RadioNet Workshop on Future Trends in Instrumentation

Monday 21 September 2020 - Tuesday 22 September 2020

Max Planck Institute for Radio Astronomy

Book of Abstracts

Here you can find all the abstracts of the sessions in our workshop. For technical and administrative issues see ‘Welcome and organization’ where you can find some important advice how to come through this workshop.

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RadioNet Workshop on Future Trends in Radio Astronomy Instru . . . / Book of Abstracts

Inhalt

Dial In ...... 3

Welcome and technical issues ...... 3

Director’s welcome address ...... 3

SKA1 Developement Plan ...... 3

IRAM telescope instrumentation overview and future plans ...... 4

LOFAR2.0: extending LOFAR observational capabilities for the coming decade ...... 4

The VLBA New Digital Architecture ...... 4

The Effelsberg Direct Digitizaion Project ...... 5

BRAND EVN Broadband Receiver - a technological chal- lenge ...... 5

Developing Digital Receiver for Radio Astronomy Receiver using RFSoC ...... 5

Smart Ambient-Temperature Very Low Noise LNAs for Radio Astronomy Arrays ...... 6

Accelerating astronomy using Atomic COTS ...... 6

Bluering Prototype System Results ...... 7

VLBI with a remote maser and a COTS formatter ...... 7

A Q-band 19 pixel multifeed receiver for the Sardinia ...... 8

Latest calibration results from QUBIC: The Q&U Bolomet- ric Interferometer for Cosmology ... 8

Simulations of the Optical System of the LSPE‐STRIP Instrument ...... 8

Application of TES bolometers and KID cameras to pulsar observations ...... 9

Solar power mirror arrays for radio astronomy - towards a test with the Juelich Solar Power Tower ...... 9

Managing hundreds of wideband receiving signals at the SRT ...... 9

A Compact Triple Band Receiver System working at K-, Q- and W-band for Medicina, Noto and Sardinia Radio Tele- scopes ...... 10

Science applications of multiband receivers and frequency-phase transfer ...... 10

Design and Implementation of Remote RFI Monitoring System ...... 10

Efficient wide-area sky monitoring ...... 11

Development of an Optimized Real-Time Radio Transient Imager for LWA-SV ...... 11

Earth-Orbit ...... 11

Open discussion, workshop summary, and closure ...... 11

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RadioNet Workshop on Future Trends in Radio Astronomy Instru . . . / Book of Abstracts Registration / 0 Dial In

The zoom link including the password will be distributed shortly before the workshop by e-mail. We will give you 30min to open your connection to the workshop so please use the time for connection and testing. As we have more than 100 participants this could take some time. In case you have problems please contact our moderator Zegeye Kidane under zkidane(at)mpifr.de.

Welcome / 19 Welcome and technical issues

Some technical/administrative issues will be explained: how to use zoom with screen sharing and the chat function for questions, how the trivia evening is working, how we want to make a group photo.

Welcome / 20 Director’s welcome address Corresponding Author(s): [email protected]

Session 1: / 3 SKA1 Observatory Developement Plan 1 Mr. STRINGHETTI, Luca

1 SKA Organisation

Corresponding Author(s): [email protected] It is universally recognised that a well-funded and carefully targeted development programme is essential to maintain the scientific competitiveness of any observatory. The purpose of the SKA Observatory Development Programme (SODP) is to enhance the scientific productivity of the Observatory by: adapting to changes in the scientific landscape and priorities, enabling new science, restoring descoped functionality, improving output and reliability and reducing operational cost. The SODP is divided into Projects, which deliver major improvements, and Studies, which are intended to evaluate new ideas and bring them to an adequate Technology and Manufacturing Readiness Level (TRL/MRL) to become potential projects. The process requires prioritisation of research and development in the context of science and technology roadmaps. The present discussion is restricted to SKA1 and concentrates on the initiation of the SODP and its evolution as the Observatory transitions from the Construction phase into the operational phase. The talk will present the current plan for the SKA observatory development program as part of the SKA Operation. It will present the organization of the SKA1 roadmaps (science Roadmap and Technological Roadmap) how they are organized and how they will work together to realize the SODP objectives. It will also show the current schedule and the funding mechanism for the programme.

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RadioNet Workshop on Future Trends in Radio Astronomy Instru . . . / Book of Abstracts Session 1: / 10 IRAM telescope instrumentation overview and future plans 1 Dr. RISACHER, christophe

1 IRAM Corresponding Author(s): [email protected] IRAM operates two millimetre on two sites: the NOEMA interferometer located in the French Alps at 2500m altitude with currently 11 antennas of 15m diameter and the 30m telescope in southern Spain, Pico Veleta (3000m). They observe in the 70-373 GHz frequency range. We’ll summarise the current receivers status and performance, and present the plans for the near and far future. In particular, we are starting an upgrade of the current NOEMA receivers to allow interferometric dual frequency observations. On the longer term, new generation of SIS mixers will allow extending the RF and IF bandwidths. Very large heterodyne array receivers are also under development, at 3 mm and 1.3 mm for the 30m Telescope.

Session 1: / 26 LOFAR2.0: extending LOFAR observational capabilities for the coming decade 1 Dr. BOONSTRA, Albert-Jan

1 ASTRON

Corresponding Author(s): [email protected] ASTRON operates the pan-European Low -Frequency Array (LOFAR), a unique instrument that will complement phase one of the (SKA), planned for construction in the coming three to five years. After nearly a decade of scientific operations, LOFAR science output is still ramping up. However, to keep the telescope at the forefront of science, a staged upgrade programme LOFAR2.0 was set in motion. This programme includes upgrading LOFAR phased-array stations by increasing the number of connected antennas, and by jointly observing the low-band and high-band frequencies. This will greatly increase the sensitivity, especially at the lowest frequencies where ionospheric effects are most severe. Simultaneous observations with both bands will allow to calibrate out these effects at the low band by using the ionospheric calibration solutions at the high band. The presentation will describe the new station architecture, show the first laboratory tests, and will also highlight the new design methodology.

Session 1: / 5 The VLBA New Digital Architecture 1 Dr. BRISKEN, Walter

1 National Radio Astronomy Observatory

Corresponding Author(s): [email protected] A new digital back-end architecture for the (VLBA) is being developed at NRAO. The system will consist of several main components that are interconnected through a 100 Gbps Ethernet switch. A pair of dual-channel IF samplers will be placed in the VLBA receiver cabin, producing four VDIF streams at 2048 Gsps and with greater than 8 bits per sample quanitzation. These “digital IFs” are to be injected into the 100 Gbps switch as VDIF packets over multicast UDP, allowing one or more “consumer” modules to perform further processing. For the VLBI use case, a module that channelizes and requantizes the data will feed Mark6 recorders. the architecture will allow other commensal uses of the digital IF streams such as transient searching, pulsar timing, or spectroscopy. In this talk, I will discuss the overall system architecture, the status of the project, and the motivations that led to this particular design choice.

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RadioNet Workshop on Future Trends in Radio Astronomy Instru . . . / Book of Abstracts Session 2 / 24 The Effelsberg Direct Digitizaion Project Dr. WINCHEN, Tobias 1, BANSOD, Amit 1, BEHREND, Jan 1, Dr. BARR, Ewan 1, Mr. ESSER, Niclas Alexander 1, Ms. SATHYANARAYANAN, Sakthi Priya 1, WIECHING, Gundolf 1 1 WU, Jason

1 Max Planck Institute for Radio Astronomy

Corresponding Author(s): [email protected] Recent developments in high-speed networking and PCIe-mounted accelerator cards have made possible new backend designs that provide vastly improved flexibility and capability in signal processing for radio astronomy. While direct digitization close to the receiver improves the quality of the physical signal by reducing analog transmission and filtering losses, it also enables the building of a backend based on commercial-off-the-shelf (COTS) hardware that is able to exploit modern cloud computing paradigms. In the Effelsberg Direct Digitization (EDD) project we are developing a versatile backend that takes advantage of these benefits. The EDD backend orchestrates data processing on COTS computing systems hosting GPUs as well as FPGA that can be rapidly and easily adapted to a wide range of observing use cases, e.g. spectroscopy, polarimetry, pulsar timing, etc. The highly modular system uses a unified interface for the control of its subsystems. This interface abstracts the telescope into well defined components which allows for a universal design suitable for deployment at any radio observatory only minimal customisation.

Session 2 / 15 BRAND EVN Broadband Receiver - a technological chal- lenge None TUCCARI, Gino Corresponding Author(s): [email protected] The BRAND wideband receiver is being developed with support from the European Union’s Horizon 2020 research and innovation programme as a part of RadioNet. The project represents a big technological challenge in the entire signal chain from the feed section to the digital processing. Its continuous frequency range from 1.5 GHz to 15 GHz makes it a scientifically extremely interesting development for the EVN network and radio astronomy in general. It also covers the VGOS frequencies and even extends them to lower and higher frequencies. It will allow to retrofit traditional prime focus antennas to become compatible with VGOS antennas in terms of frequency coverage, with a much greater output data rate. The status of the project is reported with the goals achieved and the items still under way.

Session 2: / 8 Developing Digital Receiver for Radio Astronomy Receiver using RFSoC 1 Dr. LIU, Chao

1 Oxford University

Corresponding Author(s): [email protected] The ultra-wideband redshift search receiver (RSR) on Large Millimetre Telescope (LMT), which covers 73 - 110.5 GHz simultaneously, has been built about 10 years ago. Due to the limits in the speed, performance and cost of the high speed sampler when the receiver was designed, the receiver was implemented using analog autocorrelator. As the price-performance rate in digital technologies is constantly improving, replacing the analog RSR receiver by a digital one becomes feasible. The digital system could offer higher frequency resolution and more system flexibility for more advanced science cases. This project was aimed to design and implement digital backend system for RSR. The RFSoC from Xilinx caught the attention of radio astronomy community when first released. RFSoC device has been selected as a core platform for the RSR receiver, as it offer 8x4G ADCs, large amount of programmable logic resources and powerful processor with multiple cores. Therefore, the RFSoC can integrate signal sampling, data processing and transmission and control functions in a single IC, which will be beneficial in both system design and costing perspectives. The talk will be focused on the digital backend system built for RSR and general radio astronomy receivers based on the RFSoC. The system at the present stage is fully functional as a spectrometer and can be extended in any shape base on system requirement of different telescopes and science cases. The experimental ADC characterization demonstrates around 80 dB Spurious Free Dynamic Range (SFDR) over the spectrum from DC to 2.048 GHz. The evaluation Page 5

RadioNet Workshop on Future Trends in Radio Astronomy Instru . . . / Book of Abstracts results of the RFSoC based spectrometer performs with high level of stability and dynamic range with hundreds of seconds’ real-time integration time. The results give us solid confidence in using RFSoC for radio astronomy receivers. It is a critical milestone of the RSR receiver project and we can carry on by just scaling the system up. The RFSoC based receiver modules will be extend to CBASS, Goonhilly GHY3 and other receiver platforms under development in Oxford. The system is not only suitable for high bandwidth signal but also hugely beneficial for systems with high channel counts, such as SKA, ATA and other radio astronomy telescopes. The RFSoC data converters can digitize as many as 16 channels simultaneously, the programmable logic can handle the channelization and beamforming and the control and communication can be managed by the applications on ARM processors. It can largely save the system cost and development effort in both hardware and software perspectives.

Session 2 / 27 Smart Ambient-Temperature Very Low Noise LNAs for Radio Astronomy Arrays 1 Dr. WEINREB, Sander

1 Caltech

Corresponding Author(s): [email protected] Most radio telescopes can have greatly expended survey speed and imaging capability by utilizing multiple receivers either as feed clusters, phased-array feeds, or a larger number of individual antennas. The number of receivers is often limited by the cost of the cryogenic cooling required for sensitivity at frequencies > 1 GHz. This paper will describe a new class of LNAs for the low microwave range that operate at ambient temperature and are “smart” in that they include functions such as noise calibration, tuning, switching, and monitoring within the LNA package. In addition, the LNAs are powered and controlled by just one wire, the output coaxial cable. A first generation of this new class of LNAs has been developed for detection and location of fast radio bursts (FRBs) in a 110 x 5m array at the Caltech Radio Observatory in Owens Valley, CA. These DSA110 LNAs have noise temperature in the 7 to 9 K range to realize system noise temperatures in the 22 to 25 K range in the frequency band of 1.28 to 1.53 GHz. Over 40 of the LNAs have now been completed and have internal, temperature-compensated, noise calibration signals so they can be directly attached to the dual -linear polarized feed without the directional coupler usually required for calibration. Further development of this LNA for a proposed DSA2000 array is in process and will include internal cooling to -40C of the InP HEMT input transistor utilizing a Peltier micro- cooler. This cooling is motivated by the large decrease in noise temperature with physical temperature measured for the DSA110 LNAs; the noise decreases by approximately a factor of two upon cooling from +40C to -40C, a much greater factor than the change in absolute temperature, 313K to 233K. This change is believed to be due to a large decrease in the transistor hot-electron noise, an effect not noted in previous studies and a subject of a theoretical study at Caltech.

Session 3 / 6

Accelerating astronomy using Atomic COTS 1 Dr. HAMPSON, Grant

1 CSIRO

Corresponding Author(s): [email protected] In the 20th century high end correlators were built with ASICs (VLA, Westerbork, Australia Telescope). As we entered the 21st century FPGAs came to the fore (eVLA, CABB, etc.) but due to the huge data flows they needed massive dedicated data transport systems. The CASPER group followed a different path and used network switches for data transport but this imposed a significant extra cost and for large systems such as MeerKAT with considerable effort and interaction with the switch vendor to get the system to work. The last 5 years has seen the appearance of a new generation of Ethernet switches (In-Network Processors) where the data plane is fully programmable using languages such as P4 and OpenFlow. These languages not only allow precise routing of packets based on metadata within the Ethernet packets but also open the door to a precise monitoring of the data flow. Thus, the designer now has the control available with older designs but without the complexity and with more advanced features. The second revolution was the combination of FPGAs and High Bandwidth (attached) Memory (HBM). HBM memory has an I/0 bandwidth that is more than 30 times that of a 100GbE link. This allows the full data to be buffered to memory multiple times. Each stage of processing can now operate Page 6

RadioNet Workshop on Future Trends in Radio Astronomy Instru . . . / Book of Abstracts independently of any other, effectively independent asynchronous subroutines (whereas all early correlator designs were synchronous). The multiple “subroutines” can now implement end-to-end processing. These FPGAs are now available as COTS hardware ready to plug into a standard server and have 100GbE ports that can connect to the In-Network Processor. The combination of these two technology advances allows a new approach to radio astronomy correlators and beamformers - what we have called “Atomic COTS”. This is a design that uses COTS In-Network Processors to route data to COTS FPGA cards such that each card receives part of the total bandwidth for all receiving elements. The FPGA then completes all processing to implement a correlator or beamformer independent of any other FPGA (an Atomic operation). The resulting astronomy data products can be routed back through the In-Network Processors to the next stage of processing such as imaging with visibilities and searches for FRBs on tied array beams. An Atomic COTS architecture will enable astronomy backends to upgrade and deploy incrementally.

Session 3 / 7 Bluering Prototype System Results 1 Dr. HAMPSON, Grant

1 CSIRO

Corresponding Author(s): [email protected] Bluering is the CSIRO name given to a new generation of radio astronomy array receivers based on Xilinx’s Radio Frequency System on Chip (RFSOC) technology. Bluering was initially designed for low frequency radio astronomy applications (such as the MWA telescope), but has grown to be a receiver also capable of L-band radio astronomy (such as Phased Array Feeds). Bluering is not only an array receiver; the spare FPGA resources can be used to form multiple wideband beams, compute the array covariance matrix, RFI mitigation, and even pulsar timing. To enable many types of astronomy receiver applications an RF daughter board, called Taipan, can be customised to have coaxial and fibre inputs. Available to each Taipan is a tuneable LO signal (which can double the number of RF inputs for some frequencies), attenuator control bits as well as a calibration signal. With all these features it is possible to customise the Taipan to most astronomy applications. CSIRO has developed a prototype Bluering system based around the 16 input 2GSPS 12-bit ADC version of the RFSOC. This paper presents some of the design details, including liquid cooling, RFI shielding, optical timing, embedded control system, as well as signal processing and communications firmware. Prototyping results are also presented - in particular RFI shielding, power, weight, SNR, etc. will be shown. Following the development and testing of this initial version CSIRO is planning on building a second version (without some of the bugs!) and aims to improve the general performance of the system.

Session 3 / 17 VLBI with a remote maser and a COTS formatter 1 Mr. BOVEN, Paul

1 JIVE

Corresponding Author(s): [email protected] The Hydrogen maser is required equipment for any VLBI station, and so is a formatter such as a DBBC(1,2 or 3) or DBE. Together, these ensure that the received spectrum gets digitized, timestamped with sufficient stability, and provided with headers to allow playback at a correlator. These necessities however don’t come cheap. White Rabbit is an open standard for time and frequency distribution over fiber. It was originally intended to synchronize and control the experiments at the LHC, but we show that it is possible to extend its reach and frequency stability in such a way that it can be used to transport a reference clock for VLBI. GNU Radio is a “free and open-source software development toolkit that provides signal processing blocks to implement software defined radios”. Using this software, I’ve designed a VLBI receiver and formatter using an off the shelf software-defined radio. It generates standard compliant VDIF data, which can be processed by the EVN SFXC correlator, and many others. Our first experiments were not able to be processed in real-time and only provided two subbands, but work is ongoing to develop this into a 1024 Mb/s capable VLBI formatter. Page 7

RadioNet Workshop on Future Trends in Radio Astronomy Instru . . . / Book of Abstracts Using these two methods, and the H-maser at the WSRT, we have successfully demonstrated VLBI fringes between the historical 25m Dwingeloo telescope and many EVN stations.

Session 3 / 1 A Q-band 19 pixel multifeed receiver for the 1 Dr. ORFEI, Alessandro

1 INAF-IRA Corresponding Author(s): a.orfei@ira..it A 19 feed 33-50GHz receiver under construction for the SRT antenna will be presented. The key modules will be described as well as their measurements in the laboratory.

Session 4 / 12 Latest calibration results from QUBIC: The Q&U Bolomet- ric Interferometer for Cosmology 1 MOUSSET, Louise

1 obsparis Corresponding Author(s): [email protected] QUBIC is an experiment dedicated to the measurement of the B-mode polarization from the Cosmic Microwave Background (CMB), using a novel technology: Bolometric Interferometry. The instrument will have 2 focal planes at 150 GHz and 220 GHz. Thanks to its unique spectroimaging capabilities, QUBIC will also be a powerful instrument to constrain foreground contamination (thermal galaxy dust emission, synchrotron emission, ...). The technical demonstrator has been tested and the concept of this new instrument has been validated. In this talk, I will 1rst explain the instrument architecture, focussing on the optical design. Some of the calibration results will be presented, showing that we actually have a working bolometric interferometer. The unique design of QUBIC brings new possibilities to CMB polarization mapping

Session 4 / 22 Simulations of the Optical System of the LSPE‐STRIP Instrument 1 Ms. REALINI, Sabrina

1 Università degli Studi di Milano Corresponding Author(s): [email protected] We present the analysis of the optical system of the STRIP instrument, the ground-based telescope of the Large Scale Polarization (LSPE) experiment, which aims at polarization measurements of the Cosmic Microwave Background on large angular scales. STRIP will observe the polarized emission from the "Observatorio del Teide" in Tenerife, starting in late 2021. The instrument consists of an array of forty-nine coherent polarimeters at 43 GHz (Q-band), coupled to a 1.5 m fully rotating crossed-Dragone telescope. An additional frequency channel with six-elements at 95 GHz (W-band) will be exploited as an atmospheric monitor. We modelled and characterized the STRIP optics by means of electromagnetic simulations. The model includes the two nominal reflectors, forty-nine Q- band feedhorns, six W-band feedhorns, and the shielding structures. We present the results of the optical simulations of both main beam and sidelobes, including the effects of the infrared filters and the dielectric window of the cryostat. An analysis of the mirrors imperfections and deformations completes our understanding of the LSPE-STRIP optical response in its real configuration.

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RadioNet Workshop on Future Trends in Radio Astronomy Instru . . . / Book of Abstracts Session 4 / 18 Application of TES bolometers and KID cameras to pulsar observations 1 Dr. TORNE, Pablo

1 Instituto de Radioastronomia Milimetrica (IRAM) Corresponding Author(s): [email protected] Pulsar studies are generally carried out at centimetre wavelengths and high-energies (X-ray, Gamma- ray), where pulsars are brighter and the available instrumentation is well adapted to fast time-domain science. In the last years, pulsar astronomy in the millimetre band has intensified, supported mainly by large-bandwidth instrumentation with fast-sampling capabilities at the IRAM 30-m telescope. However, receiver and backend combinations suitable for pulsar observations at (sub)millimetre facilities are rare. In this contribution, we will discuss a novel application of continuum cameras to pulsar astronomy in the (sub)millimetre range, which offers a new possibility to enable pulsar observations with high sensitivity at observatories where these type of receivers are (or will be) available. This promises to extend the spectral window in which pulsars can be studied, often with minimal or no extra modifications to the original hardware. Two proof-of-concept experiments will be presented, showing detections of a radio magnetar with the NIKA2 KID camera on the IRAM 30-m Telescope, and the SCUBA2 TES bolometer on the James Clerk Maxwell Telescope.

Session 4 / 9 Solar power mirror arrays for radio astronomy - towards a test with the Juelich Solar Power Tower None Author(s): ROY, Alan 1 Co-author(s): WUCKNITZ, Olaf ; Dr. CAMARA MAYORGA, Ivan

1 MPIfR

Corresponding Author(s): [email protected] We have presented the idea at past meetings to use the mirror arrays of concentrating solar power stations as vast collecting areas for high-sensitivity radio astronomy. Since the signals do not combine coherently they will produce an extended speckle pattern over the focal region that requires a large phased array feed to collect and combine in-phase. The 4000 element EMBRACE array developed under the RadioNet SKADS project is such array feed and might conceivably be re-purposed for this application. We will give an update on the idea and the plans for a proof-of-concept experiment on the Juelich experimental solar array. For simplicity these start with a two-pixel receiver before scaling up.

Session 5 / 2 Managing hundreds of wideband receiving signals at the SRT 1 Dr. ORFEI, Alessandro

1 INAF-IRA Corresponding Author(s): [email protected] The completion of the receiver suite up to 116 GHz at the Sardinia radio telescope asks for a completely new infrastructure for routing hundreds of large bandwidth signals to several back-ends of different type. In this talk I’ll describe how these signals is thought to be handled as well as the status of the work in progress.

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RadioNet Workshop on Future Trends in Radio Astronomy Instru . . . / Book of Abstracts Session 5 / 11 A Compact Triple Band Receiver System working at K-, Q- and W-band for Medicina, Noto and Sardinia Radio Tele- scopes 1 Dr. BOLLI, Pietro

1 INAF Corresponding Author(s): [email protected] A Compact Triple Band Receiver System working at K-, Q- and W-band for Medicina, Noto and Sardinia Radio Telescopes Pietro Bolli (Italian National Institute for Astrophysics), Seog-Tae Han (Korea Astronomy and Space Science Institute), Jihoon Choi (Korea Astronomy and Space Science Institute) and Alessandro Orfei (Italian National Institute for Astrophysics) A compact triple band receiver system is under development by a mutual collaboration between INAF, Italy and KASI, Korea. Three receivers will be fabricated and installed on the 64 m Sardinia radio telescope, 32 m Noto and Medicina radio telescopes respectively. Each receiver enables simultaneous observations in the three frequency intervals: K-band (18–26 GHz/8 GHz IF bandwidth), Q- band (34–50 GHz/16 GHz IF bandwidth) and W-band (85–116GHz/32 GHz IF bandwidth). An integrated quasi-optical circuit plus a compact triple-band receiver located in a single cryostat is chosen in order to circumvent difficulties in installation and beam alignment. A frequency-independent quasi-optical circuit for each band is adopted to obtain constant aperture efficiency as a function of the observed frequencies. The simulation results show that total aperture efficiency of each recommended frequency band is maintained almost constant within 1%. We present the design details of the compact wideband quasi-optical circuit and the properties of the triple-band receiver optimized for simultaneous multi-frequency observations. It is expected that it will be dedicated to conduct millimeter wave VLBI and Sun observations.

Session 5 / 25 Science applications of multiband receivers and frequency- phase transfer 1 LOBANOV, Andrei

1 MPIfR Corresponding Author(s): [email protected] The technological developments pioneered at the Korean VLBI Network for designing and implementing simultaneous multfiband (SMB) receivers paved the way to extending phase calibration and phase referencing techniques to the frequency space. Numerous advantages of this extension have been convincingly demonstrated at the KVN, and the time is now right to explore them on a larger scale. This would enable reaching an astrometric accuracy of ~10 microarcseconds, performing relative astrometric measurements at multiple frequencies, and increasing the dynamic range of mm-VLBI observations by factors of 20-50. A possible extension of the frequency-phase transfer (FPT) to 230 GHz is likely to bring a critically needed improvement of the quality of EHT imaging. Scientific potentials of implementing the SMB for mm- and sumnn-VLBI on a global scale will be discussed in this presentation

Session 6 /4 Design and Implementation of Remote RFI Monitoring System 1 NSOR, Joseph A. K

1 Ghana Space Science & Technology Inst.

Corresponding Author(s): [email protected] Design and Implementation of Remote RFI Monitoring System

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RadioNet Workshop on Future Trends in Radio Astronomy Instru . . . / Book of Abstracts Session 6 / 14 Efficient wide-area sky monitoring 1 WUCKNITZ, Olaf

1 MPIfR

Corresponding Author(s): [email protected] The enigmatic Fast Radio Bursts (FRBs) are motivating new instruments to monitor large areas of the sky with high time resolution. With a field of view of about 200 square degrees, CHIME is currently finding several per day. Gravitationally lensed FRBs could be used as a new cosmological probe, but this requires the continuous monitoring of even wider areas. Regular antenna arrays can be combined with extremely efficient Fast-Fourier-Transform beamformers to map good fractions of the sky with full time resolution. We discuss some options, including the (mis-)use of existing phased-array- feed receivers as aperture arrays.

Session 6 / 16 Development of an Optimized Real-Time Radio Transient Imager for LWA-SV 1 Dr. KRISHNAN, Hariharan

1 Arizona State University

Corresponding Author(s): [email protected] In this paper, we describe our efforts towards the development of a real-time radio imaging correlator for the Long-Wavelength Array station in Sevilleta, New Mexico. We briefly discuss the direct-imaging algorithm and present the architecture of the GPU implementation. We describe the code-level modifications carried out to some of the modules in the algorithm that improves GPU-memory management and highlight the performance improvements achieved through it. We emphasize our ongoing efforts in tuning the overall run-time duration of the correlator which in turn is expected to increase the operating bandwidth in order to address the demands of wide-band capability for radio transient science.

Session 6 / 13 Earth-Orbit Aperture Synthesis None ROY, Alan Corresponding Author(s): [email protected] I investigate the idea that VLBI might be done between one antenna and itself as it moves along the Earth’s orbit, provided the bandwidth is sufficiently small that the coherence time is longer than the time needed for the antenna to sweep out the baseline. Such a technique offers the tantalizing prospect of synthesizing space-VLBI-like baselines without needing a satellite, or the ability to fill in missing short baselines in EVN. However the initial result from a numerical model is that it does not work, at least for uniform linear motion, for an interesting reason.

Summary / 21 Open discussion, workshop summary, and closure

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