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Proposals are thus invited for the 5 antenna interferometer, with the same set of stations
as last year. Moreover, because of the access restrictions, we wish to minimize logistic
problems on the Plateau de Bure next winter.
Possible ways to do so which are currently under consideration include:
We want our decisions to be based on scientific requirements as much as possible.
Accordingly, proposers are strongly encouraged to emphasize in their proposals:
- A reduced set of configurations (e.g. no C1 or no B2 configuration)
- Minimizing snow cleaning by e.g. dropping the longest baseline (A) configuration,
or fixing the configuration schedule well in advance.
- Focusing the efforts on a particular type of projects
(e.g. detection demanding D configuration)
In view of the serious impact that the accident has, IRAM will seek the advice from an
exceptional advisory panel before taking a final decision on the overall strategy for
the next winter (and summer) period.
- The uniqueness of Plateau de Bure for the scientific goals
- The possible observing tradeoff, in particular for mapping projects
- The relative urgency of the proposition, in particular if it is relevant
for a PhD thesis
- The degree of internal priority when several proposals are issued by the same team.
We still expect to be able to perform the equivalent of about 30-40 full synthesis
during next winter. However, projects will be carried on a ``best effort'' basis.
Following the above rules, proposals are invited for the IRAM Plateau de Bure
Interferometer (PdBI) for the period Nov. 15th, 1999 to May 15, 2000. The deadline for
applications is Sept 10 th, 1999 18:00h (MET). Applications may now be
submitted via the World-Wide-Web using the new
electronic proposal submission
facility, which will be activated three weeks before the deadline.
IRAM expects to schedule and complete at least 30-40 projects with elapsed
time of at least two months between start and end of any given project.
Selection will be based on scientific merit, technical feasibility, and
adequacy to the instrument.
Details of the PdBI and the observing procedures are given in the
document ``The Plateau de Bure
Interferometer (PdBI)''. A copy can
be obtained from the address below or from Internet via the
World-Wide-Web (use IRAM's page at http://iram.fr/PDBI/bure.html). Proposers should read this
document carefully before submitting any proposal.
Applications sent by fax or postal mail should be addressed to:
IRAM Scientific Secretariat
Interferometer Observing Proposal
300 Rue de la Piscine
F-38406 Saint Martin d'Hères Cedex
Proposal templates as well as the Latex style file proposal.sty
may be obtained by anonymous ftp from iram.fr (directory dist/proposal); or from Internet via the
http://iram.fr/proposal/proposal.html. In case of problems, contact
the secretary, Cathy Berjaud.
We encourage the use of the electronic submission facility. Proposals
sent by e-mail, however, will not be accepted. Do not
use characters smaller than 11pt, which could make your proposal
illegible when copied or faxed. For the same reasons, also avoid
sending by fax figures with grey scale maps. In case your proposal
reaches us in time, but is incomplete or unreadable when copied, we
will try out best to contact you. The Principal Investigator will
receive by return mail an acknowledgement of receipt and the
The scientific aims of the proposed programme should be explained in 2
pages of text maximum, plus up to two pages of figures,
tables, and references. Proposals should be self-explanatory,
clearly state the scientific aims, and explain the need of the Plateau de
In all cases, indicate on the first page whether your proposal is (or
is not) the resubmission of a previously rejected proposal or
the continuation of a previously accepted proposal. In case of
a resubmission, state very briefly in the introduction why the
proposal is being resubmitted (e.g. improved scientific
For this call for proposals, please note the following specificities.
longer than foreseen antenna maintenance, not all the backup projects for the
summer period will be scheduled. We urge proposers to re-submit
them unless they have explicitly been notified of their effective
Proposals should be submitted for one
of the five categories:
The proposal category will have to be specified on the proposal cover
sheet and should be carefully considered by proposers.
- Proposals that ask for 1.3mm data only.
3mm receivers will be used for pointing and calibration purposes,
but cannot provide any imaging.
- Proposals that ask for 3mm data only. 1.3
mm receivers can still be used to provide either phase stability
information or purely qualitative information such as the mere
existence of fringes.
- dual freq.:
- Proposals that ask for dual-frequency
observations (i.e. simultaneous observations at 3mm and 1.3mm).
- time filler:
- Proposals that have to be considered as
background projects to fill in periods where the atmospheric
conditions do not allow mapping, or eventually, to fill in gaps in
the scheduling, or even periods when only a subset of the standard 4
and 5-antenna configurations will be available. These proposals will
be carried out on a ``best effort'' basis only.
- Exploratory proposals: proposals whose
scientific interest justifies the attempt to use the PdB array
beyond its guaranteed capabilities. This category includes for
example non-standard frequencies for which the tuning cannot be
guaranteed, and more generally all
non-standard observations; for this winter non-standard configurations
will not be considered.
Standard configurations for the next winter period are:
|5 Antenna configurations
||W05 W00 E03 N05 N09
||W05 W01 E10 N07 N13
||W12 W09 E10 N05 N15
||W12 E18 E23 N13 N20
||W23 W12 E12 N17 N29
||W27 W23 E16 E24 N29
The following configuration sets are available:
||``Low'' resolution at 1.3 mm
||D, C2 or C1
||3.5'' resolution at 3mm, 1.8'' resolution at 1.3 mm
||Slightly higher resolution than CD.
||2'' resolution at 3 mm
||B1, B2, C2
||Better sensitivity than BC
||A, B1, B2
||1'' resolution at 3 mm, 0.5'' resolution
The time order of the configurations for a given project cannot be guaranteed.
Enter ANY in the proposal
form if your project doesn't need any particular configuration.
All antennas are equipped with fully operational dual frequency
receivers. The available frequency range will be 82 GHz to 116 GHz for
the 3mm band, and 210 to 245 GHz for the 1.3 mm band. The 3mm and
1.3mm receivers are aligned to within about 2''.
Below 110 GHz, receivers offer best performances in LSB tuning
with high rejection (20 dB): expected system temperatures are
scale) 100 to 150 K for the winter time. Above 110 GHz,
best performances are obtained with USB tuning, low rejection
(4 to 6 dB): expected system temperatures are 250 K at 115 GHz.
DSB tuning is possible over the whole frequency range, but the
system temperature may degrade significantly.
The 1.3 mm receivers give DSB tuning with typical T
50 K. Expected SSB system temperature are 250 to 350 K. The
guaranteed tuning range is 210-245 GHz, but it may be possible to
reach lower frequencies for specific cases. Higher frequencies are not
feasible because of limitations in the triplers.
Experience based on past years shows that sub-arc-second resolution
can be achieved in good winter conditions, but cannot be guaranteed.
Note that the field of view at 1.3 mm is very restricted (about
Software is available to provide real-time atmospheric phase
compensation on spectral and continuum data, as well as a-posteriori
processing for continuum data. Experience shows that a final phase
noise below 30 degrees at 230 GHz is obtained under good
The rms noise can be computed from
is the system temperature in Tr* scale (150 K below
110 GHz, 200 K at 115 GHz, 400 K at 230 GHz)
is the conversion factor from Kelvin to Jansky (22 at 3mm,
40 at 1.3mm)
is an efficiency factor due to atmospheric phase noise
(0.9 at 3 mm, 0.8 at 1.3 mm)
is the number of antennas (5), and
is the basic number
of configurations (1 for D, 2 for CD, 3 for BC)
- T is the integration time per configuration in seconds (3 to 8
hours, depending on source declination)
- B is the channel bandwidth in Hz (500 MHz for continuum, 40
kHz to 2.5 MHz for spectral line observations, according to the spectral
The interferometer operates in the J2000.0 system. For best
positioning accuracy, source coordinates must be in the J2000.0 system;
position errors up to 0.3'' may occur otherwise.
Please do not forget to specify LSR velocities for the sources. For
pure continuum projects, the ``special'' velocity NULL (no Doppler
tracking) can be used.
Coordinates and velocities in the proposal MUST BE CORRECT:
A coordinate error is a potential cause for proposal rejection.
The correlator has 6 independent units, each being tunable anywhere in
the 110-610 MHz band, and providing 4 choices of bandwidth/channel
configuration: 160 MHz/64, 80 MHz/128, 40 MHz/256 and 20 MHz/256. For
the 40, 80 and 160 MHz bandwidth, the two central channels may be
perturbed by the Gibbs phenomenon (depending on continuum strength):
it is recommended to avoid centering the most important part of the
lines in the middle of the band of the correlator unit.
The 6 units can be independently placed either on IF1 (3 mm receiver)
or on IF2 (1.3 mm receiver).
One (and only one) of the 6 units has been retrofitted to offer a
higher frequency resolution (40 kHz instead of 80 kHz). This is
obtained by operating at half clock speed and inserting an
anti-aliasing filter of effective bandwidth 8 MHz. Because the filter
reduces the input power to the sampler, this unit should be placed
near the maximum amplitude of the IF bandpass: band edges must be
For safety reasons, the sun avoidance circle extends to 45
degrees. Please take this into account for your sources and for the
The PdBI has mosaicing capabilities, but the pointing accuracy may be
a limiting factor at the highest frequencies. Please contact R. Neri
in case of doubt.
Proposers should be aware of constraints for data reduction:
Data reduction will be carried out on the dedicated HP workstations.
- In general, data should be reduced in Grenoble. Proposers
will not come for the observations, but will have to come for the
- We keep the data reduction schedule very flexible, but wish to
avoid the presence of more than 2 groups at the same time in
Grenoble. Please contact us in advance.
- IRAM may consider splitting the data reduction in two phases:
intermediate calibration and final mapping. Such a splitting is
often necessary for the high resolution images. In such a case, the
proposers must be ready to come at IRAM for fast data reduction of
the ``compact'' configurations.
- CLIC is still evolving fast to cope with the evolution of the
PdBI array. The newer versions are upward compatible with the
previous releases, but the reverse is not true. Observers wanting
to finish data reduction at their home institute should obtain an
updated version of CLIC, which is now available. Because
differences between CLIC versions may potentially result in imaging
errors if new data are reduced with an old package, we insist that
observers having a copy of CLIC take special care in maintaining it
A local contact will be assigned to every proposal which does not
involve an in-house collaborator. Depending upon the programme
complexity, IRAM may require an in-house collaborator instead of the
normal local contact.
All proposals will be reviewed for technical feasibility in parallel
to being sent to the members of the programme committee. Please help
in this task by submitting technically precise proposals. Note that
your proposal must be complete and exact: velocities, position
and frequency setup must be exactly specified.
Please contact R.Neri, R.Lucas, or A. Dutrey in case of doubt about
non-standard program feasibility.
All documents can be retrieved on Internet via the World-Wide-Web.
IRAM's home page is http://iram.fr/
Finally, we would like to stress again the importance of the quality
of the observing proposal. The technical preparation of observing
proposals is unfortunately often insufficient. In the past, proposals
were received which did not even include exact observing frequencies
or even source coordinates, or worse, with coordinates with the wrong
epoch !... The IRAM interferometer is a powerful, but complex and
unique instrument, and proposal preparation requires special
care. Information is available in the documentation and at
http://iram.fr/PDBI/bure.html. The IRAM staff can help in case of
doubts if contacted well before the deadline. Note that the proposal
should not only justify the scientific interest, but also demonstrate
how the Plateau de Bure interferometer will bring new information.
Next: Technical report
Up: IRAM Newsletter 41(August 1999)
Previous: News from the interferometer