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Parkes Narrabri Mopra Tidbinbilla VLBI | |
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All ATNF Telescope Applications must be submitted using OPAL.
Target of Opportunity proposals can be submitted at any time.
For 2010 APRS, the array configurations 6A, 6C, 1.5D, 750C, EW352, H214, H168 and H75 will be offered. Configurations will only be scheduled if there is sufficient proposal demand for them.
The Compact Array Broadband Backend (CABB) hardware was installed in March/April 2009, replacing the original array backend and correlator. CABB is currently in use with a single observing mode that has a bandwidth of 2 GHz and 2048 channels, corresponding to a spectral resolution of 1 MHz, in both of the two IF bands. As the current (2009 OCTS) semester progresses, zoom mode capabilities will be implemented and commissioned, and additional observing modes for CABB will become progressively available.
At the present time, three CABB modes are expected to be, or become, available during 2010 APRS:
In the 12, 7 and 3-mm bands, two frequency bands may be selected. Both band centres must be either greater than 41 GHz, or both less than 39 GHz. The full 8-GHz frequency coverage is possible for these ranges. Observing will be possible with the standard 12-mm (16-25 GHz) and 7-mm (30-50 GHz) systems on all six antennas, and 3-mm systems (83.5-106 GHz) on five antennas. In the 6 and 3-cm bands the existing front-ends allow a 2 GHz bandwidth to be used, with 4.5 to 6.5 GHz and 8.0 to 10.0 GHz being the nominal ranges. Simultaneous 6/3cm observing is possible. Simultaneous observing at 20/13cm is not possible.
Once these CABB modes have been implemented, two of the three observing modes can be selected simultaneously, corresponding to two independent radio frequencies. This allows for a wide range of possible configurations. For example, it will be possible to observe simultaneously in the 3 and 6 cm bands, using CFB 1M–0.5k for the 3-cm band and CFB 16M–8k for the 6-cm band (or vice-versa). Another option would be to select the same central frequency for both bands with a total of eight zoom modes within the same 2-GHz bandwidth.
Ultimately CABB will have up to 16 zooms per IF. Some progress toward increasing the number of zoom bands from 4 to 16 may be made during the semester. However, the timescale is uncertain. For a full description of the available modes and the latest information on CABB upgrades, please check the CABB web page.
In November 2009 a prototype for the new 20/13cm receiver was installed on CA03. This provides an instantaneous frequency coverage of 1.1 to 3.0 GHz, and an improved sensitivity over the existing, separate, 20cm and 13cm receivers. During the 2010 APRS semester it is expected that additional 20/13cm receivers will be removed from antennas and modified with installation of the new receiver. This may result in periods when the array has only five antennas functioning at 20/13cm, and during these periods 20/13cm observing will not be scheduled, unless proposals specifically state that their scientific goals can be met with observations during such periods.
Proposers are reminded that the primary flux density calibrator at 3 mm is Uranus, which for 2010 APRS will be at a R.A. of 0h0m and declination of -0d30m. Proposals for 3-mm observations that require accurate flux calibration should request time for observations of Uranus (if the array configuration allows). For 7-mm observations with CABB, it appears that 1934-638 is sufficiently strong to be used as a primary flux density calibrator. However, the flux scale of 1934-638 at frequencies above ~ 25 GHz still requires full characterisation and it is advisable to also observe Uranus at 7 mm in array configurations for which the planet is not resolved out. Proposers requiring their own observations of Uranus (at special frequencies, or at a time when their main target has set, for example), should make this clear in the observations table and justification of their proposal.
For secondary calibration at 3 and 7-mm, Observatory staff will calibrate a number of bright AGN, spread over the full range of R.A., against Uranus at the standard continuum observing frequencies throughout the semester.
During the latter half of the 2009 OCTS, the array will be outfitted with Water Vapour Radiometers (WVRs) provided by UNSW. Experience with two prototype WVRs in the early 2000s indicates that these units will, in some conditions, allow corrections to the measured phases on each baseline to be made, improving phase stability and, hence, sensitivity. Commissioning of the WVRs will take place in the first half of next year, and it is expected that there will be an opportunity for interested mm-wavelength observers to trial the use of this capability as the 2010 APRS semester progresses.
For further information please contact the Head of Science Operations, Phil Edwards (Philip.Edwards[at]csiro.au).
In 2010 APRS the 70-m and 34-m antennas at Tidbinbilla will be available for single-dish use. Time is allocated after scheduled NASA tracking commitments, so submitted proposals remain in the pool for up to one year and are observed in a service mode when scheduling permits. Successful proposals require the submission of a source list with accurate target and calibrator positions.
The 70-m antenna is equipped with 1.6, 2.3, 8.4 and 22 GHz receivers. The pointing performance is adequate for observations at the three lowest frequencies. The 22 GHz system is the most sensitive in the southern hemisphere, covering 18.0 to 26.5 GHz at a system temperature of 60 Jy.
In addition the 34-m beam-waveguide at Tidbinbilla will be available for single-dish use at 32 GHz.
Tidbinbilla is equipped with an ATNF multibeam correlator block capable of two polarisation products, with up to 2048 channels, each with 32 or 64 MHz bandwidth, or up to 4 polarisation products with a total of 8192 channels (e.g., 2 x 4096 channels) and bandwidth of 16 MHz or less.
Details of available observing time, frequency coverage, correlator capabilities and other technical information are available from the Tidbinbilla Information web page. (See also the NASA Deep Space Communication Complex web pages ). An on-line sensitivity calculator is available to assist in proposal preparation.
Jimi Green is the ATNF Friend for Tidbinbilla. If you have any comments or questions regarding single-dish observations at Tidbinbilla, please email James.Green [at] atnf.csiro.au
All currently-supported receiver systems, including the 20-cm multibeam and the seven-beam methanol receiver, are available for the 2010 APRS Semester. It is currently expected that the AT-multiband 6-cm receiver will be fully operational again by the 2010 APRS semester.
A K-band receiver covering 16-26 GHz has been available since September 2008. This receiver has wider frequency coverage than the older K-band receiver and has a ~3-fold advantage in Tsys at 22 GHz over the older package. The receiver can be installed with either of two feeds: a narrow-band feed and quarter-wave plate providing dual orthogonal circular polarization over the frequency range 21.0 to 22.3GHz, or the standard feed providing dual orthogonal linear polarization over the 16 to 26 GHz range. The package has two independent conversion systems allowing simultaneous operation at any two arbitrarily-spaced frequencies within the band limits.
The MARS receiver is capable of being used over an extended band of 8.0 to 8.9 GHz, on a limited basis, by special request. Observers interested in using this extended band should contact Phil Edwards.
Details of available receivers and other technical information are available in the Parkes Radio Telescope Users Guide.
The digital filterbank DFB3 has recently been supplemented by DFB4, a similar instrument but containing only one CABB processor and one digitiser rather than the dual digitisers and processors in DFB3. Both systems are now fully operational. DFB4 has similar characteristics and performance to DFB3 for normal pulsar timing, except for short period pulsars, where DFB3 has an advantage owing to the extra processing power. DFB3 can be used in time-binning mode for time resolutions down to 0.25 seconds with up to 8192 (single IF) or 4096 (dual IF) channels. Both spectral line and continuum observers are encouraged to use the digital filter banks (DFB3/DFB4) for their observations.
The pulsar baseband recorder CPSR2 (Caltech-Parkes-Swinburne Recorder Mark 2) is expected to be phased out in 2010, once the ATNF Parkes Swinburne Recorder (APSR) baseband system is fully commissioned and has been run in parallel with CPSR2 for a six-month overlap period.
APSR uses DFB3 as a front-end to sample a single pair of inputs (two polarizations, single frequency) of up to 1 GHz bandwidth and record the baseband data at an aggregate rate of up to 8 Gbit/s. It is expected that APSR will be fully commissioned and available for 2010 APRS.
A new 13-beam digital filterbank, the Berkeley-Parkes-Swinburne Recorder (BPSR) will be available during 2010 APRS on a shared-risk basis. The system allows higher time resolution, and much greater spectral resolution than the analogue 13-beam filterbanks (400kHz versus 3MHz) and also allows more bits of precision in sampling. Intending proposers without prior experience of this system are advised to contact Ettore Carretti before submission.
All advertised configurations with the Multibeam correlator are available, including those hybrd configurations which use part of the Wideband Correlator (WBC). The standalone WBC and also the older filterbanks DFB1 and DFB2 are now effectively decommissioned. The Multibeam correlator supports 4 and 8 MHz bandwidths on all 13 beams, with up to 2048 spectral channels per product.
The digital filterbanks DFB3 and DFB4 can also be used as spectrometers in both simple and time-binning modes. DFB3 for example can be used as a two-frequency, dual-polarization spectrometer with 8192 spectral channels over two 256-MHz bandwidth bands. Proposers are encouraged to contact Ettore Carretti to discuss their requirements before submission.
For further information on all Parkes facilities please refer to the Parkes Radio Telescope Users Guide, or contact Phil Edwards (Philip.Edwards[at]csiro.au)
In 2010 APRS, the Mopra radio telescope is available for observations in the 20, 13, 6, 3cm, 12-mm (16-27 GHz), 7mm (30-50 GHz) and 3-mm (76-117 GHz) bands. Observing at 3-mm usually commences in late April and ends in late October. In the 7mm band, the conversion chain imposes limitations in the tuning ranges: The centre of the 8-GHz MOPS band must lie between 34 and 38 GHz or 44 and 46 GHz. This covers the full 30 to 50 GHz band, but the gap between 38 to 44 GHz cannot be processed as one frequency setting. Requests for 20-cm to 3-cm observations should make a very strong case for why Mopra is the preferred facility.
The MOPS spectrometer offers an instantaneous bandwidth of 8 GHz, divided into four overlapping 2.2 GHz sub-bands. In wide-band mode, 8192 frequency channels are available in each 2.2 GHz band (in both polarizations). In narrow-band mode, up to four 138 MHz wide "zoom" bands are available within in 2.2 GHz band, with 4096 frequency channels in each zoom band.
Observing with the Mopra telescope is conducted from Narrabri. However, remote observing requests from competent observers, who have taken Mopra observations from Narrabri within the last year, are permitted.
Large proposals (e.g., large-sky maps, surveys, large samples) for the use of Mopra are encouraged. It is expected that large proposals in particular will be able to make increased use of the Mopra remote observing facilities at Marsfield and/or from home institutions. Observers planning large proposals are recommended to contact Phil Edwards before submitting their proposal to discuss any other special requirements (e.g., related to data storage or processing) of their project.
Pointed observations requiring long integration times to detect weak line emission (e.g., for extragalactic targets) will be affected by single-dish spectral baseline ripple. Trials have been made involving the continuous movement of the sub-reflector to counter this, with encouraging results. Please contact Balt Indermuehle (Balt.Indermuehle [at] csiro.au) for more details.
Recent changes to MOPS have enabled "fast mapping" observations to be made, with a correlator cycle time of 256-milliseconds rather than the standard 2-seconds, for a reduced number of MOPS zoom bands (no more than 4 is recommended). Trials of this new mode are continuing, but it is expected that this mode will be available on a shared-risk basis for observers during 2010 APRS.For assistance with proposal preparation please consult the Mopra web pages, or contact Phil Edwards.
The Long Baseline Array (LBA) utilises all the ATNF telescopes, Tidbinbilla, and the Hobart and Ceduna antennas operated by the University of Tasmania to observe in VLBI mode. Other telescopes may be also requested for special observations. Note that the Tidbinbilla 70-m antenna may be available only for short periods. Specific system availability may be dependent on availability at individual antennas. For details consult the ATNF VLBI webpages. Potential first-time users should note that the Novices Guide available from the VLBI webpage has recently been updated.
For assistance with planning proposals and observations please consult the VLBI sensitivity calculator.
Recent developments at the LBA have resulted in new capabilities, briefly outlined below:
The disk-based system is very flexible and can be used to obtain high sensitivity and/or ultra-high spectral resolution observations, useful for a number of novel scientific studies. These facilities improve the compatibility between Australian VLBI antennas and international antennas using other disk-based recording systems such as the Mark5 and K5 systems. Extensive user support will be provided, including assistance with proposal preparation, scheduling, observing and data reduction.
The disk-based system may be limited by the availability of hard disks and observations at the highest data rates will require a compelling scientific justification and very high proposal rating. Potential users must consult the Upgraded VLBI National Facilities capabilities .
Real-time eVLBI capabilities to the Hobart antenna are also available. Currently the data rates to Hobart are limited to 128 Mbps or less due to limited network speeds to Tasmania. Users are invited to propose shared-risk observations suitable for such real-time observations that include Hobart.
For more information contact Dr Tasso Tzioumis (Tasso.Tzioumis[at]csiro.au) or Prof. Steven Tingay (s.tingay[at]ivec.org).