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evn:guidelines

The European VLBI Network (EVN)

Guidelines for proposal submission




Introduction

The European VLBI Network (EVN) is a VLBI network of radio telescopes in Europe and beyond, operated by an international Consortium of institutes. The EVN operates an “open sky” policy and observing proposals are accepted (and peer-reviewed) from astronomers from all over the world. It invites observing proposals for deadlines on February 1st, June 1st and October 1st each year. The capabilities of the EVN, and details on proposal submission, are presented below.

Use of the Network by astronomers not specialised in the VLBI technique is encouraged. The Joint Institute for VLBI ERIC (JIVE) can provide support for schedule making (Bob Campbell, campbell@jive.eu), for correlation and data analysis of EVN projects, as well as advice during proposal preparation, contact Zsolt Paragi (zparagi@jive.eu).

Latest science highlights from the network were presented at the 14th EVN Symposium & Users Meeting, on October 8-11, 2018, in Granada: http://EVNSymp2018.iaa.es.

A selection of recent highlights is presented here: recent EVN Science

A selection of recent refereed EVN publications is presented here: recent EVN publications

The EVN meetings page provides links to the proceedings of all past EVN symposia as well as links to the European Radio Interferometry Schools, ERIS.

The VLBI20-30: a scientific roadmap for the next decade -- The future of the European VLBI Network is now available.

Submitting EVN Proposals

The most recent Call for Proposals

The most recent Call for Proposals can be found on the EVN website.

Deadline

Proposals must be received by 16:00 UTC on the appropriate 1st February, 1st June or 1st October deadlines.

Contact

Before submission the PI should ensure that all named co-proposers have given their consent to be included in the list of investigators. All communication between the Proposer(s), and the EVN Program Committee or Scheduler will be via the Contact Author designated in the proposal.

How to submit

  • All EVN and GLOBAL VLBI proposals (except target-of-opportunity proposals) must be submitted with the on-line NorthStar proposal tool.
  • Any proposal may contain disk-based and/or e-VLBI observations.
  • Proposals can optionally include e-MERLIN and/or telescopes of EVN affiliates (e.g. NASA DSN, Kunming Radio Observatory; see the help associated with the array-selection table within the “Observing Request” tab in the NorthStar tool).
  • Global proposals will be copied to both the EVN and to NRAO for assessment; proposers should not themselves submit to NRAO.
  • Requests for inclusion of any other antennas or resources NOT AFFILIATED with the EVN or NRAO should be indicated in the proposal, but the PROPOSER MUST SEND A COPY (printable file can be downloaded from NorthStar) to the Director/Scheduler of the observatory involved, and will be responsible for arranging all aspects of their participation, including observing support, disk supply and acquiring telescope time for the EVN time allocated. See also the Code of Practice for operational details.
  • Proposers WHO DO NOT REQUEST THE EVN, and in particular proposers who request only the VLBA, the VLBA + Effelsberg alone, the HSA, or the Global 3mm VLBI Array should NOT use NorthStar but follow instructions in the call for proposals issued by these institutions and networks separately.

Guidelines on using Northstar

  • Prior to the first time using Northstar, people should register. Once in the proposal tool itself, enter the information about the investigators and the technical specifications of the proposed observations using the on-line forms, and upload a scientific justification in pdf or ps format. The preparation of the scientific justification is a separate activity that can take place at any time.
  • Once you have registered, you can create, edit, preview, and, eventually submit proposals. Online help is available. An email notification will be sent by Northstar to all co-proposers when a proposal is submitted.
  • NorthStar supports retraction, further editing, and resubmission of proposals until the deadline. The final submission remains the responsibility of the Contact author (others can view or even edit but not submit or retract a proposal).
  • Proposers are STRONGLY ADVISED to prepare and submit proposals A FEW DAYS BEFORE the deadline. This provides some flexibility in case problems are encountered, and time to contact JIVE for assistance.
  • To enable proposals that contain both e-VLBI and disk-based components, the NorthStar tool has consolidated e-EVN observations into the EVN+MERLIN and GLOBAL proposal classes. A single proposal can now request e-VLBI and/or disk-based observations. You can choose each “observation” within the proposal to be e-VLBI or disk-based, independently of any other observations it may contain.
  • A single proposal may contain both ”GLOBAL” and EVN-only observations. Such proposal should be submitted as ”GLOBAL”.
  • Based on requests from the EVN user community, the EVN CBD has decided that the abstracts of any proposal (including ToOs and Short observations) submitted starting from the October 1 2017 deadline that receive observing time will become public at the EVN Data Archive (http://jive.eu/select-experiment).

Old LaTex/e-mail way

This style of submission is continued ONLY for target-of-opportunity (ToO) proposals. It has been discontinued for ALL EVN and GLOBAL proposals submitted at the regular deadlines. The template can be downloaded here.

After submission

A list of all proposals received will be posted shortly after the deadline. All communication between the Proposer(s), and the EVN Program Committee or Scheduler will be via the Contact Author designated in the proposal. Proposals should be referred to via the “legacy code” mentioned in the posting in all communications with the PC or the Scheduler. The results from proposal review will be communicated after the next meeting of the EVN Program Committee, and will be SENT BY EMAIL unless otherwise requested in the proposal.

Guidelines on proposal writing

All proposals must include a scientific and technical justification as well as figures, tables and references, with a total length limited to 4 pages (A4 or US Letter format, with a font size no smaller than 11 points). The Justification must be uploaded as a single PDF document into the Northstar proposal tool.

Proposals should have ​up to 2 pages of text for the Science & Technical justification and 2 pages for figures, tables and references.​ Figures and tables may be interleaved with the science and technical justification, so that e.g. figures appear close to the location in the text where references are made to them. Where relevant, a brief summary of any related EVN proposals already observed or scheduled should be included in the justification. Proposers should indicate if it is a resubmission of an earlier proposal.

  • Proposers should identify any individual antenna(s) whose inclusion is considered ESSENTIAL for achieving their goals.
  • Only a limited amount of time is available at some antennas for joint observations with the EVN - these include MERLIN, ARECIBO and the DSN. A SPECIAL JUSTIFICATION is needed for requesting any of these facilities.
  • Hartebeesthoek will not normally observe sources north of declination +30 deg.
  • More complete help about telescope-specific considerations can be found in the on-line help in the array selection table of the “Observing Request” tab of the NorthStar tool.

Phase-referencing observations

Observers are advised to find phase calibrators as close as possible to their target source. The links at VLBI sources, surveys and calibrators may be useful here. For proposals where phase-referencing is essential, the calibrator source(s) must be specified. Note that there cannot be more than 12 source changes per hour on the Jodrell Bank Lovell Telescope due to slewing limitations.

Proposal Details for e-VLBI

Because detailed scheduling of e-VLBI runs will be done by JIVE staff, all e-VLBI observations must include the observing frequency, the requested GST range, the minimum bit rate and minimum number and configuration of telescopes required. It is essential that all proposals containing e-VLBI observations also include accurate target and calibrator positions (for exceptions, see the Triggered e-VLBI observations and Automated e-VLBI trigger observations). Proposals containing triggered observations should give as much information as possible about potential targets and their calibrators, which will ease evaluating the technical feasibility of the proposed observations.

The technical details of all proposals can be discussed with JIVE staff prior to submission to ensure proper and efficient scheduling (contact Bob Campbell, campbell@jive.eu).

Previous EVN observations and proposals

A list of previous EVN observations currently updated at IRA, Bologna, can be used to search for observations of particular sources, and provides links to the relevant experiments on the EVN data archive for experiments correlated at JIVE. In addition, the EVN archive itself provides a FITS-finder utility. Searches can key to source names or coordinates, observing frequency, and/or participating telescopes, among other characteristics. The EVN archive is also accessible as menu items in either the main EVN or JIVE web page.

Standard EVN and e-VLBI

General Information

Consult the EVN User Guide for the following:

Targets of Opportunity (ToO)

Targets of opportunity (ToO) are defined to be extremely rare and/or unpredictable events where there is a limited opportunity to make scientifically important observations. This limited opportunity and the potential scientific impact of the observations together constitute the justification for an exceptional response to a ToO proposal, by-passing the normal EVN review and scheduling procedures. The policy to apply for ToO time can be found here. Note that ToOs should not be submitted using NorthStar. Proposers should use the tex-based VLBI cover sheet to provide the observational details. The scientific and technical justification should be submitted as one pdf document consisting of max. 4 pages in A4 or US Letter format with a font size no smaller than 11 pt. The proposal should have up to 2 pages of text for the Science & Technical justification and 2 pages for figures, tables and references.​ Figures and tables may be interleaved with the science justification, so that e.g. figures appear close to the location in the text where references are made to them. See https://www.evlbi.org/target-opportunity-proposals for more information.

Note that the proprietary period for ToO observations, during which the proposer has exclusive access to the data, is reduced to 6 MONTHS from the date of receipt of the correlated data from the last epoch of a proposal, see EVN Data Access Policy for further details.

Based on requests from the EVN user community, the EVN CBD has decided that the abstracts of any proposal (including ToOs and Short observations) submitted starting from the October 1 2017 deadline that receive observing time will become public at the EVN Data Archive (http://jive.eu/select-experiment).

Short Observation Requests (Standard EVN and e-VLBI)

Short requests (≤ 4 hours) are intended for short exploratory observations, such as checking calibrators or the feasibility of an observational setup, in preparation for a VLBI observation or proposal. Short requests are not intended as short scientific observations and will have no proprietary time; after correlation and pipeline calibration they become public through the EVN Archive.

Short requests must use standard observing and recording modes. They will be scheduled on a best effort basis. The observing time (≤ 4 hours) should be justified in the request; shorter projects may be easier to schedule.

The format of short observation requests should include:

  • A brief motivation, up to 250 words
  • The coordinates of the target(s) and calibrator(s)
  • The observing time justification
  • The frequency band
  • The GST range
  • Essential stations for the observation
  • Any other information necessary for central scheduling by JIVE staff, e.g., preferred phase-referencing cycle (in case the short observation runs during an e-EVN day).

Standard Disk Recording: Short observation requests may be submitted up to 6 weeks before an observing session begins by email to the EVN Program Committee Chair (Kazi Rygl, INAF-IRA, kazi.rygl@inaf.it) with the EVN Scheduler (Alastair Gunn, alastair.g.gunn@manchester.ac.uk) and JIVE (Bob Campbell, campbell@jive.eu and Zsolt Paragi, zparagi@jive.eu) in copy. The EVN PC Chair will, at her discretion, authorize scheduling in any gaps in the session plan.

e-VLBI: Short observation requests may be submitted up to 3 weeks before e-VLBI run begins by email to the EVN Program Committee Chair (Kazi Rygl, INAF-IRA, kazi.rygl@inaf.it) with the EVN Scheduler (Alastair Gunn, alastair.g.gunn@manchester.ac.uk) and JIVE (Bob Campbell, campbell@jive.eu and Zsolt Paragi, zparagi@jive.eu) in copy. The EVN PC Chair will, at her discretion, authorize scheduling in any gaps in the e-VLBI schedule.

Based on requests from the EVN user community, the EVN CBD has decided that the abstracts of any proposal (including ToOs and Short observations) submitted starting from the October 1 2017 deadline that receive observing time will become public at the EVN Data Archive (http://jive.eu/select-experiment).

Out-of-Session observing time

Out-of-Session observing time (up to a maximum of 144 hours/year), is now available to all proposals. Proposals requesting Out-of-Session observing time must provide full scientific (and technical if appropriate) justification as to why observations must be made outside regular sessions. Out-of-Session observing blocks should be no less than 12 hours in duration (although individual observations can be shorter), and occur no more than 10 times per year (up to a maximum of 144 hours). Proposals should specify which dates/GST ranges are being requested and indicate the minimum requirement in terms of numbers of telescopes (and any particular telescopes). Proposals will only be considered for dates occurring after the regular EVN session that follows EVN proposal review. Observations requiring much shorter lead times must be submitted as a Target-of-Opportunity, if appropriate for this category.

Large projects

Most proposals request 12-48hrs observing time. The EVN Program Committee (PC) also encourages larger projects (>48 hrs); these will be subject to more detailed scrutiny, and the EVN PC may, in some cases, attach conditions on the release of the data.

Further details on Standard EVN

Combining EVN antennas with other arrays

Proposers may request EVN antennas together with other telescopes and arrays.

EVN + e-MERLIN Observations

e-MERLIN is an array of 7 radio telescopes connected by a optical fiber network. It is located in England, and provides a maximum baseline of 217 km. Combined EVN+e-MERLIN projects add the short e-MERLIN baselines (10-217 km), which will help to image more extended sources. e-MERLIN+EVN time will be allocated by the EVN Program Committee, but the case for joint observations must be made in the proposal. Information on e-MERLIN and joint EVN+e-MERLIN observations may be found here.

Including other antennas

Antennas of the NASA Deep Space Network (DSN), including the 70-m antenna at Robledo (Spain) may be available for a small number of projects requiring very high sensitivity. The EVN and the Australian Long Baseline Array (LBA) have agreed to make some time available for joint LBA/EVN observations. See the most recent Call for Proposals on the EVN website for up-to-date information.

Global VLBI

GLOBAL projects add the Very Long Baseline Array (VLBA), and/or the JVLA or GBT, creating a larger array suitable for very high dynamic range imaging and “snap-shot” observations of many sources. PIs wishing to apply for Global VLBI time should continue to submit their proposals at the EVN deadlines using the Northstar on-line proposal submission tool. Further details can be found in the most recent Call for Proposals on the EVN website.

Correlation of EVN observations

Correlation of EVN projects at JIVE

Correlation of disk-based observations at JIVE has shifted to the EVN software correlator at JIVE (SFXC). This provides much more flexibility in terms of the output number of spectral points and integration time compared to the earlier EVN MkIV Data Processor at JIVE, and overcomes the explicit 16-station limit to a correlator pass. It also provides features that were never available on the MkIV, such as pulsar gating/binning, more than 2048 spectral points across each subband/polarization, and multiple correlation phase-centers. These features are now reflected in the correlation-parameters section of the NorthStar on-line EVN proposal tool.

All EVN proposals are subject to a technical assessment by the correlator staff, and any technical difficulties of correlation are discussed during the EVN proposal review. Contact Bob Campbell (campbell@jive.eu) with further questions.

Correlation of EVN projects at Bonn

Limited time may be available for the correlation of EVN experiments at the Bonn DiFX Correlator, but only by arrangement with MPIfR correlator staff prior to submission. Suitable projects will be those for which the scientific advantage of using the MPIfR Correlator is given in the proposal, or those which include an MPIfR collaborator who wishes to have a closer “hands-on” approach to the data flow. For details contact the Correlator Manager, Walter Alef (walef@mpifr-bonn.mpg.de).

Correlation of Global VLBI Projects

GLOBAL projects can be processed by either the EVN correlator at JIVE or the VLBA correlator at Socorro. Details of the VLBA DiFX correlator's capabilities are given in Section 6 of the VLBA Observational Status Summary. A specific correlator may be requested for technical reasons, which should be explained in the proposal. The EVN Program Committee and the NRAO and EVN Schedulers will consider the correlator requested for each proposal submitted, and assign one if no preference was given, also taking into account the load on the correlators, the logistics of disk distribution and the proximity of the PI to the correlator.

Correlation of non-EVN observations at the EVN correlator at JIVE

It is possible to submit an EVN correlator proposal only. The rules are as follows:

  1. Correlator-only proposals will receive an official EVN proposal/legacy code
  2. Requests for observing time at the telescopes desired for the observations must be made directly to the management of those observatories by the proposers themselves
  3. The EVN-PC grades correlator-only proposals following the standard process. This grade is advisory only, but may be useful for any observatory which seeks an external opinion before deciding whether to grant the project observing time on its telescope(s)
  4. Correlator-only projects will be recognised as EVN projects for all intents and purposes, except that time allocated by EVN observatories for correlator-only proposals is not subtracted from that observatory's commitment of time to the EVN
  5. Correlator-only projects will not be permitted to access the EVN disk pool
  6. PIs of correlator-only proposals will be required to demonstrate the availability of disks
  7. The EVN Scheduler will not be involved in the scheduling of antennas for correlator-only proposals

Further details on e-VLBI

Technical details

Continuum observations

Continuum observations will be run at the highest possible reliable bit rate.

Continuum observations can be proposed for only one of the available frequency bands in any given 24 hour session.

Spectral line observations

Real-time e-EVN spectral line observations would be similar to those recorded on disk, but without the possibility of multiple correlation passes, which may limit the tactics for achieving higher spectral resolutions. The minimum data rate remains 32 Mbps (e.g. 2 dual-pol 2 MHz subbands).

Note that [guidelines#General e-VLBI observations|general]] and short observation proposal types are mostly suited for spectral line observations. Triggered proposals (see below) for spectral-line observations requiring only a single spectral line pass may be accepted if technically possible. Triggered proposals requiring multiple correlator passes will not be accepted.

e-VLBI observations that can take place on the scheduled runs fall into the three classes as defined below. Time within these classes will only be allocated in response to proposals submitted for the standard proposal deadlines of 1st Feb, 1st June or 1st October. Proposals should make clear in the proposal text which class of observations is being requested.

General e-VLBI observations

Any e-VLBI observation during one or several e-VLBI sessions, not falling into one of the below classes.

General e-VLBI proposals can be for any scientific purpose and do not need to be justified based on the rapid data delivery of e-VLBI. Any proposal may contain both standard disk-based and e-VLBI observations. Note that the e-VLBI portion of monitoring proposals cannot be guaranteed in every requested run, as they may be overridden by higher rated, triggered e-VLBI proposals (see below).

General e-VLBI proposals can be either continuum or spectral line. Scheduling will be done by JIVE staff using the technical information included in the proposal; it is therefore vital that all technical aspects are fully specified in the proposal.

Triggered e-VLBI observations

An observation to be scheduled during an e-VLBI run only if a specific triggering criterion is met.

Generally, a proposal for triggered observations would provide a list of potential targets, with an explanation of how these sources form a coherent set for achieving the goals of the proposal. However, a triggered-observation proposal for which such an explicit target list can not be provided at the time of proposing (generic trigger proposal) will be accepted for evaluation, provided that it presents a clear and well-argued case for this situation, and why an approach via target-of-opportunity observation(s) would also not be suitable.

Accurate source coordinates need only be included in the trigger request, not in the original proposal. Continuum observations, or spectral line observations requiring a single correlator pass (when technically possible) can be proposed for within this class. Triggered proposals must include a precise and justified triggering criterion and a minimum number and configuration of telescopes required. The latter information is needed in case a triggered observation forces a change of observing frequency for an eVLBI slot. In such a case all participating EVN stations will endeavor to change observing frequency on a 'best effort basis'; however the participation of every advertised antenna in such triggered observations is not 100 % assured.

PIs of successful proposals containing a triggered e-VLBI observation will be informed after proposal review that their trigger request has been accepted. Such trigger requests should be sent by e-mail to the EVN PC Chair (Kazi Rygl, kazi.rygl@inaf.it) with copies to the EVN Scheduler (Alastair Gunn, alastair.gunn@manchester.ac.uk) and JIVE (Bob Campbell, campbell@jive.eu and Zsolt Paragi, zparagi@jive.eu). These trigger requests must be received no later than 0800 UT the day before the e-VLBI run starts. The e-mail should provide evidence that the trigger criterion in the original proposal has been met, and give the exact GST range and source position requested. All requested technical parameters must match those in the original proposal. The PC Chair will evaluate the trigger request (and decide on priorities if more than one conflicting trigger request is received) and will inform the PI by 1200 UT whether their experiment is to be observed. The experiment will then be scheduled by JIVE staff in accordance with the instructions given in the original proposal.

Note that both trigger and generic trigger proposals:

  • Should have very well defined trigger criteria, specified for each source separately, if necessary;
  • Should indicate the desired period for which the proposal should be active, based on an assessment of the probability of triggering events. The PC will set a maximum duration of 1 year;
  • Should indicate the maximum number of trigger events to be observed;
  • Should demonstrate the capability of the proposers to locate and respond to triggering events within the period for which the proposal should be active.

New: Trigger activation in EVN Sessions is now also possible with the following restrictions:

  • Performed on best effort basis; only if there is an available observing slot in the right frequency range and if media resources are sufficient.
  • Performed in disk-recording only.
  • Trigger activation should be done at least one week before the start of the desired frequency block in the schedule by writing a mail to the PC Chair.

Note that not all gaps in the observing schedule may be available for observations!

Automated e-VLBI trigger observations

An observation to be scheduled automatically during an e-VLBI run only if a specific set of triggering criteria is met.

The expected response time to execute a new program may be as low as 10 minutes. The station experiment setup, including frequency, will be the same as the interrupted program. Only continuum observations can be proposed for within this proposal class.

Proposals for this class are accepted for evaluation, provided that they present a clear and well-argued case as to why the requested observations cannot be made as a general e-VLBI observation, or as a ToO.

Source coordinates need only be included in the trigger request, not in the original proposal. The positional accuracy must be high enough to allow acceptable bandwith- and time-smearing fields of view during correlation. This must be addressed in the proposal. Bob Campbell (JIVE Science Operations, campbell@jive.eu) can provide guidance in these matters.

This type of proposal:

  • Must have very well defined trigger criteria, specified for each class of source separately, if necessary;
  • Should indicate the desired period for which the proposal would be active, based on an assessment of the probability of triggering events. The PC will set a maximum duration of 9 months;
  • Should indicate the maximum number of trigger events to be observed;
  • Must demonstrate the capability of the proposers to locate and respond to rapid triggering events on short timescales required by science drivers, either through automated triggers (e.g. VOEvent), or otherwise.
  • Should discuss minimum requirement in terms of numbers of telescopes (and any particular telescopes). Note that some stations can not participate in this observing class, see below;
  • Should address the required sensitivity;
  • Should contain the minimum/maximum observing time;
  • Should contain the start and end of the time range relative to receipt of the trigger notification for which e-EVN observations would be useful;

In addition,

  • The PI should be willing to work with JIVE on the implementation of the trigger criteria (VOEvent or other form of automated/manual trigger response) and automatic schedule generation within the EVN automatic trigger software.

This class of proposal will only be allowed to interrupt another project (which can be another interrupt program) if it has a better/higher science grade as given by the EVN PC.

Note that at present neither Jb (any telescope) nor Wb will participate in this class of observations.

Contacts

Informal enquiries about technical feasibility of EVN or global projects may be directed to Bob Campbell (JIVE Science Operations, campbell@jive.eu).

Future EVN Calls for Proposals and other VLBI news can be received from the VLBI e-mail exploder. To subscribe, follow the instructions in this link. Instructions for joining the evntech e-mail exploder can be found here.

EVN Data Access Policy

The EVN Data Access Policy is described here.

Acknowledgement

Publications resulting from your EVN observations should carry the standard EVN acknowledgment:

The European VLBI Network (www.evlbi.org) is a joint facility of independent European, African, Asian, and North American radio astronomy institutes. Scientific results from data presented in this publication are derived from the following EVN project code(s):

If your observations were performed with the joined EVN + e-MERLIN array, please add also the e-MERLIN acknowledgement phrase:

e-MERLIN is a National Facility operated by the University of Manchester at Jodrell Bank Observatory on behalf of STFC.

For an example of how to mention the EVN project code see: http://www.evlbi.org/access/.

Press Releases

If you plan to issue a press release (or even just a news item on your institute web pages), please inform Zsolt Paragi (zparagi@jive.eu) at JIVE. Please do inform JIVE already in the advance stages of publication, to make sure your result gets wide-enough attention, and the EVN gets the appropriate credits.

Kazi Rygl - EVN Programme Committee Chairperson kazi.rygl@inaf.it

evn/guidelines.txt · Last modified: 2021/01/04 08:27 by poll