1. Pulsar Timing with ASKAP Simon Johnston ATNF, CSIRO

2. Looking to the future
Pulsar timing and surveys in the last 20 years have mostly been carried out with large single dishes some with multiple pixels
For surveys this is the only option computationally
WSRT the honourable exception
Bandwidth generally small (< 1 GHz)
Limited by front end and RFI
Coherent de-dispersion limited by cpu power
By 2015 with SKA coming on-line most cutting edge pulsar work will be carried out on a interferometer, potentially with very large bandwidths (10 GHz).
ASKAP can provide a transition between large single dishes and interferometers (at least in the south).

3. ASKAP - The next gen radio telescope on the path to the SKA
45 parabolic dishes, 12 m diameter
990 baseline interferometer, ~5000 m2 collecting area
30 square degree field of view on the sky
Focal plane array technology and digital beamforming
Frequency range 0.7 – 1.8 GHz
Bandwidth 300 MHz, channels (20 kHz resolution)
Tsys = 35 K (cooled)
Located in Murchison Shire, Western Australia
6 element outstation in NSW
ASKAP is not very sensitive but it has a fast survey speed. ASKAP observing will be dominated by surveys which can exploit the large FoV capability.

4. Sensitivity Instantaneous sensitivity ~ ND2/T
Parkes = 1 x 642 x 0.7 / = 1.0
ASKAP = 45 x 122 x 0.8 / = 1.1
ASKAP will be somewhat more sensitive providing the specs can be met (N, , T)
At sub GHz frequencies ASKAP will be much more sensitive than Parkes
Bandwidth ~ 256 MHz for both at 1.4 GHz
ASKAP has 30 square degrees FoV
If you can observe more than 1 pulsar at a time the efficiency gains go up proportionally
RFI conditions in WA should be better than anywhere else in the world.

5. Millisecond pulsar timing
Only one source per Field of View
Need to form tied array beam at the phase centre and sample at baseband
Would like to record the full 1 GHz band
Can FoV be traded against bandwidth?
In any case should think about sub GHz observing
Would like high frequency capability
Needs good polarization calibratability
Needs lots of regular observations (100 days/yr!)
Parkes would still be the instrument of choice but ASKAP would be a good test bed for future work

6. General pulsar timing
Benefits from multiple pulsars per FoV, especially in the Galactic plane
Integration time determined by weakest pulsar in the FoV so the gain is not quite proportional to N
Requires multiple tied array beams
Beamformer capability?
Off axis polarization?
For e.g. the GLAST timing program ASKAP would be a factor 5 faster than Parkes
ASKAP would be the instrument of choice for a big timing campaign

7. Summary of Requirements
FRONT END
Good polarization properties
Would like to exploit 1 GHz bandwidth
Ability to have at least 10 tied array beams
BACK END
Baseband recording for MSPs with at least 300 MHz possibly 1 GHz bandwidth and associated cpu power for data reduction
10 digital filterbank systems with high freq resolution, high time resolution and on-line folding mode
TIMING
MSP timing very competitive with 1 GHz bandwidth
Timing of survey discoveries much faster with ASKAP.