Search

Your search keyword '"Thoudam, S."' showing total 33 results
Start Over Author "Thoudam, S." Publisher edp sciences
33 results on '"Thoudam, S."'

1. Properties of the Lunar Detection Mode for ZeV-Scale Particles with LOFAR

Author

Winchen T., Bonardi A., Buitink S., Corstanje A., Falcke H., Hare B. M., Hörandel A., Mitra P., Mulrey K., Nelles A., Rachen J.P., Rossetto L., Schellart P., Scholten O., ter Veen S., Thoudam S., and Trinh T.N.G.

Subjects
Physics, QC1-999
Abstract

The steep decrease of the flux of ultra-high energy cosmic rays (UHECR) provides a challenge to answer the long standing question about their origin and nature. A significant increase in detector volume may be achieved byemploying Earth’s moon as a detector that is read out using existing Earth-bound radio telescopes by searching for the radio pulses emitted by the particle shower in the lunar rock. In this contribution we will report on the properties of a corresponding detection mode currently under development for the LOFAR Radio telescope.

Published
2019
Full Text
View/download PDF

2. Updated Calibration of the LOFAR Low-Band Antennas

Author

Mulrey K., Bonardi A., Buitink S., Corstanje A., Falcke H., Hare B.M., Hörandel J., Mitra P., Nelles A., Rachen J.P., Rossetto L., Schellart P., Scholten O., ter Veen S., Thoudam S., Trinh T.N.G., and Winchen T

Subjects
Physics, QC1-999
Abstract

The LOw-Frequency ARray (LOFAR) telescope measures radio emission from air showers. In order to interpret the data, an absolute, frequency dependent calibration is required. Due to a growing need for a better understanding of the measured frequency spectrum, we revisit the calibration of the LOFAR antennas in the range of 30—80 MHz. Using the galactic radio emission and a detailed model of the LOFAR signal chain, we find a calibration that provides an absolute energy scale and allows us to study frequency dependent features in measured air shower signals.

Published
2019
Full Text
View/download PDF

3. A new parametrization for the radio emission of air showers applied to LOFAR data

Author

Plaisier I., Bonardi A., Buitink S., Corstanje A., Falcke H., Hare B.M., Hörandel J.R., de Jong S., Mitra P., Mulrey K., Nelles A., Rachen J., Rossetto L., Schellart P., Scholten O., ter Veen S., Thoudam S., Trinh T.N.G., and Winchen T.

Subjects
Physics, QC1-999
Abstract

The energy and mass composition of cosmic rays influence how the energy density of the radio emission of air showers is distributed on the ground. A precise description of the radio profiles can, therefore, be used to reconstruct the properties of the primary cosmic rays. Here, such a description is presented, using a separate treatment of the two radio-emission mechanisms, the geomagnetic effect and the charge excess effect. The model is parametrized as a function that depends only on the shower parameters, allowing for a precise reconstruction of the properties of the primary cosmic rays. This model is applied to cosmic-ray events measured with LOFAR and it is capable of reconstructing the properties of air showers correctly.

Published
2019
Full Text
View/download PDF

4. The mass composition of cosmic rays measured with LOFAR

Author

Hörandel Jörg R., Bonardi A., Buitink S., Corstanje A., Falcke H., Mitra P., Mulrey K., Nelles A., Rachen J.P., Rossetto L., Schellart P., Scholten O., ter Veen S., Thoudam S., Trinh T.N.G., and Winchen T.

Subjects
Physics, QC1-999
Abstract

High-energy cosmic rays, impinging on the atmosphere of the Earth initiate cascades of secondary particles, the extensive air showers. The electrons and positrons in the air shower emit electromagnetic radiation. This emission is detected with the LOFAR radio telescope in the frequency range from 30 to 240 MHz. The data are used to determine the properties of the incoming cosmic rays. The radio technique is now routinely used to measure the arrival direction, the energy, and the particle type (atomic mass) of cosmic rays in the energy range from 1017 to 1018 eV. This energy region is of particular astrophysical interest, since in this regime a transition from a Galactic to an extra-galactic origin of cosmic rays is expected. For illustration, the LOFAR results are used to set constraints on models to describe the origin of high-energy cosmic rays.

Published
2017
Full Text
View/download PDF

5. Circular polarization of radio emission from air showers in thunderstorm conditions

Author

Trinh T.N.G., Scholten O., Bonardi A., Buitink S., Corstanje A., Ebert U., Enriquez J. E., Falcke H., Hörandel J.R., Mitra P., Mulrey K., Nelles A., Thoudam S., Rachen J.P., Rossetto L., Rutjes C., Schellart P., ter Veen S., and Winchen T.

Subjects
Physics, QC1-999
Abstract

We present measured radio emission from cosmic-ray-induced air showers under thunderstorm conditions. We observe for these events large differences in intensity, linear polarization and circular polarization from the events measured under fair-weather conditions. This can be explained by the effects of atmospheric electric fields in thunderclouds. Therefore, measuring the intensity and polarization of radio emission from cosmic ray extensive air showers during thunderstorm conditions provides a new tool to probe the atmospheric electric fields present in thunderclouds.

Published
2017
Full Text
View/download PDF

6. Search for Cosmic Particles with the Moon and LOFAR

Author

Winchen T., Bonardi A., Buitink S., Corstanje A., Enriquez J. E., Falcke H., Hörandel J. R., Mitra P., Mulrey K., Nelles A., Rachen J. P., Rossetto L., Schellart P., Scholten O., Thoudam S., Trinh T.N.G., and ter Veen S.

Subjects
Physics, QC1-999
Abstract

The low flux of the ultra-high energy cosmic rays (UHECR) at the highest energies provides a challenge to answer the long standing question about their origin and nature. A significant increase in the number of detected UHECR is expected to be achieved by employing Earth’’s moon as detector, and search for short radio pulses that are emitted when a particle interacts in the lunar rock. Observation of these short pulses with current and future radio telescopes also allows to search for the even lower fluxes of neutrinos with energies above 1022 eV, that are predicted in certain Grand-Unifying-Theories (GUTs), and e.g. models for super-heavy dark matter (SHDM). In this contribution we present the initial design for such a search with the LOFAR radio telescope.

Published
2017
Full Text
View/download PDF

7. Shock location and CME 3D reconstruction of a solar type II radio burst with LOFAR

Author

Zucca, P., primary, Morosan, D. E., additional, Rouillard, A. P., additional, Fallows, R., additional, Gallagher, P. T., additional, Magdalenic, J., additional, Klein, K.-L., additional, Mann, G., additional, Vocks, C., additional, Carley, E. P., additional, Bisi, M. M., additional, Kontar, E. P., additional, Rothkaehl, H., additional, Dabrowski, B., additional, Krankowski, A., additional, Anderson, J., additional, Asgekar, A., additional, Bell, M. E., additional, Bentum, M. J., additional, Best, P., additional, Blaauw, R., additional, Breitling, F., additional, Broderick, J. W., additional, Brouw, W. N., additional, Brüggen, M., additional, Butcher, H. R., additional, Ciardi, B., additional, de Geus, E., additional, Deller, A., additional, Duscha, S., additional, Eislöffel, J., additional, Garrett, M. A., additional, Grießmeier, J. M., additional, Gunst, A. W., additional, Heald, G., additional, Hoeft, M., additional, Hörandel, J., additional, Iacobelli, M., additional, Juette, E., additional, Karastergiou, A., additional, van Leeuwen, J., additional, McKay-Bukowski, D., additional, Mulder, H., additional, Munk, H., additional, Nelles, A., additional, Orru, E., additional, Paas, H., additional, Pandey, V. N., additional, Pekal, R., additional, Pizzo, R., additional, Polatidis, A. G., additional, Reich, W., additional, Rowlinson, A., additional, Schwarz, D. J., additional, Shulevski, A., additional, Sluman, J., additional, Smirnov, O., additional, Sobey, C., additional, Soida, M., additional, Thoudam, S., additional, Toribio, M. C., additional, Vermeulen, R., additional, van Weeren, R. J., additional, Wucknitz, O., additional, and Zarka, P., additional

Published
2018
Full Text
View/download PDF

8. Low-frequency radio absorption in Cassiopeia A

Author

Arias, M., primary, Vink, J., additional, de Gasperin, F., additional, Salas, P., additional, Oonk, J. B. R., additional, van Weeren, R. J., additional, van Amesfoort, A. S., additional, Anderson, J., additional, Beck, R., additional, Bell, M. E., additional, Bentum, M. J., additional, Best, P., additional, Blaauw, R., additional, Breitling, F., additional, Broderick, J. W., additional, Brouw, W. N., additional, Brüggen, M., additional, Butcher, H. R., additional, Ciardi, B., additional, de Geus, E., additional, Deller, A., additional, van Dijk, P. C. G., additional, Duscha, S., additional, Eislöffel, J., additional, Garrett, M. A., additional, Grießmeier, J. M., additional, Gunst, A. W., additional, van Haarlem, M. P., additional, Heald, G., additional, Hessels, J., additional, Hörandel, J., additional, Holties, H. A., additional, van der Horst, A. J., additional, Iacobelli, M., additional, Juette, E., additional, Krankowski, A., additional, van Leeuwen, J., additional, Mann, G., additional, McKay-Bukowski, D., additional, McKean, J. P., additional, Mulder, H., additional, Nelles, A., additional, Orru, E., additional, Paas, H., additional, Pandey-Pommier, M., additional, Pandey, V. N., additional, Pekal, R., additional, Pizzo, R., additional, Polatidis, A. G., additional, Reich, W., additional, Röttgering, H. J. A., additional, Rothkaehl, H., additional, Schwarz, D. J., additional, Smirnov, O., additional, Soida, M., additional, Steinmetz, M., additional, Tagger, M., additional, Thoudam, S., additional, Toribio, M. C., additional, Vocks, C., additional, van der Wiel, M. H. D., additional, Wijers, R. A. M. J., additional, Wucknitz, O., additional, Zarka, P., additional, and Zucca, P., additional

Published
2018
Full Text
View/download PDF

9. 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
Full Text
View/download PDF

10. Circular polarization of radio emission from air showers in thunderstorm conditions

Author

Trinh, T.N.G., Scholten, O., Bonardi, A., Buitink, S., Corstanje, A., Ebert, U.M., Enriquez, J.E., Falcke, H., Hörandel, J.R., Mitra, P., Mulrey, K., Nelles, A., Thoudam, S., Rachen, J.P., Rossetto, L., Rutjes, C., Schellart, P., Ter Veen, S., Winchen, T., Trinh, T.N.G., Scholten, O., Bonardi, A., Buitink, S., Corstanje, A., Ebert, U.M., Enriquez, J.E., Falcke, H., Hörandel, J.R., Mitra, P., Mulrey, K., Nelles, A., Thoudam, S., Rachen, J.P., Rossetto, L., Rutjes, C., Schellart, P., Ter Veen, S., and Winchen, T.

Abstract

We present measured radio emission from cosmic-ray-induced air showers under thunderstorm conditions. We observe for these events large differences in intensity, linear polarization and circular polarization from the events measured under fair-weather conditions. This can be explained by the effects of atmospheric electric fields in thunderclouds. Therefore, measuring the intensity and polarization of radio emission from cosmic ray extensive air showers during thunderstorm conditions provides a new tool to probe the atmospheric electric fields present in thunderclouds.

Published
2017

11. The association of aJ-burst with a solar jet

Author

Morosan, D. E., primary, Gallagher, P. T., additional, Fallows, R. A., additional, Reid, H., additional, Mann, G., additional, Bisi, M. M., additional, Magdalenić, J., additional, Rucker, H. O., additional, Thidé, B., additional, Vocks, C., additional, Anderson, J., additional, Asgekar, A., additional, Avruch, I. M., additional, Bell, M. E., additional, Bentum, M. J., additional, Best, P., additional, Blaauw, R., additional, Bonafede, A., additional, Breitling, F., additional, Broderick, J. W., additional, Brüggen, M., additional, Cerrigone, L., additional, Ciardi, B., additional, de Geus, E., additional, Duscha, S., additional, Eislöffel, J., additional, Falcke, H., additional, Garrett, M. A., additional, Grießmeier, J. M., additional, Gunst, A. W., additional, Hoeft, M., additional, Iacobelli, M., additional, Juette, E., additional, Kuper, G., additional, McFadden, R., additional, McKay-Bukowski, D., additional, McKean, J. P., additional, Mulcahy, D. D., additional, Munk, H., additional, Nelles, A., additional, Orru, E., additional, Paas, H., additional, Pandey-Pommier, M., additional, Pandey, V. N., additional, Pizzo, R., additional, Polatidis, A. G., additional, Reich, W., additional, Schwarz, D. J., additional, Sluman, J., additional, Smirnov, O., additional, Steinmetz, M., additional, Tagger, M., additional, ter Veen, S., additional, Thoudam, S., additional, Toribio, M. C., additional, Vermeulen, R., additional, van Weeren, R. J., additional, Wucknitz, O., additional, and Zarka, P., additional

Published
2017
Full Text
View/download PDF

12. 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

13. 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
Full Text
View/download PDF

15. Timing calibration and spectral cleaning of LOFAR time series data

Author

Corstanje, A., primary, Buitink, S., additional, Enriquez, J. E., additional, Falcke, H., additional, Hörandel, J. R., additional, Krause, M., additional, Nelles, A., additional, Rachen, J. P., additional, Schellart, P., additional, Scholten, O., additional, ter Veen, S., additional, Thoudam, S., additional, and Trinh, T. N. G., additional

Published
2016
Full Text
View/download PDF

16. Imaging Jupiter’s radiation belts down to 127 MHz with LOFAR

Author

Girard, J. N., primary, Zarka, P., additional, Tasse, C., additional, Hess, S., additional, de Pater, I., additional, Santos-Costa, D., additional, Nenon, Q., additional, Sicard, A., additional, Bourdarie, S., additional, Anderson, J., additional, Asgekar, A., additional, Bell, M. E., additional, van Bemmel, I., additional, Bentum, M. J., additional, Bernardi, G., additional, Best, P., additional, Bonafede, A., additional, Breitling, F., additional, Breton, R. P., additional, Broderick, J. W., additional, Brouw, W. N., additional, Brüggen, M., additional, Ciardi, B., additional, Corbel, S., additional, Corstanje, A., additional, de Gasperin, F., additional, de Geus, E., additional, Deller, A., additional, Duscha, S., additional, Eislöffel, J., additional, Falcke, H., additional, Frieswijk, W., additional, Garrett, M. A., additional, Grießmeier, J., additional, Gunst, A. W., additional, Hessels, J. W. T., additional, Hoeft, M., additional, Hörandel, J., additional, Iacobelli, M., additional, Juette, E., additional, Kondratiev, V. I., additional, Kuniyoshi, M., additional, Kuper, G., additional, van Leeuwen, J., additional, Loose, M., additional, Maat, P., additional, Mann, G., additional, Markoff, S., additional, McFadden, R., additional, McKay-Bukowski, D., additional, Moldon, J., additional, Munk, H., additional, Nelles, A., additional, Norden, M. J., additional, Orru, E., additional, Paas, H., additional, Pandey-Pommier, 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, Swinbank, J., additional, Tagger, M., additional, Thoudam, S., additional, Toribio, M. C., additional, Vermeulen, R., additional, Vocks, C., additional, van Weeren, R. J., additional, Wijers, R. A. M. J., additional, and Wucknitz, O., additional

Published
2016
Full Text
View/download PDF

17. 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
Full Text
View/download PDF

18. LOFAR sparse image reconstruction

Author

Garsden, H., Girard, J. N., Starck, J. L., Corbel, S., Tasse, C., Woiselle, A., McKean, J. P., van Amesfoort, A. S., Anderson, J., Avruch, I. M., Beck, R., Bentum, M. J., Best, P., Breitling, F., Broderick, J., Brüggen, M., Butcher, H. R., Ciardi, B., de Gasperin, F., de Geus, E., de Vos, Marco, Duscha, S., Eislöffel, J., Engels, D., Falcke, H., Fallows, R. A., Fender, R., Ferrari, C., Frieswijk, W., Garrett, M. A., Griessmeier, J., Gunst, A. W., Hassall, T. E., Heald, G., Hoeft, M., Hörandel, J., van der Horst, A., Juette, E., Karastergiou, A., Kondratiev, V. I., Kramer, M., Kuniyoshi, M., Kuper, G., Mann, G., Markoff, S., McFadden, R., McKay-Bukowski, D., Mulcahy, D. D., Munk, H., Norden, M. J., Orru, E., Paas, H., Pandey-Pommier, M., Pandey, V. N., Pietka, G., Pizzo, R., Polatidis, A. G., Renting, A., Röttgering, H., Rowlinson, A., Schwarz, D., Sluman, J., Smirnov, O., Stappers, B. W., Steinmetz, M., Stewart, A., Swinbank, J., Tagger, M., Tang, Y., Thoudam, S., Toribio, C., Vermeulen, R., Vocks, C., van Weeren, R. J., Wijnholds, S. J., Wise, M. W., Wucknitz, O., Yatawatta, S., Zarka, P., Zensus, A., Garsden, H., Girard, J. N., Starck, J. L., Corbel, S., Tasse, C., Woiselle, A., McKean, J. P., van Amesfoort, A. S., Anderson, J., Avruch, I. M., Beck, R., Bentum, M. J., Best, P., Breitling, F., Broderick, J., Brüggen, M., Butcher, H. R., Ciardi, B., de Gasperin, F., de Geus, E., de Vos, Marco, Duscha, S., Eislöffel, J., Engels, D., Falcke, H., Fallows, R. A., Fender, R., Ferrari, C., Frieswijk, W., Garrett, M. A., Griessmeier, J., Gunst, A. W., Hassall, T. E., Heald, G., Hoeft, M., Hörandel, J., van der Horst, A., Juette, E., Karastergiou, A., Kondratiev, V. I., Kramer, M., Kuniyoshi, M., Kuper, G., Mann, G., Markoff, S., McFadden, R., McKay-Bukowski, D., Mulcahy, D. D., Munk, H., Norden, M. J., Orru, E., Paas, H., Pandey-Pommier, M., Pandey, V. N., Pietka, G., Pizzo, R., Polatidis, A. G., Renting, A., Röttgering, H., Rowlinson, A., Schwarz, D., Sluman, J., Smirnov, O., Stappers, B. W., Steinmetz, M., Stewart, A., Swinbank, J., Tagger, M., Tang, Y., Thoudam, S., Toribio, C., Vermeulen, R., Vocks, C., van Weeren, R. J., Wijnholds, S. J., Wise, M. W., Wucknitz, O., Yatawatta, S., Zarka, P., and Zensus, A.

Abstract

CONTEXT. The LOw Frequency ARray (LOFAR) radio telescope is a giant digital phased array interferometer with multiple antennas distributed in Europe. It provides discrete sets of Fourier components of the sky brightness. Recovering the original brightness distribution with aperture synthesis forms an inverse problem that can be solved by various deconvolution and minimization methods AIMS. Recent papers have established a clear link between the discrete nature of radio interferometry measurement and the "compressed sensing" (CS) theory, which supports sparse reconstruction methods to form an image from the measured visibilities. Empowered by proximal theory, CS offers a sound framework for efficient global minimization and sparse data representation using fast algorithms. Combined with instrumental direction-dependent effects (DDE) in the scope of a real instrument, we developed and validated a new method based on this framework METHODS. We implemented a sparse reconstruction method in the standard LOFAR imaging tool and compared the photometric and resolution performance of this new imager with that of CLEAN-based methods (CLEAN and MS-CLEAN) with simulated and real LOFAR data Results. We show that i) sparse reconstruction performs as well as CLEAN in recovering the flux of point sources; ii) performs much better on extended objects (the root mean square error is reduced by a factor of up to 10); and iii) provides a solution with an effective angular resolution 2-3 times better than the CLEAN images. CONCLUSIONS. Sparse recovery gives a correct photometry on high dynamic and wide-field images and improved realistic structures of extended sources (of simulated and real LOFAR datasets). This sparse reconstruction method is compatible with modern interferometric imagers that handle DDE corrections (A- and W-projections) required for current and future instruments such as LOFAR and SKA

Published
2015

19. Wide-field LOFAR imaging of the field around the double-double radio galaxy B1834+620: A fresh view on a restarted AGN and doubeltjes

Author

Orru, E., Van Velzen, S., Pizzo, R., Yatawatta, S., Paladino, R., Iacobelli, M., Murgia, M., Falcke, H., Morganti, R., De Bruyn, A., Ferrari, C., Anderson, J., Bonafede, A., Mulcahy, D., Asgekar, A., Avruch, I., Beck, R., Bell, M., Van Bemmel, I., Bentum, M., Bernardi, G., Best, P., Breitling, F., Broderick, J., Bruggen, M., Butcher, H., Ciardi, B., Conway, J., Corstanje, A., De Geus, E., Deller, A., Duscha, S., Eisloffel, J., Engels, D., Frieswijk, W., Garrett, M., Grießmeier, J., Gunst, A., Hamaker, J., Heald, G., Hoeft, M., Van Der Horst, A., Intema, Hubertus, Juette, E., Kohler, J., Kondratiev, V., Kuniyoshi, M., Kuper, G., Loose, M., Maat, P., Mann, G., Markoff, S., McFadden, R., McKay-BGBRowski, D., Miley, G., Moldon, J., Molenaar, G., Munk, H., Nelles, A., Paas, H., Pandey-Pommier, M., Pandey, V., Pietka, G., Polatidis, A., Reich, W., Rottgering, H., Rowlinson, A., Scaife, A., Schoenmakers, A., Schwarz, D., Serylak, M., Shulevski, A., Smirnov, O., Steinmetz, M., Stewart, A., Swinbank, J., Tagger, M., Tasse, C., Thoudam, S., Toribio, M., Orru, E., Van Velzen, S., Pizzo, R., Yatawatta, S., Paladino, R., Iacobelli, M., Murgia, M., Falcke, H., Morganti, R., De Bruyn, A., Ferrari, C., Anderson, J., Bonafede, A., Mulcahy, D., Asgekar, A., Avruch, I., Beck, R., Bell, M., Van Bemmel, I., Bentum, M., Bernardi, G., Best, P., Breitling, F., Broderick, J., Bruggen, M., Butcher, H., Ciardi, B., Conway, J., Corstanje, A., De Geus, E., Deller, A., Duscha, S., Eisloffel, J., Engels, D., Frieswijk, W., Garrett, M., Grießmeier, J., Gunst, A., Hamaker, J., Heald, G., Hoeft, M., Van Der Horst, A., Intema, Hubertus, Juette, E., Kohler, J., Kondratiev, V., Kuniyoshi, M., Kuper, G., Loose, M., Maat, P., Mann, G., Markoff, S., McFadden, R., McKay-BGBRowski, D., Miley, G., Moldon, J., Molenaar, G., Munk, H., Nelles, A., Paas, H., Pandey-Pommier, M., Pandey, V., Pietka, G., Polatidis, A., Reich, W., Rottgering, H., Rowlinson, A., Scaife, A., Schoenmakers, A., Schwarz, D., Serylak, M., Shulevski, A., Smirnov, O., Steinmetz, M., Stewart, A., Swinbank, J., Tagger, M., Tasse, C., Thoudam, S., and Toribio, M.

Abstract

The existence of double-double radio galaxies (DDRGs) is evidence for recurrent jet activity in active galactic nuclei (AGN), as expected from standard accretion models. A detailed study of these rare sources provides new perspectives for investigating the AGN duty cycle, AGN-galaxy feedback, and accretion mechanisms. Large catalogues of radio sources, on the other hand, provide statistical information about the evolution of the radio-loud AGN population out to high redshifts. Aims. Using wide-field imaging with the LOFAR telescope, we study both a well-known DDRG as well as a large number of radio sources in the field of view. Methods. We present a high resolution image of the DDRG B1834+620 obtained at 144 MHz using LOFAR commissioning data. Our image covers about 100 square degrees and contains over 1000 sources. Results. The four components of the DDRG B1834+620 have been resolved for the first time at 144 MHz. Inner lobes were found to point towards the direction of the outer lobes, unlike standard FR II sources. Polarized emission was detected at +60 rad m-2 in the northern outer lobe. The high spatial resolution allows the identification of a large number of small double-lobed radio sources; roughly 10% of all sources in the field are doubles with a separation smaller than 1'. Conclusions. The spectral fit of the four components is consistent with a scenario in which the outer lobes are still active or the jets recently switched off, while emission of the inner lobes is the result of a mix-up of new and old jet activity. From the presence of the newly extended features in the inner lobes of the DDRG, we can infer that the mechanism responsible for their formation is the bow shock that is driven by the newly launched jet. We find that the density of the small doubles exceeds the density of FR II sources with similar properties at 1.4 GHz, but this difference becomes smaller for low flux densities. Finally, we show that the significant challenges of wide-field

Published
2015

20. 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

21. Wide-field LOFAR imaging of the field around the double-double radio galaxy B1834+620

Author

Orrù, E., primary, van Velzen, S., additional, Pizzo, R. F., additional, Yatawatta, S., additional, Paladino, R., additional, Iacobelli, M., additional, Murgia, M., additional, Falcke, H., additional, Morganti, R., additional, de Bruyn, A. G., additional, Ferrari, C., additional, Anderson, J., additional, Bonafede, A., additional, Mulcahy, D., additional, Asgekar, A., 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, Broderick, J. W., additional, Brüggen, M., additional, Butcher, H. R., additional, Ciardi, B., additional, Conway, J. E., additional, Corstanje, A., additional, de Geus, E., additional, Deller, A., additional, Duscha, S., additional, Eislöffel, J., additional, Engels, D., additional, Frieswijk, W., additional, Garrett, M. A., additional, Grießmeier, J., additional, Gunst, A. W., additional, Hamaker, J. P., additional, Heald, G., additional, Hoeft, M., additional, van der Horst, A. J., additional, Intema, H., additional, Juette, E., additional, Kohler, J., additional, Kondratiev, V. I., additional, Kuniyoshi, M., additional, Kuper, G., additional, Loose, M., additional, Maat, P., additional, Mann, G., additional, Markoff, S., additional, McFadden, R., additional, McKay-Bukowski, D., additional, Miley, G., additional, Moldon, J., additional, Molenaar, G., additional, Munk, H., additional, Nelles, A., additional, Paas, H., additional, Pandey-Pommier, M., additional, Pandey, V. N., additional, Pietka, G., additional, Polatidis, A. G., additional, Reich, W., additional, Röttgering, H., additional, Rowlinson, A., additional, Scaife, A., additional, Schoenmakers, A., additional, Schwarz, D., additional, Serylak, M., additional, Shulevski, A., additional, Smirnov, O., additional, Steinmetz, M., additional, Stewart, A., additional, Swinbank, J., additional, Tagger, M., additional, Tasse, C., additional, Thoudam, S., additional, Toribio, M. C., additional, Vermeulen, R., additional, Vocks, C., additional, van Weeren, R. J., additional, Wijers, R. A. M. J., additional, Wise, M. W., additional, and Wucknitz, O., additional

Published
2015
Full Text
View/download PDF

22. Updated Calibration of the LOFAR Low-Band Antennas.

Author

Riccobene, G., Biagi, S., Capone, A., Distefano, C., Piattelli, P., Mulrey, K., Bonardi, A., Buitink, S., Corstanje, A., Falcke, H., Hare, B.M., Hörandel, J., Mitra, P., Nelles, A., Rachen, J.P., Rossetto, L., Schellart, P., Scholten, O., ter Veen, S., and Thoudam, S.

Subjects
RADIO telescopes, CALIBRATION, COSMIC ray showers, PARTICLE detectors, RADIO antennas
Abstract

The LOw-Frequency ARray (LOFAR) telescope measures radio emission from air showers. In order to interpret the data, an absolute, frequency dependent calibration is required. Due to a growing need for a better understanding of the measured frequency spectrum, we revisit the calibration of the LOFAR antennas in the range of 30—80 MHz. Using the galactic radio emission and a detailed model of the LOFAR signal chain, we find a calibration that provides an absolute energy scale and allows us to study frequency dependent features in measured air shower signals. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

23. 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
Full Text
View/download PDF

24. 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
Full Text
View/download PDF

25. LOFAR sparse image reconstruction

Author

Garsden, H., primary, Girard, J. N., additional, Starck, J. L., additional, Corbel, S., additional, Tasse, C., additional, Woiselle, A., additional, McKean, J. P., additional, van Amesfoort, A. S., additional, Anderson, J., additional, Avruch, I. M., additional, Beck, R., additional, Bentum, M. J., additional, Best, P., additional, Breitling, F., additional, Broderick, J., additional, Brüggen, M., additional, Butcher, H. R., additional, Ciardi, B., additional, de Gasperin, F., additional, de Geus, E., additional, de Vos, M., 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, Hassall, T. E., additional, Heald, G., additional, Hoeft, M., additional, Hörandel, J., additional, van der Horst, A., additional, Juette, E., additional, Karastergiou, A., additional, Kondratiev, V. I., additional, Kramer, M., additional, Kuniyoshi, M., additional, Kuper, G., additional, Mann, G., additional, Markoff, S., additional, McFadden, R., additional, McKay-Bukowski, D., additional, Mulcahy, D. D., additional, Munk, H., 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, Renting, A., additional, Röttgering, H., additional, Rowlinson, A., additional, Schwarz, D., additional, Sluman, J., additional, Smirnov, O., additional, Stappers, B. W., additional, Steinmetz, M., additional, Stewart, A., additional, Swinbank, J., additional, Tagger, M., additional, Tang, Y., additional, Thoudam, S., additional, Toribio, C., additional, Vermeulen, R., additional, Vocks, C., additional, van Weeren, R. J., additional, Wijnholds, S. J., additional, Wise, M. W., additional, Wucknitz, O., additional, Yatawatta, S., additional, Zarka, P., additional, and Zensus, A., additional

Published
2015
Full Text
View/download PDF

26. The LOFAR long baseline snapshot calibrator survey

Author

Moldón, J., primary, Deller, A. T., additional, Wucknitz, O., additional, Jackson, N., additional, Drabent, A., additional, Carozzi, T., additional, Conway, J., additional, Kapińska, A. D., additional, McKean, J. P., additional, Morabito, L., additional, Varenius, E., additional, Zarka, P., 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, Bregman, J., additional, Breitling, F., additional, Broderick, J. W., additional, Brüggen, M., additional, Butcher, H. R., additional, Carbone, D., additional, Ciardi, B., additional, de Gasperin, F., 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, Hamaker, J. P., additional, Hassall, T. E., additional, Heald, G., additional, Hoeft, M., 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, Markoff, S., additional, McFadden, R., additional, McKay-Bukowski, D., additional, Morganti, R., additional, Munk, H., additional, Norden, M. J., additional, Offringa, A. R., additional, Orru, E., additional, Paas, H., additional, Pandey-Pommier, M., 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, Sluman, J., additional, Smirnov, O., additional, Stappers, B. W., additional, Steinmetz, M., additional, Tagger, M., additional, Tang, Y., additional, Tasse, C., additional, Thoudam, S., additional, Toribio, M. C., additional, Vermeulen, R., additional, Vocks, C., additional, van Weeren, R. J., additional, White, S., additional, Wise, M. W., additional, Yatawatta, S., additional, and Zensus, A., additional

Published
2015
Full Text
View/download PDF

27. The LOFAR pilot surveys for pulsars and fast radio transients

Author

Coenen, Thijs, primary, van Leeuwen, Joeri, additional, Hessels, Jason W. T., additional, Stappers, Ben W., additional, Kondratiev, Vladislav I., additional, Alexov, A., additional, Breton, R. P., additional, Bilous, A., additional, Cooper, S., additional, Falcke, H., additional, Fallows, R. A., additional, Gajjar, V., additional, Grießmeier, J.-M., additional, Hassall, T. E., additional, Karastergiou, A., additional, Keane, E. F., additional, Kramer, M., additional, Kuniyoshi, M., additional, Noutsos, A., additional, Osłowski, S., additional, Pilia, M., additional, Serylak, M., additional, Schrijvers, C., additional, Sobey, C., additional, ter Veen, S., additional, Verbiest, J., additional, Weltevrede, P., additional, Wijnholds, S., additional, Zagkouris, K., additional, van Amesfoort, A. S., 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, Bonafede, A., additional, Breitling, F., additional, Broderick, J., additional, Brüggen, M., additional, Butcher, H. R., additional, Ciardi, B., additional, Corstanje, A., additional, Deller, A., additional, Duscha, S., additional, Eislöffel, J., additional, Fender, R., additional, Ferrari, C., additional, Frieswijk, W., additional, Garrett, M. A., additional, de Gasperin, F., additional, de Geus, E., additional, Gunst, A. W., additional, Hamaker, J. P., additional, Heald, G., additional, Hoeft, M., additional, van der Horst, A., additional, Juette, E., additional, Kuper, G., additional, Law, C., additional, Mann, G., additional, McFadden, R., additional, McKay-Bukowski, D., additional, McKean, J. P., additional, Munk, H., additional, Orru, E., additional, Paas, H., additional, Pandey-Pommier, M., additional, Polatidis, A. G., additional, Reich, W., additional, Renting, A., additional, Röttgering, H., additional, Rowlinson, A., additional, Scaife, A. M. M., additional, Schwarz, D., additional, Sluman, J., additional, Smirnov, O., additional, Swinbank, J., additional, Tagger, M., additional, Tang, Y., additional, Tasse, C., additional, Thoudam, S., additional, Toribio, C., additional, Vermeulen, R., additional, Vocks, C., additional, van Weeren, R. J., additional, Wucknitz, O., additional, Zarka, P., additional, and Zensus, A., additional

Published
2014
Full Text
View/download PDF

28. 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
Full Text
View/download PDF

29. 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
Full Text
View/download PDF

30. 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

31. 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
Full Text
View/download PDF

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
Full Text
View/download PDF

33. Wide-field LOFAR imaging of the field around the double-double radio galaxy B1834+620

Author

E. Orrù, S. van Velzen, R. F. Pizzo, S. Yatawatta, R. Paladino, M. Iacobelli, M. Murgia, H. Falcke, R. Morganti, A. G. de Bruyn, C. Ferrari, J. Anderson, A. Bonafede, D. Mulcahy, A. Asgekar, I. M. Avruch, R. Beck, M. E. Bell, I. van Bemmel, M. J. Bentum, G. Bernardi, P. Best, F. Breitling, J. W. Broderick, M. Brüggen, H. R. Butcher, B. Ciardi, J. E. Conway, A. Corstanje, E. de Geus, A. Deller, S. Duscha, J. Eislöffel, D. Engels, W. Frieswijk, M. A. Garrett, J. Grießmeier, A. W. Gunst, J. P. Hamaker, G. Heald, M. Hoeft, A. J. van der Horst, H. Intema, E. Juette, J. Kohler, V. I. Kondratiev, M. Kuniyoshi, G. Kuper, M. Loose, P. Maat, G. Mann, S. Markoff, R. McFadden, D. McKay-Bukowski, G. Miley, J. Moldon, G. Molenaar, H. Munk, A. Nelles, H. Paas, M. Pandey-Pommier, V. N. Pandey, G. Pietka, A. G. Polatidis, W. Reich, H. Röttgering, A. Rowlinson, A. Scaife, A. Schoenmakers, D. Schwarz, M. Serylak, A. Shulevski, O. Smirnov, M. Steinmetz, A. Stewart, J. Swinbank, M. Tagger, C. Tasse, S. Thoudam, M. C. Toribio, R. Vermeulen, C. Vocks, R. J. van Weeren, R. A. M. J. Wijers, M. W. Wise, O. Wucknitz, High Energy Astrophys. & Astropart. Phys (API, FNWI), Kapteyn Astronomical Institute, Astronomy, Orru, E., Van Velzen, S., Pizzo, R.F., Yatawatta, S., Paladino, R., Iacobelli, M., Murgia, M., Falcke, H., Morganti, R., De Bruyn, A.G., Ferrari, C., Anderson, J., Bonafede, A., Mulcahy, D., Asgekar, A., Avruch, I.M., Beck, R., Bell, M.E., Van Bemmel, I., Bentum, M.J., Bernardi, G., Best, P., Breitling, F., Broderick, J.W., Bruggen, M., Butcher, H.R., Ciardi, B., Conway, J.E., Corstanje, A., De Geus, E., Deller, A., Duscha, S., Eisloffel, J., Engels, D., Frieswijk, W., Garrett, M.A., Grießmeier, J., Gunst, A.W., Hamaker, J.P., Heald, G., Hoeft, M., Van Der Horst, A.J., Intema, H., Juette, E., Kohler, J., Kondratiev, V.I., Kuniyoshi, M., Kuper, G., Loose, M., Maat, P., Mann, G., Markoff, S., McFadden, R., McKay-BGBRowski, D., Miley, G., Moldon, J., Molenaar, G., Munk, H., Nelles, A., Paas, H., Pandey-Pommier, M., Pandey, V.N., Pietka, G., Polatidis, A.G., Reich, W., Rottgering, H., Rowlinson, A., Scaife, A., Schoenmakers, A., Schwarz, D., Serylak, M., Shulevski, A., Smirnov, O., Steinmetz, M., Stewart, A., Swinbank, J., Tagger, M., Tasse, C., Thoudam, S., Toribio, M.C., Vermeulen, R., Vocks, C., Van Weeren, R.J., Wijers, R.A.M.J., Wise, M.W., and Wucknitz, O.

Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO), Radio galaxy, Astrophysics::High Energy Astrophysical Phenomena, interferometers [instrumentation], galaxies: active, Population, FOS: Physical sciences, Field of view, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Astroparticle physic, Radio continuum: galaxie, 01 natural sciences, Instrumentation: interferometer, law.invention, Telescope, law, 0103 physical sciences, Bow shock (aerodynamics), instrumentation: interferometers, education, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, radio continuum: galaxies, Physics, education.field_of_study, Accretion (meteorology), 010308 nuclear & particles physics, Astronomy and Astrophysics, LOFAR, Astronomy and Astrophysic, radiation mechanisms: non-thermal, non-thermal [radiation mechanisms], Astrophysics - Astrophysics of Galaxies, galaxies [radio continuum], Redshift, interferometric [techniques], techniques: interferometric, astroparticle physics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), active [galaxies], Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

The existence of double-double radio galaxies (DDRGs) is evidence for recurrent jet activity in AGN, as expected from standard accretion models. A detailed study of these rare sources provides new perspectives for investigating the AGN duty cycle, AGN-galaxy feedback, and accretion mechanisms. Large catalogues of radio sources provide statistical information about the evolution of the radio-loud AGN population out to high redshifts. Using wide-field imaging with the LOFAR telescope, we study both a well-known DDRG as well as a large number of radio sources in the field of view. We present a high resolution image of the DDRG B1834+620 obtained at 144 MHz using LOFAR commissioning data. Our image covers about 100 square degrees and contains over 1000 sources. The four components of the DDRG B1834+620 have been resolved for the first time at 144 MHz. Inner lobes were found to point towards the direction of the outer lobes, unlike standard FR~II sources. Polarized emission was detected in the northern outer lobe. The high spatial resolution allows the identification of a large number of small double-lobed radio sources; roughly 10% of all sources in the field are doubles with a separation smaller than 1 arcmin. The spectral fit of the four components is consistent with a scenario in which the outer lobes are still active or the jets recently switched off, while emission of the inner lobes is the result of a mix-up of new and old jet activity. From the presence of the newly extended features in the inner lobes of the DDRG, we can infer that the mechanism responsible for their formation is the bow shock that is driven by the newly launched jet. We find that the density of the small doubles exceeds the density of FR-II sources with similar properties at 1.4 GHz, but this difference becomes smaller for low flux densities., Comment: 13 pages, 8 figures, Accepted for publication in Astronomy & Astrophysics

Published
2015

Catalog

Books, media, physical & digital resources
See catalog results