A broadband FFT spectrometer for radio and millimeter astronomy

The core architecture, tests in the lab and first results of a Fast Fourier Transform (FFT) spectrometer are described. It is based on a commercially available fast digital sampler (AC240) with an on-board Field Programmable Gate Array (FPGA). The spectrometer works continuously and has a remarkable total bandwidth of 1 GHz, resolved into 16384 channels. The data is sampled with 8 bits, yielding a dynamic range of 48 dB. An Allan time of more than 2000 s and an SFDR of 37 dB were measured. First light observations with the KOSMA telescope show a perfect spectrum without internal or external spurious signals.Comment: Astronomy and Astrophysics, in pres

Extreme Kinematics of the 2017 September 10 Solar Eruption and the Spectral Characteristics of the Associated Energetic Particles

We report on the 2017 September 10 ground level enhancement (GLE) event associated with a coronal mass ejection (CME) whose initial acceleration (~9.1km s^-2) and initial speed (~4300 km/s) were among the highest observed in the SOHO era. The GLE event was of low intensity (~4.4% above background) and softer-than-average fluence spectrum. We suggest that poor connectivity (longitudinal and latitudinal) of the source to Earth compounded by the weaker ambient magnetic field contributed to these GLE properties. Events with similar high initial speed either lacked GLE association or had softer fluence spectra. The shock-formation height inferred from the metric type II burst was ~1.4 Rs, consistent with other GLE events. The shock height at solar particle release (SPR) was ~4.4+/-0.38 Rs, consistent with the parabolic relationship between the shock height at SPR and source longitude. At SPR, the eastern flank of the shock was observed in EUV projected on the disk near the longitudes magnetically connected to Earth: W60 to W45.Comment: 13 pages, 5 figures, to appear in the Astrophysical Journal Letter

A World-Wide Net of Solar Radio Spectrometers: e-CALLISTO

Radio spectrometers of the CALLISTO type to observe solar flares have been distributed to nine locations around the globe. The instruments observe automatically, their data is collected every day via internet and stored in a central data base. A public web-interface exists through which data can be browsed and retrieved. The nine instruments form a network called e-CALLISTO. It is still growing in the number of stations, as redundancy is desirable for full 24h coverage of the solar radio emission in the meter and low decimeter band. The e-CALLISTO system has already proven to be a valuable new tool for monitoring solar activity and for space weather researc

Geomagnetic storm related to intense solar radio burst type II and III due to M3.9 class flare and coronal mass ejections

The strong energetic particles ejected during sun’s activity will propagate towards earth and contribute to solar radio bursts. These solar radio bursts can be detected using CALLISTO system. The open website of the NASA provides us the data including CALLISTO, TESIS, solar  monitor,  SOHO  and  space  weather.  The type  III  and  II  solar radio  burst  on  9th November 2015 due to M3.9 class solar flare and coronal mass ejections event has expected to cause the geomagnetic storm on 11th November 2015. The geomagnetic storm reached the Earth a day earlier than expected date due to high speed coronal mass ejections that more than 950 km/s and high energy of ejected particle that causes the M3.9 class flare and coronal mass ejections. The geomagnetic storm luckily does not give high impact on earth because the event on sun, which triggered this storm not heading toward earth.Keywords: solar radio burst; coronal mass ejections; geomagnetic storm; solar flar

Molecular identification of CTX-M and blaOXY/K1 β-lactamase genes in Enterobacteriaceae by sequencing of universal M13-sequence tagged PCR-amplicons

<p>Abstract</p> <p>Background</p> <p>Plasmid encoded ^<it>bla</it>CTX-M enzymes represent an important sub-group of class A β-lactamases causing the ESBL phenotype which is increasingly found in <it>Enterobacteriaceae </it>including <it>Klebsiella </it>spp. Molecular typing of clinical ESBL-isolates has become more and more important for prevention of the dissemination of ESBL-producers among nosocomial environment.</p> <p>Methods</p> <p>Multiple displacement amplified DNA derived from 20 <it>K. pneumoniae </it>and 34 <it>K. oxytoca </it>clinical isolates with an ESBL-phenotype was used in a universal CTX-M PCR amplification assay. Identification and differentiation of ^<it>bla</it>CTX-M and ^<it>bla</it>OXY/K1 sequences was obtained by DNA sequencing of M13-sequence-tagged CTX-M PCR-amplicons using a M13-specific sequencing primer.</p> <p>Results</p> <p>Nine out of 20 <it>K. pneumoniae </it>clinical isolates had a ^<it>bla</it>CTX-M genotype. Interestingly, we found that the universal degenerated primers also amplified the chromosomally located K1-gene in all 34 <it>K. oxytoca </it>clinical isolates. Molecular identification and differentiation between ^<it>bla</it>CTX-M and ^<it>bla</it>OXY/K1-genes could only been achieved by sequencing of the PCR-amplicons. <it>In silico </it>analysis revealed that the universal degenerated CTX-M primer-pair used here might also amplify the chromosomally located ^<it>bla</it>OXY and K1-genes in <it>Klebsiella </it>spp. and K1-like genes in other <it>Enterobacteriaceae</it>.</p> <p>Conclusion</p> <p>The PCR-based molecular typing method described here enables a rapid and reliable molecular identification of ^<it>bla</it>CTX-M, and ^<it>bla</it>OXY/K1-genes. The principles used in this study could also be applied to any situation in which antimicrobial resistance genes would need to be sequenced.</p

Variable emission mechanism of a Type IV radio burst

Context. The Sun is an active star and the source of the largest explosions in the solar system, such as flares and coronal mass ejections (CMEs). Flares and CMEs are powerful particle accelerators that can generate radio emission through various emission mechanisms. Aims. CMEs are often accompanied by Type IV radio bursts that are observed as continuum emission in dynamic spectra at decimetric and metric wavelengths, but their emission mechanism can vary from event to event. Here, we aim to determine the emission mechanism of a complex Type IV burst that accompanied the flare and CME on 22 September 2011. Methods. We used radio imaging from the Nancay Radioheliograph, spectroscopic data from the e-Callisto network, ARTEMIS, Ondrejov, and Phoenix3 spectrometers combined with extreme-ultraviolet observations from NASA's Solar Dynamic Observatory to analyse the Type IV radio burst and determine its emission mechanism. Results. We show that the emission mechanism of the Type IV radio burst changes over time. We identified two components in the Type IV radio burst: an earlier stationary Type IV showing gyro-synchrotron behaviour, and a later moving Type IV burst covering the same frequency band. This second component has a coherent emission mechanism. Fundamental plasma emission and the electron-cyclotron maser emission are further investigated as possible emission mechanisms for the generation of the moving Type IV burst. Conclusions. Type IV bursts are therefore complex radio bursts, where multiple emission mechanisms can contribute to the generation of the wide-band continuum observed in dynamic spectra. Imaging spectroscopy over a wide frequency band is necessary to determine the emission mechanisms of Type IV bursts that are observed in dynamic spectra.Peer reviewe

Baryon acoustic oscillations from Integrated Neutral Gas Observations: Radio frequency interference measurements and telescope site selection

The Baryon acoustic oscillations from Integrated Neutral Gas Observations (BINGO) telescope is a new 40-m class radio telescope to measure the large-angular-scale intensity of Hi emission at 980-1260 MHz to constrain dark energy parameters. As it needs to measure faint cosmological signals at the milliKelvin level, it requires a site that has very low radio frequency interference (RFI) at frequencies around 1 GHz. We report on measurement campaigns across Uruguay and Brazil to find a suitable site, which looked at the strength of the mobile phone signals and other radio transmissions, the location of wind turbines, and also included mapping airplane flight paths. The site chosen for the BINGO telescope is a valley at Serra do Urubu, a remote part of Paraiba in North-East Brazil, which has sheltering terrain. During our measurements with a portable receiver we did not detect any RFI in or near the BINGO band, given the sensitivity of the equipment. A radio quiet zone around the selected site has been requested to the Brazilian authorities ahead of the telescope construction.Comment: Preprint of an article accepted in the Journal of Astronomical Instrumentation, copyright 2018 World Scientific Publishing Company https://www.worldscientific.com/worldscinet/ja

Observations of Low Frequency Solar Radio Bursts from the Rosse Solar-Terrestrial Observatory

The Rosse Solar-Terrestrial Observatory (RSTO; www.rosseobservatory.ie) was established at Birr Castle, Co. Offaly, Ireland (53 05'38.9", 7 55'12.7") in 2010 to study solar radio bursts and the response of the Earth's ionosphere and geomagnetic field. To date, three Compound Astronomical Low-cost Low-frequency Instrument for Spectroscopy and Transportable Observatory (CALLISTO) spectrometers have been installed, with the capability of observing in the frequency range 10-870 MHz. The receivers are fed simultaneously by biconical and log-periodic antennas. Nominally, frequency spectra in the range 10-400 MHz are obtained with 4 sweeps per second over 600 channels. Here, we describe the RSTO solar radio spectrometer set-up, and present dynamic spectra of a sample of Type II, III and IV radio bursts. In particular, we describe fine-scale structure observed in Type II bursts, including band splitting and rapidly varying herringbone features