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Your search keyword '"McFadden, R. A."' showing total 18 results
Start Over Author "McFadden, R. A." Publisher edp sciences
18 results on '"McFadden, R. A."'

1. 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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2. 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
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3. 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

4. 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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5. 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
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6. 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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7. 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

8. 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

9. 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

10. 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
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11. 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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12. 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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13. 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
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14. 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
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15. The LOFAR pilot surveys for pulsars and fast radio transients

Author

Coenen, T., Van Leeuwen, J., Hessels, J., Stappers, B., Kondratiev, V., Alexov, A., Breton, R., Bilous, A., Cooper, S., Falcke, H., Fallows, R., Gajjar, V., Grießmeier, J., Hassall, T., Karastergiou, A., Keane, E., Kramer, M., Kuniyoshi, M., Noutsos, A., Oslowski, S., Pilia, M., Serylak, M., Schrijvers, C., Sobey, Charlotte, Ter Veen, S., Verbiest, J., Weltevrede, P., Wijnholds, S., Zagkouris, K., Van Amesfoort, A., Anderson, J., Asgekar, A., Avruch, I., Bell, M., Bentum, M., Bernardi, G., Best, P., Bonafede, A., Breitling, F., Broderick, J., Brüggen, M., Butcher, H., Ciardi, B., Corstanje, A., Deller, A., Duscha, S., Eislöffel, J., Fender, R., Ferrari, C., Frieswijk, W., Garrett, M., De Gasperin, F., De Geus, E., Gunst, A., Hamaker, J., Heald, G., Hoeft, M., Van Der Horst, A., Juette, E., Kuper, G., Law, C., Mann, G., McFadden, R., McKay-Bukowski, D., McKean, J., Munk, H., Orru, E., Paas, H., Pandey-Pommier, M., Polatidis, A., Reich, W., Renting, A., Röttgering, H., Rowlinson, A., Scaife, A., Schwarz, D., Sluman, J., Smirnov, O., Swinbank, J., Coenen, T., Van Leeuwen, J., Hessels, J., Stappers, B., Kondratiev, V., Alexov, A., Breton, R., Bilous, A., Cooper, S., Falcke, H., Fallows, R., Gajjar, V., Grießmeier, J., Hassall, T., Karastergiou, A., Keane, E., Kramer, M., Kuniyoshi, M., Noutsos, A., Oslowski, S., Pilia, M., Serylak, M., Schrijvers, C., Sobey, Charlotte, Ter Veen, S., Verbiest, J., Weltevrede, P., Wijnholds, S., Zagkouris, K., Van Amesfoort, A., Anderson, J., Asgekar, A., Avruch, I., Bell, M., Bentum, M., Bernardi, G., Best, P., Bonafede, A., Breitling, F., Broderick, J., Brüggen, M., Butcher, H., Ciardi, B., Corstanje, A., Deller, A., Duscha, S., Eislöffel, J., Fender, R., Ferrari, C., Frieswijk, W., Garrett, M., De Gasperin, F., De Geus, E., Gunst, A., Hamaker, J., Heald, G., Hoeft, M., Van Der Horst, A., Juette, E., Kuper, G., Law, C., Mann, G., McFadden, R., McKay-Bukowski, D., McKean, J., Munk, H., Orru, E., Paas, H., Pandey-Pommier, M., Polatidis, A., Reich, W., Renting, A., Röttgering, H., Rowlinson, A., Scaife, A., Schwarz, D., Sluman, J., Smirnov, O., and Swinbank, J.

Abstract

© 2014 ESO .We have conducted two pilot surveys for radio pulsars and fast transients with the Low-Frequency Array (LOFAR) around 140 MHz and here report on the first low-frequency fast-radio burst limit and the discovery of two new pulsars. The first survey, the LOFAR Pilot Pulsar Survey (LPPS), observed a large fraction of the northern sky, ~ 1.4 × 104 deg2, with 1 h dwell times. Each observation covered ~75 deg2 using 7 independent fields formed by incoherently summing the high-band antenna fields. The second pilot survey, the LOFAR Tied-Array Survey (LOTAS), spanned ~600 deg2, with roughly a 5-fold increase in sensitivity compared with LPPS. Using a coherent sum of the 6 LOFAR "Superterp" stations, we formed 19 tied-array beams, together covering 4 deg2 per pointing. From LPPS we derive a limit on the occurrence, at 142 MHz, of dispersed radio bursts of < 150 day-1 sky-1, for bursts brighter than S> 107 Jy for the narrowest searched burst duration of 0.66 ms. In LPPS, we re-detected 65 previously known pulsars. LOTAS discovered two pulsars, the first with LOFAR or any digital aperture array. LOTAS also re-detected 27 previously known pulsars. These pilot studies show that LOFAR can efficiently carry out all-sky surveys for pulsars and fast transients, and they set the stage for further surveying efforts using LOFAR and the planned low-frequency component of the Square Kilometer Array.

Published
2014

16. 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
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17. 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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18. 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
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