International LOFAR Telescope Proposal Call to the Worldwide Community
Cycle 13: 1 December 2019 – 31 May 2020
Submission deadline Wednesday 11 September 2019, 12 UT
Submission only via the online tool NorthStar.
** Proposers must ensure that their justification files adhere to the instructions given in Northstar, including restrictions on formats and proposal length, repeated online here.
SINGLE-CYCLE ONLY: Proposals are invited for new projects, in any supported general-user mode. Single-cycle projects should achieve their science goals with an allocation only in the upcoming semester (1 December 2019 – 31 May 2020). While they may, of course, stem from results of any previous LOFAR observations, they should stand on their own, and should not request supplements to Long-Term projects that are already allocated for Cycles 10-13. Genuine filler and expert shared-support projects are only considered for long-term projects, and such proposals thus are not admitted to this proposal round. The next long-term proposal opportunity will be offered in the Cycle 14 proposal call, in 2020.
COMMUNITY ACCESS: Time on the International LOFAR Telescope (ILT) is available to scientists from the worldwide community. It is allocated in tandem between National Consortia and the ILT-PC, and endorsed by the ILT Board. Scientific excellence and breadth as well as the technical strength of the proposals are taken along in the evaluations. In view of the novel and evolving character of the ILT, first-time proposers are strongly urged to get in contact with Science Operations & Support at ASTRON through the Radio Observatory helpdesk system well ahead of the deadline, or to seek suitable collaborators; novice groups should also consider keeping the scope of initial projects modest while they become familiar with the complexities of data handling and analysis.
OBSERVING TIME, PROCESSING, AND DATA RIGHTS: Allocations will consist of observing time, as described above and detailed online. Restrictions on the available processing resources and on the total data storage in the archive will also be taken into account. For Cycle 13, there will be 700 observing hours, 1200 processing hours and 1.8 PB of archive storage available. Of the 700 observing hours available, up to 500 hours could be observed at night. The availability of observing time as a function of LST after taking into account the already allocated long-term projects is presented online. Each proposal must request processing time to match the observing time within appropriate documented ratios (see documentation online), or should justify how processing will proceed elsewhere. In relation to this, if a proposing group needs the data to be archived at a specific LTA site, this should be explicitly requested and justified in the proposal. The PC will define restricted data access rights (default period 1 year) based on the specific science goals and arguments in the proposal. Other groups may be allocated simultaneous access for different science.
MINIMUM USEFUL ALLOCATIONS: For all proposals, the technical case must argue both the optimal and the minimal required total amount of time and other resources (and any requirements on cadence or time span). Appropriate fields in NorthStar are available to specify this. If the stated minimum requirements cannot be allocated, the proposal will not be carried out at all.
PRIORITISED OBSERVING LIST: If proposals request multiple observations (e.g. multiple fields/pointings, or multiple instrumental settings), these will be taken in all cases to be listed in decreasing order of preference/priority in the target list. In case only a partial allocation can be made, the ILT-PC may decide, based on its scientific assessment, to deviate from the proposed priorities, but these must anyway be clear in advance.
SYSTEM CAPABILITIES: The ILT is a powerful radio telescope for frequencies below 240 MHz that offers state-of-the-art observing capabilities thanks to its phased-array technology with digital beam-forming. LOFAR delivers correlated visibility data for synthesis imaging, plus (in)coherently-added single and multiple station data (several beam-formed modes) as well as transient buffer read-out, for example for studies of pulsars, transients, and cosmic rays. LOFAR capabilities are described in detail online. LOFAR is now a responsive system capable of automatically responding to triggers within 5 minutes, overriding any lower priority observations. PIs interested in using the latest system enhancements or who are otherwise unsure of the possibilities for their projects after studying the details given online should get in contact with Science Operations & Support through the Radio Observatory helpdesk system.
The ASTRON Radio Observatory is currently implementing in production Prefactor, the direction-independent calibration pipeline, which produces direction-independent calibrated visibilities and wide-band images of the target field, and diagnostic plots. Details about this pipeline, including its performance, are given online. Commissioning of Prefactor in the operational system is in an advanced stage of completion. While Prefactor cannot yet be widely offered in Cycle 13, the Radio Observatory will select a sample of appropriate projects that will be offered the opportunity to obtain data products processed through this pipeline. In this respect, PIs who are interested in taking advantage of this option for the reduction of their data in the operational system should clearly indicate that in their proposals.
CO-OBSERVING WITH THE SURVEYS KSP PROGRAMME: The ILT encourages co-observing and co-processing of data for the Surveys KSP team and the PIs of standalone Cycle proposals requiring targeted imaging. By utilising the multi-beam capability of LOFAR, some Surveys KSP Tier-1 pointings could be observed alongside other science targets, maximising the telescope efficiency. As a benefit of co-observing, the PIs of the standalone projects will receive the standard results of the data processing performed by the Surveys KSP team (see details online). There will be no requirement for joint science analysis or publications.
To apply for this option, the observing setup of the standalone project should be the same as that of Surveys KSP Tier-1 observations (see details online). Any of the proposers interested in this opportunity should clearly state so in their proposals. Moreover, they should confirm that their observations could adopt the Surveys KSP Tier-1 observing and processing setup.
While planning their projects, proposers are solicited to check the availability of public LOFAR data for their targets in the long-term archive. Additionally, in case the Survey observing/processing setup could apply to their observations, they are requested to verify the (current or forthcoming) availability of Survey Tier 1 data for their targets at this page.
ADDITIONAL INFORMATION
The Observatory will explore the possibility for a few users unfamiliar with the reduction of LOFAR data to come to ASTRON for assistance with this by Observatory personnel. If this is desired, it must be specified in the proposal. Limited travel subsidies for eligible users can be supported by RadioNet. Further details are given online.
R.C. Vermeulen
Director, International LOFAR Telescope
Image (C) ASTRON