Science status of the Australian Square Kilometre Array Pathfinder (ASKAP)

Simon JohnstonASKAP Project Scientist14 May 2009ATUC Open Session

High-dynamic range, wide field-of-view imagingNumber of dishes 36 Dish diameter 12 mMax baseline 6km (30 dishes inside 2 km)Resolution 10 Sensitivity 65 m2/KSpeed 1.3x105 m4/K2.deg2

Observing frequency 700 – 1800 MHzField of View 30 deg2

Processed Bandwidth 300 MHzChannels 16384Integration time 5 secondsFocal Plane Phased Array 192 elements

+ Infrastructure for new SKA-ready observatory Murchison Radio Observatory (MRO)

ASKAP Design Goals

High-dynamic range, wide field-of-view imagingNumber of dishes 36 Dish diameter 12 mMax baseline 6km (30 dishes inside 2 km)Resolution 10 Sensitivity 65 m2/KSpeed 1.3x105 m4/K2.deg2

Observing frequency 700 – 1800 MHzField of View 30 deg2

Processed Bandwidth 300 MHzChannels 16384Integration time 5 secondsFocal Plane Phased Array 192 elements

+ Infrastructure for new SKA-ready observatory Murchison Radio Observatory (MRO)

ASKAP Design Goals

Gupta et al. 2008, ATNF ASKAP Memo 21

36 Antenna Array Configuration

Spectral Line: Inner 30 dishes only, resolution of 30 arcsec at 1.4 GHz

Highest resolution is 10 arcsec at 1.4 GHz, continuum only

Natural weighting gives 20 arcsec beam at 1.4 GHz

ASKAP Science - Papers

Johnston et al. 2007, PASA 24, 174-188

Johnston et al. 2008, Exp Ast 22, 151-273

ASKAP is a fast survey telescope and will spend 75% of its time doing large-scale surveys

• ASKAP telescope time will be assigned to astronomical research projects subject only to scientific merit and to technical and operational feasibility

 • No a priori guaranteed science time will be allocated to particular countries, institutions,

nor to any individuals currently on existing (2008) working groups • ASKAP will not be a user-operated telescope; generally users interact with the Science

Archive

• ASKAP data and data products will be released publicly through the ASKAP Science Archive on a timescale designed to maximise scientific utilization and impact

 • The ASKAP Science Archive will be available to astronomers from all over the world • Simultaneous observing programs will be encouraged where possible;

• In general there will be three classes of observing time allocated on ASKAP; Survey Science Projects, Guest Science Projects and Target of Opportunity over-rides.

• Time Assignment will be made by the ATNF Director, subject to advice received from the appropriate Times Assignment / Survey Review committees 

ASKAP - Operational Principles

• What are they?• Large (>1500hrs) and coherent science projects that utilise ASKAP’s wide field-of-view and fast

survey speed to enable major science outcomes early in its lifetime.

• Who has access to the data?• All data and data products produced by the Survey Science Projects (subject to storage capacity) will

be made publicly available to the ASKAP Science Archive, on a timescale determined by operational issues (e.g. quality control) and not proprietorial interests.

 

• How much time will they take?• During the first five years of science operations, up to 75% of observing time will be available.

• How will they be chosen?• There will be a proposal process and surveys will be selected by competitive peer review. • Membership and leadership of Survey Teams will be open access but should include at least one

ATNF affiliated person.• Survey Teams must provide clear statements on data release• Project ranking will take into account the intention of teams to provide value added data products into

the Archive and the timeline for so doing.

Survey Science Projects

• For the first five years of routine science operations with ASKAP, up to 25% of observing time will be available for Guest Science Programs.

• TAC process similar to current ATNF facilities.

• Default is no proprietary period, but reasonable grounds will allow 12 months

Guest Science Projects

• ToO events are unexpected astronomical events of extraordinary scientific interest for which observations on a short time scale are justified

• ToO is allocated at the discretion of the ATNF Director and may displace other scheduled observations at short notice.

• No proprietary period for ToO data or data products

Target of Opportunity

ASKAP Current Status

• Expression of Interest for survey science projects• Open access, international call, closed Dec 15, 2008

• 38 received, 354 authors, 25 years telescope time

Expressions of Interest

Science areas:1.Extragalactic spectral line2.Continuum3.Polarization4.Galactic spectral line5.Slow transients6.Fast transients7.Pulsars8.VLBI

ASKAP Current Status

• Expression of Interest for survey science projects• Open access, international call, closed Dec 15, 2008

• 38 received, 354 authors, 25 years telescope time

• Review Committee• Dickey (UTas), Feain (ATNF), Freeman (ANU), Johnston

(ATNF), Lazio (SKA), Morganti (ASTRON), Stairs (UBC), Tingay (Curtin)

• 27 invites to submit Survey Science Proposals• Due date June 15, 2009

ASKAP Current Status

• 27 invites to submit Survey Science Proposals• Due date June 15, 2009

• 15-20 proposals expected (following mergers)

• Review Committee• Lazio (SKA; Chair), Booth (ZA), Condon (NRAO), Diamond

(Manchester), Ekers (ATNF), Jarrett (CalTech), Osterloo (ASTRON), Schmidt (ANU)

• Facilitated by SJ & IF

• Proposal (~20 pages) evaluation based on • Science (50%)

• Design Study (25%)

• Community Benefit (15%)

• Team Management (10%)

• Technical and functional requirements

• Decision on ranking on 1 August

ASKAP – Next steps

• Successful proposals move to design study• Aug 2009 – End 2011

• Science simulations, software development, collaborations

• ATNF support for the top-ranked teams

• First antenna December 2009• 6 element test array operational mid 2010

• Commissioning data for teams to play with

• ASKAP operational early 2013• First 5 years scheduled

• Capabilities come on-line as time progresses

• Never too late to join a Survey Science Team and participate in ASKAP science

ASKAP - Archive Facility

• Science archive likely to be located in Perth• Typical data volumes are:

• Continuum visibilities – 500 Tbyte/year

• Continuum images – 70 Tbyte/year

• Spectral cubes – 2200 Tbyte/year

• Transient images – 4200 Tbyte/year

• Spectral visibilities not archived

• User Access• Open access, 24/7 availability, helpdesk etc

• Search / examine / extract data, images etc via VO tools

• Export large volumes of data to outside world

• User software support

• No re-processing of visibilities envisaged

• Status: Currently under negociation with ICARA

Contact UsPhone: 1300 363 400 or +61 3 9545 2176

Email: enquiries@csiro.au Web: www.csiro.au

Thank you

Australia Telescope National FacilitySimon JohnstonCSIRO Science LeaderASKAP Project Scientist

Phone: 02 9372 4573Email: Simon.Johnston@csiro.auWeb: www.csiro.au/atnf/

Cape Town, Feb 2009