English
Related papers

Related papers: LOFAR: Recent imaging results & future prospects

200 papers

Large-format (sub)millimeter wavelength imaging arrays are best operated in scanning observing modes rather than traditional position-switched (chopped) modes. The choice of observing mode is critical for isolating source signals from…

Astrophysics · Physics 2014-11-18 A. Kovacs

Large radio telescopes in the 21st century such as the Low-Frequency Array (LOFAR) or the Murchison Widefield Array (MWA) make use of phased aperture arrays of antennas to achieve superb survey speeds. The Square Kilometer Array low…

Instrumentation and Methods for Astrophysics · Physics 2017-12-06 Ha Bui-Van , Christophe Craeye , Eloy de Lera Acedo

We determined Faraday rotation measures (RMs) towards 137 pulsars in the northern sky, using Low-Frequency Array (LOFAR) observations at 110-190 MHz. This low-frequency RM catalogue, the largest to date, improves the precision of existing…

The application of the non conventional imaging technique LOFI (Laser Optical Feedback Imaging) to coherent microscopy is presented. This simple and efficient technique using frequency-shifted optical feedback needs the sample to be scanned…

The energy reconstruction of extensive air showers measured with the LOFAR Radboud Air Shower Array (LORA) is presented in detail. LORA is a particle detector array located in the center of the LOFAR radio telescope in the Netherlands. The…

One of the key science projects of the Low-Frequency Array (LOFAR) is the detection of the cosmological signal coming from the Epoch of Reionization (EoR). Here we present the LOFAR EoR Diagnostic Database (LEDDB) that is used in the…

Instrumentation and Methods for Astrophysics · Physics 2013-02-20 O. Martinez-Rubi , V. K. Veligatla , A. G. de Bruyn , P. Lampropoulos , A. R. Offringa , V. Jelic , S. Yatawatta , L. V. E. Koopmans , S. Zaroubi

Low-frequency radio astronomy is limited by severe ionospheric distortions below 50 MHz and complete reflection of radio waves below 10-30 MHz. Shielding of man-made interference from long-range radio broadcasts, strong natural radio…

Cosmology and Nongalactic Astrophysics · Physics 2009-03-09 Sebastian Jester , Heino Falcke

In this paper we present the Low Frequency Instrument (LFI), designed and developed as part of the Planck space mission, the ESA program dedicated to precision imaging of the cosmic microwave background (CMB). Planck-LFI will observe the…

Instrumentation and Methods for Astrophysics · Physics 2015-05-18 M. Bersanelli , N. Mandolesi , R. C. Butler , A. Mennella , F. Villa , B. Aja , E. Artal , E. Artina , C. Baccigalupi , M. Balasini , G. Baldan , A. Banday , P. Bastia , P. Battaglia , T. Bernardino , E. Blackhurst , L. Boschini , C. Burigana , G. Cafagna , B. Cappellini , F. Cavaliere , F. Colombo , G. Crone , F. Cuttaia , O. D'Arcangelo , L. Danese , R. D. Davies , R. J. Davis , L. De Angelis , G. C. De Gasperis , L. De La Fuente , A. De Rosa , G. De Zotti , M. C. Falvella , F. Ferrari , R. Ferretti , L. Figini , S. Fogliani , C. Franceschet , E. Franceschi , T. Gaier , S. Garavaglia , F. Gomez , K. Gorski , A. Gregorio , P. Guzzi , J. M. Herreros , S. R. Hildebrandt , R. Hoyland , N. Hughes , M. Janssen , P. Jukkala , D. Kettle , V. H. Kilpia , M. Laaninen , P. M. Lapolla , C. R. Lawrence , J. P. Leahy , R. Leonardi , P. Leutenegger , S. Levin , P. B. Lilje , S. R. Lowe , D. Lawson P. M. Lubin , D. Maino , M. Malaspina , M. Maris , J. Marti-Canales , E. Martinez-Gonzalez , A. Mediavilla , P. Meinhold , M. Miccolis , G. Morgante , P. Natoli , R. Nesti , L. Pagan , C. Paine , B. Partridge , J. P. Pascual , F. Pasian , D. Pearson , M. Pecora , F. Perrotta , P. Platania , M. Pospieszalski , T. Poutanen , M. Prina , R. Rebolo , N. Roddis , J. A. Rubino-Martin , n M. J. Salmon , M. Sandri , M. Seiffert , R. Silvestri , A. Simonetto , P. Sjoman , G. F. Smoot , C. Sozzi , L. Stringhetti , E. Taddei , J. Tauber , L. Terenzi , M. Tomasi , J. Tuovinen , L. Valenziano , J. Varis , N. Vittorio , L. A. Wade , A. Wilkinson , F. Winder , A. Zacchei , A. Zonca

The radio sky at lower frequencies, particularly below 20 MHz, is expected to be a combination of increasingly bright non-thermal emission and significant absorption from intervening thermal plasma. The sky maps at these frequencies cannot…

Instrumentation and Methods for Astrophysics · Physics 2021-09-01 Akhil Jaini , Avinash A. Deshpande , Sainath Bitragunta

The Ultra-Long Wavelength (ULW) regime of longer than 10 m (corresponding to frequencies below 30 MHz), remains as the last virtually unexplored window in radio astronomy, and is presently attracting considerable attention as an area of…

Instrumentation and Methods for Astrophysics · Physics 2019-09-04 Linjie Chen , Yihua Yan

We present the upGREAT THz heterodyne arrays for far-infrared astronomy. The Low Frequency Array (LFA) is designed to cover the 1.9-2.5 THz range using 2x7-pixel waveguide-based HEB mixer arrays in a dual polarization configuration. The…

In almost 30 years of operation, the Very Large Array (VLA) has proved to be a remarkably flexible and productive radio telescope. However, the basic capabilities of the VLA have changed little since it was designed. A major expansion…

Instrumentation and Methods for Astrophysics · Physics 2015-05-14 R. Perley , P. Napier , J. Jackson , B. Butler , B. Carlson , D. Fort , P. Dewdney , B. Clark , R. Hayward , S. Durand , M. Revnell , M. McKinnon

We present LOFAR High-Band Array (HBA) observations of the Herschel-ATLAS North Galactic Pole survey area. The survey we have carried out, consisting of four pointings covering around 142 square degrees of sky in the frequency range…

We have used LOFAR to perform targeted millisecond pulsar surveys of Fermi gamma-ray sources. Operating at a center frequency of 135 MHz, the surveys use a novel semi-coherent dedispersion approach where coherently dedispersed trials at…

When an ultra-high energy neutrino or cosmic ray strikes the Lunar surface a radio-frequency pulse is emitted. We plan to use the LOFAR radio telescope to detect these pulses. In this work we propose an efficient trigger implementation for…

In radio astronomy, holography is a commonly used technique to create an image of the electric field distribution in the aperture of a dish antenna. The image is used to detect imperfections in the reflector surface. Similarly, holography…

Instrumentation and Methods for Astrophysics · Physics 2021-06-09 U. Kiefner , R. B. Wayth , D. B. Davidson , M. Sokolowski

The Large Array Survey Telescope (LAST) is designed to survey the variable and transient sky at high temporal cadence. The array is comprised of 48 F/2.2 telescopes of 27.9cm aperture, coupled to full-frame backside-illuminated cooled CMOS…

This article reports the advances on the development of mid-infrared integrated optics for stellar interferometry. The devices are fabricated by laser writing techniques on chalcogenide glasses. Laboratory characterizaton is reported and…

Instrumentation and Methods for Astrophysics · Physics 2015-06-05 L. Labadie , Guillermo Martin , Airan Rodenas , Norman C. Anheier , Brahim Arezki , Robert R. Thomson , Hong A. Qiao , Pierre Kern , Ajoy K. Kar , Bruce E. Bernacki

Since radio continuum observations are not affected by dust obscuration, they are of immense potential diagnostic power as cosmological probes and for studying galaxy formation and evolution out to high redshifts. However, the power-law…

Astrophysics of Galaxies · Physics 2015-06-19 Daniel J. B. Smith

In this paper we present the European Low Frequency Survey (ELFS), a project that will enable foregrounds-free measurements of the primordial $B$-mode polarization and a detection of the tensor-to-scalar ratio, $r$, to a level $\sigma(r) =…