Limits on Fast Radio Bursts at 145 MHz with ARTEMIS, a real-time software backend
A. Karastergiou, J. Chennamangalam, W. Armour, C. Williams, B. Mort, F. Dulwich, S. Salvini, A. Magro, S. Roberts, M. Serylak, A. Doo, A. V. Bilous, R. P. Breto… 展开作者
A. Karastergiou, J. Chennamangalam, W. Armour, C. Williams, B. Mort, F. Dulwich, S. Salvini, A. Magro, S. Roberts, M. Serylak, A. Doo, A. V. Bilous, R. P. Breton, H. Falcke, J. -M. Griessmeier, J. W. T. Hessels, E. F. Keane, V. I. Kondratiev, M. Kramer, J. van Leeuwen, A. Noutsos, S. Oslowski, C. Sobey, B. W. Stappers, P. Weltevrede
Fast Radio Bursts (FRBs), are millisecond radio signals that exhibit dispersion larger than what the Galactic electron density can account for. We have conducted a 1446 hour survey for Fast Radio Bursts (FRBs) at 145~MHz, covering a total of 4193 sq. deg on the sky. We used the UK station of the LOFAR radio telescope -- the Rawlings Array -- , accompanied for a majority of the time by the LOFAR station at Nançay, observing the same fields at the same frequency. Our real-time search backend, ARTEMIS, utilizes graphics processing units to search for pulses with dispersion measures up to 320 cm$^{-3}$ pc. Previous derived FRB rates from surveys around 1.4~GHz, and favoured FRB interpretations, motivated this survey, despite all previous detections occurring at higher dispersion measures. We detected no new FRBs above a signal-to-noise threshold of 10, leading to the most stringent upper limit yet on the FRB event rate at these frequencies: 29 sky$^{-1}$ day$^{-1}$ for 5~ms-duration pulses above 62~Jy. The non-detection could be due to scatter-broadening, limitations on the volume and time searched, or the shape of FRB flux density spectra. Assuming the latter and that FRBs are standard candles, the non-detection is compatible with the published FRB sky rate, if their spectra follow a power law with frequency ($\propto ν^α$), with $α\gtrsim+0.1$, demonstrating a marked difference from pulsar spectra. Our results suggest that surveys at higher frequencies, including the low frequency component of the Square Kilometre Array, will have better chances to detect, estimate rates and understand the origin and properties of FRBs.
The LOw Frequency ARray - LOFAR - is a new radio interferometer designed with emphasis on flexible digital hardware instead of mechanical solutions. The array elements, so-called stations, are located in the Netherlands and in neighbouring countries. The design of LOFAR allows independent use of its international stations, which, coupled with a dedicated backend, makes them very powerful telescopes in their own right. This backend is called the Advanced Radio Transient Event Monitor and Identification System (ARTEMIS). It is a combined software/hardware solution for both targeted observations …
We present the improved solar radio spectrograph of the University of Athens operating at the Thermopylae Satellite Telecommunication Station. Observations now cover the frequency range from 20 to 650 MHz. The spectrograph has a 7-meter moving parabola fed by a log-periodic antenna for 100 650 MHz and a stationary inverted V fat dipole antenna for the 20 100 MHz range. Two receivers are operating in parallel, one swept frequency for the whole range (10 spectrums/sec, 630 channels/spectrum) and one acousto-optical receiver for the range 270 to 450 MHz (100 spectrums/sec, 128 channels/spectrum).…
The Solar Radiospectrograph of the University of Athens (ARTEMIS-IV) is in operation at the Thermopylae Satellite Communication Station since 1996. The observations extend from the base of the Solar Corona (650 MHz) to about 2 Solar Radii (20 MHz) with time resolution 1/10-1/100 sec. The instruments recordings, being in the form of dynamic spectra, measure radio flux as a function of height in the corona; our observations are combined with spatial data from the Nancay Radioheliograph whenever the need for 3D positional information arises. The ARTEMIS-IV contribution in the study of solar radio…
NenuFAR (New extension in Nançay upgrading LoFAR) is a new radio telescope developed and built on the site of the Nançay Radio Observatory. It is designed to observe the largely unexplored frequency window from 10 to 85\,MHz, offering a high sensitivity across its full bandwidth. NenuFAR has started its "early science" operation in July 2019, with 58\% of its final collecting area being available. Pulsars are one of the major topics for the scientific exploitation of this frequency range and represent an important challenge in terms of instrumentation. Designing instrumentation at these freque…
We have observed regions of three galaxy clusters at z$\sim$ [0.06, 0.09] (Abell85, Abell1205, Abell2440), as well as calibration sources with the Nancay radiotelescope (NRT) to search for 21 cm emission and fully characterize the FPGA based BAORadio digital backend. The total observation time of few hours per source have been distributed over few months, from March 2011 to January 2012, due to scheduling constraints of the NRT, which is a transit telescope. Data have been acquired in parallel with the NRT standard correlator (ACRT) back-end, as well as with the BAORadio data acquisition syste…
Pulsar Backend for 21 CentiMeter Array: Implementation of Data Acquisition and Initial Results
Peking University（北京大学）；National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；State Key Laboratory of Radio Astronomy and Technology, National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台射电天文与技术重点实验室）；Yunnan Observatories, Chinese Academy of Sciences（中国科学院云南天文台）；School of Astronomy and Space Science, University of Chinese Academy of Sciences（中国科学院大学天文与空间科学学院）；Xinjiang Astronomical Observatory, Chinese Academy of Sciences（中国科学院新疆天文台）
The antennas of NASA's Madrid Deep Space Communications Complex (MDSCC) in Robledo de Chavela are available as single-dish radio astronomical facilities during a significant percentage of their operational time. Current instrumentation includes two antennas of 70 and 34 m in diameter, equipped with dual-polarization receivers in K (18 - 26 GHz) and Q (38 - 50 GHz) bands, respectively. We have developed and built a new wideband backend for the Robledo antennas, with the objectives (1) to optimize the available time and enhance the efficiency of radio astronomy in MDSCC; and (2) to tackle new sc…
The new era of software signal processing has a large impact on radio astronomy instrumentation. Our design and implementation of a 32 antennae, 33 MHz, dual polarization, fully real-time software backend for the GMRT, using only off-the-shelf components, is an example of this. We have built a correlator and a beamformer, using PCI-based ADC cards and a Linux cluster of 48 nodes with dual gigabit inter-node connectivity for real-time data transfer requirements. The highly optimized compute pipeline uses cache efficient, multi-threaded parallel code, with the aid of vectorized processing. This …
This paper describes a new real-time versatile backend, the Pulsar Ooty Radio Telescope New Digital Efficient Receiver (PONDER), which has been designed to operate along with the legacy analog system of the Ooty Radio Telescope (ORT). PONDER makes use of the current state of the art computing hardware, a Graphical Processing Unit (GPU) and sufficiently large disk storage to support high time resolution real-time data of pulsar observations, obtained by coherent dedispersion over a bandpass of 16 MHz. Four different modes for pulsar observations are implemented in PONDER to provide standard red…
We report the first radio interferometric search at 843 MHz for fast transients, particularly Fast Radio Bursts (FRBs). The recently recommissioned Swinburne University of Technology's digital backend for the Molonglo Observatory Synthesis Telescope array (the UTMOST) with its large collecting area (18,000 $\mathrm{m^2}$) and wide instantaneous field of view (7.80 $\mathrm{deg^2}$) is expected to be an efficient tool to detect FRBs. As an interferometer it will be capable of discerning whether the FRBs are truly a celestial population. We show that UTMOST at full design sensitivity can detect …
The Five-hundred-meter Aperture Spherical radio Telescope(FAST) was launched on September 25,2016.From early 2017,we began to use the FAST wideband receiver,which was designed,constructed and installed on the FAST in Guizhou,China.The front end of the receiver is composed an uncooled Quad Ridge Flared Horn feed(QRFH) with the frequency range of 270 to 1620 MHz,and a cryostat operating at 10 K.Stephen et al. 2016We have coop-erated with the Institute of Automation of the Chinese Academy of Sciences to developed the China Reconfigurable ANalog-digital backEnd.The system covers the 3 GHz operatin…
A joint collaborative project was recently developed to provide the Madrid Deep Space Communications Complex with a state-of-the-art wideband backend. This new backend provides from 100 MHz to 6 GHz of instantaneous bandwidth, and spectral resolutions from 6 to 200 kHz. The backend includes a new IF processor, as well as a FPGA-based FFT spectrometer, which manage thousands of spectroscopic channels in real time. All these equipment need to be controlled and operated by a common software, which has to synchronize activities among affected devices, and also with the observing program. The final…
CHIME/Slow overview and pilot survey: A new backend to search for second-duration radio transients with the CHIME telescope
Tata Institute of Fundamental Research（塔塔基础研究所）；Raman Research Institute（拉曼研究所）；LUX, Observatoire de Paris, Université PSL, Sorbonne Université, CNRS（巴黎天文台，巴黎文理研究大学，索邦大学，法国国家科学研究中心）；National Centre for Radio Astrophysics（国家射电天体物理中心）；Indian Institute of Astrophysics（印度天体物理研究所）；Anton Pannekoek Institute for Astronomy, University of Amsterdam（阿姆斯特丹大学安东·潘内克天文研究所）；ASTRON, the Netherlands Institute for Radio Astronomy（荷兰射电天文研究所）；York University（约克大学）
Here we describe the Compact Array Broadband Backend (CABB) and present first results obtained with the upgraded Australia Telescope Compact Array (ATCA). The 16-fold increase in observing bandwidth, from 2 x 128 MHz to 2 x 2048 MHz, high bit sampling, and addition of 16 zoom windows (each divided into a further 2048 channels) provide major improvements for all ATCA observations. The benefits of the new system are: (1) hugely increased radio continuum and polarization sensitivity as well as image fidelity, (2) substantially improved capability to search for and map emission and absorption line…
The LOw FRequency ARray - LOFAR is a new radio telescope that is moving the science of radio pulsars and transients into a new phase. Its design places emphasis on digital hardware and flexible software instead of mechanical solutions. LOFAR observes at radio frequencies between 10 and 240 MHz where radio pulsars and many transients are expected to be brightest. Radio frequency signals emitted from these objects allow us to study the intrinsic pulsar emission and phenomena such as propagation effects through the interstellar medium. The design of LOFAR allows independent use of its stations to…
The PSRIX backend is the primary pulsar timing instrument of the Effelsberg 100-m radio telescope since early 2011. This new ROACH-based system enables bandwidths up to 500 MHz to be recorded, significantly more than what was possible with its predecessor, the Effelsberg-Berkeley Pulsar Processor (EBPP). We review the first four years of PSRIX timing data for 33 pulsars collected as part of the monthly European Pulsar Timing Array (EPTA) observations. We describe the automated data analysis pipeline, CoastGuard, that we developed to reduce these observations. We also introduce TOASTER, the EPT…
We present a concept, developed at the National Astronomy and Ionosphere Center (NAIC) at Arecibo, Puerto Rico, for active suppression of Global Positioning System (GPS) signals in the 305 m dish radio receiver path prior to backend processing. The subsystem does not require an auxiliary antenna and is intended for easy integration with radio telescope systems with a goal of being a turnkey addition to virtually any facility. Working with actual sampled signal data, we have focused on the detection and cancellation of the GPS L3 signal at 1381.05 MHz which, during periodic test modes and parti…
We present a description of the Prototype All-Sky Imager (PASI), a backend correlator and imager of the first station of the Long Wavelength Array (LWA1). PASI cross-correlates a live stream of 260 dual-polarization dipole antennas of the LWA1, creates all-sky images, and uploads them to the LWA-TV website in near real-time. PASI has recorded over 13,000 hours of all-sky images at frequencies between 10 and 88 MHz creating opportunities for new research and discoveries. We also report rate density and pulse energy density limits on transients at 38, 52, and 74 MHz, for pulse widths of 5 s. We …
We present the findings from the Prototype All-Sky Imager (PASI), a backend correlator of the first station of the Long Wavelength Array (LWA1), which has recorded over 11,000 hours of all-sky images at frequencies between 25 and 75 MHz. In a search of this data for radio transients, we have found 49 long (10s of seconds) duration transients. Ten of these transients correlate both spatially and temporally with large meteors (fireballs), and their signatures suggest that fireballs emit a previously undiscovered low frequency, non-thermal pulse. This emission provides a new probe into the physic…
First fast radio burst search campaign at the Argentine Institute of Radio Astronomy
Rochester Institute of Technology（罗切斯特理工学院）；Instituto Argentino de Radioastronomía (CCT La Plata, CONICET（阿根廷射电天文研究所）；CICPBA（科尔多瓦大学数学、天文学、物理与计算学院）；UNLP)（理论与实验天文学研究所）；Facultad de Matemática, Astronomía, Física y Computación, UNC（马克斯·普朗克引力物理学研究所（阿尔伯特·爱因斯坦研究所））；Instituto de Astronomía Teórica y Experimental, CONICET-UNC；Max Planck Institute for Gravitational Physics (Albert Einstein Institute)
The Murchison Widefield Array (MWA) is one of three Square Kilometre Array Precursor telescopes and is located at the Murchison Radio-astronomy Observatory in the Murchison Shire of the mid-west of Western Australia, a location chosen for its extremely low levels of radio frequency interference. The MWA operates at low radio frequencies, 80-300 MHz, with a processed bandwidth of 30.72 MHz for both linear polarisations, and consists of 128 aperture arrays (known as tiles) distributed over a ~3 km diameter area. Novel hybrid hardware/software correlation and a real-time imaging and calibration s…
The Canadian Hydrogen Intensity Mapping Experiment (CHIME) is a novel transit radio telescope operating across the 400-800-MHz band. CHIME is comprised of four 20-m x 100-m semi-cylindrical paraboloid reflectors, each of which has 256 dual-polarization feeds suspended along its axis, giving it a >200 square degree field-of-view. This, combined with wide bandwidth, high sensitivity, and a powerful correlator makes CHIME an excellent instrument for the detection of Fast Radio Bursts (FRBs). The CHIME Fast Radio Burst Project (CHIME/FRB) will search beam-formed, high time-and frequency-resolution…
Electromagnetic radiation from human activities, known as man-made Radio Frequency Interference (RFI), adversely affects radio astronomy observations. In the vicinity of the Upgraded Giant Metrewave Radio Telescope (uGMRT) array, the sparking on power lines is the major cause of interference at observing frequencies less than 800 MHz. A real-time broadband RFI detection and filtering system is implemented as part of the uGMRT wideband signal processing backend to mitigate the effect of broadband RFI. Performance analysis techniques used for testing and commissioning the system for observations…
Next-generation radio arrays, including the Square Kilometre Array (SKA) and its pathfinders, will open up new avenues for exciting transient science at radio wavelengths. Their innovative designs, comprising a large number of small elements, pose several challenges in digital processing and optimal observing strategies. The Giant Metrewave Radio Telescope (GMRT) presents an excellent test-bed for developing and validating suitable observing modes and strategies for transient experiments with future arrays. Here we describe the first phase of the ongoing development of a transient detection sy…
