ASKAP’s primary mission is to conduct an ongoing set of large-scale Survey Science Projects (SSPs) with high efficiency. However, a small amount of time (up to 150 hours) is made available per semester to Guest Science Projects (GSPs) that can slot in around the SSPs without impacting their operational efficiency. We use an automated adaptive operations model that requires Guest Science Projects (GSPs) to be fully specified in advance. The observing mode and operational constraints specified as part of a GSP will determine the technical feasibility of the proposal. This means that users should carefully consider the likely impact of their request on the telescope’s existing commitments. GSPs should be as flexible as possible, allowing them to be used dynamically to fill gaps between survey observations. Requesting, for example, narrow scheduling windows or long sequences of repeated observations with specific cadence will downgrade the technical feasibility of the GSP and may lead to it not being scheduled.

Data will be calibrated, processed, and archived according to a pre-defined processing template (see below for examples). Users should attempt to minimise the number of data products archived and the overall data rate. This involves keeping only the data products strictly necessary for the science goals. Projects involving multiple short observations need to be conscious of the total amount of data generated across all observations, not just one. CASDA’s storage allocation is primarily intended for the SSPs, so requesting multiple terabytes of data or high data rates will reduce the technical feasibility of a GSP and may lead to it not being scheduled.

Proposers will be notified when their data products are available in the science data archive CASDA, which is accessible through the Data Access Portal. Recipients of data will be required to submit a short validation report after being granted access and before the data can be released and used for science.

Examples of well-tested observing and processing strategies include continuum observations with 10” resolution at a sky frequency of 944 MHz, bandwidth of 288 MHz. and a typical integration time of 10 hours (EMU-mode), or spectral line observations with 18.5 kHz spectral channels and 30” resolution at a sky frequency of 1368 MHz with 144 MHz of bandwidth and a typical integration time of 8 hours (WALLABY-mode). Various combinations of these modes are possible and the ASKAP Operations team will work with guest science teams to define a specific configuration for each project. ASKAP generates Stokes I data products by default but can produce full polarisation products if needed. Further examples of well-tested modes include the following:  

• POSSUM mode extends the EMU or WALLABY mode by adding full Stokes parameters, additionally with a “continuum cube” containing 1 MHz frequency resolution for spectral index or rotation measure studies. 
• VAST mode differs from EMU continuum mode by providing Stokes I & V data and is optimised for snapshot observations of 12 minutes, for covering wide areas or searching for transients with multiple epoch-based observations of the same field(s). It uses a slightly different sky frequency of 888 MHz. 
• FLASH mode is a form of spectral line observing designed for absorption-line science, with some adjustments to the beamforming to ensure broad lines are well characterised, and a sky frequency of 856 MHz optimised for high-redshift HI. 

We are currently working with the CRAFT team to integrate a new high-time-resolution visibility system and offer it as a National Facility observing mode. The current implementation allows for shared-risk use and temporary non-archival data storage, but with minimal visibility of the status of the CRACO instrument, making the mode high-risk compared with other ASKAP modes. Users who accept this risk and would be willing to trial the new mode can indicate their desire for CRACO data products. These will take the form of Stokes I visibilities with 110ms time resolution, 288×1 MHz channels in UVFITS format, recorded for up to 2 hours at a time, for a total of less than 10 hours per month. Users can also elect to receive a list of single pulse search candidates in a csv file. More information on data access procedures will be made available to successful proposers and will minimally require that the GSP team has access to the Pawsey Acacia storage system. 

ASKAP’s continuum sensitivity yields an RMS noise level of about 200 μJy/beam at 900 MHz in 15 minutes of observing time. With longer 10-hour observations the RMS noise level drops to about 20 μJy/beam.

ASKAP GSPs should address how ASKAP’s unique capabilities (e.g. wide field of view) benefit the proposed science outcomes. GSPs should avoid direct competition with the existing Survey Science Projects and describe how their goals differ from existing plans. 

ASKAP can be included in Large and Long-term projects, within the constraints of the total time available for allocation via GSPs (currently, 150 hours per semester). Users may request all this time for a single project if they have a compelling science case and the number of hours may be increased up to 300 in future if we become oversubscribed with good quality proposals.

Detailed system information can be found in the following locations: 

1. Australian square kilometre array pathfinder 1: system description. Hotan et al.  https://ui.adsabs.harvard.edu/abs/2021PASA…38….9H/abstract 
2. The ASKAP Guest Science user guide and observation guide via this resource kit (in development): https://research.csiro.au/askap-guide

Please use this form to request Target of Opportunity time for ASKAP if you have a time-critical request for a small amount of observing time that cannot wait for the next call for proposals. 

Being a survey telescope, ASKAP generates a rich amount of data for potential follow-up by other telescopes in radio and other wavelengths. A few other observatories have expressed an interest in shadowing ASKAP observations in real-time to maximise the chances of simultaneously detecting any interesting event. Although we do not yet officially support such activities with a metadata service, ASKAP’s current pointing direction is visible on public web pages and other observatories may choose to shadow your observations without our knowledge. As with source coordinates that may be sensitive in nature, ASKAP’s wide field of view affords the opportunity to displace the field centre and observe your object of interest off-axis if reasonable justification is provided.