LOFAR Newsletters February 2015

Distributed on 13 February 2015.


Array status:



- 38  stations operational in the Netherlands: 24 core stations and 14 remote stations


- 9 international stations are operational: DE601, DE602, DE603, DE604, DE605, FR606, SE607, UK608, DE609


- 3 new international stations are being built in Poland and should become part of the array by the end of 2015


- On Dec 16th, ASTRON and the lead scientists from Hamburg Observatory and the University of Bielefeld have signed the official handover of the 6th German LOFAR Station DE609, which is located in Norderstedt. After having solved some network problems, DE609 participated successfully on February 4th to the first LOFAR observation correlating 71 antenna fields, of which 48 are core stations, 14 remote stations and 9 international stations. See ASTRON daily image from February 11th 2015.


- DE604: airco issue affected the station since December 8th 2014. Problem identified and fixed on January 22nd 2015.


- The overview of non-operational antenna elements for LBA and HBA is available here. Because of the winter season, maintenance is currently on hold - it will restart in the spring


- New calibration tables for some stations are being tested and will be applied during the following week - the current status can be found here.




Observing System Status:



- Weights for [partly] flagged stations were recorded incorrectly by COBALT between 19th March 2014 and 31st October 2014. As a result, baselines involving these stations were not being flagged correctly during processing and this affected the quality of demixing and calibration results. This does not affect the recorded visibilities and methods of fixing the Measurement Sets have been described in an email to all affected users, as well as online. 


- An Issue was experienced when recording multi-beam observations in HBA_DUAL_INNER mode, where HBA1 stations had significantly higher amplitudes than HBA0 stations. This was temporarily solved by rolling back the stations to software v. 2.6. Roll out on Jan 26th 2015 fixed the issue in development.


- Pulsar pipelines are now fully supported by the Radio Observatory. Current setup means that several pipelines, both imaging and pulsar, are run in parallel. Processing queue is long and needs careful managing, especially in view of the limited disk space available on CEP2.


- Issues with incorrect status of pipelines experienced on Dec 22nd 2014: Investigations showed that this was related to a MAC bug: If a pipeline ObservationXXXABC is running and another pipeline Observation YYYABC starts, where ABC is the same for both pipelines, there will be a collision in MAC and both pipelines might or might not correctly report back their status to OTDB/MAC/ MoM. Pipelines are being scheduled at a reduced pace till the bug will be fixed in production during the next couple of weeks.




Software Development Status:



During the last couple of months, the focus for LOFAR software development has been on responsive functionality and further integration and improvement of processing pipelines. The Long Baseline processing pipeline has been integrated into the LOFAR Observatory pipeline framework. Support has been given to commissioning and characterization of the SelfCal pipeline. Analyses have been made of requirements for responsive functionality, integration of TBB observations, and parallel observing capabilities. Memory issues in NDPPP have been investigated and addressed. A processing pipeline feedback issue is being addressed by introducing a more robust information exchange mechanism based on message brokers. (NB The latter is a promising technology for implementation of more robust and responsive functionality throughout the LOFAR system; more on this in a future bulletin). Other activities include: integration of the new Hamburg LOFAR station; generation of project progress reports to support operations; functionality enhancements in preparation for public access to LOFAR data in the LTA; station driver enhancements to improve reliability and performance.




CITT Status:



The Calibration and Imaging Tiger Team (CITT) has rounded up its research into ionospheric phase screens. Now work is started to facilitate the 'extreme peeling' scheme (van Weeren et al., in prep). The new AWimager, available on the CITT-release software branch, provides new CASA functionality (in particular wide-band and multi-scale clean) yet works as fast as the old AWimager. Calibration using DPPP (on the LofIm branch) works very well for diagonal and phase calibration and with greatly increased performance. In the near future, the CITT will be working on a faster imaging algorithm, calibration of frequency-dependent effects, and drawing all of these improvements together to facilitate the extreme peeling scheme.




Observing Programmes and miscellaneous items:



- Cycle 2 observing programme: 90% complete. Remaining 10% is being observed with second priority during the current Cycle


- Cycle 3 observing programme: ~ 40% complete. Observing schedule advertised here. All Cycle PI's are solicited to check the schedule and get in contact with Science Support at sciencesupport [at] astron [dot] nl in case of questions/remarks.


-  The Cycle 4  proposal call was advertised on January 30th 2015 (see here). Proposal submission deadline:


**Wednesday, March 11th 2015, 12 UT**


- When submitting a proposal, all PI's should check the quality of their final pdf document: proposals that are not easily readable (i.e., messed-up figures, margins, etc.) may be rejected.


-  For Cycle 4, there are important extensions to the set of standard observing capabilities, particularly high resolution (long baseline) imaging - described in detail online – and self-calibration. Note: the self-calibration pipeline is being commissioned and characterized at the moment. Results will be uploaded on the LOFAR pages on February 23rd 2015


- According to the ILT data policy, all Cycle data should become public one year after the last data installment in the LTA of the full observing project. Consequently, various Cycle 0 and 1 projects are already publishable. The tools to practically allow users to retrieve public data are currently under development and will become available on March 1st 2015. Since December 2014, we made available to users the functionality to query the LTA database for all datasets present in the archive and know, among other observational details, what their release date.


- New policies regulating when production observations are carried out in case of unavailable stations are now available online.




CEP news:




- CEP2:


a) locus100 has been cannibalized for spare parts for other locus nodes.

b) Disk space situation is often critical, especially in case of instability of the processing and ingest systems and after week-ends.


- CEP1 lse and lce nodes have been switched off at the beginning of January 2015.


- CEP3 is the new commissioning cluster. Access to and use of CEP3 are regulated by the policies published online.


- The LOFAR software version activated by the command 'use Lofar' on CEP3 does not yet include the bug fix to correct for the wrong weight information recorded by COBALT between March 19th 2014 and October 31st 2014. An update is planned for March 3rd 2015. If you need a newer version sooner than that, you can use the daily build ('use LofIm').




Calendar next LOFAR activities:



- Next LSM's : 18/02, 04/03, 18/03, 01/04, 15/04, 29/04


- Next Stop days: 03/03, 07/04


- Next software roll outs: 17/03, 20/04


- Cycle 4 proposal submission deadline: Wednesday March 11th 2015, 12 UT


- Magnetism KSP Meeting: March 9-13th 2015, Nijmegen (NL)


- 2nd LOFAR Users Meeting + 2015 LOFAR Science Workshop: June 1-3 2015, Assen (NL):


a) Meetings page here

b) Registration and abstract submission deadline: 1 May 2015


- next LOFAR bulletin: April 2015


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