CALL FOR PROPOSALS

                         GLOBAL 3mm VLBI ARRAY

                       Deadline:  1 February 2021

        VLBI proposals for observing at 3mmwavelength (86 GHz) using:

         the VLBA,  GBT*,  EFFELSBERG, PICO VELETA,  NOEMA,  ONSALA,  

         METSAEHOVI, YEBES  and  KVN telescopes should be submitted by

                       1 FEBRUARY 2021 (UT 22:00)

                       ==========================

     Successful proposals will be considered forscheduling in GMVA

     Session II 2021 (30 September - 4 October) orin a later session.

       *  SEE ALSO THE SECTION BELOWREGARDING PROPOSALS FOR GMVA

       *  OBSERVATIONS TOGETHER WITHPHASED-ALMA IN ALMA CYCLE 8

              ===================================================

              |                                                           |

              | ALL PROPOSALSSHOULD BE SUBMITTED USING   |

              |                                                           |

              | THE NRAOPROPOSAL SUBMISSION TOOL (PST):  |

              |                                                           |

              |          https://my.nrao.edu                           |

              ===================================================

     In order to maximize the sensitivity for continuumobservations

     the GMVA will record at the highest bitratewhich instrumentation

     and resources permit. Currently all telescopeswill record at 

     4 Gbps (except the KVN, which will record in acompatible 1 Gbps

     mode).  All data will be correlated atthe Bonn DiFX software

     correlator.

     * The GBT may be included in GMVA observationsif a sufficiently

     compelling justification is given in theproposal but the amount

     of time available will be reduced compared toearlier observing

     semesters, and observing blocks greater than 6hours will be

     very difficult to schedule.

     ALMA, the KVN and the Greenland Telescope(GLT) can be selected using 

     the "Other Stations" text field inthe PST. Rules for requesting the 

     participation of the Mexican LMT in GMVAobservations are given 

     in a separate section below.

     Note that the availability of NOEMA (PLATEAUDE BURE) for GMVA

     Session II in 2021 and later sessions is notconfirmed. 

     For further details on proposing, includingthe possibility of

     additional support observations at 7mm (43GHz), please consult

     the administrative and technical informationhosted at the MPIfR:

           http://www3.mpifr-bonn.mpg.de/div/vlbi/globalmm

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         PARTICIPATION OF ALMA IN GMVAOBSERVATIONS IN ALMA CYCLE 8

         ==========================================================

     Due to the Corona virus pandemic, ALMA wasunable to observe

     together with the GMVA for observationsscheduled for GMVA

     Session I in 2020 (ALMA Cycle 7). Theseobservations are now

     re-scheduled for GMVA Session I in 2021.

     ALMA is expected to re-issue a call forproposals for Cycle 8

     in March 2021. Successful proposals will bescheduled in

     GMVA Session I 2022. New GMVA+ALMA proposalsfor ALMA Cycle 8 must

     be submitted by the GMVA February 2021deadline, and separately

     to ALMA by the ALMA 2021 deadline.

     GMVA+ALMA proposals which were alreadysubmitted to the GMVA in

     February 2020 for ALMA Cycle 8 have beenreviewed by

     the GMVA observatories (but not by ALMA) andwill be held

     over (with their grades) for possiblescheduling in

     GMVA Session I 2022. A separate proposal toALMA for these projects 

     needs to be submitted following the (new) ALMACall for

     Cycle 8 proposals in March 2021.  SeeCycle 8 pre-announcement at:

       https://almascience.nrao.edu/news/alma-cycle-8-2021-pre-announcement

     Proposers may, instead, submit a revisedversion of their GMVA+ALMA

     proposal to the GMVA by the February 2021deadline, 

     which will then be re-evaluated by the GMVAobservatories.

     Proposers should give the code number of theearlier proposal

     which is superseded.

     Proposals which have already been submittedwill, of course,

     compete with any new GMVA+ALMA proposalssubmitted at the

     February 2021 deadline.

     Restrictions on GMVA+ALMA proposals in ALMACycle 8

     ===================================================

     GMVA observations with ALMA will be limited toa fixed recording

     mode, which currently provides 4 Gbps on allbaselines.

     The KVN telescopes will not be available inthis mode.

     Only VLBA telescopes will be available at 7mmin this mode.

     Direct phasing up of the ALMA array is limitedto sources with a 

     correlated flux density of >500 mJy withinan unresolved core on ALMA

     baselines of up to 1 km. Direct phasing-up onthe target source

     ("active" phasing) thus limits thestrength of the target.

     For weaker sources (<500 mJy), Cycle 8 willintroduce the option of 

     "passive" phasing. In this mode, theALMA array is periodically phased up

     on a bright calibrator source close in angulardistance to the

     science target. There will be no restrictionson the flux density of 

     science targets using passive phasing (asidefrom SNR considerations

     on VLBI baselines). However, the phasingcalibrator properties must meet

     the same criteria as for actively phasedobservations, and it is

     recommended that the calibrator lie within anangular separation of no

     more than 5 degrees from the science target.

     Proposers must specify any such calibrator intheir proposal; consult

     the ALMA calibrator catalogue: https://almascience.eso.org/sc/

     In order to make a clean linear-to-circular polarisation

     transformation of ALMA recordings, any targetsource must be

     observed for a duration of at least 3h (breaksfor calibrators

     permitted) to sample a range of parallacticangles.

     Large Programs (>50 hours of observingtime) are not permitted

     because phased ALMA is a non-standard mode.

     No long-term programs may be proposed, and noproposals will be

     carried over into the next cycle.

     There is a cap for VLBI of 5% of ALMA Cycle 8observing time. As

     time for GMVA observations will thus bescarce, proposals should

     include a quantitative justification as to whyALMA is essential

     for the goals of the project.

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        PARTICIPATION OF THE LMT IN GMVAOBSERVATIONS

        =============================================

     The Mexican LARGE MILLIMETER TELESCOPE ALFONSOSERRANO (LMT) may

     be available to participate in some GMVAobservations.

     For this a SEPARATE PROPOSAL must be submittedto the LMT

     with a P.I. from the LMT community, asdescribed under

      http://lmtgtm.org/proposal-submission-process/

     Time is allocated to the community as follows:

      - Mexico                     68.25%

      - Uni. Massachusetts Amherst  15%

      - USA (rest)                 15%

      - Spain                       1.75%   (15h per session)

     The P.I. of this LMT proposal need not be theleader (i.e., P.I.) of

     the GMVA proposal, but must agree to takeresponsibility for all

     necessary arrangements for observing at theLMT, and must be identified

     in the GMVA proposal.

     The proposal should emphasize the value andimportance of adding 

     the LMT to the GMVA observations.

     NOTE that the LMT proposal deadline forobservations in both

             GMVA  SessionII 2021       

      AND    GMVA  Session I  2022

    is in April/May 2021 (i.e. before the August 2021GMVA proposal deadline).