Gamma-ray astronomy

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The Hot and Energetic Universe: Luminous extragalactic transients

(2013)

Authors:

Peter Jonker, Paul O'Brien, Lorenzo Amati, Jean-Luc Atteia, Sergio Campana, Phil Evans, Rob Fender, Chryssa Kouveliotou, Giuseppe Lodato, Julian Osborne, Luigi Piro, Arne Rau, Nial Tanvir, Richard Willingale
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A return to strong radio flaring by Circinus X-1 observed with the Karoo Array Telescope test array KAT-7

(2013)

Authors:

RP Armstrong, RP Fender, GD Nicolson, S Ratcliffe, M Linares, J Horrell, L Richter, MPE Schurch, M Coriat, P Woudt, J Jonas, R Booth, B Fanaroff
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LOFAR: The LOw-Frequency ARray

ArXiv 1305.355 (2013)

Authors:

MP van Haarlem, MW Wise, AW Gunst, G Heald, JP McKean, JWT Hessels, AG de Bruyn, R Nijboer, J Swinbank, R Fallows, M Brentjens, A Nelles, R Beck, H Falcke, R Fender, J Hörandel, LVE Koopmans, G Mann, G Miley, H Röttgering, BW Stappers, RAMJ Wijers, S Zaroubi, M van den Akker, A Alexov, J Anderson, K Anderson, A van Ardenne, M Arts, A Asgekar, IM Avruch, F Batejat, L Bähren, ME Bell, MR Bell, I van Bemmel, P Bennema, MJ Bentum, G Bernardi, P Best, L Bîrzan, A Bonafede, A-J Boonstra, R Braun, J Bregman, F Breitling, RH van de Brink, J Broderick, PC Broekema, WN Brouw, M Brüggen, HR Butcher, W van Cappellen, B Ciardi, T Coenen, J Conway, A Coolen, A Corstanje, S Damstra, O Davies, AT Deller, R-J Dettmar, G van Diepen, K Dijkstra, P Donker, A Doorduin, J Dromer, M Drost, A van Duin, J Eislöffel, J van Enst, C Ferrari, W Frieswijk, H Gankema, MA Garrett, F de Gasperin, M Gerbers, E de Geus, J-M Grießmeier, T Grit, P Gruppen, JP Hamaker, T Hassall, M Hoeft, H Holties, A Horneffer, A van der Horst, A van Houwelingen, A Huijgen, M Iacobelli, H Intema, N Jackson, V Jelic, A de Jong, E Juette, D Kant, A Karastergiou, A Koers, H Kollen, VI Kondratiev, E Kooistra, Y Koopman, A Koster, M Kuniyoshi, M Kramer, G Kuper, P Lambropoulos, C Law, J van Leeuwen, J Lemaitre, M Loose, P Maat, G Macario, S Markoff, J Masters, D McKay-Bukowski, H Meijering, H Meulman, M Mevius, E Middelberg, R Millenaar, JCA Miller-Jones, RN Mohan, JD Mol, J Morawietz, R Morganti, DD Mulcahy, E Mulder, H Munk, L Nieuwenhuis, R van Nieuwpoort, JE Noordam, M Norden, A Noutsos, AR Offringa, H Olofsson, A Omar, E Orrú, R Overeem, H Paas, M Pandey-Pommier, VN Pandey, R Pizzo, A Polatidis, D Rafferty, S Rawlings, W Reich, J-P de Reijer, J Reitsma, A Renting, P Riemers, E Rol, JW Romein, J Roosjen, M Ruiter, A Scaife, K van der Schaaf, B Scheers, P Schellart, A Schoenmakers, G Schoonderbeek, M Serylak, A Shulevski, J Sluman, O Smirnov, C Sobey, H Spreeuw, M Steinmetz, CGM Sterks, H-J Stiepel, K Stuurwold, M Tagger, Y Tang, C Tasse, I Thomas, S Thoudam, MC Toribio, B van der Tol, O Usov, M van Veelen, A-J van der Veen, S ter Veen, JPW Verbiest, R Vermeulen, N Vermaas, C Vocks, C Vogt, M de Vos, E van der Wal, R van Weeren, H Weggemans, P Weltevrede, S White, SJ Wijnholds, T Wilhelmsson, O Wucknitz, S Yatawatta, P Zarka, A Zensus, J van Zwieten

Abstract:

LOFAR, the LOw-Frequency ARray, is a new-generation radio interferometer constructed in the north of the Netherlands and across europe. Utilizing a novel phased-array design, LOFAR covers the largely unexplored low-frequency range from 10-240 MHz and provides a number of unique observing capabilities. Spreading out from a core located near the village of Exloo in the northeast of the Netherlands, a total of 40 LOFAR stations are nearing completion. A further five stations have been deployed throughout Germany, and one station has been built in each of France, Sweden, and the UK. Digital beam-forming techniques make the LOFAR system agile and allow for rapid repointing of the telescope as well as the potential for multiple simultaneous observations. With its dense core array and long interferometric baselines, LOFAR achieves unparalleled sensitivity and angular resolution in the low-frequency radio regime. The LOFAR facilities are jointly operated by the International LOFAR Telescope (ILT) foundation, as an observatory open to the global astronomical community. LOFAR is one of the first radio observatories to feature automated processing pipelines to deliver fully calibrated science products to its user community. LOFAR's new capabilities, techniques and modus operandi make it an important pathfinder for the Square Kilometre Array (SKA). We give an overview of the LOFAR instrument, its major hardware and software components, and the core science objectives that have driven its design. In addition, we present a selection of new results from the commissioning phase of this new radio observatory.
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LOFAR: The LOw-Frequency ARray

(2013)

Authors:

MP van Haarlem, MW Wise, AW Gunst, G Heald, JP McKean, JWT Hessels, AG de Bruyn, R Nijboer, J Swinbank, R Fallows, M Brentjens, A Nelles, R Beck, H Falcke, R Fender, J Hörandel, LVE Koopmans, G Mann, G Miley, H Röttgering, BW Stappers, RAMJ Wijers, S Zaroubi, M van den Akker, A Alexov, J Anderson, K Anderson, A van Ardenne, M Arts, A Asgekar, IM Avruch, F Batejat, L Bähren, ME Bell, MR Bell, I van Bemmel, P Bennema, MJ Bentum, G Bernardi, P Best, L Bîrzan, A Bonafede, A-J Boonstra, R Braun, J Bregman, F Breitling, RH van de Brink, J Broderick, PC Broekema, WN Brouw, M Brüggen, HR Butcher, W van Cappellen, B Ciardi, T Coenen, J Conway, A Coolen, A Corstanje, S Damstra, O Davies, AT Deller, R-J Dettmar, G van Diepen, K Dijkstra, P Donker, A Doorduin, J Dromer, M Drost, A van Duin, J Eislöffel, J van Enst, C Ferrari, W Frieswijk, H Gankema, MA Garrett, F de Gasperin, M Gerbers, E de Geus, J-M Grießmeier, T Grit, P Gruppen, JP Hamaker, T Hassall, M Hoeft, H Holties, A Horneffer, A van der Horst, A van Houwelingen, A Huijgen, M Iacobelli, H Intema, N Jackson, V Jelic, A de Jong, E Juette, D Kant, A Karastergiou, A Koers, H Kollen, VI Kondratiev, E Kooistra, Y Koopman, A Koster, M Kuniyoshi, M Kramer, G Kuper, P Lambropoulos, C Law, J van Leeuwen, J Lemaitre, M Loose, P Maat, G Macario, S Markoff, J Masters, D McKay-Bukowski, H Meijering, H Meulman, M Mevius, E Middelberg, R Millenaar, JCA Miller-Jones, RN Mohan, JD Mol, J Morawietz, R Morganti, DD Mulcahy, E Mulder, H Munk, L Nieuwenhuis, R van Nieuwpoort, JE Noordam, M Norden, A Noutsos, AR Offringa, H Olofsson, A Omar, E Orrú, R Overeem, H Paas, M Pandey-Pommier, VN Pandey, R Pizzo, A Polatidis, D Rafferty, S Rawlings, W Reich, J-P de Reijer, J Reitsma, A Renting, P Riemers, E Rol, JW Romein, J Roosjen, M Ruiter, A Scaife, K van der Schaaf, B Scheers, P Schellart, A Schoenmakers, G Schoonderbeek, M Serylak, A Shulevski, J Sluman, O Smirnov, C Sobey, H Spreeuw, M Steinmetz, CGM Sterks, H-J Stiepel, K Stuurwold, M Tagger, Y Tang, C Tasse, I Thomas, S Thoudam, MC Toribio, B van der Tol, O Usov, M van Veelen, A-J van der Veen, S ter Veen, JPW Verbiest, R Vermeulen, N Vermaas, C Vocks, C Vogt, M de Vos, E van der Wal, R van Weeren, H Weggemans, P Weltevrede, S White, SJ Wijnholds, T Wilhelmsson, O Wucknitz, S Yatawatta, P Zarka, A Zensus, J van Zwieten
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Bounds on the density of sources of ultra-high energy cosmic rays from the Pierre Auger Observatory

JCAP 1305:5 (2013) 009

Abstract:

We derive lower bounds on the density of sources of ultra-high energy cosmic rays from the lack of significant clustering in the arrival directions of the highest energy events detected at the Pierre Auger Observatory. The density of uniformly distributed sources of equal intrinsic intensity was found to be larger than $\sim (0.06 - 5) \times 10^{-4}$ Mpc$^{-3}$ at 95% CL, depending on the magnitude of the magnetic deflections. Similar bounds, in the range $(0.2 - 7) \times 10^{-4}$ Mpc$^{-3}$, were obtained for sources following the local matter distribution.
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