International LOFAR Telescope
Proposal Call to the Worldwide Community
Cycle 4: 15 May 2015 - 14 November 2015
Submission deadline Wednesday 11 March 2015, 12:00 UT
Submission only via the online tool NorthStar.
** Proposers must ensure that their justification files adhere to the instructions given below and in Northstar, repeated online here. **
NEW CAPABILITIES: The International LOFAR Telescope (ILT) is a powerful next-generation radio telescope for frequencies below 240 MHz that offers revolutionary new 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. 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, whose detailed performance and sensitivity information will be updated online on 23 February 2015.
WORLDWIDE COMMUNITY: Time on the ILT is available to scientists from the worldwide community, partly through Open Skies, and partly through allocations in tandem between national consortia and the independent Programme Committee (PC). Scientific and technical strengths of the proposals are taken along in the evaluation; in view of the novel character of the ILT, first-time proposers are advised to get in contact with Science Support at ASTRON well ahead of the deadline or to seek suitable collaborators.
TIME AND DATA RIGHTS: Allocations consist of observing time (available 1600 hrs of which 750 hrs at night) and/or processing resources (available 2400 hrs on CEP2). 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.
PROCESSOR REQUESTS: Each proposal must request processing
time to match the observing time within appropriate documented ratios, or
should justify how processing will proceed elsewhere. The ILT standard data
processor is CEP2. Access
to the CEP3 cluster for
advanced processing by users should be mentioned in the proposal, as well as any envisioned
additional use of ILT-related facilities in Amsterdam or
Juelich for offline processing (see details online).
LOCAL ADD-ON EQUIPMENT: Some ILT stations have added privately
owned facilities, such as ARTEMIS and others, to capture and process their
individual station data streams “locally”. The relevant facilities are listed
For Cycle 4, the worldwide community may request general ILT observing time aimed
at using that private equipment, but with the important proviso that the
submission of any such ILT proposal will be taken as certification by the PI that
consent has been individually arranged beforehand with all appropriate owners that
they will facilitate the use of their equipment for the proposed project (if centrally
allocated ILT time). More details are given online.
SUBMISSION RULES: Proposers must use the online submission tool and adhere strictly to the instructions concerning format, page limits, and content, as given online.
COMPLETE INFORMATION: Please refer online to important additional information on the proposal process and on the capabilities of LOFAR. From the main ASTRON website, http://www.astron.nl, navigate to Radio Observatory, LOFAR. Please note the "Important further instructions and information" section in the Regular Proposal Call page.
Director, International LOFAR Telescope
Important further instructions and information
Cycle 4 will run from 15 May 2015 to 14 November 2015.
1600 hours of observing time will be allocated for the Cycle, of which about 750 hours can be observed at night, depending on details of the requests and allocations.
There will be 2400 hours of CEP2 processing time available. Each proposal should request processing time to match the observing time within appropriate ratios, or should justify how processing will proceed elsewhere.
Long-Term proposals with explicit requests for allocations in future semesters may be submitted as a separate category (restricted rules apply, details given online).
20% of Cycle 4 will be allocated directly by the independent Programme Committee (PC) based only on scientific merit, while the remainder will be allocated in tandem between national consortia and the PC; in addition to scientific merit these allocations may reflect national interests (detailed mechanism online).
sciencesupport [at] astron [dot] nl
Proposals must be self-contained (except that proposals that aim to share parts of surveys or other larger overlapping sets of observations may have an Envelope Sheet as an additional technical supplement).
Proposals must be typeset in 11pt font, or larger.
Page limits are dependent on the amount of observing time requested. The total of the science and technical justification, including any desired figures and tabular material, will have page limit of 4 pages for small requests, and the following rules may increase this limit to at most 8 pages:
1. The base allowance is 3 pages, plus 1 page per 250 hours of observing time requested (request 1 hour: 4 pages, from 251 hours: 5 pages, ... from 1001 hours: 8 pages)
2. For any proposal that has an associated Envelope Sheet, 2 pages are subtracted from the allowance for the main proposal, but at least 4 pages will always be allowed for the main proposal
3. For a Long-Term proposal, the observing time requested is added up over all cycles to determine the page limit
4. A Long-Term proposal that has no associated Envelope Sheet may take 2 additional pages, but devoted only to information project phasing, management plan, etc. The total allowed is never more than 8 pages
5. An Envelope Sheet has a limit of 5 pages
Proposals exceeding the page limits will be rejected.
Proposers must use the online submission tool NorthStar.
Science and Technical justifications
All Proposals must contain a cohesive, focused science justification for a specific research project.
All projects also require a careful technical justification, referring to the baseline performance and data quality described online, and, where appropriate, discussing expertise, tools, manpower, and computing capacity required either from the ILT and/or supported within the proposing team. In particular, the proposals must include detailed information on (i) instrument setup, (ii) desired sensitivity, (iii) data volume, (iv) processing strategy through automatic pipelines, (v) post processing strategy. Proposers should take careful note of guidelines and limitations, such as on maximum field sizes, resolutions, and achievable noise levels in automatic pipeline runs. The technical justification should be entered by completing the "technical questions" section within the Northstar tool and by adding any remaining technical detail in the justification file.
Requests for night time must be explicitly indicated and justified.
Each proposal must be self-contained except that an "Envelope Sheet" may additionally be used as a joint TECHNICAL supplement, when several proposals aim to share parts of surveys or other larger overlapping sets of observations; these can explain the broader observing and processing setups and plans, but not the individual science cases.
Data processing resources
In addition to observing time requests, all proposals also must include requests for required data processing and storage resources. Access to the CEP3 cluster for advanced processing by users should be mentioned in the proposal, as well as any envisioned additional use of ILT-related facilities in Amsterdam or Juelich for offline processing (see details online). Central computing and storage for data processing will be a limiting resource for many projects.
Automatic pre-processing and imaging pipeline run times scale strongly with field size and resolution, and in many cases considerably exceed the observing time (see details online)
Allocations of observing time and of central processing time to a given project will often be unequal, based on technical considerations and optimisation of the overall science yield of the ILT. Allocations of processing times on the ILT central processing system far in excess of observing times will only be possible for exceptionally interesting science projects of modest size.
In addition, proposals may justify a data reduction plan where, after initial steps on the ILT central processors, data is copied from the ILT archive to privately maintained external resources and software for further processing.
The standard capabilities and performance published online must be used as the baseline in the technical justification of the proposal. It is expected that the capabilities and user-friendliness of LOFAR will significantly improve in the coming cycles. Expert users may already be able to profit from some of these improvements earlier, but for Cycle 4 the ILT does not guarantee any availability beyond that published online. If further functionality or performance is crucial for their proposal, the ability of the group to reach their extended goals must be appropriately demonstrated.
Groups with relevant expertise may include a carefully argued technical request to carry out other/further analysis steps on the ILT central processing system for any imaging or non-imaging application, bearing in mind the scarcity of these resources. Of course, as above, the technical case may in addition justify how, starting from the standard initial data or pipeline products, or after some particular central processing, the group will carry out specific additional processing on data from the archive with privately maintained external computing resources and software.
Proprietary time and other data policies
Groups will obtain from the PC specific rights to use LOFAR data in response to their proposals. The data themselves, as observed and as obtained from the standard pipelines run on ILT computers, remain the property of the ILT. Data rights for specific science are by default granted for a one-year proprietary period, after which the data become public. Exceptions can be proposed to the PC; extensions of the proprietary period will only be granted in rare cases. Furthermore, deposition of refined "derived" data products into the ILT archive may be offered by the proposers, or can be stipulated by the PC; by default these further products are the property of the proposers.
The same observed data or standard pipeline products may be assigned to different teams, to be used for different science purposes. Proposals may include "commensal observing", for example to allow certain forms of transient patrols or cosmic ray event monitoring during imaging or beamformed observations for another primary project. When doing this, the request should obviously be in line with the current capabilities of the instrument (see the online documentation). The PC will assign conditions such as precedence with regard to observing setup, interrupt rights, and so on. Proposals may also be for purely offline use (but possibly with processing time) for different science goals using data in the archive that is to be obtained with other proposals known to the proposers. Hence, the intended observing strategy and data use have to be clearly delineated by the proposers. If teams foresee the likelihood of conflicts, it is advisable to address this in the respective proposals up-front; jointly preferred solutions may be suggested in both proposals.
Detailed rules for each case will be set by the PC, based on the PC mandate to maximise the overall science output of the ILT, and covering the circumstances that can be foreseen with the proposals at hand. The ILT Director will decide on any further eventualities.
Further questions can be addressed to the Radio Observatory science support group: sciencesupport [at] astron [dot] nl