Guidelines for Global VLBI Proposals at 3mm wavelength

Deadlines: Wednesday closest to February 1st and August 1st in each year

We announce the opportunity for coordinated, high angular resolution and high sensitivity GLOBAL VLBI observations in the 3mm band (85 - 95 GHz), complementing stand-alone VLBA or HSA observations at this frequency. The GMVA proposal call is: here. It is also synchronized with a corresponding proposal call of the NRAO here.

The Global 3mm VLBI Array (GMVA) consists of 8 VLBA antennas equipped with 3mm receivers, the 100m GBT, the IRAM 30m telescope on Pico Veleta (Spain), the phased NOEMA interferometer on Plateau de Bure (France), the MPIfR 100m radio telescope in Effelsberg (Germany), the OSO 20m radio telescope at Onsala (Sweden), the 14m telescope in Metsähovi (Finland), and the OAN 40m telescope in Yebes (Spain). In addition, telescopes of the Korean VLBI Network (KVN) and the Greenland Telescope (GLT) can be requested as part of the GMVA. Proposal which ask for ALMA as part of a GMVA observation must be submitted to the GMVA and in parallel to ALMA at their apropriate proposal deadline.

The GMVA offers 3-4 times more sensitivity and a factor of 2 higher angular resolution than the stand-alone VLBA or the HSA. For logistical reasons GMVA observations cannot be "dynamically" scheduled and are scheduled in time blocks, which combine the indvidual proposals and optimize the use of the available observing time and recording media. The GMVA block observations are scheduled in special observing sessions, performed twice per year, typically in spring (April, May) and autumn (September,October). The actual duration of each session depends on proposal pressure and ranges between 2 and 5 days.

The Global 3mm VLBI Array supports the same observing modes as the VLBA. In standard observing mode the recording is done at a data rate of 4 Gbps, using the digital down converter (DDC) mode, with either 128 MHz (VLBA) or 64 MHz (Europe, KVN) sub-bands.

Correlation is performed at the MPIfR VLBI correlator in Bonn unless some technical reason for using another correlator is given in the proposal. The P.I. will receive the correlated data in uv-fits format. The P.I. is supposed to contact the GMVA schedule maker for details of the non-standard amplitude calibration, which is not yet attached to the correlator output. It is the responsibility of the P.I. to analyse and publish the data timely. After the delivery of the raw data to the P.I., the data will become public after a period of 1 year, following the same rules as at the NRAO. In publications using GMVA data, the use of the GMVA and its resources should be acknowledged (see disclaimer below).

Proposal submission for the GMVA is synchronized with the VLBA. The proposal deadlines of August 1st is for GMVA observations in the next spring (or later) and of February 1st is for observations in the autumn (or later) of each year. For each VLBI session proposers are asked to submit their proposals using the NRAO proposal submission tool PST. Proposals will be reviewed by the NRAO and the programme/time allocation committees of the participating observatories.

The format of the science justification is limited to 4 pages (A4 or US Letter format). Proposals which involve GMVA plus ALMA must have a font size no smaller than 12 points. Proposals which only involve the GMVA (no ALMA) must have a font size no smaller than 11 points. The recommended breakdown is 2 pages for the science case and 2 pages for figures, tables and references. Guidelines of how to use ALMA are given on the German ARC node.

Global VLBI observations at 3mm are subject to some technical restrictions, which are summarized in the Technical Guidelines section here.

Disclaimer: Please add the following statement in all publications, which make use of data obtained by the GMVA:

"This research has made use of data obtained with the Global Millimeter VLBI Array (GMVA), which consists of telescopes operated by the MPIfR, IRAM, Onsala, Metsahovi, Yebes, the Korean VLBI Network, the Greenland Telescope, the Green Bank Observatory and the Very Long Baseline Array (VLBA). The VLBA and the GBT are facilities of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. The data were correlated at the correlator of the MPIfR in Bonn, Germany."

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