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Articles on this Page
- 12/15/16--16:00: _The launching point...
- 12/18/16--16:00: _Another 12,5-year a...
- 12/19/16--16:00: _The age, dynamics, ...
- 12/20/16--16:00: _7.33 years At ASTRON
- 12/21/16--16:00: _Christmas Market
- 12/22/16--16:00: _ASTRON Season's Gre...
- 12/27/16--16:00: _Happy holidays from...
- 01/01/17--16:00: _The schaatsen of Ja...
- 01/02/17--16:00: _Speeding things up ...
- 01/03/17--16:00: _BALTICS DSP course ...
- 01/04/17--16:00: _...placeholder Nat...
- 01/05/17--16:00: _Dwingeloo Radio Tel...
- 01/08/17--16:00: _Filming @ ASTRON fo...
- 01/09/17--16:00: _Whisper Dish stolen...
- 01/10/17--16:00: _Het Logboek -> The ...
- 01/11/17--16:00: _ASTRON RFoF purchas...
- 01/12/17--16:00: _Who was Who in post...
- 01/15/17--16:00: _Presentations Proje...
- 01/16/17--16:00: _OLFAR PhD defence S...
- 01/17/17--16:00: _DIY Aperture Arrays
- 12/15/16--16:00: The launching point of a protostellar outflow resolved
- 12/18/16--16:00: Another 12,5-year anniversary at the R&D department of ASTRON
- 12/19/16--16:00: The age, dynamics, and energetics of FR II radio galaxies
- 12/20/16--16:00: 7.33 years At ASTRON
- 12/21/16--16:00: Christmas Market
- 12/22/16--16:00: ASTRON Season's Greetings
- 12/27/16--16:00: Happy holidays from JIVE
- 01/01/17--16:00: The schaatsen of Jan Oort
- 01/02/17--16:00: Speeding things up with 3D printing
- 01/03/17--16:00: BALTICS DSP course week in Latvia
- 01/04/17--16:00: ...placeholder Nature Hessels... (unaccept, don't delete!)
- 01/05/17--16:00: Dwingeloo Radio Telescope on popular science TV-show Galileo
- 01/08/17--16:00: Filming @ ASTRON for Biostirling for SKA
- 01/09/17--16:00: Whisper Dish stolen (and returned)
- 01/10/17--16:00: Het Logboek -> The Journal
- 01/11/17--16:00: ASTRON RFoF purchased by the MWA
- 01/12/17--16:00: Who was Who in postwar Dutch astronomy
- 01/15/17--16:00: Presentations Project Management
- 01/16/17--16:00: OLFAR PhD defence Steven Engelen
- 01/17/17--16:00: DIY Aperture Arrays
© (1) Per Bjerkeli and co-authors, as well as ESASky (European Space Astronomy Centre; ESAC, Madrid, Spain). (2) Per Bjerkeli and co-authors.Molecular outflows are signposts of the star formation process and when they were first discovered in the 1980s, they came as a total surprise. The expectation at that time was to detect infall of matter, not outflows. It has since then been realized that outflows are important, since their efficient removal of angular momentum allows for inward accretion and the continued growth of stars. Observationally, outflows are now recognized to be ubiquitously present in protostellar systems. But until very recently, the limited angular resolution of observations has prevented us from probing the central engine directly, and thus, the nature of the ejection mechanism has been heavily debated. The main difference between the proposed models is the region in which the acceleration of material takes place: close to the protostar itself (the stellar surface or the disk-star interface) or in an extended region in the circumstellar disk.
An international team of astronomers, led by Per Bjerkeli (Copenhagen University) and Matthijs van der Wiel (ASTRON), have used ALMA in its most extended configuration with the aim of resolving the launching region of a rotating molecular outflow. The CO images of the protostar TMC1A, with a resolution of 0.04 arcsec (6 au at 140 parsec distance), are presented in a Letter appearing in this week's issue of Nature: Bjerkeli, Van der Wiel, et al. (2016). These data provide the first direct evidence that a protostellar outflow is launched from an extended region in the circumstellar disk. The launching region extends up to 25 au from the central protostar. The outflow is seen to corotate with the disk from which it is launched.
Images: (1) ALMA observations of the TMC1A protostellar system showing how the outflow is lifted from the disk. Green color scale: dust continuum emission at 1.3mm, emanating from the disk. Blue and red colors denote, respectively, blue- and redshifted CO J=2-1 emission emanating from the outflow. The redshifted side of the rotating outflow is partly masked out by a combination of projection effects and self-absorption. (2) Artist impression of the disk wind launching the protostellar outflow. An animated version of this image is available.
© ASTRONThis time it's Ronald Nijboer his 12,5-year anniversary. On 1 May, 2004 Ronald started his career at the Research & Development department of ASTRON with working on LOFAR, in the MeqTrees group. His development in�the following years is impressive.
He played an important role as project leader in the so-called COBALT project�(COrrelator and Beamforming Application platform for the LOFAR Telescope). This project started�on 1 January, 2013 with the aim to develop a CPU-GPU based system as the central correlator and beamforming platform for the International LOFAR Telescope. In the end of 2013 the full system passed certification.
Nowadays Ronald is involved in SKA - Science Data Processor (SDP) as�MT member and for pipeline activities. In February 2006 Ronald became Competence Group Leader of the Computing Group and thus also member of the R&D MT. Through his friendly and hardworking attitude many consider him as a nice colleague with a lot of expertise.
During a R&D meeting on 1 November, a beautiful bouquet of flowers was handed over to him by Gert Kruithof, which he gladly accepted.
© Jeremy HarwoodFigure: Top: 368 MHz radio images of the FR II radio galaxies 3C452 (left) and 3C223 (right) overlaid on optical backgrounds. Bottom: The spectral age of each source as a function of position made using the Broadband Radio Astronomy ToolS (BRATS; http://www.askanastronomer.co.uk/brats ). Credit: Jeremy Harwood; Radio images: Harwood et al., 2016; Optical images: DSS/SDSS
Radio galaxies, highly energetic structures which are observed on scales of anything up to a few million light years in size, are thought to be a key component in galaxy evolution by providing an injection of energy to the surrounding environment. However, limitations imposed by the old generation of radio telescopes have meant that the detailed spectra of these sources at low frequencies remains largely unexplored.
Using the LOw Frequency ARray (LOFAR) and the Jansky Very Large Array (VLA) at frequencies between 50 and 460 MHz we have recently investigated the age, dynamics, energetics, and particle acceleration processes of two Fanaroff and Riley (1974) class II (FR II) radio galaxies. For the first time, these instruments have allowed us to undertake detailed studies of these powerful radio sources on small spatial scales at low frequencies and map the age and spectrum of the emission as a function of position.
By placing tight constraints on the low-energy electron population, magnetic field strength, and total energy content of the radio galaxy's lobes we are able to better understand their life cycle, the total amount of energy they transfer to their environment, and the impact this has on the evolution of galaxies as a whole.
© ASTRONLife in ASTRON was diverse, interesting, and never boring. I joined ASTRON in 2009, the period when LOFAR was being rolled out. After about a year, on June 10, 2016, LOFAR was inaugurated by Queen Beatrix. Then followed the intense period of making LOFAR operational. Most of my effort was spent on coordinating the software development, as part of the LOFAR Commisioning Coordination Group, nicknamed the "Four Horsemen of the Apocalypse" by one, now retired ASTRON employee.
Then LOFAR became operational, in December 2012. And that's when life really started, because keeping a new instrument based on new technology operational proved to be the challenge, both in hardware and in software.
On top of that, DIGESTIF was succeeded by APERTIF, and that meant changes at the WSRT. To keep the 40+ year old dishes operational for another five to ten years meant some serious maintenance besides removing old and installing new receivers and signal processing equipment.
The last two years were spent on software development for LOFAR, and especially on handling the post processing pipelines. But also on coordinating the HILADO work package of the RadioNet 3 project, in which both ASTRON and JIVE partipicated.
But life at ASTRON is not only work, it also is pleasure. Especially partaking in the famous ASTRON cabaret was a great source of merriment: dreaming up the script, designing and making the decors, the rehearsals, and of course the performances themselves. The picture tells it all.
After these seven point something years, I exchange ASTRON for TNO, looking back on a stimulating period being part of a great team at ASTRON, and cooperating with JIVE.
© ASTRON / Hiddo HanenburgToday at 15:00, we have our very own Christmas Market. This year we have a different approach to the annual Christmas High Tea. This time we chose for a Christmas Market with a variety of activities.
The Market marks the end of the year for ASTRON, JIVE and NOVA. All of the personnel, retired personnel, students and visitors come together to celebrate Christmas.
At the end of the celebrations the Christmas parcels will be handed out and many people will start their holidays.
© ASTRONOn behalf of our Board, Management Team and all of our staff, we wish you a Merry Christmas and a Happy New Year! We are looking forward to a great 2017!
© JIVEBest wishes from JIVE!
This year's image highlights the special science one can do with the European VLBI Network and JIVE. With more to come in 2017!
From all of us at JIVE, we wish you all great holidays and all the best for 2017!
The JIVE staff
© LeidraadProf Oort was a giant of 20th century astronomy, and the founding father of Dutch radio astronomy (he also dabbled in comets). But whenever the canals froze over, he grabbed his schaatsen (skates) and left the Universe to fend for itself.
His enthousiasm was contagious, and many aspiring astronomers of all nationalities ventured out onto the ice after him. But while they dubiously tested the freshly formed surface, which made alarming creaking sounds, they knew that Oort had already skated on it the day before. He was a tough act to follow.
Oort's other sport was rowing. In 1918, he coxed the crew of Aegir (Groningen) to their first victory in the highly prestigious Varsity race. And every morning, if there was no ice, he did 20 km in his single sculls. He kept this up well into his eighties.
The picture shows the very traditional pair of skates that he skillfully used for many years. They can be admired in the Boerhave Museum for scientific instruments in Leiden. This is right and proper because skating is highly conducive to rumination, for instance about Life, the Universe and Everything. Therefore, his humble skates were definitely consistent with the ASTRON Mission Statement: They made discoveries happen.
Happy New Year, and let's hope for an (increasingly rare) bit of skating.
© R.H. van den BrinkThe mechanical workshop of ASTRON is known for quick and effective solutions. Sometimes we encounter a small issue which needs a simple solution in order not to delay the process too much, and to continue as fast as possible.
For such occasions, the 3D printer is ideal. In the short period that it has been in use at the workshop, many products have been produced with success.
The picture shows the most recent product, which is meant for APERTIF. During installation Juergen Morawietz noticed that the connection of the PPS was very vulnerable. Due to good interaction, Sjouke Kuindersma managed to design a small product to tackle the problem in a very short time.
The flexibility of the production method allowed us to produce a prototype in a few minutes. Some adjustments in the design were quickly made, after which multiple final objects were produced in one batch and installed in the system.
Currently we are looking into the possibility of offering a 3D printer for general use, accessible to all colleagues, and supported by the mechanical workshop. This should allow everybody to reap the benefits of the flexibility and short-time-to-production of 3D printing.
© ASTRONBALTICS is an educational program funded by the European Unio. It is meant to share our expertise with the staff of Ventspils International Radio Astronomy Center (VIRAC) in Latvia, so that they will be able to join our scientific endeavours. ASTRON is one of the two partners involved in this project, together with University of Manchester (UMAN).
Last September the "BALTICS Phased Array Digital Signal Processing I" school started in Ventspils. It was the first of two weeks in which the basics of digital signal processing were revisited, and specific subjects on processing data from phased array systems.
The two-week DSP course is titled: Signal Processing - an intensive course. In this first week, the full scope of basic topics on digital signal processing was treated. This was to get the participants to the level needed for the second week, which will take place at the end of 2017.
The picture shows ASTRON's Ronald de Wild presenting a full week of lectures packed with theory.
© Erik Tiddens (CAMRAS)On August 2nd the crew of the popular science TV-show Galileo visited the Dwingeloo Radio Telescope. Presenter Shelly Sterk, a camera man and a sound technician came to Dwingeloo to make shots of the radio telescope and to reveal the capabilities of it by interviewing two CAMRAS-volunteers.
Jan van Muijlwijk (PA3FXB) explained moon-bouncing (i.e. using the moon as a reflector for radio waves) by receiving photo's sent by a Swiss radio amateur, including a picture of Shelly. Harry Keizer (PE1CHQ) explained about SETI and pulsars.
On November 17th the item was broadcast on RTL5. You can still watch it on YouTube:
From left to right: Jan van Muijlwijk, presenter Shelly Sterk, the camera man and Harry Keizer.
© B4S@ASTRONRecently, a film crew from Spain came over to ASTRON as partner in the FP7 project BioStirling for SKA (B4S). The emphasis in this project is to see if and how a solar concentrator dish with a Stirling motor in its focus might generate sufficient electrical power to operate a large radio-astronomical installation, for example the SKA. Alternatively, the heat could also be generated through the burning of bio-gas; hence the name BioStirling.
Of course there are many ways to generate sustainable power to research infrastructures like the SKA, each with their own pros and cons. The B4S project has been set up as a system-level approach, but eventually had to seriously cut back on its ambitions for reasons of cost and time. This in itself could of course be seen as a legitimate project outcome, as cost and technological maturity are coupled, and so more work needs to be done to develop the idea. Nevertheless, a single installation will be built at Moura in Portugal, which has been identified long ago as a hot (really!) and excellent low-RFI site for radio astronomy (test) stations.
In preparation for this installation, a movie is being made in which ASTRON features as a modest partner in terms of actual work, but as an important model for the application of renewable energies in radio astronomy. In practice ASTRON will assess the Radio Frequency Interference (RFI) generated by the BioStirling machine in Moura, and its impact on a locally installed test-instrument based on Embrace tiles.
The pictures show ASTRON's Nico Ebbendorf and Wim van Cappellen, under the watchful eyes of Marco de Vos and yours truly, captured in the highly spirited act of explaining how things work in radio astronomy.
No doubt we will brief you on further progress, and report on a renewable future in radio astronomy as much as we can!
© Tammo Jan Dijkema, RTV Drenthe, Tied ZatIn the last week of 2016, one of the whisper dishes disappeared from its spot along the Milky way path. In its place we found a tiny TV satellite dish. Paths on the grass clearly showed that the dish had been loaded onto a truck.
It turns out that we were the victim of a dubious tradition from the Northern part of the Netherlands. In this tradition, called 'Oudejaarsstunt' ('New Year's Eve Stunt') or 'nieuwjaarsslepen' or 'nieuwjaarstogen', remarkable objects are purloined, only to appear on another location on January 1st, usually to make some political point.
The whisper dish indeed turned up on January 1st. New Years club 'Tied Zat' showed the whisper dish in their village Zorgvlied. With their action, they wanted to draw attention to the poor mobile reception in some parts of Drenthe. They did not elaborate on how a whisper dish would solve this problem.
Luckily, the dish was returned to its original location last weekend. For their dubious purposes, Tied Zat constructed a special trailer, and the damage is limited to some trails on the grass, which they will repair when the weather permits.
Of course, we are not happy with the dish being stolen, even if it was only temporary. However, no damage has been done, apart from disappointment on the part of people who expected to use the whisper dishes during the Christmas break. Therefore, we can only be happy that the dish has been properly placed back, and be relieved no 25 meter dish was used for this stunt.
Local news coverage of the events (all in Dutch): 'Where is the whisper dish', 'Mystery solved: whisper dish found', 'Stolen whisper dish returned in Hooghalen' (with video), reaction Staatsbosbeheer.
© Curtin UniversityIn 2014 ASTRON commissioned Het logboek, a youth novel by Anke den Duyn. Het Logboek intertwines adventures around the Dwingeloo telescope with Dutch radio astronomy history, science and even a bit of engineering and links to the SKA sites in South Africa and Western Australia.
Prof. Peter Hall from Curtin University, Perth, Western Australia, recognized the potential of Het logboek for Australian kids and commissioned a translation of the book into English. In its translation the title changes to The Journal. An Australian of Dutch descent, Kim van Lent, and Anke had a great time converting the Dutch story into Australian-English.
The release of The Journal coincided, not accidentally, with the state visit of Their Majesties King Willem-Alexander and Queen Maxima, to Australia in November. This was a great opportunity to present the Royal couple with three copies of the book, one for each of the Dutch princesses Amalia, Alexia and Ariane. A chance for them to enjoy exciting adventures around the Dwingeloo telescope and to catch up with the role their great-grandmother Queen Juliana played in ASTRONs glorious past.
Curtin University Vice-Chancellor Prof. Deborah Terry presented the books to the Royal couple.
p.s. The Australian-English Journal is a good read but of course a copy of the Dutch Logboek was included in the package...
© ASTRONASTRON RFoF purchased by the MWA
With great pleasure, we report on the purchase of 256 ASTRON Radio Frequency of Fibre (RFoF) modules by ICRAR/Curtin, towards the MWA telescope.
The Murchison Widefield Array (MWA) is a low-frequency radio telescope operating between 80 and 300 MHz. It is located at the Murchison Radio-astronomy Observatory (MRO) in Western Australia, the planned site of the future SKA-LOW telescope, and is one of four telescopes designated as a Precursor for the SKA. The MWA has been developed by an international collaboration, including partners from Australia, Canada, India, New Zealand, and the United States.
Currently, MWA is being upgraded (Phase II) towards improved EoR capabilities, implementing a higher filling factor within the core of the telescope.
Also, by creating extended baselines up to 5 km, improved survey and imaging capabilities will be come available.
It is the latter on which the ASTRON RFoF modules will be used, making the sure the long-distance RF-links won’t suffer from the traditional coaxial cable approach.
For such long links, there are no real alternatives to RFoF technology, which offers the lowest cost and the lowest signal loss. Also, RFoF systems are highly immune to RFI pickup, static and lightning, as well as causing no electromagnetic interference themselves.
More information on the ASTRON RFoF developments (supported by the Dome project) can be found at the ASTRON R&D website.
We enjoy the fruitful collaboration with the local, Dutch SMEs, enabling us to produce this hardware, as well as early prototyping during development.
Many thanks for all the work done by the ASTRON and MWA team.
© RUGIn late August Huug van Woerden celebrated his 90th birthday. The Kapteyn Institute organized a one-day symposium to mark this event. The picture shows the more than 100 people that attended, and made it an unforgettable experience. It is a wonderful cross-section of the (glorious? happy? blessed?) postwar generation of Dutch astronomy. The intrinsic image quality is good enough to make everyone clearly recognizable, even the (relatively) young ones in the back.
NB: Of course Huug is not quite the Nestor of Dutch astronomy. Cees de Jager (second row, with blue tie) is five years older, but does not look it.
Happy hunting down memory lane.
© ASTRONPresentations Project management
Just before the Christmas holidays for�some people of the R&D department it wasn't all about astronomy, antennas, phased arrays, front and back ends, etc. They attended a second meeting�in a series of presentations on project management in other companies. These presentations serve as an important mirror on our project management approach and where we can improve.
The�first presentation by Niek Govers regarding project management for the�development and introduction of the�smart card for public transport (OV Chip kaart) took place in June 2016. For this second presentation, we invited Leon Sluiman of ENGIE LNG Solutions In Zwolle.
He shared his experiences as project manager of an innovative and complex project:�the first LNG* filling station of ENGIE LNG Solutions in the Netherlands. Leon has been closely involved in the planning, implementation, construction�and operation of this plant. From a commercial point of view he described the way he and his colleagues are dealing with roles and responsibilities within project teams. He also gave a short explanation on various project management styles and different review methodologies.�
A few high lights from his presentation/discussion:
- Internal clients are sometimes more difficult to handle, since it is easier to say "we will do this tomorrow". At the same time communication, can be much easier since the customer is nearby.
- You need the right balance between project structure and high quality team members. This required balance will depend on the type of project.
- For a commercial organisation like ENGIE, an overrun of 300 KEuro on a total project budget of 1.5 MEuro�is considered to be large.
- Leadership�is important. Be open�and honest.�Leon presented the 'Theory U' from Otto Scharmer. This is a very inspiring theory on leadership. For the readers of this daily image maybe also worth taking a look.
* LNG means Liquefied Natural Gas, used as a fuel for trucks and ships. When natural gas is cooled to -162 degrees Celsius (boiling temperature of gas), it becomes liquid. This liquefied natural gas has a high-energy density and is therefore an excellent and safe fuel for trucks and ships. Due to stricter regulations and new emission rules, more and more transport and shipping companies switch to LNG as a fuel, because LNG contains little nitrogen and sulfur, resulting in�lower emission of particulate matter, nitrogen oxide, sulfur oxide and CO2 than a fuel like Diesel and Marine Gas Oil.
© Steven EngelenOn Thursday November 3 at the TUDelft, Steven Engelen successfully defended his PhD thesis with the title "Swarm Satellites, design, characteristics and applications".
In his thesis Steven explains how to design and optimize a satellite swarm such that it achieves a certain mission goal. In this case the mission is OLFAR, an envisioned swarm of order 50 satellites in lunar orbit acting as a distributed interferometric radio telescope.
Due to the distributed nature of the telescope antenna swarm, the system as a whole is to a certain extent insensitive to component failure. Using Markov modeling, Steven has simulated degradation of the OLFAR satellite, and using Monte-Carlo analysis he has investigated the impact of component degradation on various properties of the swarm. He has also performed a full orbital analysis for a lunar science orbit.
This work was done within the ASTRON-TUDelft-UTwente OLFAR STW project, aiming at developing scalable autonomous nano satellite systems for low-frequency radio astronomy in space. Steven is the third OLFAR PhD student graduating in this project. Alex Budianu (University of Twente) and Raj Thilak Rajan (TU-Delft) were the other two successful PhD students.
With the OLFAR work, together with R&D projects and studies such as NCLE, DARIS, DEX, DSL, SURO etc, the community is gradually preparing technologies for a future low-frequency interferometric mission in space.
© Centre for Space Research, Faculty of Natural Sciences, North-West University, South AfricaArmed with nothing more than a Gerber-file, a couple of low-noise amplifiers and a pair of running shoes, the recent visit by Paulus Kruger served as a refreshing reminder of the rapid prototyping capabilities of ASTRON's R&D department. Paulus is a senior lecturer with the Centre for Space Research at the Potchefstroom campus of North-West University, South Africa. Currently, he is working towards a DIY aperture array prototype to serve as an educational instrument within their department.
During his visit, Paulus was quick to identify the key figures needed within the Radio Group to bring one of his antenna prototypes to life. Once established, things went fast. Handing the Gerber-file over to the capable hands of Albert van Duin before coffee on Wednesday morning, the antenna with low-noise amplifier and ground plane stood ready for measurements (on top of the Vivaldi tile) within our THACO noise temperature measurement facility, 24 hours later. Ready at hand was our resident THACO expert, Martijn Brethouwer, ensuring the noise measurements were completed in time for Paulus to accompany a fellow South African on the 15 km leg of the Telescooploop in the afternoon.
As seen from the RFI-infused noise temperature measurement, DIY antennas do not necessarily imply compromised performance. This active antenna achieves a respectable noise temperature varying between 20 and 45 Kelvin. These results, produced in this time frame, is a clear demonstration of the solid foundation that has been laid by the aperture array development at ASTRON.