MeerKAT Commissioning & NRAO in South Africa
Deb Shepherd NRAO & SKA Africa 10 Nov 2010 Radio telescopes around the World:
Very Large Array (VLA), NM Very Long Baseline Array Green Bank Telescope (VLBA) , USA (GBT), WV
Sub-Millimeter Array (SMA), Mauna Kea
Owens Valley Radio Observatory (OVRO) + Berkeley-Illinois-Maryland Array (BIMA) = CARMA, CA http://www.ska.ac.za MeerKAT!
QuickTime™ and a YUV420 codec decompressor are needed to see this picture. MeerKAT & the SKA
3000-4000 antennas
MeerKAT: 64 - 13.5m Offset Gregorian antennas The MeerKAT Team MeerKAT Precursor Array MPA (or KAT-7) Today
2 1 3 4 5 Commissioning Accomplishments To Date
• March 2010 - Regular commissioning activity began, tipping scans, pointing determination, gain curves. • April 2010 - First demonstration single dish image made (Centaurus A) • May 2010 - First demonstration interferometric image (4 antennas, warm receivers) • July 2010 - Holography system built and demonstrated on XDM and KAT antennas 5 & 6. • July 2010 - Noise diode calibration and Tsys determination for antennas 1-4 completed. Preliminary single dish commissioning evaluation complete for antennas 1-4 with warm receivers. • Aug/Sept 2010 - Commissioning paused; RFI measurement campaign • Nov 2010 - First cold feed installed on antenna 5 Tipping Curves • Antennas 1-4: tipping curve, warm receivers
1694-1960 MHz
Tipping curve shape compares well with theoretical predictions, including spillover model provided by EMSS.
AfriStar Pointing Determination • Antennas 1-4: pointing determination, warm receivers
1822 MHz center frequency All sky coverage 1.5’ RMS using all sources 0.76’ RMS using only 6 brightest sources Gain Curves • Antennas 1-4: Gain curve determination, warm receivers 1694-1950 MHz Preliminary gain, aperture efficiency, Tsys and SFED as a function of elevation. (Noise Diode calibration not done at this point.) Centaurus A A galaxy seen at multiple wavelengths
Visible
Infrared
X-ray Centaurus A - The First MPA “Single Dish” Image May 2010 Rhodes/HartRAO Antenna 1 1836 MHz 2326 MHz survey
Moon
(Jonas, Baart, Nicolson 1998, MNRAS 297) Centaurus A - The First MPA-2 Fringes Centaurus A
Centaurus A
Centaurus A (+ coarse delay)
MPA- 4 - The First Interferometric Image
Moon Centaurus A - Image comparison
With only 4 dishes, the image fidelity is not great but the general source structure is what we expect Holography Antennas 5 & 6 first results (Collaboration with Mike Kestevan, Australia)
Peak-to-peak: -12 to +7mm Measurements with 3 geostationary satellites at different elevations (EUTELSAT W2M, INTELSAT IS10 and INTELSAT IS1R). No discernable trend of surface figure with elevation.
First Fringes: Cold Feed Installation Cold Feed Antenna 5 Installation Oct 2010 PKS 0521-36
Antenna 5 A4 - warm A5 - cold performance Ant 5 performance demonstrated 2 Nov 2010
A4 - warm A5 - cold
PKS 0408-65 MeerKAT & SKA scientific potential is clear The world is watching South Africa to see if there are adequate resources, technical expertise & human capital to go
From MPA (7): To MeerKAT (80): To SKA (1000’s):
How does NRAO fit into this commissioning, development and discovery in the Southern Hemisphere? NRAO: KAT-7 Commissioning Lead • Ensuring KAT-7 is commissioned adequately, development is geared toward MeerKAT early science, and operations are defined to support an international user base. • Defined & implemented KAT-7 commissioning & resource plan • Managing commissioning schedule & activities to ensure KAT-7 operations will be successful and be ready for MeerKAT. • Established components of industrialized commissioning model – yet to be vetted. • Established Focused Commissioning Teams pairing SA graduate students with SKA SA staff to solve targeted commissioning issues. • Wrote first scientific and operational use cases and organizing effort to expand use cases, including user support scenarios. • CASA: • CASA chosen in July 2010 by the MeerKAT project as the official data processing package for operations & user support staff. • Supervising graduate student, Brad Frank, to expand the CASA simdata2 capabilities to simulate MeerKAT data. • Gave CASA tutorials to grad students and local astronomers. • Drove requirements to develop a filler to get the first KAT data into CASA and began to use CASA for the first data visualization and analysis of KAT commissioning data. NRAO: KAT-7 Commissioning Lead MeerKAT Industrialized Commissioning
• MeerKAT - Karoo Array Telescope – 64 antennas, about 1% of the collecting area of SKA. – ~ 3 antennas commissioned/month, focus on industrial commissioning methods
• Rapid, Industrialized Commissioning: – Heavy reliance on fully functional hardware and software delivered by contractors – Thorough verification by systems engineering and software teams before hand over to commissioning – Often repeated procedures performed by operator/technicians. – Multiple, parallel commissioning teams evolving into site operations teams and maintenance personnel. NRAO-SA MOU Key Areas
• To collaborate closely on the development and implementation of new software capabilities, data processing and archiving, and state-of –the-art receiving systems and other instrumentation for the radio astronomy facilities in SA and in the US. • To hold joint discussions, scientific workshops and to form joint research groups on specific scientific or technical goals of common interest. • To form a joint effort specifically devoted to algorithm development that are required for both the EVLA and MeerKAT, to be managed jointly and to follow a time schedule agreed by the SASPO and the NRAO. • To have an active exchange program of students, postdoctoral fellows, scientific and engineering staff. • To second staff from each organization to the other for agreed on periods. • To include senior NRAO staff in a Science and Technology Advisory Board for the MeerKAT • To work towards a policy for SASPO which is consistent with Open Skies policy, with the desired result that MeerKAT’s time allocation policy make use of all the telescopes of the NRAO and SASPO optimally available for the two user committees.
Cape Town