scholarly journals GBTrans: a commensal search for radio pulses with the Green Bank 20-m telescope

2019 ◽  
Vol 489 (3) ◽  
pp. 4001-4006 ◽  
Author(s):  
Golnoosh Golpayegani ◽  
Duncan R Lorimer ◽  
Steven W Ellingson ◽  
Devansh Agarwal ◽  
Olivia Young ◽  
...  
Keyword(s):  
Real Time ◽  
Radio Telescope ◽  
Power Law ◽  
Confidence Level ◽  
Educational Programme ◽  
Radio Bursts ◽  
Search System

ABSTRACT We describe GBTrans, a real-time search system designed to find fast radio bursts (FRBs) using the 20-m radio telescope at the Green Bank Observatory. The telescope has been part of the Skynet educational programme since 2015. We give details of the observing system and report on the non-detection of FRBs from a total observing time of 503 d. Single pulses from four known pulsars were detected as part of the commensal observing. The system is sensitive enough to detect approximately half of all currently known FRBs and we estimate that our survey probed redshifts out to about 0.3 corresponding to an effective survey volume of around 124 000 Mpc3. Modelling the FRB rate as a function of fluence, ${\cal F}$, as a power law with ${\cal F}^{-\alpha }$, we constrain the index α < 2.5 at the 90 per cent confidence level. We discuss the implications of this result in the context of constraints from other FRB surveys.

scholarly journals PAFINDER – Searching for FRBs and pulsars using Phased Array Feeds

2017 ◽  
Vol 13 (S337) ◽  
pp. 370-371
Author(s):  
Mateusz Malenta ◽  
Ewan Barr ◽  
Aaron Chippendale ◽  
Xinping Deng ◽  
Daniel George ◽  
...  
Keyword(s):  
Real Time ◽  
Radio Telescope ◽  
Phased Array ◽  
Single Pulse ◽  
Radio Bursts ◽  
Pulse Detection ◽  
Phased Array Feeds

AbstractThe challenges of detecting and localising Fast Radio Bursts in real time can be met with the use of Phased Array Feeds. One such system, capable of creating up to 36 simultaneous beams, is currently being commissioned at the Effelsberg radio telescope in Germany following testing at the 64 m Parkes radio telescope. The PAFINDER (Phased Array Feed FRB Finder) pipeline will be used with this receiver to enable real–time single–pulse detection and localisation.

scholarly journals First interferometric detections of Fast Radio Bursts

2017 ◽  
Vol 13 (S337) ◽  
pp. 322-323
Author(s):  
M. Caleb ◽  
C. Flynn ◽  
M. Bailes ◽  
E. D. Barr ◽  
T. Bateman ◽  
...  
Keyword(s):  
Real Time ◽  
Radio Telescope ◽  
Near Field ◽  
Radio Bursts ◽  
Field Region ◽  
Transient Detection ◽  
Local Sources ◽  
Fast Transient ◽  
Radio Transients ◽  
Better Than

AbstractThe class of radio transients called Fast Radio Bursts (FRBs) encompasses enigmatic single pulses, each unique in its own way, hindering a consensus for their origin. The key to demystifying FRBs lies in discovering many of them in order to identity commonalities – and in real time, in order to find potential counterparts at other wavelengths. The recently upgraded UTMOST in Australia, is undergoing a backend transformation to rise as a fast transient detection machine. The first interferometric detections of FRBs with UTMOST, place their origin beyond the near-field region of the telescope thus ruling out local sources of interference as a possible origin. We have localised these bursts to much better than the ones discovered at the Parkes radio telescope and have plans to upgrade UTMOST to be capable of much better localisation still.

scholarly journals Tidal disruption events seen in the XMM-Newton slew survey

2016 ◽  
Vol 12 (S324) ◽  
pp. 123-126
Author(s):  
Richard Saxton ◽  
S. Komossa ◽  
Andrew Read ◽  
Paulina Lira ◽  
Kate D. Alexander ◽  
...  
Keyword(s):  
Radio Emission ◽  
Real Time ◽  
Power Law ◽  
Early Phase ◽  
Classical Model ◽  
Thermal Processes ◽  
Tidal Disruption ◽  
X Ray ◽  
Hard Power ◽  
Sky Survey

AbstractXMM-Newton performs a survey of the sky in the 0.2-12 keV X-ray band while slewing between observation targets. The sensitivity in the soft X-ray band is comparable with that of the ROSAT all-sky survey, allowing bright transients to be identified in near real-time by a comparison of the flux in both surveys. Several of the soft X-ray flares are coincident with galaxy nuclei and five of these have been interpreted as candidate tidal disruption events (TDE). The first three discovered had a soft X-ray spectrum, consistent with the classical model of TDE, where radiation is released during the accretion phase by thermal processes. The remaining two have an additional hard, power-law component, which in only one case was accompanied by radio emission. Overall the flares decay with the classical index of t−5/3 but vary greatly in the early phase.

Real-time Closed-loop Active Surface Technology of a Large Radio Telescope

2022 ◽  
Vol 134 (1031) ◽  
pp. 015003
Author(s):  
Yong Zhang ◽  
Guoping Li ◽  
Guohua Zhou ◽  
Qishuai Lu ◽  
Heng Zuo ◽  
...  
Keyword(s):  
Real Time ◽  
Radio Telescope ◽  
Closed Loop ◽  
Preliminary Test ◽  
Active Surface ◽  
Angle Measurement ◽  
Quality Data ◽  
Surface Accuracy ◽  
Surface System ◽  
Reflector Surface

Abstract The surface accuracy of a large radio telescope’s primary reflector is easily affected by gravity and temperature change during observations. An active surface system is crucial to ensure the regular operation and high-quality data output of the radio telescope. We propose a real-time closed-loop active surface system including two components. The first component, a new type of photoelectric edge sensor, detects the angle change of the adjacent panels. The second component, the displacement actuator, adjusts the panels’ position and posture to compensate for the angle changes. So, over the entire observation, the closed-loop surface control system with these two components could actively maintain the primary reflector’s accuracy in real time. Using this approach, we constructed an experimental active surface system for the Xinjiang Qitai 110 m Radio Telescope (QTT) to test the maintenance of the surface accuracy. The angle measurement accuracy is better than 0.″2, and the positioning accuracy of the displacement actuator could achieve ±15 μm over the whole 50 mm stroke. The preliminary test results show that the accuracy requirements of the QTT’s primary reflector surface can be met using the active surface system we propose.

scholarly journals Pulsar science with the CHIME telescope

2017 ◽  
Vol 13 (S337) ◽  
pp. 179-182 ◽  
Author(s):  
Cherry Ng
Keyword(s):  
Northern Hemisphere ◽  
Radio Telescope ◽  
Field Of View ◽  
Radio Bursts ◽  
Radio Telescopes ◽  
Acoustic Oscillations ◽  
Daily Monitoring ◽  
Intensity Mapping ◽  
Pulsar Timing ◽  
Pulsar Timing Array

AbstractThe CHIME telescope (the Canadian Hydrogen Intensity Mapping Experiment) recently built in Penticton, Canada, is currently being commissioned. Originally designed as a cosmology experiment, it was soon recognized that CHIME has the potential to simultaneously serve as an incredibly useful radio telescope for pulsar science. CHIME operates across a wide bandwidth of 400–800 MHz and will have a collecting area and sensitivity comparable to that of the 100-m class radio telescopes. CHIME has a huge field of view of ~250 square degrees. It will be capable of observing 10 pulsars simultaneously, 24-hours per day, every day, while still accomplishing its missions to study Baryon Acoustic Oscillations and Fast Radio Bursts. It will carry out daily monitoring of roughly half of all pulsars in the northern hemisphere, including all NANOGrav pulsars employed in the Pulsar Timing Array project. It will cycle through all pulsars in the northern hemisphere with a range of cadence of no more than 10 days.

scholarly journals Differences in power-law growth over time and indicators of COVID-19 pandemic progression worldwide

2020 ◽  
Author(s):  
Jack Merrin
Keyword(s):  
Error Analysis ◽  
Real Time ◽  
Power Law ◽  
Growth Phase ◽  
Exponential Growth ◽  
Spreading Rate ◽  
Exponential Growth Phase ◽  
Power Law Exponent ◽  
Disease Spreading ◽  
Over Time

1AbstractAn automated statistical and error analysis of 45 countries or regions with more than 1000 cases of COVID-19 as of March 28, 2020, has been performed. This study reveals differences in the rate of disease spreading rate over time in different countries. This survey observes that most countries undergo a beginning exponential growth phase, which transitions into a power-law phase, as recently suggested by Ziff and Ziff. Tracking indicators of growth, such as the power-law exponent, are a good indication of the relative danger different countries are in and show when social measures are effective towards slowing the spread. The data compiled here are usefully synthesizing a global picture, identifying country to country variation in spreading, and identifying countries most at risk. This analysis may factor into how best to track the effectiveness of social distancing policies and quarantines in real-time as data is updated each day.

Data storage and real time observations at the Mexican Array Radio Telescope

2010 ◽  
Vol 46 (7) ◽  
pp. 968-972
Author(s):  
Gilberto A. Casillas-Pérez ◽  
Solai Jeyakumar ◽  
Armando Carrillo-Vargas ◽  
Ernesto Andrade ◽  
Americo González-Esparza ◽  
...  
Keyword(s):  
Real Time ◽  
Data Storage ◽  
Radio Telescope

scholarly journals Extending the Observable Zenith Angle of FAST Using an Offset Feed

2001 ◽  
Vol 182 ◽  
pp. 255-259
Author(s):  
Li Guoding ◽  
R. Nan ◽  
B. Peng
Keyword(s):  
Real Time ◽  
Active Control ◽  
Radio Telescope ◽  
Zenith Angle ◽  
Spherical Reflector ◽  
Paraboloid Of Revolution ◽  
Reflecting Surface

AbstractThe five hundred meter aperture spherical radio telescope is will use an active spherical reflector. When the zenith scan angle is changed, the illuminated part of the reflecting surface is made to fit a paraboloid of revolution in real time by active control. The maximum zenith scan angle | ψmax | of FAST is 30° under conditions of the geometry selected in order that the feed does not illuminate the ground. The result of this paper shows that the maximum zenith scan angle | ψmax | can be extended to 69° by offsetting the feed.

scholarly journals Time forecast of a break-off event from a hanging glacier

2016 ◽  
Vol 10 (3) ◽  
pp. 1191-1200 ◽  
Author(s):  
Jérome Faillettaz ◽  
Martin Funk ◽  
Marco Vagliasindi
Keyword(s):  
Real Time ◽  
Power Law ◽  
Surface Displacement ◽  
Early Warning Systems ◽  
Warning Systems ◽  
Safety Measures ◽  
Periodic Oscillations ◽  
Ice Volume ◽  
Surface Displacements ◽  
Displacement Measurements

Abstract. A cold hanging glacier located on the south face of the Grandes Jorasses (Mont Blanc, Italy) broke off on the 23 and 29 September 2014 with a total estimated ice volume of 105 000 m3. Thanks to accurate surface displacement measurements taken up to the final break-off, this event was successfully predicted 10 days in advance, enabling local authorities to take the necessary safety measures. The break-off event also confirmed that surface displacements experienced a power law acceleration along with superimposed log-periodic oscillations prior to the final rupture. This paper describes the methods used to achieve a satisfactory time forecast in real time and demonstrates, using a retrospective analysis, their potential for the development of early-warning systems in real time.

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