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32nd International Union of Radio Science General Assembly & Scientific Symposium * Montreal, Canada * 19-27 August 2017 Home Page

Program
Scientific Program - Commission J

Commission J Chair:
Prof. Willem Baan;
baan@astron.nl

Commission J - Tutorial

Lars-Ake Nyman - "The Atacama Large Millimeter Array (ALMA)"

Convener: Willem Baan

Commission J -
"Very Long Baseline Interferometry"

Conveners: Huib-Jan van Langevelde, Hideyuki Kobayashi

At an age of 50, the VLBI technique is still advancing thanks to the developments in digital instrumentation. An increasing amount of bandwidth can be samples, using wide-band receivers, increasing the sensitivity of VLBI networks. New solutions are becoming available for storing large amounts of raw telescope data and transporting it to the correlator. And innovations are even foreseen for distributing timing references that are more economic and accurate than maser clocks. There are also various options to implement correlators efficiently and provide more flexibility than in the past. The science communities that use VLBI are presented with more capabilities, but also some additional complexity, as many different economic solutions are adopted on a regional scale. But there is in fact a global case for more intercontinental VLBI collaboration, as unique science cases require the highest possible resolution and new telescope arrays (ALMA, SKA and its pathfinders) are coming on-line. Common data interfaces, software standards and operational practices will be in demand. As the plans for the next generation radio instrumentation are becoming a reality, there are certainly many scientific options and technical challenges for the VLBI community to discuss.

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Commission J - "The Square Kilometre Array"

Conveners: Robert Braun, Justin Jonas, Douglas Bock

The Square Kilometre Array concept has grown from the answer to a simple question: What size radio telescope would it take to permit us to read the history of the Universe as written in the language of its most abundant constituent, Hydrogen? What has become apparent, is that the same radio telescope that will answer fundamental questions about our cosmic origins and fate will also permit a wealth of other discoveries to be made, in areas as diverse as the formation of planets similar to the Earth, detection of gravitational distortions of Space-Time, the origin of cosmic magnetic fields and understanding the formation and growth of Black Holes. In this session we provide an update on the progress toward realising the Square Kilometre Array Observatory, as well as highlighting early outcomes from precursor telescopes on the two SKA sites, the MeerKAT facility in South Africa and the ASKAP in Australia.

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Commission J - "Millimeter/Submillimeter Arrays"

Conveners: Jongsoo Kim, Lars-Ake Nyman

The mm/submm arrays, CARMA, SMA, NOEMA and ALMA, have continuously provided unprecedented images and spectra for the study of gas and dust structures in the Universe. ALMA has now revolutionized our understanding of the formation of planets, stars and galaxies as well as created a new ecosystem from proposal handing to data archiving for around 3000 world-wide astronomers. These arrays have also improved the sensitivity, resolution and spectral coverage of this type of observations. In this session, highlights of science cases and on-going as well as future upgrade plans will be presented. The new ecosystem of ALMA will be also presented.

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Commission J - "Single Dish Instruments"

Conveners: Karen O'Neil, Ettore Carretti, Zhiqiang Shen

While recent years have seen a rapid development of large radio telescope arrays; there are many single dish instruments planned or operated in the world, which will be making significant impacts within astronomy. Session J4 will look at current and planned single dish telescopes, focusing on their unique science and technical developments within the era of the SKA. Related technical issues and concerns will also be covered (RFI, antenna metrology, active surface controls, etc.).

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Commission J - "Historical Radio Astronomy"

Conveners: Richard Wielebinski, Ken Kellermann, Richard Schilizzi

Radio astronomy has a rich heritage of interferometers and arrays that have transformed our view of the universe. Each of these projects has accumulated a wealth of experience in the technical, managerial and political domains, which will be distilled in invited and contributed presentations. The definition of "past" is a fluid concept since most instruments are in a continual state of upgrade, but we define it to mean projects that are or have been operational for science using the full array for which construction funding was received. The presentations should be of interest for those interested in the history of radio astronomy as well as for those involved in the new telescope projects expected to further deepen our understanding of the cosmos.

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Commission J - "Receivers and Radiometers: Design and Calibration"

Conveners: S. Srikanth, Miroslav Pantaleev, Arnold van Ardenne, Roberto Neri

In order to meet emerging challenges in receiver technology, there is a need for global collaboration of the astronomical community. The new generation of receivers for radio telescopes needs to have increased bandwidth, wider field of view and enhanced sensitivity. This session will focus on progress and advances in receiver and radiometer technology. Suggested topics include design and construction of cryogenically cooled heterodyne and bolometers receivers, receivers with LNAs at ambient temperature for traditional multi-beams and phased array feeds (PAF), radiometers, RFI mitigation using PAFs, narrow band filters, HTS filters etc., technology development in the areas of improved dynamic range, time response, spectral bandwidth, spectral resolution, compactness in size etc. Calibration techniques for single telescopes, interferometers and array receivers will also be covered.

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Commission J - "Digital Signal Processing Hardware"

Conveners: Albert-Jan Boonstra, Dan Werthimer

Exciting recent technological advances in digital processing hardware have contributed to better sensitivity, larger bandwidths, larger fields of view, and higher spatial resolution for the radio astronomer. These advances allow, for example, correlation of larger numbers of telescopes and phased-array processing. For the first time they make processing of phased-array feed systems feasible, and they increasingly allow accelerated processing further downstream. This session aims to highlight state-of-the-art hardware systems planned or recently deployed at radio telescopes, for example but not limited to the SKA radio telescope and its precursors and pathfinders. Session papers are invited that address new architectures and new instrumentation, including beam-formers, correlators, spectrometers, and systems for pulsar search and timing, FRB search, VLBI, and SETI.

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Commission J - "Detection of Short-Duration Transients and Pulsars"

Conveners: Ben Stappers, Vicky Kaspi, Joeri van Leeuwen

The focus of this session will be on the use of interferometers for time-domain detection of fast radio transients, such as Rotation Radio Transients (RRATs) and Fast Radio Bursts (FRBs), as well as on radio pulsars. Instruments to be considered are Apertif, CHIME, JVLA, LOFAR, Meerkat, MOST, SKA, etc.

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Commission J - "Recent and Future Space Missions"

Conveners: Fabrice Herpin, Martin Giard

The session aims at presenting the most recent and future (from the end of the 2000s till 2030s) far-infrared space observatories. Radioastronomy covers indeed a domain beginning at large wavelengths but also extending to the far IR, opening the window to inaccessible molecules and transitions from the ground, e.g., water. The different talks foreseen here will show the main results of the wonderful Herschel Space Observatory whose mission ended in 2013, but also of the current facility SOFIA, the only observatory in activity in this domain for a long time. The future space mission projects such as SPICA, Millimetron, and FAR-Surveyor will be presented in details. Beyond the expected science results from these missions, the speakers will also present the different innovative technologies used or to be used.

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Commission J - "Latest News and Observatory Reports"

Conveners: Richard Bradley, Willem Baan

This session will have contributions of the latest news, exciting late submissions, interesting papers that did not fit in the other sessions, and observatory reports.

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Commissions JD - "AstroPhotonics"

Conveners: Martin Roth, Peter Maat, Stefan Minardi

Optical fibers and integrated optical devices are increasingly being used as key technologies to improve the performance of radio- and optical- astronomical interferometers and, in general, any optical astronomical instrument. To highlight the rapid development and growing importance of this specific area of applied photonics, the term AstroPhotonics has been recently devised. Beam forming devices, integrated optics delay lines, and clock distribution based on optical fiber networks are now commonly used to enhance the precision of radio-interferometric measurements, while reducing the impact of environmental electromagnetic noise and infrastructure cost. Recent advances in optical comb technologies bear promise to replace atomic clocks by much more accurate optical clocks, which could be easily interfaced to optical fiber networks to time the radio-telescopes. In the domain of optical interferometry, integrated optics multi-telescope beam combiners for near-infrared light are currently delivering the highest precision visibility measurements and enable reliable image retrieval of astronomical targets ranging from stellar surfaces to proto-planetary disks. Extension of these technologies to the visible and mid-infrared bands is currently an active research area, along with feasibility studies and on-field tests of direct telescope connection by means of optical fiber links. The aim of this session (including both invited and contributed talks as well as posters) is to bring together the radio- and optical-AstroPhotonic communities by presenting recent advances and new application concepts based on photonic technologies for astronomical interferometry. Differences and similarities between the photonic technologies and their applications employed by the two communities will be highlighted, in order to promote a fruitful cross-contamination of ideas and interdisciplinary collaboration. Eligible topics include: integrated optics devices and components for stellar interferometry (e.g. beam forming devices, homodyne and/or heterodyne interferometric beam combiners, integrated phase and/or amplitude modulators), all-optical delay lines, frequency combs generation, optical clocks, optical fiber networks and their opto-electronic management, long-haul interferometric fiber links.

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Commissions JEFGH - "Characterization and Mitigation of Radio Frequency Interference"

Conveners: Frank Gronwald, V. Deniau, Richard Bradley, Terry Bullet, Hanna Rothkaehl, David LeVine, Amit Kumar Mishra, M. Haredim, J. Gavan

In this session, radio frequency interference (RFI) issues will be discussed that are of particular importance for observational sciences such as radio astronomy, microwave remote sensing of the Earth, and solar and ionospheric studies where highly sensitive measurements are necessary.

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Commissions JG - "Ionospheric Models and their Validation"

Conveners: Stefan Wijnholds, Sean Elvidge

The ionosphere has a profound effect on the propagation of radio waves, making measurements of distortions of RF signals an effective tool for ionospheric research. These same distortions hamper ground-based radio astronomical observations of cosmic source structure and position, in particular at frequencies below 1 GHz. Radio astronomers are, therefore, using different ionospheric models to reduce the number of parameters required for calibration of instrumental and environmental effects affecting their observations. In turn this calibration process provides information on the ionospheric conditions above the array, such as turbulence scales, TID wavelengths and TID velocity. This session aims to bring low-frequency radio astronomers and ionospheric researchers together to stimulate cross-fertilization between these two fields with emphases on the modelling of RF propagation through the ionosphere, the ionospheric models themselves and validation of those models.

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Commissions DJ - "Special Session on Gravitational Wave Detection"

Conveners: Roman Schnabel, Lisa Borsotti, Willem Baan

The first observation of gravitational waves on September 14, 2015, by the two detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO) heralded the field of gravitational-wave astronomy. It is expected that this field will provide information about the universe that was previously not accessible at all. Although gravitational-wave observatories are already extremely sensitive measurement devices, there are many ideas for further enhancements to increase the event rate by several orders of magnitude and to target specific sources of gravitational waves. A particular goal is reaching a sensitivity that will allow us to listen to the gravitational-wave background originating from the Big Bang.

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Commissions ECJ - "Spectrum Management"

Conveners: J. Pedro , A. Tipaldy, A. Shukla, H. Liszt

The focus of this session on spectrum management and spectrum utilization is of high interest to the community. We expect to give a short report of the related WG06 activities during the last period, along with our views on spectrum management, and on hot topics of today. International and local Chinese contributors will be invited such that first-hand reports on controversial spectrum management issues will be presented.

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Commissions EFGHJ - "One-Day Workshop on RFI Mitigation and Characterization"

Conveners: F. Gronwald, R. Bradley, T. Bullet, H. Rothkaehl, D. Le Vine, A. Maitra, M. Haredim, J. Gavan, V. Deniau, P. de Matthaeis

It is the aim of this workshop to bring together researchers, engineers and users from all radio science disciplines to consider how RFI affects their respective fields, to develop mitigation strategies, and to foster cooperation and collaboration. Particular attention will be given to the impact of new and future sources of RFI, spectrum management challenges, and new technology developments. Recent progress towards the ultimate goal of being able to do observations with real-time mitigation of the undesired signals, while leaving the desired signals minimally affected, will be discussed.

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Commissions GHJ - "Workshop on Extreme Space Weather Environments"

Workshop Chair: Mike Hapgood,
Workshop Co-Chair: Terry Onsager,
Conveners: Tony Mannucci, Viviane Pierrard, Mauro Messerotti, Ludwig Klein

Over recent years extreme space weather has been recognized as a global risk with significant societal and economic risks affecting many domains, including but not limited to electrical power grids, satellites, aircraft passengers and crew, avionics, GPS, Galileo and other GNSS positioning, navigation and timing systems and communications systems. In order to evaluate the consequences of space weather on these systems it is essential (a) to identify what are the factors in space weather environments that interact with the systems at risk, and then (b) to estimate what are reasonable worst cases for these factors. This workshop will bring together experts and other interested parties to review and refine a process for developing an internationally agreed set of specifications for the extreme space weather environment, and to test the process by applying it to a number of key domains. It is hoped that this will be the first of a series of workshops, hosted by different organizations and fora, developing these specifications.

The workshop will be led by Professor Mike Hapgood of the Rutherford Appleton Laboratory and will be hosted by URSI Commissions G, H and J. The focus will be on environments appropriate to the work of these Commissions, namely neutron, proton and electron fluxes, solar radio fluxes, ionospheric electron density enhancements, TEC and related electron gradients and radio scintillation. Talks and related presentations will be by invitation only, however, there will be plenty of opportunities for discussion and possibly for showing targeted data and information. Poster papers will be accepted.

The workshop will require additional registration on the URSI web site (but there is no additional cost). Additional preparatory materials will be sent out prior to the meeting.

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Commissions HJ - "Solar, Planetary, and Heliospheric Radio Emissions"

Conveners: P. Galopeau, G. Mann, H. O. Rucker, Y. Yan, S. White, T. Bastian

The Sun, solar system magnetized planets, and the heliosphere are sources of intense non-thermal radio emissions. Thus solar system radio astronomy and plasma physics provide most important tools that complement those of other space- or ground-based observations in Gamma rays, X-rays, EUV/UV, and the visible, etc., for understanding these non-thermal processes and energetic particles occurring in solar bursts and their influence from the solar surface to heliospheric space. New generation or upgraded radio telescopes, either solar-dedicated or non-solar-dedicated, have (will) come into use, including ALMA, E-OVSA, EVLA, GMRT, LOFAR, MUSER, and MWA, as well as the Ukrainian radio telescopes UTR-2, URAN, and GURT, the radio spectrometers aboard Stereo spacecraft, and the future SKA. These instruments provide new possibilities to measure the non-thermal radiation in an unprecedented way and open new windows for a better understanding of the radio emission processes in space (with applications to astrophysical objects, like supernovae remnants or active galactic nuclei). They also provide diagnostic tools for extrasolar planets, since these processes are the same basic plasma processes in space. Complementary studies are highly welcome including analysis from spaceborne experiments (e.g. Cassini, Galileo, Ulysses, Wind, Juno), laboratory and experimental studies, theoretical investigations devoted to the generation mechanisms and particle acceleration processes, and preparatory studies of forthcoming space missions (such as Bepi-Colombo and JUICE). Resonance, Solar Orbiter, Solar Probe, Taranis). This session will provide an important platform for solar radio astronomers, plasma physicists, planetary scientists, astrophysicists, and radio scientists to communicate and discuss a wide range of interesting and exciting topics, including the recent progress of radio observations of the Sun , solar wind, and planets, spacecraft measurements, data processing, theories, new technologies, and beyond.