ATNF Telescopes Current Status for 2013 OCT
Advice to the community on the Future of ATNF Operations was provided in December 2011. A number of changes are being made for ATNF Operations and these will have an impact on the facilities provided for the 2013 OCT semester. Please read the information given below carefully.
For 2013 OCTS, ATNF proposals will be accepted for the:
The deadline for all proposals is 07:00 UT (17:00 Sydney local time), Monday, 17 June 2013.It is expected ATNF proposals will next be accepted for Mopra for the 2014APR semester.
Target of Opportunity proposals can be submitted at any time.
Large Projects are projects that require a total of more than 400 hours of observing time. Please read the Large Projects web page in addition to the information on this page.
New users are advised to read the information on the ATNF Scientific Support of Facilities. This web page explains the different levels of support provided to visitors and observers.
For further information on all facilities please contact the Head of Science Operations, Phil Edwards (Philip.Edwards[@]csiro.au).
For 2013 OCT, the array configurations 6A, 6D, 1.5B, 1.5C, 750A, 750B, EW352, EW367 and H168 will be offered. Configurations will only be scheduled if there is sufficient proposal demand for them. The 2013 APR semester ends in H214 array, and the ATCA may remain in this array for the first weeks of the 2013 OCT semester.
The Compact Array Broadband Backend (CABB) modes that will be available from the beginning of the 2013 OCT semester are:
- CFB 1M: A bandwidth of 2 GHz with 2048 x 1-MHz channels in each IF band, but no "zoom" bands.
- CFB 1M-0.5k: A bandwidth of 2 GHz with 2048 x 1-MHz channels and (optionally) a fine resolution of 0.5 kHz in up to 16 "zoom" bands (each with 2048 channels across 1 MHz) in each IF band.
- CFB 64M-32k: A bandwidth of 2 GHz with 32 x 64-MHz channels and (optionally) a fine resolution of 32 kHz in up to 16 zoom bands (each with 2048 channels across 64 MHz) in each IF Band.
- CFB 1M/64M: ( Description corrected 20-may-2013) CFB 1M/64M: A "hybrid" mode with 2048 x 1-MHz (but no zooms) in one IF, and 32 x 64-MHz channels with (optionally) up to 16 zoom bands with 2048 channels across each in the other IF.
The CFB 4M-2k and CFB-16M-8k CABB modes are not expected to be available in 2013 OCT.
For the latest information on CABB, please check the CABB web page.
High time resolution observations
For high time resolution observations, a time resolution of order 10 milliseconds is possible, though with a reduced number of channels across each 2 GHz band (achieved by averaging over 1 MHz channels). Pulsar binning modes are available, with the minimum time bin being around 110 micro-seconds, allowing, for example, 32 phase bins for a 3.5 milli-second pulsar.
Compact Array receivers and frequency ranges
The 16-cm band receivers, installed in 2010, provide an instantaneous frequency coverage from 1.1 to 3.1 GHz (although the usable bandwidth is reduced by RFI). The 16-cm band receivers have an improved sensitivity over the original 20- and 13-cm receivers, and include new ortho-mode-transducers, significantly improving the polarisation performance toward the top end of the band.
All six antennas have now been outfitted with 4-cm band receivers, covering the 4 to 10.8 GHz band. The new receivers provide significantly improved system temperatures over the original 6- and 3-cm receivers.
The recently enhanced ATCA sensitivity calculator provides a means of determining the sensitivity characteristics of observations.
In the 15-mm (16 - 25 GHz), 7-mm ( 30 - 50 GHz) and 3-mm (83.5 - 106 GHz) bands, two 2GHz-wide intermediate frequency bands may be selected within an 8 GHz bandwidth. In the 7-mm band, both band centres must be either greater than 41 GHz (the point at which the conversion changes from lower side-band to upper side-band) or both less than 41 GHz. Observing is possible with the standard 15-mm and 7-mm systems on all six antennas, and 3-mm systems (83.5-106 GHz) on five antennas.
Observing at 3 mm generally starts in May and ends in mid-October. Proposers are reminded that the primary flux density calibrator at 3 mm is Uranus, which in December 2013 will be near a R.A. of 0h30m and declination of +2d45m. 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, 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. 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.
The array has been outfitted with Water Vapour Radiometers (WVRs) provided by the University of New South Wales. Experience to date indicates that these units will, in some conditions, allow corrections to the measured phases on longer baselines to be made, improving phase stability and sensitivity. Interested mm-wavelength observers will be able to use of this capability during 2013 OCT. Details of the system are available in this preprint.
- Latest information on the Compact Array Broadband Backend (CABB)
- Australia Telescope Compact Array Users Guide The User Guide describes how to apply for observing time, make a schedule file, and carry out observations with the ATCA.
- Target of Opportunity and NAPA (Non-A-Priori-Assignable) proposals
Over the last two years considerable effort has been made towards the upgrading and development of the Parkes telescope for future remote observing. The upgrades include the installation of a RF switching matrix, the replacement of the manual control panel (MCP), improvements to the backup power supplies, and, in December 2012, installation of a Telescope Protection System (TPS). Remote observing with the Parkes telescope from the Marsfield Science Operations Centre (SOC) commenced in December 2012 -- still with the requirement of someone in the tower at Parkes. Remote observing from the SOC (without the requirement for someone in the tower at Parkes) is expected to be the default mode of observing by the start of the 2013 OCT semester. Observing from Parkes will still be permitted for complex or non-standard observations, or in other circumstances where this is the more sensible option. Observers who have successfully observed from the SOC will be permitted to carry out subsequent Parkes observations from other remote locations: all observers must observe at least once from the SOC in order to become a qualified Parkes remote observer.
Reductions in the Parkes Operating budget will necessarily result in a decrease in the observing support able to be provided. It is expected that proposal teams with experienced Parkes observers will become more self-sufficient, with a member of each team being designated the Project Expert and being the first point of contact (most often remotely) for questions relating to the observations after work hours. Inexperienced teams are encouraged to seek experienced collaborators: if this is not possible, the teams should be prepared to arrive several days before their observations commence in order for observer training to be completed during work hours so that a member of the team is qualified for the Project Expert role. All Parkes proposal teams are asked to nominate on the cover sheets of their proposal the member(s) in their team who will be (or will be trained to be) the Project Expert and who will be the first point of contact after hours. (However, it is recognised that the availability of team members can not be known until the observing schedule has been released.) Local Parkes staff will continue to provide the first point of contact for matters relating to safety of on-site personnel, the telescope, and equipment.
As has been previously outlined, reduced resources at Parkes will result in a more limited suite of instruments available to observers. A reduction in the number of receiver changes per semester will further constrain the number of receivers able to be deployed in a given semester. Projects requiring multiple epochs within a semester (e.g., pulsar timing) should clearly justify their requested observing cadence. Limitations on the number of Parkes receiver changes may constrain the scheduling of such projects.
It is anticipated that the 20-cm multi-beam, 10/50, and H-OH receivers will be available in the 2013 OCT semester, with the availability of other receivers driven by proposal pressure. Highly graded proposals requesting a receiver that is not installed in the focus cabin in 2013 OCT will be reconsidered for scheduling in the 2014 APR semester with the same grade, without the need to resubmit the proposal. Teams will be notified after the scheduling process is complete, if this applies to their proposal. For projects requiring frequencies above 3.6 GHz, please keep in mind the possibility of an extended, uncertain timeframe for scheduling of observations. In particular, this timeframe may be unreasonable for student projects and users should consider whether other ATNF facilities could be used instead.
Details of available receivers and other technical information are available in the Parkes Radio Telescope Users Guide. The seven-beam methanol receiver is not available: the single pixel 6.7-GHz receiver is still available. The H-OH receiver was outfitted in 2011 with a new feed offering improved performance across a wider frequency range, 1.2 to 1.8 GHz (and so providing better sensitivity at the 21 cm hydrogen line than the old receiver).
The 13-mm (K-band) receiver (available since 2008) covers a frequency range of 16 to 26 GHz. The receiver can be installed with either of two feeds: a narrow-band feed and quarter-wave plate providing dual orthogonal circular polarisation over the frequency range 21.0 to 22.3 GHz, or the standard feed providing dual orthogonal linear polarisation over the 16 to 26 GHz range. The package has two independent conversion systems, which currently allows simultaneous operation at any two frequencies within the 22-GHz band. (Note, however, that it is not possible to perform dual-IF observations in frequency-switching mode -- the options in this case are to use a single IF and use frequency-switching for each line separately, or use position-switching with dual IFs.)
Pulsar Digital Filterbanks
The digital filterbanks DFB3 and DFB4 are available. DFB4 is a similar instrument to DFB3, but contains only one CABB processor and one digitiser rather than the dual digitisers and processors in DFB3. 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 for their observations.
The ATNF Parkes Swinburne Recorder (APSR) baseband system has replaced and extended the functionality previously offered by CPSR2. APSR uses DFB3 as a front-end to sample a single pair of inputs (two polarisations, single frequency) of up to 1 GHz bandwidth and record the baseband data at an aggregate rate of up to 8 Gbit/s.
The 13-beam digital filterbank, the Berkeley-Parkes-Swinburne Recorder (BPSR) has been replaced by the HIPSR backend, which will be available during 2013 OCT on a shared-risk basis. The system allows higher time resolution, and much greater spectral resolution than the analog filterbanks provided (400 kHz versus 3 MHz) and also allows more bits of precision in sampling. In single beam mode, Analog Filter Bank functionality has been replaced by DFB3 and DFB4.
Spectral Line Correlators
All advertised multibeam configurations with the Multibeam correlator are available, including those hybrid configurations which use part of the Wideband Correlator (WBC). The Multibeam correlator supports 4, 8, and 64 MHz bandwidths on all 13 beams, with up to 2048 spectral channels per product. The Multibeam correlator is expected to be decommissioned when its functionality is replaced by HIPSR. HIPSR supports a bandwidth of 400 MHz bandwidths on all 13 beams, with 8192 spectral channels per product, but does not yet support narrower bandwidths. 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-polarisation spectrometer with 8192 spectral channels over two bands with bandwidths between 8 and 1024 MHz.
Continuum and Polarisation Backends
The digital filterbanks DFB3 and DFB4 can also be used as continuum backends both for total intensity and polarisation observations offering bandwidths up to 1024 MHz and full Stokes products. The number of available frequency channels (512 to 8192) allows spectral behaviour analysis and RFI flagging. In combination with either circular or linear feeds they can be used for Stokes Q & U or Stokes V observations respectively. A time resolution down to 0.25s is achievable in time-binning mode allowing fast scanning options.
Proposers intending to start a new project are advised to contact Ettore.Carretti [at] csiro.au to discuss their requirements and availability of configurations before proposal submission. For further information on all Parkes facilities please refer to the Parkes Radio Telescope Users Guide.
In the 2013 OCT semester the 70-m and 34-m antennas at Tidbinbilla will have limited availability for single-dish use. Tidbinbilla proposals remain active for one year. All observations are taken 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 and the 34-m antenna is equipped with 2.3, 8.4 and 32 GHz receivers. The pointing performance of the 70-m is adequate for observations at the three lowest frequencies (1.6, 2.3 and 8.4 GHz) with no additional calibration, but observations at 22-GHz require a small overhead (~10% of observing time) for determining pointing corrections using bright AGN near the target of interest. It should be noted that the 22 GHz system is the most sensitive in the southern hemisphere, covering 18.0 to 26.5 GHz with a system temperature of 60 Jy. The 8.4 GHz system (also available on the 34-m antenna) is well-suited for radio recombination line observations.
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.
Full 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. These pages also include details of current projects.
There are two projects underway at Tidbinbilla to enhance the 70-m 22-GHz observational capability:
- A new 4-channel K-band receiver and down-converter system has recently been installed on the 70m. This new system supports two simultaneous beams per polarisation (four beams in total) across the current frequency coverage of 21 GHz to 25 GHz. It is planned that this range will be extended to 17-27 GHz during phase two of the upgrade.
- A project is underway to establish on-the-fly mapping for spectral line observations. Development is ongoing, with testing of the mode expected in the coming year. In the interim a pipeline has been set up to utilize python scripted ASAP/gridzilla/miriad to generate maps from spectral line fits of grids of pointed observations. This has been tested and demonstrated to work with observations of ammonia lines at 23 GHz and radio recombination lines at 8.3 GHz.
For the latest information of availability please refer to the Tidbinbilla website, or contact the ATNF Friend for Tidbinbilla, Jimi Green (James.Green [at] atnf.csiro.au).
For 2013 OCT semester, the Long Baseline Array (LBA) will use the Compact Array and Parkes radio telescope, together with the Hobart and Ceduna antennas operated by the University of Tasmania. In addition, the Warkworth 12-m telescope, operated by the Auckland University of Technology, is available at 20, 13 and 3cm. A limited amount of time may be available with the Tidbinbilla 70-m antenna or one of the 34-m antennas. A single ASKAP antenna with a single pixel feed at 20cm or 3cm is offered on a best-efforts basis for projects where its use will significantly add to the likely science outcomes. The AuScope Yarragadee and Katherine 12-m antennas may also be available at 13cm or 3cm subject to their availability.
It is now possible to operate the ATCA in hybrid mode where one frequency chain is setup in VLBI mode and the other frequency chain in ATCA continuum mode (2 GHz bandwidth at 1 MHz resolution). Proposers should explicitly request this mode and provide additional scientific justification.
Under its new operating model, the Mopra telescope will continue to be available for use with the Long Baseline Array. However, there is likely to be some restrictions on Parkes receivers due to the limited number of receiver changes at Parkes in this semester. Projects requiring multiple epochs within a semester (e.g., VLBI of variable phenomena) should clearly justify their requested observing cadence. Limitations on the number of Parkes receiver changes may constrain the scheduling of such projects.
Other telescopes may be also requested for special observations. Specific system availability may be dependent on availability at individual antennas. For details consult the ATNF VLBI webpages.
A Novices Guide is available for potential first-time users from the VLBI webpage.
For assistance with planning proposals and observations please consult the VLBI sensitivity calculator. (Note: Link to new version of calculator added 28-may-2013.)
The current capabilities of the LBA are briefly outlined below:
- The disk-based recording system is now used for all recorded VLBI observations and very high data rates (up to 1 Gbps) can be achieved;
- All recorded observations will be correlated with the DiFX software correlator running on the Curtin University of Technology supercomputer. The software correlator is capable of correlating the high data rate observations at high spectral resolution with arbitrary correlator integration times;
- Real-time e-VLBI observations are offered, using the ATNF antennas connected together via high-speed links and the DiFX software correlator running at the ATCA. Data-rates for e-VLBI observations of 1 Gbps from each ATNF antenna are now available. Real-time eVLBI capabilities to the Hobart and Warkworth antennas are also now available at 512 Mbps.
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.
A bit rate of 256 Mbps (2x16MHz bandwidth in 2 polarisations, with 2 bit digitisation and Nyquist sampling) can be sustained at all LBA telescopes and is the standard observing mode. Observations requesting higher bit rates will need to include a clear justification for the requested rate. Potential users must consult the Upgraded VLBI National Facilities capabilities .
For more information contact Dr Tasso Tzioumis (Tasso.Tzioumis [at] csiro.au)
or Prof. Steven Tingay (s.tingay [at] ivec.org).