e-MERLIN / VLBI National Radio Astronomy Facility

Very Long Baseline Interferometry

European VLBI Network - Guidelines for proposal submission

with the ONLINE PROPOSAL SUBMISSION tool Northstar.

The EVN consists of a VLBI network of radio telescopes in Europe and beyond, operated by an international Consortium of institutes. Real time observing capabilities are under development in the EVN, and part of the EVN array is now able to offer real time e-VLBI observations.

To enable proposals that contain both e-VLBI and disk-based components, the NorthStar on-line EVN proposal tool has consolidated the e-EVN and EVN+MERLIN proposal classes. A single EVN+MERLIN proposal can now request e-VLBI 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. The links below lead to further discussion of each of these two types of observation.

The European VLBI Network (EVN) invites standard (disk recording) and e-VLBI real time observing proposals for deadlines on February 1st, June 1st and October 1st each year. See below for general guidelines on the EVN and e-VLBI capabilities, and details on proposal submission.

Standard VLBI

1. Introduction
2. EVN and other available arrays and special features
3. Submitting EVN proposals
4. Guidelines on proposal writing
5. Previous EVN observations and proposals
6. Correlation of EVN observations
7. Short Observations
8. Targets of Opportunity (ToO)
9. Large Projects


1. General information
2. Technical details
3. e-VLBI observation classes
4. Proposal details
5. How to submit
6. Acknowledgement

Standard EVN

1. Introduction

Consult the EVN User Guide for the following:

Use of the Network by astronomers not specialised in the VLBI technique is encouraged. The Joint Institute for VLBI in Europe (JIVE) can provide support for schedule making, correlation and data analysis of EVN projects, as well as advice during proposal preparation. Contact Bob Campbell (campbell@jive.nl) for information about EVN User Support.

The EVN is able to support users via RadioNet, an Integrated Infrastructure Initiative (I3) that is funded under the EC FP7 (Seventh Framework Programme), for the period 2012-2015. Eligible projects are those where both the PI and at least half of the full list of proposers work at institutes located in EU Member or Associated States. As well as providing Transnational Access to the EVN, the programme provides financial support for visits to JIVE or any other EVN institute. Contact Bob Campbell (campbell@jive.nl) for more information or see the "Access to the EVN" menu item of the EVN web page, which in turn links to the Transnational Access section of the RadioNet page.

2. 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 new 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, as well as providing VLBI baselines to the Cambridge antenna. 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 at Robledo (Spain) may be available for a small number of projects requiring very high sensitivity.

Global VLBI

GLOBAL projects add the NRAO Very Long Baseline Array (VLBA) and/or other NRAO antennas (e.g. the VLA or GBT), creating a larger array suitable for very high dynamic range imaging and "snap-shot" observations of many sources.
Note that NRAO has moved from a trimester system to a semester system with proposal deadlines of February 1st and August 1st. The first semester-based deadline will be 2011 February 1 (see http://www.nrao.edu/admin/do/vlba-gvlbi.shtml). 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 (see below).

3. Submitting EVN Proposals


Proposals must be received by 23:59:59 UTC on the appropriate 1st February, 1st June and 1st October.


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

Guidelines on using Northstar

Old LaTex/e-mail way

This style of submission has been discontinued for ALL EVN and GLOBALS, starting with the 1 June 2007 deadline. Its use is continued for ToO proposals. 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. 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.

4. Guidelines on proposal writing

All proposals should include a text NOT EXCEEDING 2 SIDES that must be uploaded to Northstar. This text should contain both a scientific and a technical justification for the resources requested. It should include a brief summary of any related EVN proposals which have already been observed or scheduled. Proposers should indicate if it is a resubmission of an earlier proposal. Up to 2 additional sides with diagrams may be included; the total, including cover sheet, should not exceed 4 sides.

Phase-referencing observations

Observers are advised to find phase calibrators as close as possible to their target source. The VLBA Calibrator Survey 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 Lovell telescope due to slewing limitations.

5. Previous EVN observations and proposals

A list of previous EVN observations currently updated at IRA (Pietro Cassaro) 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 accessible as menu items in either the main EVN or JIVE web page.

A list of previous EVN proposals is also available:
Most recent EVN proposals
Complete EVN proposal list

6. 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 corrlator 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.nl) with further questions.

Correlation of EVN projects at Bonn

Limited time may be available for the correlation of EVN experiments at the Bonn MK4 VLBI Correlator , but only by arrangement with MPIfR correlator staff PRIOR TO SUBMISSION. The DiFX capabilities are identical to those offered by NRAO DiFX correlator (see Section 7 of the VLBA Observational Status Summary). 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 closer "hands-on" approach to the data flow. For details contact the Correlator Manager, Walter Alef (walef@mpifr-bonn.mpg.de). The policy can be found at the Bonn Mk4 Correlator Status Page.

Correlation of Global VLBI Projects

GLOBAL projects must be observed using VLBA/MKIV-compatible recording modes, and will be processed by either the EVN correlator at JIVE or the VLBA correlator at NRAO. As of 2010 January 1, the original, hardware-based VLBA correlator has been replaced by NRAO's implementation of the DiFX software correlator. Details of the new correlator's capabilities are given in Section 7 of the VLBA Observational Status Summary. Especially relevant to global projects is support for Mark 5B recordings. 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.

7. Short Observations

"Short" observations (< 4 hours) may be proposed up to 6 weeks before an observing session begins, by means of a brief justification to the Chairman of the EVN Program Committee (Tom Muxlow, JBCA, University of Manchester, tom.muxlow@manchester.ac.uk), who will, at her discretion, authorise scheduling in any gaps in the session plan. They are intended to facilitate short, pilot observations, if needed in preparation for a full proposal. They can only be granted limited resources (number of telescopes, disks, correlator time) and must use standard recording modes. They should not involve any special observing set-ups.

8. 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 are invited to use the tex-based VLBI cover sheet to provide the observational details.  

9. 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.

10. Contacts

Informal enquiries about technical feasibility of EVN, EVN+MERLIN, or global projects may be directed to Bob Campbell (JIVE Science Operations and Support Group, campbell@jive.nl).

Future EVN Calls for Proposals and other VLBI news can be received from the VLBI email exploder. To subscribe, send the message "subscribe vlbi" in the body (not the subject line) of an email to: Majordomo@zia.aoc.nrao.edu.

Tom Muxlow - Chairperson EVN Program Committee (twbm@jb.man.ac.uk)


1. General information and current features

The current antenna capabilities can be found on the e-VLBI status table. The full array now includes: Ef, Wb (tied array except at 5 cm), Ys, Tr, On, Mh, Mc, Jb, Cm, Ar and Sh. The wavebands covered are 18/21 cm, 6 cm, 5 cm and 1.3 cm.

2. 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 2MHz subbands). Recirculation can be used during e-VLBI correlation, obviating the need for oversampling in most cases, see the EVN MkIV correlator-capacity web-page.

Observations may be proposed for the 18/21cm, 5cm and 1cm bands.
Note that only standard and short observation proposal types (see below for definitions) are allowed for spectral line observations.
Triggered spectral line proposals will not be accepted.

3. e-VLBI observation classes

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

1) General e-VLBI observations

Any e-VLBI observation during one or several e-VLBI sessions, excluding triggered response science (see below).

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. Proposals for source monitoring 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.

2) Triggered e-VLBI proposals

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

Accurate source coordinates need only be included in the trigger request, not in the original proposal. Only continuum observations 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.

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 request should be sent by e-mail to the EVN PC Chair (Tom Muxlow, tom.muxlow@manchester.ac.uk) with copies to the EVN Scheduler (Richard Porcas,  porcas@mpifr-bonn.mpg.de) and JIVE/NEXPReS (Bob Campbell, campbell@jive.nl and  Zsolt paragi, zparagi@jive.nl). These trigger requests must be received no later than 0800 UT  the day before the e-VLBI run. 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 requests is received) and will inform the PI by 1700 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.

3) Short e-VLBI observations

Short e-VLBI observations may be requested for checking calibrator or target source compactness in preparation for or as part of a larger VLBI observation or proposal. These projects are limited to 2 hours or less in length. Such requests may be submitted up to three weeks prior to the start of any e-VLBI run directly to the PC Chair. There is no need to submit a full proposal via Northstar but email to the Chair must clearly indicated the purposes and observing details of the proposed observation. A tex-based VLBI cover sheet should also be sent including information on proposed observing modes, stations/GST ranges and precise positions for all targets and calibrators. The information sent must be sufficient to allow central scheduling of the observations by JIVE personnel.

4) Generic e-VLBI trigger observations

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

Note that both trigger and generic trigger proposals:

A list of previous e-VLBI proposals is available:

4. Proposal Details

Proposals requesting observing time for the e-VLBI runs should be submitted by the normal 1st February, 1st June and 1st October deadline.

Proposals can be made for any length of time within the advertised slots up to 24 hours in length. Short time requests (defined above) of up to 2 hours in length can be submitted directly to the PC Chair up to three weeks before each run. Proprietary rights on all eVLBI data are the standard ones  of one year after data distribution (see archive policy). All standard and triggered proposals must use the Northstar online submission tool (see details below).

Because detailed scheduling of eVLBI runs will be done by JIVE staff all eVLBI 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. 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 should be discussed with JIVE staff prior to submission to ensure proper and efficient scheduling (contact Bob Campbell, campbell@jive.nl).

5. How to submit

The on-line proposal submission tool Northstar replaces the old  Latex-email way of submission for proposals involving EVN, including proposals for e-VLBI runs (an exception to this at present are ToO proposals which are submitted by email according to the procedure described here).

To use Northstar proposers should register (only for the first proposal  submission), complete the technical  information on-line (equivalent to that previously in the cover sheet) and upload a scientific justification in pdf or ps format. Standard page limitations apply and will be enforced.
The deadline for submission of standard and triggered proposals is 23:59:59 UTC on 1st February, 1st June and 1st October.

6. Acknowledgement

Please see Acknowledgements which includes complete lists of the approppriate acknowledgements for EVN and e-VLBI users.

Paco Colomer - Chairman of EVN eVSAG (E-VLBI Science Advisory Group) f.colomer@oan.es