air showers in thunderstorms

Author: Buitink, S., primary, Apel, W. D., additional, Asch, T., additional, Badea, F., additional, Bähren, L., additional, Bekk, K., additional, Bercuci, A., additional, Bertaina, M., additional, Biermann, P. L., additional, Blümer, J., additional, Bozdog, H., additional, Brancus, I. M., additional, Brüggemann, M., additional, Buchholz, P., additional, Butcher, H., additional, Chiavassa, A., additional, Cossavella, F., additional, Daumiller, K., additional, Di Pierro, F., additional, Doll, P., additional, Engel, R., additional, Falcke, H., additional, Gemmeke, H., additional, Ghia, P. L., additional, Glasstetter, R., additional, Grupen, C., additional, Haungs, A., additional, Heck, D., additional, Hörandel, J. R., additional, Horneffer, A., additional, Huege, T., additional, Kampert, K.-H., additional, Kolotaev, Y., additional, Krömer, O., additional, Kuijpers, J., additional, Lafebre, S., additional, Mathes, H. J., additional, Mayer, H. J., additional, Meurer, C., additional, Milke, J., additional, Mitrica, B., additional, Morello, C., additional, Navarra, G., additional, Nehls, S., additional, Nigl, A., additional, Obenland, R., additional, Oehlschläger, J., additional, Ostapchenko, S., additional, Over, S., additional, Petcu, M., additional, Petrovic, J., additional, Pierog, T., additional, Plewnia, S., additional, Rebel, H., additional, Risse, A., additional, Roth, M., additional, Schieler, H., additional, Sima, O., additional, Singh, K., additional, Stümpert, M., additional, Toma, G., additional, Trinchero, G. C., additional, Ulrich, H., additional, van Buren, J., additional, Walkowiak, W., additional, Weindl, A., additional, Wochele, J., additional, Zabierowski, J., additional, Zensus, J. A., additional, and Zimmermann, D., additional
Published: 2007
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41. Radio emission of highly inclined cosmic ray air showers measured with LOPES

Author: Petrovic, J., primary, Apel, W. D., additional, Asch, T., additional, Badea, F., additional, Bähren, L., additional, Bekk, K., additional, Bercuci, A., additional, Bertaina, M., additional, Biermann, P. L., additional, Blümer, J., additional, Bozdog, H., additional, Brancus, I. M., additional, Brüggemann, M., additional, Buchholz, P., additional, Buitink, S., additional, Butcher, H., additional, Chiavassa, A., additional, Cossavella, F., additional, Daumiller, K., additional, Di Pierro, F., additional, Doll, P., additional, Engel, R., additional, Falcke, H., additional, Gemmeke, H., additional, Ghia, P. L., additional, Glasstetter, R., additional, Grupen, C., additional, Haungs, A., additional, Heck, D., additional, Hörandel, J. R., additional, Horneffer, A., additional, Huege, T., additional, Kampert, K.-H., additional, Kolotaev, Y., additional, Krömer, O., additional, Kuijpers, J., additional, Lafebre, S., additional, Mathes, H. J., additional, Mayer, H. J., additional, Meurer, C., additional, Milke, J., additional, Mitrica, B., additional, Morello, C., additional, Navarra, G., additional, Nehls, S., additional, Nigl, A., additional, Obenland, R., additional, Oehlschläger, J., additional, Ostapchenko, S., additional, Over, S., additional, Petcu, M., additional, Pierog, T., additional, Plewnia, S., additional, Rebel, H., additional, Risse, A., additional, Roth, M., additional, Schieler, H., additional, Sima, O., additional, Singh, K., additional, Stümpert, M., additional, Toma, G., additional, Trinchero, G. C., additional, Ulrich, H., additional, van Buren, J., additional, Walkowiak, W., additional, Weindl, A., additional, Wochele, J., additional, Zabierowski, J., additional, Zensus, J. A., additional, and Zimmermann, D., additional
Published: 2006
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42. The nature of the low-frequency emission of M51: First observations of a nearby galaxy with LOFAR.

Author: Mulcahy, D. D., Horneffer, A., Beck, R., Heald, G., Fletcher, A., Scaife, A., Adebahr, B., Anderson, J. M., Bonafede, A., Brüggen, M., Brunetti, G., Chy˙zy, K. T., Conway, J., Dettmar, R.-J., Enßlin, T., Haverkorn, M., Horellou, C., Iacobelli, M., Israel, F. P., and Junklewitz, H.
Subjects: *COSMIC rays, *POLARIZATION (Nuclear physics), *MAGNETIC fields, *SPIRAL galaxies, *FARADAY effect
Abstract: Context. Low-frequency radio continuum observations (<300 MHz) can provide valuable information on the propagation of low-energy cosmic ray electrons (CRE). Nearby spiral galaxies have hardly been studied in this frequency range because of the technical challenges of low-frequency radio interferometry. This is now changing with the start of operations of LOFAR. Aims. We aim to study the propagation of low-energy CRE in the interarm regions and the extended disk of the nearly face-on spiral galaxy Messier 51. We also search for polarisation in M51 and other extragalactic sources in the field. Methods. The grand-design spiral galaxy M51 was observed with the LOFAR High Frequency Antennas (HBA) and imaged in total intensity and polarisation. This observation covered the frequencies between 115 MHz and 175 MHz with 244 subbands of 8 channels each, resulting in 1952 channels. This allowed us to use RM synthesis to search for polarisation. Results. We produced an image of total emission of M51 at the mean frequency of 151 MHz with 20" resolution and 0.3 mJy rms noise, which is the most sensitive image of a galaxy at frequencies below 300 MHz so far. The integrated spectrum of total radio emission is described well by a power law, while flat spectral indices in the central region indicate thermal absorption. We observe that the disk extends out to 16 kpc and see a break in the radial profile near the optical radius of the disk. The radial scale lengths in the inner and outer disks are greater at 151 MHz, and the break is smoother at 151 MHz than those observed at 1.4 GHz. The arm-interarm contrast is lower at 151 MHz than at 1400 MHz, indicating propagation of CRE from spiral arms into interarm regions. The correlations between the images of radio emission at 151 MHz and 1400 MHz and the FIR emission at 70 μm reveal breaks on scales of 1.4 and 0.7 kpc, respectively. The total (equipartition) magnetic field strength decreases from about 28 μG in the central region to about 10 μG at 10 kpc radius. No significant polarisation was detected from M51, owing to severe Faraday depolarisation. Six extragalactic sources are detected in polarisation in the M51 field of 4.1° × 4.1° size. Two sources show complex structures in Faraday space. Conclusions. Our main results, the scale lengths of the inner and outer disks at 151 MHz and 1.4 GHz, arm-interarm contrast, and the break scales of the radio-FIR correlations, can be explained consistently by CRE diffusion, leading to a longer propagation length of CRE of lower energy. The distribution of CRE sources drops sharply at about 10 kpc radius, where the star formation rate also decreases sharply. We find evidence that thermal absorption is primarily caused by Hii regions. The non-detection of polarisation from M51 at 151 MHz is consistent with the estimates of Faraday depolarisation. Future searches for polarised emission in this frequency range should concentrate on regions with low star formation rates. [ABSTRACT FROM AUTHOR]
Published: 2014
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