© Bo Thide (Swedish Institute of Space Physics)

© Astron

This year we went back to Exloo, in the very informal setting of the Diner-Cafe Bussemaker. Erwin de Blok, Zsolt Paragi and Marjan Tibbe took care of the organisation, including the great weather we had that day!

After the success of last year, all participants were asked to prepare a short, informal presentation, and we would randomly draw (from a magic hat) names of speakers during the day. In this way, we got a very nice overview across the many fields of research we are covering: quite impressive to see all the breadth of what we do!

We finished off with Jayanne English telling us what to keep in mind when making (convincing) images for public outreach or press releases, a topic that triggered some discussion.

During the lunch break, many of us went for a visit to the LOFAR core, enjoying the beautiful weather and a lively explanation by Richard Fallows (and his dog).

© Astron

As part of her work with NASA's Hubble Space Telescope, she coordinated the Hubble Heritage project (http://heritage.stsci.edu/ ) and authored the Hubble Heritage website. She has been also very active during the International Year of Astronomy (2009), producing art work as well as an astronomy image-making video.

The visit of Jayanne to ASTRON has been fun but also extremely useful. In addition to the workshop, she has worked with some of us to apply her techniques and produce nice images from both WSRT and LOFAR data (some shown in the figure). She has also joined us during the AstroFest in Exloo. Jayanne really enjoyed the visit to LOFAR that we had during the AstroFest but she also gave a short "guest lecture" on the "making of" the pretty - but also explanatory - image of UGC 10288. This image was used for a press release of a paper involving also our George Heald (and posted also as our Daily Image of November 15 last year ).

© ASTRON

The parties present at the workshop are closely involved in designing the microserver printed circuit board. They received information about the newest technologies in PCB design, rigid and flexible printed circuit boards as well as application areas and constraints. This led to vivid discussion concerning design approaches and constraints, for example how much data can be transported over the flexible connections between rigid and flexible parts of such electronic circuit boards.

This particular seminar was a semi-closed Users Platform event. Future technology seminars organized by the Exascale Centre can be either closed or open, depending on the topic. Thanks to the Hanze Institute of Technology for hosting us.

© Madroon Community Consultants (MCC)

The past six years have seen an alarming increase in the poaching of Rhinos for their horns, which are highly valued in some East Asian countries for their (imaginary) medicinal and magical powers. The only real solution would be the elimination of this market, which is easier said than done. In the meantime, the poachers have to be resisted as much as possible.

First of all, the reporting of incidents by rangers can be greatly improved by means of technology like smartphone apps that instantly report images and position information back to base. In addition, it should be possible to make the "smart fence" around the park even smarter, to give timely and accurate warnings of poacher incursions. And finally, the Netherlands Forensic Institute (NFI) can help with the judicial prosecution of poachers.

ASTRON and the South African SKA project are involved because of their expertise in image processing, e.g. for reconnaissance from above. We might also play a role in combining large amounts of surveillance data, and their compact presentation to the enforcers in the field.

The image shows the tagging of a rhino that has been drugged by means of a dart fired from a helicopter, and the implantation of a tracing chip in its precious horn. When seeing and touching these mighty beasts, it is impossible not to feel distressed about their plight.

© ASTRON

We have done this using observations with the Australia Telescope Compact Array (ATCA) of the young (

The asymmetries at the edges of the disk can be used to date the last interaction of PKS B1718-649 with a companion to more than 1 Gyr ago. The tilted-ring model of the HI disk shows that this event may have formed the disk as we see it now, but that it is not responsible for triggering the AGN.

In absorption, we detect two separate lines (Fig. 2). A link between these clouds and the radio activity is quite possible. The most likely possibility is that the absorption components come from two small clouds that are not part of the regularly rotating disk(Fig. 3). They may belong to a larger population present within the galaxy and which may contribute to fueling the AGN. Simulations of the accretion proces into the AGN, show that cold clouds and filaments may be forming from condensation of the hot halo. These clouds would chaotically collide with the surrounding medium, loosing angular momentum, falling toward the center of the galaxy and triggering the AGN acticity.

These results have been presented in an A&A paper, now in press, by F. M. Maccagni, R. Morganti, T.A Oosterloo, E. K Mahony: http://arxiv.org/abs/1409.0566

© LWA

© C. Sobey on behalf of the LOFAR collaboration; no connection with Joy Division, Peter Saville, et al.

The average pulse profile shapes of radio pulsars are remarkably stable when summed over at least a few hundred rotations. This reflects their clock-like rotational predictability, and enables their use as precision physical probes, for example, towards testing theories of gravity.

Nonetheless, pulsar emission variability has been recognised on almost all timescales that are observationally accessible: from nano-second 'shots', expected to be the quanta of pulsar emission; to multidecadal variations, presumably due to evolution of the magnetic field.

PSR B0823+26 displays a plethora of magnetospheric emission characteristics over a wide range of timescales. Low radio-frequency, single-pulse observations obtained using LOFAR (the Low-Frequency Array telescope) provided us with a fresh look at this pulsar. This allowed us to identify a sporadic and weakly-emitting 'quiet' mode over hour-long periods, which displays rotating radio transient-like features and a nulling fraction forty-times greater than that during the more regularly-emitting 'bright' mode. Furthermore, the transition from the newly-discovered 'quiet' mode (the lower three nulls from the bottom of the image) to the 'bright' mode (the rest of the pulses in the image) occurs within one rotational period of the pulsar (0.5 s), and is concurrent across a broad range of radio frequencies.

Studying pulsars like PSR B0823+26 (including PSR B0943+10 - another interesting mode changing pulsar - see here and here for previous daily images) furthers our insight into the relationship between the host of magnetospheric radio emission characteristics and what they might teach us about the elusive magnetospheric radio emission mechanism. The paper describing these and further results has been submitted.

© ASTRON

In close cooperation with CAMRAS, Anke den Duyn launched the youth novel "Het Logboek" by handing the first copies to Anne Margreet Muller, daughter of Lex Muller, one of the first directors of ASTRON. And to Marc Oort, grandson of Jan Oort, founder of Dutch radio astronomy.

Today, the author will sign copies of the book for ASTRON and JIVE employees.

ASTRON has asked Anke to write Het Logboek. It is a breathtaking adventure against the background of the Dwingelderveld, with an important role for the 25m Dwingeloo Radio Telescope. The story is based on the input gathered from a large number of (former) ASTRON employees and others, and the creative talents of Anke.

The launch of the book marks the kick-off of a new adventure: "Kijk eens wat verder dan de sterren" (Just look beyond the stars). This is a project in which primary schools are challenged to embark their pupils on a journey to radio astronomy, and by doing so to arouse their interest in science and technology.

We are eagerly awaiting what the future will bring..

© Astron

The latest observations were done last year. Twenty days of observation were used to cover the entire extent of the galaxy (about 1 degree). Compared to the observations of the early 70's, the new data reveal features that are about hundred times fainter than the weakest HI clouds in the first observations. The main aim of the observations is to study, in the greatest possible detail, the effects of star formation and of gas accretion on the disk of a spiral galaxy. For this purpose, these HI data will be combined with WSRT and LOFAR observations of the (polarised) continuum emission of M101 (also involving George Heald and Sarrvesh Sridhar).

The blue (but less beautiful) version of the poster above won 1st prize in the Astronomy Pretty Poster Pageant (APPP) 2014. This poster I was able to make thanks to the lessons of Jayanne English, who visited ASTRON recently

© ASTRON

Luna and her friends are confronted with mysterious events when camping in the forest around Lhee. Fences disappear, game computer GPUs get stolen, remarkable characters cross the forest... Will they be able to unravel the secret?

The adventure novel "Het logboek" is also a journey through Dutch astronomy, featuring prof. Jan Oort and prof. Lex Muller, the Wurzburg telescope were it all began, and related historical events in 70 years of radio astronomy in the Netherlands.

At the presentation of the book, schools from villages with a connection to ASTRON will be present as well. Children from Diever, Beilen and Borger-Odoorn will get a first copy of the book. Will they pick up the excitement of science and technology?

More information: www.hetlogboekankedenduyn.nl

© LOFAR CITT

The twenty-first installment of LOFAR's successful series of Imaging Busy Weeks took place during the first week of September 2014 at ASTRON. The focus of this busy week was the developments being made by the Calibration and Imaging Tiger Team (CITT). Enhancements are being made by the CITT to the Standard Imaging Pipeline, in order to quickly and robustly produce science-grade images from LOFAR interferometric observations. These enhancements are still in development and require expert testing to ensure that they are up to scratch! For that reason the CITT is working closely with a broad range of scientists within the collaboration.

Highlights of the busy week included: testing of our fast calibration routine (based on "Stefcal") that offers a vast improvement in runtime and memory usage; imaging with the new and more capable LOFAR awimager; testing the CITT automated self-calibration pipeline; and testing of determination and application of ionospheric phase screens to LBA and HBA imaging data. We also experimented with some of the tools developed by the EoR group (for example, producing movies like this one), heard an exciting update on the "extreme peeling" strategy employed by Reinout van Weeren, and took steps toward making that sophisticated scheme available to other users.

Today's image shows some candid photos of the Busy Week team hard at work. The background is a high resolution (5"), deep (~500 μJy/beam), broad bandwidth (55 MHz) image produced using data calibrated by the CITT selfcal pipeline (see this image from the archives). It demonstrates that deep, wide field of view and broad bandwidth imaging is within our grasp � and that there is still more progress to be made in the pipeline to implement direction dependent calibration and imaging! These developments will be the focus of future busy weeks.

© Jimi Green

© Sally Cooper / PWG

LOTAAS has been observing since December 2012, and we have processed 160 pointings on the Dutch supercomputer Cartesius (operated by SURFsara). Using Fourier-based pulsar searching methods we have produced more than 3 million pulsar candidates. A machine learning classifier is then applied to the candidates and the most promising go forward for human inspection. LOTAAS has so far discovered 8 new pulsars. These are marked with large red stars in the above figure, which also shows the current observed sky coverage in green. Along with LOFAR's first two pulsar discoveries in the commissioning survey LOTAS, which are marked with orange stars above (Coenen et al. 2014), LOFAR now has a total of 10 pulsar discoveries. The LOTAAS survey has also redetected 80 known pulsars including 4 independent discoveries of pulsars originally discovered by the Green Bank North Celestial Cap Survey. The survey is only one third of the way through its first pass (of three) of the sky, with many more pulsars waiting to be discovered. We are also sifting through the already processed data to find intermittent pulsars, and single dispersed bursts.

© ASTRON/IBM

Dome and SKA

Among other things, the group discussed the mapping of Dome work onto SKA design work. A preliminary design review (PDR) is planned early next year. The discussion also covered ways of contributing to the SKA beyond PDR. There was also an exchange of thoughts on fundamental aspects, such as the extent to which the physical bulk of SKA data should be kept close to the telescope or at regional science data centres.

Progress and more progress

Researchers from various work streams were happy to report significant progress. For instance, there is now a concept-design of an extremely power-efficient chip for the low-frequency aperture array (LFAA) systems. It will be included as an alternative design in the PDR documentation set. Two work streams, Novel Algorithms and Real-time Communication, have started only recently. Nevertheless, researchers were able to share some initial results, and plans for the near future. Another great example is the microserver. It is now ready for ASTRON and SKA South Africa to start implementing and testing software on it (think correlator and imaging algorithms).

The next face-to-face meeting is planned for March 2015. The picture shows the members of the Dome team in front of one of the ZRL buildings just before the final session. Inset left: Erik Vermij explaining his award-winning accelerator research. Inset right: Yan Grange reporting progress on access patterns (storage).

© astropix.nl

Adjusting such a fast optical system is not easy, the depth of field at focus is only 17 micron, so the tilt of the imaging sensor has to be precisely adjusted to get sharp star images across the entire field.

The image above is a mosaic made from two completely different integrations. The left part was exposed for 15 x 60 seconds at 1600ISO, the right part 12 x 300seconds at 400ISO, as a result the latter has much less noise. A mosaic was made using PixInsight software, and it did a very good job equalizing both sides of the image and putting them together seamlessly. The result is a 34 Megapixel image that shows the North America nebula (NGC7000) and to its right the Pelican nebula (IC5070 and IC5067) Flat, dark and bias frames were used for image calibration.

© Astron/DESP

As shown in the pictures, the setup consists of an array of 16 dual polarized antennas, 2 receiver racks and 1 UniRack with 4 ADUs (Analog to Digital converter Unit), and 2 Uniboards.

A hexacopter was used to create an artificial radio source above the array. It flew 100-150 m above the antenna field, with a speed of 3-4 m/s along a GPS-controlled path. It made several 10-minute flights, carrying a RF source transmitting on different frequencies in the range of 50-450 MHz. One of the photos shows it carrying a dipole antenna for a 50 MHz test.

The output signals of the array antannas were captured from the Uniboards using the modified EMBRACE Capture software. The Uniboards are in full control with the Uniserver software.

The plot shows a first result of the 50 MHz flight, in which the hexacopter flew several times through zenith. It shows the signal power of the Y polarization from the 16 antennas and the blue line is the sum of all 16 antennas.

© R. Jay GaBany

The picture shows an edge-on, warped spiral galaxy, NGC 59007, and an extended stellar tidal stream, created through gravitational interaction.

© ASTRON

The main thrust of the proposal is to typical problems that are common to all of these facilities, in particular the Big Data challenge faced by these facilities and the ambition to properly interface their various data products with the Virtual Observatory. In addition, there are several interesting common technical projects, in particular the synchronisation of time and frequency across distributed arrays. Another interesting feature of ASTERICS is the ambition to open-up the data generated by the ESFRI related astronomy facilities to the general public with a strong commitment to the principles of the recent Science 2.0 initiative and the anticipated development of several citizen scientist applications. The PIs of the major work packages are Giovanni Lamanna (LAPP, Paris), Francoise Genova (CDS, Strasbourg), Huib Jan van Langevelde (JIVE, Dwingeloo) and Stephen Serjeant (Open University, UK).

ASTRON coordinated the submission of the ASTERICS proposal with major contributions from Gert Kruitoff, Rob van der Meer, Emmy Boerma, Andre van Es, Marco de Vos & Anneke Steenbergen.

The proposal is expected to be evaluated over the next few months. The Call is known to be heavily over-subscribed but hopefully it will be well received by the independent review panels. Fingers crossed... !

© Onsala Space Observatory/L. Wennerback (aerial picture) and Magnus Thomasson (owl)

As to that, the work appears to be overseen by the wisdom of an eagle-eyed eagle-owl (or Oehoe in the Netherlands, see (*) below) shown here in a magnificent picture by Magnus Thomasson. Alternatively, it might be wondering whether this egg will hatch into anything edible.

By the way, note the Swedish LOFAR station which is clearly visible in the background.

(*) From WIKIPEDIA: The Eurasian eagle-owl (Bubo bubo) is a species of eagle-owl resident in much of Eurasia. It is sometimes called the European eagle-owl and is, in Europe, where it is the only member of its genus besides the snowy owl (B. scandiacus), occasionally abbreviated to just eagle-owl. The Eurasian eagle-owl has a wingspan of 160-188 cm, with the largest specimens attaining 200 cm . The total length of the species can range from 56 to 75 cm. Females weigh 1.75-4.2 kg and males weigh 1.53 kg.