VLBI with KAIRA, LOFAR and the LWA

As we write this, KAIRA is carrying out its first VLBI experiment. We are recording 122 beamlets from RCU mode 4 (LBA, but with 30-80 MHz filters). The subband statistics, beamlet statistics and antenna cross-correlation files are being recorded, but it is the raw beamlet data that is significant here, as it can be used to correlate with the other VLBI stations involved. This particular experiment, organised by Olaf Wucknitz, is being done together with LOFAR stations Effelsberg (DE601), Jülich (DE605), Onsala (SE607) and the LWA in the United States. The map shows the location of these sites:

Sites used in this VLBI experiment. (Background map: ESRI/Penn)

Although this is not the first international experiment with KAIRA, it is the first with recorded raw beamlet data and, therefore, our first attempt to get radio interferometric fringes. Although this is a very ambitious project, if we do manage to get this to work it will be a major technical success.

Updates:

03:26 UTC — In the end, DE605 did not take part. DE601, KAIRA and the LWA reported in okay. No news yet, from SE607.

05:49 UTC — SE607 have now reported it. Their observations went well too.

First international experiment

This week, KAIRA is participating for the first time in a large international experiment with baselines of several thousands of kilometres. Apart from hoping to discover some new science, this is a perfect opportunity to link EISCAT, LOFAR and, of course, KAIRA itself. As the week goes on, we will be incorporating more and more stations into this experiment network. However, on this first night of observing the following stations are involved (from North to South): 

• ESR (EISCAT Svalbard Radar, Norway)
• KAIRA (Kilpisjärvi Atmospheric Imaging Receiver Array, Finland)
• Kiruna (EISCAT receiver station, Sweden)
• SE607 (LOFAR station at Onsala, Sweden)
• DE604 (LOFAR station at Potsdam, Germany)
• UK608 (LOFAR station at Chilbolton, UK)
• FR606 (LOFAR station at Nançay, France)

 Putting them on the map, the layout is as follows:

The observations are being carried out at approximately 224 MHz (thus allowing us to use the Kiruna receiver station). The ESR is at a different frequency, but is providing concurrent observing. And both KAIRA and UK608 are using special observing modes. Kiruna and the ESR are conventional, mechanically-steered, parabolic dishes. The others are all LOFAR-design phased arrays.

People often ask if KAIRA is part of the LOFAR network. The answer to this is: "not directly". Although there are plans to one day link KAIRA directly to LOFAR via a high speed link, we are currently running as an independent station. While this gives us the flexibility to pursue our own science programme, it certainly does not preclude us from participating in large, important, observing experiment — like this one.

Oh... and we should also point out that although this particular experiment is being run by ASTRON, this work is being done by ASTRON staff at the KAIRA site!

Stay tuned as the week goes on as, no doubt, we will have some very interesting things to report!

ILTO-2012 meeting

Last month, there was an International LOFAR Telescope Operations (ILTO) meeting in Onsala, Sweden. It was held on 17/18 April 2012. This was a good opportunity to present the progress made so far with the KAIRA system to the rest of the LOFAR technical community. The meeting itself was held at the Onsala observatory, which is on the coast, just south of Gothenburg. Here are a few photographs from the visit.

In the distance is the 26m dish, which is used for VLBI, etc.

The radome with the other VLBI dish.

The LOFAR field (SE607)

LOFAR Sweden LBA complete

It wasn't long ago that we forwarded the report from our colleagues at Onsala, that they had completed their HBA. Now, they've finished the LBA field too! This photograph was taken by Robert Cumming and posted on the LOFAR-Sweden weblog:

Congratulations Onsala!

Photo: Robert Cumming, OSO.

LOFAR Sweden HBA complete

The station being installed before KAIRA is the SE607 LOFAR station at Onsala in Sweden. And, just in time for the midsommer break, the Onsala team have reported that they have completed their High-Band Array (HBA).

The completed LOFAR HBA field in Sweden. Photo: Onsala Space Observatory.

They also add that the tools are now on their way to Kilpisjärvi. That, combined with news that the shipment of tiles from the Netherlands has now also commenced means that we'll be ready to go soon.

But, for now, congratulations to the Swedish team on the successful completion of their HBA.

Link: http://lofar-se.org/

Now that's cute...

While all this work is going on at KAIRA (Finnish LOFAR station FI609), our colleagues to the south have also been busy.

Work at the Onsala Space Observatory has also been progressing well. The first HBA tiles have started arriving for LOFAR station SE607 and work is ready to get under way with their installation. If you haven't seen it yet, we recommend you visit their LOFAR-Sweden web log. Apart from some interesting articles, they have a fantastic collection of great photographs on their Picture Gallery.

This one is particularly sweet. It is not clear from their site who made that sign, but you have to admit it is cute.

Nice work, Onsala. All the best for your HBA build!


Photo: Onsala Space Observatory.

LOFAR-Sweden

There are lots of stations within the LOFAR network, some of which have been completed and others that are being constructed this year. And, for the 2011 build season, KAIRA (FI609) is not the only one!

Our colleagues in Sweden are busy building a full international station at the Onsala Space Observatory (OSO). As they are far to the south, the snow has already melted there and they are off to an early start.

The RF-container and LBA field at Onsala. Photo: Leif Helldner, OSO.

Some of the ground work was already completed last year, prior to the first snow. So that means that the field was already level when they went to start work this season. Already, the RF-container is in place and the work has moved on to the antenna fields themselves.

Laying the LBA cables for LOFAR station SE607. Photo: Haukur Sigurdarson, OSO.

As can be seen, the LBA field has been set out and the cables are being put in place. According to the ASTRON schedule, the SE607 HBA will be installed just prior to our installation at Kilpisjärvi, so we can expect to see lots of action there in Onsala over the next couple of weeks.

Like us, the Swedish project also have a web log with lots of photographs and interesting articles about their project.

Thanks go to Leif Helldner from OSO for his assistance and for permission to use some of their photographs.

Links:
http://lofar-se.org/
http://www.oso.chalmers.se/