Cycle 20B observing

The Cycle 20 observing campaign formally ended on May 31, 2024, but production observations will continue on a best effort basis and in shared risk mode for three more months to ensure the completion of the allocated cycle 20 and DDT projects, projects associated with the ORP multi-facility call and commissioning observations toward LOFAR2.0. The extended period, referred to herein as Cycle 20B, is running until August 31, 2024.

LOFAR Family Meeting 2024

The LOFAR Family Meeting 2024 was held during 3-7 June in Leiden, the Netherlands. Details about the meeting are available here. Speaker presentations from the meeting are also available on the meeting’s webpage. The information about the host of the next edition of the meeting will be communicated in due course. You may still reach out to the organizers via lofarconf@strw.leidenuniv.nl, if you have any questions.

LOFAR2.0 commissioning

Commissioning of the next generation of the LOFAR telescope is ongoing. We have identified three main commissioning areas (telescope, pipelines, and operations). The community has the opportunity to join any of the working groups that they find interesting or critical for their needs. There is a public Confluence page dedicated to these commissioning activities with links to the different commissioning teams. Proposers of LOFAR2.0 Large Programs, International stations teams, as well as other community members, are encouraged to reach out to the team leads of each of these three working groups they may be interested in joining. Exciting discussions on various topics are already going on in the working groups. People with expertise and interests in LOFAR telescope, pipelines and operations are welcome to join and help build the LOFAR2.0 telescope we are aspiring to obtain. More information on commissioning can be found in the next sections.

Data staging and downloading from the LTA sites

Data staging and downloads from the LTA sites were generally stable in the past few weeks, except the few planned maintenance days when the services were unavailable. Planned maintenance days are always mentioned on the LTA portal. Please contact SDC-Helpdesk if you are experiencing any issues with staging and downloads.

• 38 stations operational in the Netherlands: 24 core and 14 remote stations. 14 international stations in operations: DE601, DE602, DE603, DE604, DE605, FR606, SE607, UK608, DE609, PL610, PL611, PL612, IE613, LV614.

  

   

• New international stations will be built in Italy and Bulgaria . Both stations will be equipped with LOFAR2.0 hardware, whose installation/rollout is expected in 2025.
• Antenna elements of all stations are performing nominally, except, CS103 and RS503 HBAs, and DE601 and FR606 LBAs. CS103 and RS503 HBAs have 16.7% and 18.8% non-operational elements, respectively. DE601 and FR606 LBAs have rather high non-operational antenna elements percentages of 28.1% and 49.0%, respectively. Those elements are either broken to be fixed or broken beyond repairs. The overview of non-operational antenna elements of both LBAs and HBAs is available here. At the station level, all stations are online for most of the period under consideration, except RS407 and DE601. DE601 came online for a few weeks, but it is now out with the same repeated SPUs breakdown reason dating back to February 2021 from the flooding. ASTRON maintenance engineers are still working around the clock to get the station to work properly again. The fiber connection to RS407 has been severally cut; therefore, it may take longer to get the network connection restored due to the extent of the problem.
• Moreover, minor failures have been witnessed on CEP hardware/software over the past couple of months, which had little impact on the observing cycle. The COBALT cluster for example, has seen the InfiniBand on one of the nodes dying a few times over the last few weeks. A major upgrade of the processing cluster is planned to happen later this year or early next year as part of the LOFAR2.0 program.

• The Cycle 20 observing campaign started on 1 June 2023 and ended on 31 May 2024. PIs can see details of their projects directly in TMSS. There is an extension of the cycle (referred to as Cycle 20B, see above) which will conclude at the end of August. The public version of the observing schedule in TMSS can be found here. The user manual of TMSS is found here.
• The yearlong observing campaign of Cycle 20 ended with weekly observing efficiency of 60.3%, telescope observing efficiency of 67.0% and completion level of 95%.

LOFAR Development program (W. van Cappellen)

• The first LOFAR2.0 hardware has been installed in CS032. It will be followed by RS307 in a few weeks. With the rollout of these two stations, we are gaining experience to ensure that the major rollout next year runs as smoothly as possible.
• All other LOFAR2.0 hardware will be assembled in the second half of this year. The rollout of LOFAR2.0 stations continues in 2025.
• A lot of progress has been made on the monitoring and control systems, such as the new LOFAR2.0 monitoring screens in the control room. If you have the opportunity, I recommend taking a look at our new Grafana dashboards in the control room.
• The tender of CEP6 and COBALT3 has been published and the new 400 Gbps core network switch has been installed in Groningen. The network switch will be integrated into LOFAR later this year.

SDC program (J. Swinbank)

• The “LOFAR Digital Services” are the set of online systems that will form the interface by which the scientific community accesses and works with LOFAR2.0 and its data products. This includes everything from proposal submission and management through data archiving, discovery, and processing. The complete scope is shown in the figure below.

• The LOFAR Digital Services are a community effort, with contributions of expertise, development effort, and infrastructure from across the LOFAR ERIC community. Development is coordinated by ASTRON's SDC Development Programme, and the services are provided under the management of ASTRON SDC Operations. Using this structure, we are able to draw on and learn from the ongoing work to construct the SKA Regional Centre Network and maintain the Apertif Long Term Archive, as shown in the figure below.

• At the LOFAR Family Meeting in June 2024, we presented a vision for the Digital Services. Building on the feedback received at that meeting, we are continuing to refine our vision for how the LOFAR Observatory can best provide the widest possible scientific community with the services and data products it needs. In partnership with Large Programme PIs and other community experts, over the next several months we will be working towards the publication of a LOFAR2.0 Data Management Plan.
• Current development activities focus on a new proposal tool — a replacement for Northstar — which will be entering commissioning over the summer and facilitating data processing in the context of the LOFAR Data Valorization (LDV) project, which provides an excellent testbed for the sorts of workflow we expect in the LOFAR2.0 era.

Commissioning towards LOFAR2.0 on-sky (M. Brentjens, R. Pizzo, Carla Baldovin, Cees Bassa, Marco Drost, Boudewijn Hut, Marco Iacobelli, Emanuela Orru, and Tim Shimwell)

• During the past few months, the commissioning team has reviewed all DUPPLO and LOFAR-2.0 requirements (more than 2500 in total), cleaned them up, and distributed responsibilities for testing the roughly sixty L0 requirements among the telescope, operations, and pipeline commissioning teams. The teams are now creating test procedures for them.
• Meanwhile, LOFAR is working through a set of legacy observations while we still have full correlator and preprocessing capacity until a compute cluster reconfiguration early September. After this, we’ll only have approximately 25% capacity available until the new compute cluster CEP6 is installed in 2025. To accommodate the reduced capacity while securing important data, a deep clean-up (including archiving) of data presently on CEP4 is underway. Work towards ionospheric-condition-based scheduling has begun.
• To better coordinate pipeline development now, and their commissioning later, working groups on HBA/LBA data preparation processing, HBA NL processing, LBA NL/VLBI processing, HBA VLBI processing, and HBA beamformed data processing have been set up.
• While CS001 is being used intensively to demonstrate correct beam forming, station calibration, and time keeping, CS032 and RS307 are receiving their LOFAR2.0 hardware. By the end of summer, we will have three LOFAR2.0 stations available. Our focus with those is to document and automate station control, station testing, and calibration, so we are ready for full station deployment throughout 2025.
• We look forward to jointly wrangle0 into a discovery machine we will all enjoy! See you at the next Lofar Status Meeting on August 28, from 10.00 to 11.00 CEST.

The dates of LOFAR Status Meetings, roll-outs and stop days are listed in an online calendar that is available here.