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.
This GMVA proposal call is synchronized with a corresponding proposal call
of the NRAO
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 6-element IRAM 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) may now be requested as
part of the GMVA.
Proposal which request ALMA as part of a GMVA observation must be submitted to the GMVA
and in parallel to ALMA at their apropriate 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
as the VLBA. A 2048 Mbps single or dual polarization recording mode using the polyphase
filterbank (PFB) is the standard observing mode for continuum observations
in order to maximize the array sensitivity. Observations with ALMA invoke a new 2 Gbps
observing mode, which at the VLBA uses 4 IFS, each 128 MHz wide. The KVN at present
supports only a lower compatible recording mode at 1024 Mbps.
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
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 Green Bank Observatory and the Long Baseline Observatory (LBO).
The VLBA is an instrument of the LBO, which
is a facility of the National Science Foundation operated by Associated Universities, Inc.
The data were correlated at the correlator of the MPIfR in Bonn, Germany."