© ASTRON

Many of you will know that hitching a ride on both Voyager 1 and 2 is a Golden Record - a kind of time capsule that was placed on the side of the Spacecraft just before launch in 1977. The record includes sounds and images of the planet Earth, and representations of human civilisation such as music, a map of nearby Pulsars and greetings in 56 different languages. The idea of the record originated with the late, great Carl Sagan - just in case Voyager was found by another space-faring civilisation during its long sojourn through interstellar space. It could be a long wait - even at its current record speed, Voyager 1 will not make a pass by another star system for another 40000 years. It's expected that the signal from the Voyagers (powered by three large radioisotope thermoelectric generators) will be detectable until the end of this decade - it might make an interesting target for the SKA in the decade thereafter. The full set of images is available at (for example): http://webodysseum.com/art/116-images-of-the-voyager-golden-record/

What you may not know about this Golden Record, is that the Westerbork Synthesis Radio Telescope (WSRT) is one of only 116 images included on the record. The image above shows this photo (top right), along side the spacecraft itself and the record. Note that the Voyager record, really is a record - not an early CD - all the information on the disc is recorded in the audio frequency range, and the disc is designed to spin at only 16 2/3 RPM, requiring 12 seconds to play back the low-resolution images. In any case, it is nice to know that a little bit of ASTRON and the WSRT is on board the Voyager spacecraft, as they boldly go where no man has gone before...

© LEAP collaboration

On 27 July 2013, the Sardinia Radio Telescope joined in for its very first LEAP observation. It also meant the first LEAP observation in which all 5 telescopes participated.

LEAP is the Large European Array for Pulsars, an ERC-funded project in which 5 powerful European radio telescopes are phased up to observe and time millisecond pulsars with Arecibo-like sensitivity. Its purpose is to detect and study the gravitational waves emitted from supermassive black hole binary mergers.

The image shows the 5 telescopes as they participated in the LEAP-run: the Lovell Telescope (top left), Effelsberg (top right), the WSRT (middle left), the Sardinia Radio Telescope (middle right) and the Nançay Radio Telescope (bottom). Except for Nançay, all pictures were taken during the first 5-telescope LEAP observation.

© ASTRON

The grant has been awarded for studying the important question of the "Epoch of Reionization" (of the early Universe), using the LOFAR radio telescope. The latter is designed, built and operated by ASTRON, the Netherlands Institute for Radio Astronomy. With the grant money, Ger can appoint a group of seven scientists (PhD students, postdocs, and specialists in data analysis and software) for the next five years.

The observations, and the subsequent data processing, are very challenging, since the signals are extremely weak, and are being drowned by noise from radio galaxies, our own Galaxy, the ionosphere, receiver electronics, and man-made interference. Therefore, a total of 0.9 million Euro of the ERC grant will be used to acquire an extra powerful computer cluster. This will be needed to carry out the vast number of computations to process the large data volume (more than 1000 terabyte) and to filter the feeble signals from the noise.

Ger, together with colleagues Koopmans and Zaroubi of the Kapteyn Institute and Brentjens and Yatawatta from ASTRON, and supported by an international team of astronomers, students and postdocs, has been planning this LOFAR project for the past ten years. In the next five years, they intend to harvest.

The pictures show Ger, who is a keen sportsman, skating around the "SuperTerp", the 300m heart of the (much larger) LOFAR telescope. Obviously, he approaches this with the same care and thoroughness as he studies the EoR.

© Michel Arts

The approximate positions of the coils of both the key hanger and the terminal are depicted by the red lines in the photograph. The picture on top at the right shows the magnetic field lines of a coil carrying a current. One can see that the center of the coil has the largest flux density. This explains why you have to put the key hanger at the position as shown in the photograph. Also the maximum magnetic flux goes through the coil of the key hanger if the key hanger is in this position. From Faraday's law we know that the induced voltage is proportional with the magnetic flux going through the coil. This causes a stronger magnetic coupling between the two coils. Due to this stronger coupling the modulation by the integrated circuit in the key hanger causes larger variations of the input impedance of the magnetic coil of the terminal. This makes it easier for the electronics of the terminal to recognize the key hanger.

© Roy Smits & Jodrell Bank Centre for Astrophysics

The image shows part of a sound-file of the heart-beat like pulsar B0329+54, recorded by the Lovell Telescope and displayed by audacity.

The episode aired on Sunday 28 July on radio 1. It can still be heard here (in Dutch, starting after 45 minutes):

http://www.radio1.nl/terugluisteren/tijd?terugluisteren_dag=2013-07-28&terugluisteren_hour=21

© ASTRON & SKA

Top Row (l to r): Hans Olofsson (Director, Sweden), Elena Righi-Steele (Guest, European Commission), Beatrix Vierkotn-Rudolph (Director, Germany), LI Xin (Director, China), John Womersley (Chair of the SKA Board of Directors, UK), Phil Mwjara (Director, South Africa), ZHAO Jing (Director, China), Giampaolo Vettolani (Director, Italy), Jonathan Kings (Deputy Chair of the SKA Board of Directors, New Zealand), Peter Dewdney (Guest, SKA Organisation), Denis Mourard (Guest, CNRS/INSU, France).

Middle Row (l to r): Ian Corbett (Guest, Consultant), Mohsine Chefki (Guest, Federal Ministry of Education and Research, Germany), Brian Boyle (Director, Australia), Ethan Schreier (Guest, Associated Universities Inc, USA), Phil Diamond (Director-General, SKA Organisation), Paul Alexander (Director, UK), David Luchetti (Director, Australia), Bernie Fanaroff (Director, South Africa), Rowena Sirey (Guest, European Southern Observatory).

Front Row (l to r): Tim Cornwell (Guest, SKA Organisation), Yashwant Gupta (Observer, National Centre for Radio Astrophysics, India), John Conway (Director, Sweden), Mike Garrett (Director, Netherlands), Sean Dougherty (Director, Canada), Robert Braun (Guest, SKA Organisation), Luigina Feretti (Director, Italy), Colin Greenwood (Company Secretary, SKA Organisation), Patricia Vogel (Director, Netherlands).

The Board meeting itself was very constructive with the board agreeing a 650M� cost-cap for SKA-1 - see http://www.skatelescope.org/news/outcomes-ska-board-meeting-july-2013/ for further details.

© Ralph Eatough / MPIfR

This dietary analysis was possible by the discovery and follow up of PSR J1745-2900, a magnetar (ultra-magnetic neutron star formed in a supernova explosion) in the Galactic Centre region. First seen in the x-ray by the Swift and NuSTAR space telescopes, it was quickly also detected in the radio by the Effelsberg telescope, and subsequently by many others. The magnetar is separated from Sgr A* by less than half a light year in projection, which in Galactic terms is virtually on the black hole's doorstep, and multiple observational properties indicate that this is not a chance alignment. The image shows an artist's conception of PSR J1745-2900 and its surroundings, including Sgr A*. By itself this was already a thrilling discovery, since pulsar astronomers had been searching for pulsars in the Galactic Centre in vain for 40 years, and were starting to wonder whether the conditions near Sgr A* were so extreme that they might never be found. Pulsars can be used as precise cosmic clocks, and a pulsar near Sgr A* could be used to test Einstein's theory of General Relativity in a laboratory totally unlike anything available on the Earth or even elsewhere in the solar system.

PSR J1745-2900 is unfortunately unsuitable for these tests - magnetars are comparatively poor cosmic clocks, and ~0.5 light years is just a little too far from Sgr A* for a very stringent test of GR. However, the discovery of PSR J1745-2900 indicates that observable pulsars do exist in the Galactic Centre, boosting hopes of discovering a more suitable candidate. Meanwhile, PSR J1745-2900 can still be used to study the Galactic Centre environment. It emits polarised radiation, and the plane of the polarisation is rotated by the Faraday effect as it travels towards us. The magnitude of the rotation is dependent on the magnetic field along the line of sight, and so observations of PSR J1745-2900 can give the strength of the magnetic field pervading the gas destined to become Sgr A*'s next snack. As reported by Eatough et al. in Nature this week, the inferred magnetic field is quite strong - by the time the gas reaches the event horizon of the black hole, the magnetic field would be hundreds of times stronger than that of the Earth, strong enough to explain the observed synchrotron emission of Sgr A*.

For more information, see that following:

Pulblished Nature letter: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature12499.html

ASTRON press release: https://www.astron.nl/about-astron/press-public/news/new-radio-pulsar-explores-feeding-habits-milky-way%E2%80%99s-massive-black-ho

MPIfR press release: http://www.mpifr-bonn.mpg.de/461331/news_publication_7502957?c=2169

© Astro-Jeunes

During the week at the young festival, children of about 10 years old (helped by electronic engineers from IRAP, Astronomy laboratory in Toulouse) built a box that was then attached to a stratospheric balloon. It contained instruments to measure pressure, temperature and radiation as a function of altitude. We also installed a GoPro camera on the box, which sent down this image of the Earth from an altitude of 34 km, just before the balloon burst. As you see, the Earth is not flat.

In addition, during the week, we contacted the International Space Station (ISS) by radio, thanks to a collaboration between ESA and ARISS. Children were allowed to ask questions of French astronaut Luca Parmitano, who is currently aboard the ISS.

© NOVA-ASTRON

By coherently adding the light of these telescopes, MATISSE is capable of imaging at a spatial resolution of ~6 milli-arcsec in the 2.8-5 and 8-12 micrometer wavelength range. This allows the study of wavelength-dependent characteristics of gas and dust grains, which tell us about the formation and evolution of planetary systems, Active Galactic Nuclei and the high-contrast environment of evolved stars.

This weekend we had 'first light' with an important part of Matisse, i.e. the central part of the so called Beam-Shaper Box. In this unit, the light of four VLT-telescopes is combined interferometrically, and imaged onto the detector. Two cylindrical parabolic mirrors play an important role in this. They add an extra factor of six in anamorphism to the already anamorphic beams, bringing it to a total of 24. This can be seen as the four parallel red lines in one of the frames that are displayed in this sequence.

The extremely accurate mechanical structure (which vaguely resembles a racing car engine) is made out of a single solid block of aluminum. NOVA-ASTRON and VDL were also responsible for the anamorphic mirrors. In the coming period, much more optics will be mounted in this and other parts of the instrument. After having finished the sub-assemblies, all parts will be joined and integrated together.

© HALOGAS collaboration

© Arno Schoenmakers, Jurjen Sluman, the Muppets

(*) Please submit your witticisms to noordam@astron.nl before Sept 1st. Remember that humour is a tricky business.

© Pieter Benthem

Besides testing several types of ground anchors, we also constructed a long-term anchor test setup at the site of the PAPER radio telescope. Parts of this telescope can be seen on the left, where its array is being doubled in size (to 128 antennas). In the background, the KAT7 dishes are basking in the sun. And, coincidentally, taking data for our own George Heald.

© ApJ

The left-hand subpanel shows the visualization of the discovery space. The detection significance S is plotted as a function of the dispersion-measure trial number and the pulsar spin frequency. The pulsar is clearly detected at a DM of 127 pc/cc and a period of 24.4 milliseconds. PSR J2007+2722 pulse profile is remarkably wide with emission over almost the entire spin period.

The fine localization of J2007+2722 was provided by Westerbork. In the right sub-panel, the blue error circle was obtained by Arecibo gridding. In red is shown the WSRT/PuMaII error region obtained by overlapping fan beams, and looking for the dedispersed, folded pulsar period signal in each. In ten 1180s observations the position could thus quickly be much refined. We believe this is the first time that WSRT has been used for pulsar position refinement in this way. Simultaneously with pulsar data, WSRT imaging data were also acquired. This data is shown in the gray scale. As only a single radio source is visible on the southern side of the error ellipse, we conclude this too is the pulsar. The source corresponds to a cataloged NVSS source and from the long-term timing position we find it is indeed PSR J2007+2722.

This neutron star is most likely a disrupted recycled pulsar, about as old as its characteristic spin-down age of 404 Myr.

© Summer students 2013 / Mike Garrett / Carmen Toribio

This time the ASTRON director himself joined the intrepid radio astronomers unable to resist the allure of trampling through almost 10 km of mud, sand and chest high sea water on the epic trek to the island of Ameland, just off the north coast of the Netherlands.

The day was a memorable experience for all, enhanced both by the spectacular scenery, exotic wildlife and grand company of a fine group of people.

Good luck to the daring Wadlopers of 2014.

© Minju Lee, John McKean, Adam Deller, Javier Molden

By using data from mJIVE-20, the largest VLBA snapshot survey at 1.4 GHz that is still ongoing, we (Summer student : Minju Lee/ Supervisors : John McKean, Adam Deller, Javier Molden) were able to blindly rediscover 2 already known lens systems, and found 12 new candidate systems out of 17700 sources targeted by mJIVE-20. The candidates are to be followed up with multifrequency observations at 4.1 and 7.1 GHz, as well as with deeper 1.4 GHz observations, to compare the spectral indices and to see if there are other fainter counter images around the detected images.

The image shows one of the deeper observations of MJV06997 at 1.4 GHz, which is one of our strongest candidates, but is not yet confirmed. During the summer student project, we had a VLBA DDT proposal approved to carryout multifrequency observations at 4.1 and 7.1 GHz for this target and two others, we are now waiting for them to be observed. We think we are quite close to finding a new lens system, and expect find our new daily image of this one in the near future!

© Gabriele Surcis, Maria Grazia Blasi

The investigation of the polarized emission of methanol masers in this region allowed us to determine the orientation and the strength of the magnetic field in order to improve our understanding of the role played by the magnetic field during the massive star formation.

The main image shows the distribution of the twenty 6.7-GHz methanol maser features that we detected around G213.70-12.6, which is located at about 830 pc from us. The triangles symbols are the identified maser features scaled logarithmically according to their peak flux. A 5 Jy/beam symbol is plotted for illustration.

The dashed line is the best linear fit of the maser features. The black segments indicate the linear polarization vectors (scaled logarithmically according to the polarization fraction) for the six masers for which we were able to detect linearly polarized emission. The study of the linear polarization is useful for determining the magnetic field orientation, which in this case is perpendicular to the linear polarization vectors (see right bottom corner).

The three images on the bottom show the results obtained for the brightest methanol maser feature (peak flux ~ 91 Jy/beam).

On the most left image we show on the top panel a comparison between the total (black line) and linearly polarized (red line, multiplied by a factor of 3) spectra, while on the bottom panel we show the linear polarization percentage (full line) and the linear polarization angle (dashed line) across the maser emission.

On the middle image we show the result of the full radiative transfer Chi-squared model fit (also known as Full Radiative Transfer Method code, FRTM). The fit yields the emerging brightness temperature and the intrinsic thermal linewidth of the maser. Contours indicate the significance intervals 0.25, 0.5, 1, 2, 3, and 7, with the thick solid contours indicating 1 sigma and 3 sigma areas.

On the right image we show how the model of the methanol maser emission (red line), which was determined by using the best values obtained from the FRTM code, fits the total (I) and the circularly polarized (V) emission of the maser. From this last fit we estimated a Zeeman-splitting of (-7 +/- 1) m/s which indicate a magnetic field on the plane of the sky in the range between 140 mG and 1.4 G depending on the Zeeman-splitting coefficient which is still uncertain for the 6.7-GHz methanol maser emission.

© bennema

Harry Wolters of the Hunebed Centrum (Borger), an expert on the geological history of the Hondsrug, and Peter Bennema (ASTRON) were invited to open a Stone Art project consisting of rows of "Vlints"� (stones in the Drenths language) which camping guests have artfully arranged during their stay at the Camping Exloo, 3 km from the LOFAR Core. Before the official opening, short lectures were given on the LOFAR project, and on the geological formation of the Hondsrug.

The Stone Art project was inspired by two crucial links with its location. One is the Hondsrug itself, the 70 km long sand ridge in the east of Drenthe, which runs from Emmen to Groningen city. It was formed during the last ice age(s). Scientific studies have established that the stones were carried by the ice from the area where Helsinki is now located. Stones found more to the west, for example near Dwingeloo, originate from an area near present-day Stokholm.

The other link is the LOFAR project. According to the camping guests, the stones represent the LOFAR antenna stations, the stars, the Milky Way and the Mysteries of the Universe(*). Although the result may raise some eyebrows in scientific circles, it is nice to see how entrepreneurs in the vicinity of the LOFAR Core are inspired by the LOFAR project in their backyard.

(*) In other words, they represent Life, the Universe and Everything. Thus, they might offer a clue to the Question, even though there are more than 42 stones.

© MCC

In the summer, when lots of people are away on holiday, and statesmen, bankers, scientists and terrorists are visiting their mothers, the supply of real news is at a low ebb. In desperation, the media fill their mediums with even more "gebabbel" than normally. The Dutch call this period "komkommer(*) time".

Sadly, even the steady tinkle of ASTRON/JIVE Daily Images dries up to somewhat less than a trickle. Only Mike and his loyal Madroon stand shoulder-to-shoulder, submitting the occasional picture of themselves to ward off the void. In response to this intolerable situation, the komkommer will be on display whenever nothing else has been submitted. So there.

Obviously, this should not be necessary. Even in the depth of summer, lots of fascinating things go on in the ASTRON and JIVE family (which is much larger than just Dwingeloo). Think of the aperture arrays being verified. Think of the modules (hard, soft or firm) being seamlessly cobbled together. Think of the glass and aluminum being cunningly shaped to catch rare photons with the largest telescopes between Heaven and Earth. Think of the harmonious system engineering for SKA and Apertif. Think of the coming together of entire continents by means of VLBI. Think of the lovely LOFAR data stream, flowing thickly in a caleidoscope of novelty modes. Think of our scientific entrepreneurs, spending their millions wisely. Think of the nurturing strategies being hatched and burnished in the new management wing. Think of the summer students, being grateful to be at ASTROJIVE.

Submitting an AJDI is just a matter of leaning back for a moment, to reflect on what you are trying to accomplish, and why. If you can figure that out, you will naturally want to share your excitement with others, for instance by means of an insightful image and a few well-chosen words. You will find the entire process unexpectedly rewarding. And you help the rest of us through the summer as well.

(*) Komkommer is the name of a rather tasteless watery vegetable, as shown in the picture. In some cultures it is served in the form of cucumber sandwiches, at the "long, dark Teatime of the Soul". For the benefit of conscientious students of Aunt Henny's Dutch lessons: the past tense of this noun is of course "kwamkwammer".

© Astron

As every year, the width and depth of Dwingeloo astronomy presented was impressive and, also helped by the nice setting, the meeting was enjoyed very much by all.

The AstroFest was followed by drinks and nibbles at a local waterhole and, for some, with curries at the local Indian.

© ASTRON

After speeches from Rob, Philip Best and Matt Jarvis, the dedication was formally closed with Linda Rawlings cutting a red ribbon that revealed the reflective dedication plate (see images above).

Several Dutch astronomers were in attendance, including Rene Vermeulen, Huub Rottgering and Michael Garrett. The day ended with the group of about a dozen participants retiring to the nearby White Lion.