After March 2006 all MERLIN proposals should be made use the MERLIN web-based proposal submission tool, NorthStar. As a consequence these forms will not be updated in the future. The submission of the 'old-style' LaTeX forms described below should only be used in exceptional circumstances when users are unable to use the NorthStar to make an application. If you are encountering problems using NorthStar please initially email your queries to merlin-proposals@jb.man.ac.uk, before resorting to using the LaTeX application.
These notes are intended to help you complete the MERLIN Application form. They are included in the application form pack. You may edit the Latex file blank.tex (using example.tex as a guide if necessary) and use this to generate a postscript file of your proposal, which can then be submitted electronically.
The blank application form (blank.tex, blank.ps) and all
files needed to generate a completed application are available via the World Wide Web as a compressed tar file:
These files can also be obtained by anonymous ftp:
ftp ftp.jb.man.ac.uklog in as anonymous, send email address as password
cd pub/merlin/proposals
Alternatively hard copies should be sent to:
Secretary of the MERLIN TAC,
Jodrell Bank Observatory,
University of Manchester,
Macclesfield,
Cheshire,
SK11 9DL, UK.
The file blank.tex contains detailed instructions. The most important sections are marked *** in blank.tex and in Bold Italic below. If anything is unclear please contact merlin@jb.man.ac.uk.
Please consult the MERLIN USER GUIDE. This is also available in hardcopy at a number of astronomical institutions.
Date: Enter date of proposal application.
Title: Enter the Title of the proposal.
Authors: Enter the list of authors with the primary investigator as first
author. Also enter their host institutes and indicate which persons, if any,
are likely to visit Jodrell to observe or reduce the data. Also indicate if the
observations are required by an author for a PhD project together with the year
of completion.
Previous MERLIN Proposal: Enter the title and code of any related
previous MERLIN proposal.
Contact Author: Enter the name and addresses for the author who
will act as first point of contact for queries about the proposal,
scheduling, observing set-up etc. Information about whether the
proposal was awarded time and, at the end of the semester, details
of observations made will be sent to all authors.
Scientific Category and Telescope Requirements
Indicate the appropriate category. Imaging runs require all available
telescopes. Certain specialist types of observation may only require
a subset of the MERLIN telescopes. MERLIN is also used for
simultaneous observations with the EVN or other VLBI arrays. Indicate
the relevant category by placing a tick in the correct box. Proposals
for MERLIN+EVN observations should be sent to the EVN TAG for the
deadlines specified on the EVN web site.
Type of Observation: Do you want to observe a continuum or a
spectral line source? Other information should be entered if
necessary. The default continuum mode of operation for
MERLIN at frequencies above 1 GHz produces 15 MHz useable bandwidth in
1 MHz channels in all four Stokes parameters. Phase-referencing is
carried out unless there is a strong reason not to (e.g. a low
Dec. source at 22 GHz). If the target is strong enough it can be
self-calibrated, but phase-referencing alone can produce good maps of
weak sources.
However phase-reference mapping (ie periodically calibrating the
instrumental phase with respect to a nearby compact source), is recommended for
even strong objects since it gives absolute positions and simplifies any
subsequent closure mapping (self calibration).
At 408 MHz and lower frequencies there is a reduced available protected bandwidth of about 4 MHz and phase-referencing can be more difficult.
If wide-field imaging is needed then more channels can be used (to avoid band-width smearing) at the expense of either total band-width or polarizations. Time-average smearing is avoided by using a shorter integration time than the default 8 sec but there are also constraints on the maximum data rate. See MUG Ch. 3 for background information, and Ch. 4, especially Tables 4.4 and 4.6 for practical details. Such constraints also apply to spectral line imaging and the combinations needed are specified in Correlator Configuration Requirements below.
Other options include multiple short scans to establish simple structural information for relatively bright sources. Typically half-a-dozen targets will be observed for half an hour each, they cycle being repeated about four times to achieve good hour-angle coverage; obviously this will be more successful if long slewing times are not needed. Monitoring experiments involve single scans at suitable intervals (depending on the available frequencies); please state in the scientific justification if imaging or only a short-duration flux measurement is required.
For specialised modes of observation, select other and include details in your scientific justification.
Time Requested: The sensitivity and other parameters of MERLIN
at various frequencies are summarised in MUG Tables 1.1 and 4.2 and
the rest of the Guide describes how to apply this information.
A normal 12 hr observation track will include about 8 hr on target, interleaved with the phase-reference source and about 1 hr observing other calibrators. This gives full hour-angle coverage and is possible for sources above c. Dec. +10°. Sources at lower Dec. can only be observed for a shorter time in a single track, see MUG Fig. 4.5. MERLIN can observe any source above the horizon but at elevations <10° its resolution and sensitivity and the accuracy of phase-referencing are compromised, so this is avoided if possible unless the target is bright enough for self-calibration.
Longer observations (possibly involving several tracks) can be carried out to improve sensitivity. For circumpolar sources above Dec +40°, slightly improved uv coverage is also possible by observing the source over an 18 hr period or even for a full 24 hr (with the caveat above about the quality of observations at low elevations). MUG Ch. 4.6 discusses how to optimise uv coverage.
The time requested should include observations of calibrators. If phase-referencing is required then typically 70% of the total time will be spent on target; less if e.g. several sources are interleaved, or correlator configuration changes are needed during spectral line experiments.
For Target of Opportunity proposals the scientific justification
should describe what sort of observations might be required, with
as much flexibility as possible to allow a rapid response. Further
information
about Target of
Opportunity
proposals can be
found at http://www.merlin.ac.uk/propsub/TOO.html.
Key Programs are experiments involving more than 10 full imaging
runs. Successful proposals are likely to involve a significant
collaboration and an extensive case, see http://www.merlin.ac.uk/propsub/key_programmes.html.
Abstract: Enter an abstract of the scientific case for your
proposal.
Source List: Enter the individual source names and positions.
If possible enter the total flux densities of the requested sources,
as well as the peak flux density,
which determines whether self-calibration will be possible (MUG Table
1.1).
If your target has extended structure on large angular scales it may not be well mapped by MERLIN because of the spatial frequency coverage (MUG Ch. 4.6.4) so please enter the largest angular scale you are interested in as well as the total angular size of the radio source. Combining data at two or more frequencies within the band (multi-frequency synthesis) can be used to improve the imaging of extended structure.
Indicate the time on each target which is needed to produce the required sensitivity. MUG Table 1.1) gives the sigmarms noise levels, which can be scaled for different durations of observation etc (see also 4.2). Note that a sensitivity threshold of sigmarms is usual for sources strong enough to be self-calibrated at a high enough Dec. for good uv coverage, but for faint or low-Dec. sources a higher value should be allowed.
Associated Phase Reference Sources: The default observing mode
is to nod the telescopes between the target source and a nearby phase
calibrator source every few minutes. Phase calibrators will normally
be selected by the MERLIN operations staff from the catalogues listed
in MUG Appendix C. However if you have a special reason to use a
particular calibrator, e.g. in order to combine the data with
phase-referenced VLBI data, or for consistency in monitoring, enter
the source details here - check suitability by consulting MUG
Ch. 3.8.4 and Appendix C. If you specifically do NOT want to perform
phase-referencing enter none.
Correlator Configuration Requirements:
The default continuum mode is 16x1 MHz channels in all 4 Stokes parameters.
Spectral line observers must fill in the essential details. Various modes are possible: the input bandwidth may be reduced in binary steps from 16 MHz to 125 kHz and for every reduction in bandwidth the number of frequency channels can be doubled (from 16 to 1024 channels per polarization per baseline). However, the on-line computer imposes a restriction on the maximum data rate such that NfreqNpolNb/tau < 2304 where Nfreq is the number of frequency channels, Npolis the number of polarisations, Nb is the number of baselines and tau is the integration time in seconds (default 8s). See MUG Ch. 4.4 and Table 4.4 for details.
Note that MERLIN uses the radio definition of velocity and
this is measured with respect to the Local Standard of Rest, i.e.
VLSR/c = (nu -
nuobs)/nu
where nu and
nuobs are the line rest and observing frequencies
respectively. Either specify nu and VLSR in
which case the LSR correction is applied during correlation, or
calculate nuobs and leave VLSR
blank. In the latter case (which must be used if observing in 16 MHz
bandwidth) observations are made at a fixed frequency and corrections
for the Earth's rotation are applied during data processing.
Observing Style: It is only exceptionally necessary for
observers to provide schedules themselves, or to come to JBO during
observations. MERLIN normally
operates with flexible scheduling which is far more efficient
although observers may be present during observations by prior
arrangement. You are urged to come to JBO for at least the first
stages of data processing where you can be assisted by MERLIN support
staff. The initial calibration can only be carried out at JBO. Please
email merlin@jb.man.ac.uk at least 2 weeks before you intend to
visit to check availability of computers, support staff and accommodation.
However for experienced users data can be supplied in FITS format with the initial calibration applied, and in some cases further processing can be performed by the MERLIN staff. If you want this service, you must include a written request along with your proposal.
Help Required: Those planning to visit Jodrell Bank for data reduction
should indicate the level of help likely to be required whilst they reduce
their data.
Special Requirements: List any special requirements for your
MERLIN observations.
Preferred Dates: If you have pressing reasons for requiring scheduling at
certain times, they should be listed in your scientific justification. Enter the
requested date range(s).
The remaining information is required by PATT and is relevant only for UK proposers subject to funding from PPARC and their use of PATT telescopes. It is fairly self-explanatory.
For further information contact:
Secretary of the MERLIN TAC,
Jodrell Bank Observatory,
University of Manchester,
Macclesfield,
Cheshire,
SK11 9DL, UK.
Fax: +44-(0)1477-571618,
E-mail: merlin@jb.man.ac.uk
