"The Rawlings Array"

On Tuesday 27th August, a dedication ceremony was held at Chilbolton to rename the LOFAR-UK Chilbolton station as "The Rawlings Array", in tribute to Professor Steven Rawlings. Professor Rawlings was instrumental in establishing the LOFAR-UK consortium, and in the decision to site the UK station at Chilbolton. Before his tragic death in January 2012, Professor Rawlings worked at the University of Oxford, where he played a leading role in both UK Radio Astronomy and the development of the international Square Kilometer Array project. The dedication ceremony was attended by members of his family, and members of the LOFAR-UK and international LOFAR communities.

Photo credits: A.Mallet

LOFAR Overview Paper

The LOFAR overview paper is now in press at Astronomy and Astrophysics. You can read all about it in this ASTRON press release, and download the paper itself from the arxiv:1305:3550.

NAM2013 Abstract Deadline Extended

The NAM2013 Abstract deadline has been extended to April 1st. Scientists working on LOFAR, who have not already done so, can still submit their abstract via the NAM2013 website to Session 16 on "First Science from LOFAR" (which is scheduled for 2.5 hours on the afternoon of Monday 1st July):

16. First science from LOFAR (NAM+UKSP+MIST)

Organisers:
Philip Best - Royal Observatoty Edinburgh
LOFAR-UK Management Committee

The International LOFAR Telescope is a next-generation software-driven low-frequency radio interferometer, which is opening up one of the few relatively unexplored windows in the electromagnetic spectrum, between 30 and 240 MHz. After an extended commissioning period, December 2012 saw the start of Cycle-0 science observations. These observations cover a very broad range of astrophysics, from cosmology to solar system studies, including the Epoch of Re-ionisation, pulsars, transient/variable sources, wide and deep surveys, cosmic rays, the origin of magnetic fields, and studies of the Sun and space weather. This parallel session will showcase the early science results from LOFAR Cycle-0 observing, as well as highlighting the current scientific and technical capabilities of the array, and forthcoming opportunities.

Hope to see you in St. Andrews!

LOFAR discovers new giant galaxy in all-sky survey

A team of astronomers led by ASTRON astronomer Dr. George Heald has discovered a previously unknown gigantic radio galaxy, using initial images from a new, ongoing all-sky radio survey. The galaxy was found using the powerful International LOFAR Telescope (ILT), built and designed by ASTRON. The team is currently performing LOFAR's first all-sky imaging survey, the Multi-frequency Snapshot Sky Survey (MSSS). While browsing the first set of MSSS images, Dr. Heald identified a new source the size of the full moon projected on the sky. The radio emission is associated with material ejected from one member of an interacting galaxy triplet system tens to hundreds of millions of years ago. The physical extent of the material is much larger than the galaxy system itself, extending millions of light years across intergalactic space. The MSSS survey is still ongoing, and is poised to discover many new sources like this one.

Overlay of the new GRG (blue-white colors) on an optical image from the
Digitized Sky survey. The inset shows the central galaxy triplet (image
from Sloan Digital Sky Survey). The image is about 2 Mpc across.

The new galaxy is a member of a class of objects called Giant Radio Galaxies (GRGs). GRGs are a type of radio galaxy with extremely large physical size, suggesting that they are either very powerful or very old. LOFAR is an effective tool to find new GRGs like this one because of its extreme sensitivity to such large objects, combined with its operation at low frequencies that are well suited to observing old sources.

The center of the new GRG is associated with one member of a galaxy triplet known as UGC 09555. The central galaxy is located at a redshift of z=0.054536, or 750 million light years from Earth. The central radio source was previously known and has a flat radio spectrum, typical of giant radio galaxies.

LOFAR's MSSS survey is a concerted effort to image the entire northern sky at very low radio frequencies, between 30 and 160 MHz (wavelengths from 2m to 10m). The primary aim of the survey is to perform an initial shallow scan of the sky, in order to create an all-sky model that will support the calibration of much deeper observations. It is comparable in sensitivity and angular resolution to previous surveys with ‘classical' radio telescopes like the Very Large Array (VLA) in the USA, ASTRON's Westerbork Synthesis Radio Telescope (WSRT), and the Giant Metrewave Radio Telescope (GMRT) in India. MSSS is unique in that it operates at substantially lower frequencies, and is therefore poised to uncover new sources that were missed by previous surveys. Its broad bandwidth coverage is also novel in all-sky radio surveys, and will be used to provide additional information about the detected objects.

The international team of astronomers that is performing the MSSS survey is made up of about fifty members from various institutes, mostly in the Netherlands, Germany, the UK, Poland, France and Italy.

End of press release

For more information please contact:

Femke Boekhorst, PR & Communication. E-mail: boekhorst@astron.nl. Phone: +31 521 595 204.

Dr. George Heald, astronomer. E-mail: heald@astron.nl. Phone: +31 521 595 100.

More information about MSSS can be found on the ASTRON website: http://www.astron.nl/radio-observatory/lofar-msss/lofar-msss

Goodbye and Thankyou to Derek

LOFAR-UK would like to say a public thank you and goodbye to Derek McKay-Bukowski, who will cease his duties as the LOFAR Station Manager for UK608 (Chilbolton) at the end of March. Derek has been an integral part of LOFAR-UK through construction to ongoing operations, including the weeks on end without breaks when he slept in a small room at Chilbolton! We are all convinced that the LOFAR-UK station would not be the success it is without his dedication and attention to detail. 

Derek checking one of the LBA antennas during installation at Chilbolton in June 2010. Image credit: Chris Ison/PA Wire

Derek's flat-pack-station presentation at INTECH for the LOFAR-UK opening (which you can watch here) will long be remembered, as will his entertaining health and safety briefings. 

Derek (left) assisting Dame Jocelyn Bell Burnell at the official opening of UK608 in September 2010. 

We must also mention Derek's contributions to LOFAR-UK in the early part of 2012. Derek went well beyond the call of duty when storms caused damage to some of the tiles and LBAs and his rapid intervention prevented this freak event from turning into a much more costly repair. 

Derek (centre in white hat) directing volunteers helping with repairs to an HBA tile in Febuary 2012. Image credit: STFC.

It is with real sadness that we must say goodbye to Derek from the LOFAR-UK, and we him all the best in his future work with the KAIRA project in Finland. 

LOFAR Science Meeting in Dalfsen

ASTRON is announcing the next LOFAR science meeting in Dalfsen, to be held next week (19-20th March). 

This is a great opportunity to bring more attention to the science results already coming out of LOFAR, and the fact that full operations are now happening.

The below is a press release from ASTRON about the meeting: 

LOFAR telescope open for business

On Tuesday 19 and Wednesday 20 March, one hundred astronomers from all over the world will travel to the town of Dalfsen in the Netherlands for a 2-day workshop about the International LOFAR Telescope (ILT), designed and built by ASTRON. Now that the first fully operational observing cycle has started and the telescope is open to the whole astronomical community, LOFAR is officially open for business.

The LOFAR telescope owes its strength to revolutionary new techniques and software for the processing of unprecedented large data streams from an extensive network of relatively simple radio receivers, concentrated in the north-east of the Netherlands and spread over Germany, France, the UK and Sweden.

Eighteen months ago, during the commissioning and test phase of LOFAR, the first LOFAR science workshop was held, also in Dalfsen. Since then, new antenna stations have been added to the array and the sensitivity of the telescope has improved, as well as the processing software. Besides this, the first appealing scientific results have already been published in different renowned scientific journals.

During the workshop in March, builders and users of the telescope, as well as owners of the different international antenna stations, can exchange science results and technical ideas and deepen the collaboration to get the most out of the LOFAR telescope at both the national and international level.

End of press release

For more information, please contact:

Femke Boekhorst, PR & Communication, ASTRON: +31 521 595 204 and +31 6 21 23 42 43. E-mail: boekhorst@astron.nl.

I-LOFAR Event in the European Space Expo dome

On the evening of Friday, June 7, our colleagues at I-LOFAR (the Irish LOFAR consortium) will be running an event showcasing what a LOFAR station could do for Irish astronomy (and the whole of the International LOFAR Telescope) in the European Space Expo dome which will at that time be visiting Trinity College Dublin.

LOFAR Sessions at UK National Astronomy Meeting

There will be a special session celebrating early science from LOFAR at the upcoming 2013 UK National Astronomy Meeting, to be held in St Andrews, Scotland, 1-5th July 2013.

Special session 16, on "First Science from LOFAR" has provisionally been scheduled for two 75 minute blocks for the Monday afternoon (1st July).

16. First science from LOFAR (NAM+UKSP+MIST)

Organisers:
Philip Best - Royal Observatoty Edinburgh
LOFAR-UK Management Committee

The International LOFAR Telescope is a next-generation software-driven low-frequency radio interferometer, which is opening up one of the few relatively unexplored windows in the electromagnetic spectrum, between 30 and 240 MHz. After an extended commissioning period, December 2012 saw the start of Cycle-0 science observations. These observations cover a very broad range of astrophysics, from cosmology to solar system studies, including the Epoch of Re-ionisation, pulsars, transient/variable sources, wide and deep surveys, cosmic rays, the origin of magnetic fields, and studies of the Sun and space weather. This parallel session will showcase the early science results from LOFAR Cycle-0 observing, as well as highlighting the current scientific and technical capabilities of the array, and forthcoming opportunities.

Abstracts for talks, or posters (note there is a limit of 2 abstracts per first author, only one of which can be requested as a talk), should be submitted via the NAM2013 Website, before 19th March 2013. 

Upcoming LOFAR Solar KSP Meeting

FYI: Announcement of 7th LOFAR Solar KSP Workshop in Trinity College Dublin

To all members of the LOFAR Key Science Project "Solar Physics and Space Weather with LOFAR"

The 2013 annual workshop of the LOFAR solar KSP will be held in Dublin April 24-26. Peter Gallagher from the Trinity College Dublin will be the host this year.

The workshop will start at 2 pm on Wednesday (April 24) and should be finished at noon on Friday (April 26). During the workshop, attendees will hear a report on the present state of the LOFAR Solar KSP and will have a chance to present first results of LOFAR observations of the Sun. Furthermore, there will be time for
discussions on solar LOFAR observations in future, solar radio science, and the framework of the LOFAR collaboration.

For more information or to submit an abstract KSP members should contact Frank Breitling (e-mail:fbreitling 'at' aip.de). Abstract deadline March 19, 2013.

LOFAR-UK Scientists in Pulsar Press Release

A press release came out this morning from LOFAR on work involving two LOFAR-UK scientists: Ben Stappers from Manchester and Geoffrey Wright from Sussex.

Below is a direct copy of the press release found on the ASTRON news site. The paper it's based on was published in Science today.

Chameleon pulsar baffles astronomers

 An international team - led by Dutch astronomers (SRON, NOVA and ASTRON) - has made a tantalizing discovery about the way pulsars emit radiation. The emission of X-rays and radio waves by these pulsating neutron stars is able to change dramatically in seconds, simultaneously, in a way that cannot be explained with current theory. It suggests a quick change of the entire magnetosphere. In their research the team combined observations from the X-ray space telescope XMM-Newton and the radio telescope LOFAR (among others); the research results appear in today’s [date] issue of the journal Science.

Pulsars are small spinning stars about 20 km in diameter -the size of a small city - with a mass that roughly compares to the mass of our Sun. They have a strong magnetic field that is approximately one million times stronger than the fields we can make in laboratories on Earth. The pulsar emits a beam of radiation. As the star spins and the radio beam sweeps repeatedly over Earth we detect a short pulse of radiation, a bit like a lighthouse. Some pulsars emit radiation across the entire electromagnetic spectrum, including both X-ray and radio wavelengths. Although pulsars were discovered more than 40 years ago the exact mechanism by which pulsars shine is still unknown.

It has been known for some time that some radio pulsars flip their behaviour between two (or even more) states, changing the pattern and intensity of their radio pulses. The moment of flip is both unpredictable and sudden (often within a single rotation period). It is also known from satellite-borne telescopes that a handful of radio pulsars can also be detected at X-ray frequencies. However, the X-ray signal is so weak that nothing is known of its variability - could it be that the X-rays also flip?

Moments of flip

The scientists studied a particular pulsar called PSR B0943+10, one of the first pulsars discovered. The pulses from PSR B0943 + 10 change in form and brightness every few hours, and these changes happen within about a second. It is as if the pulsar has two distinct personalities.  As PSR B0943+10 is one of the few pulsars also known to emit X-ray radiation, knowing how this pulsar behaved in X-rays during the 'radio changes' could provide new insight into the nature of the emission process.

Since the source is a weak X-ray emitter, the team used the most sensitive X-ray telescope in operation, the ESA-funded XMM-Newton. The observations took place over six separate sessions of about six hours in duration. To identify the exact flips in the pulsar’s radio behaviour the X-ray observations were tracked simultaneously with two of the most powerful radio telescopes in the world, GMRT and LOFAR (developed and built by ASTRON, the Netherlands Institute for Radio Astronomy).

Two X-ray states as well

The results were totally surprising. The X-rays did indeed change their behaviour   synchronously with the radio emission, as might have been expected. But in the state where the radio signal is strong and organized, the X-rays were weak. And when the radio emission switched to weak the X-rays intensified. “To our surprise we found that when the brightness of the radio emission decreased to half the original brightness, the X-ray emission brightened by a factor of two!” says project leader Wim Hermsen. 'And only then the X-ray emission is pulsed. Lucien Kuiper, who scrutinised the data from XMM-Newton , concluded that this strongly suggests that a temporary ”hotspot” close to the pulsar’s magnetic pole switches on and off with the change of state.

Most striking was that this metamorphosis takes place within seconds, after which the pulsar remains stable in its new state for a few hours.  Why a pulsar should undergo such dramatic and unpredictable changes cannot be explained by current theory. It strongly suggests a quick change of the entire magnetosphere”.

Tale of the unexpected

This unexpected chameleon-like behaviour of the radio pulsar PSR B0943+10 bolsters fundamental research into the physical processes which occur in the extreme conditions which occur in the magnetosphere of pulsars, 45 years after the discovery of neutron stars. Wim Hermsen and his colleagues have been granted new observation time on XMM-Newton. By combining their X-ray observations with observations from a number of radio telescopes (Westerbork, GMRT and Lovell telescopes) the astronomers will also be able to simultaneously observe pulsar PSR B1822-09. In radio wavelengths PSR B1822-09 shows similar flips as PSR B0943+10.

Team

The research was led by Wim Hermsen (SRON Netherlands Institute for Space Research, UvA), Lucien Kuiper and Jelle de Plaa (SRON), Jason Hessels and Joeri van Leeuwen (ASTRON en UvA), Dipanjan Mitra (NCFRA-TIFR, Pune, India), Joanna Rankin (University of Vermont, Burlington, VS), Ben Stappers (University of Manchester, UK), Geoffrey Wright (University of Sussex, UK). The Pulsar Working Group and the Builders Group from the  LOFAR-telescope, which was at the time still in the commissioning phase,  gave support to these observations. The results of this research, entitled: Synchronous X-ray and Radio Mode Switches: a Rapid Transformation of the Pulsar Magnetosphere (link!) will appear in Science today.