1. Robbie Auld1 Simulated HI Observations 4 th SKADS Workshop, Lisbon, 2-3 October 2008 Simulated HI observations Robbie Auld Cardiff University collaborating with Oxford SKADS team

2. Robbie Auld2 Simulated HI Observations 4 th SKADS Workshop, Lisbon, 2-3 October 2008 Outline Description of the data pipeline Sky simulation (SEX)‏ Telescope Simulation Detection Technique Comparisons: HIPASS vs. SEX dN/dz – SEX vs. SAX Future THINGS: IC 2574

3. Robbie Auld3 Simulated HI Observations 4 th SKADS Workshop, Lisbon, 2-3 October 2008 Data Pipeline Cleaned datacube Web query Sky model SKA simulator ParselTongue script (HRK) that uses AIPS routines. Includes: antenna Tsys, antenna layout, gain factors, integration time per visibility, total observation time Corrupted cube Source Finder S 3 simulation (RW & FL) Query generated via the web interface, source list and datacube generated locally with S 3 Tools. Duchamp source finder package (ATNF)‏

4. Robbie Auld4 Simulated HI Observations 4 th SKADS Workshop, Lisbon, 2-3 October 2008 Resulting datacube Filled UV plane!

5. Robbie Auld5 Simulated HI Observations 4 th SKADS Workshop, Lisbon, 2-3 October 2008 Source detector: Duchamp Locates sets of contiguous voxels (3D pixels) above some threshold. Threshold determination:  Manual (absolute value / S/N value)‏  Automatic (False Discovery Rate method)‏ Enhancement  Spectral smoothing (Hanning)‏  Spatial smoothing (Gaussian convolution)‏  A trous (wavelet procedure)‏ Voxels above threshold are flagged, merging algorithm rejects multiple detections

6. Robbie Auld6 Simulated HI Observations 4 th SKADS Workshop, Lisbon, 2-3 October 2008 Duchamp output Postscript file of all detections VO compatible catalogue file

7. Robbie Auld7 Simulated HI Observations 4 th SKADS Workshop, Lisbon, 2-3 October 2008 Comparisons with HIPASS

8. Robbie Auld8 Simulated HI Observations 4 th SKADS Workshop, Lisbon, 2-3 October 2008 SEX shortcomings HIMF (0 < z < 0.1)‏ Wilman et al. 2008

9. Robbie Auld9 Simulated HI Observations 4 th SKADS Workshop, Lisbon, 2-3 October 2008 SEX vs. SAX: dn/dz Abdalla & Rawlings (2005)‏ Diamonds – SAX Stars – SEX SEX differential number counts too low.

10. Robbie Auld10 Simulated HI Observations 4 th SKADS Workshop, Lisbon, 2-3 October 2008 Future THINGS: IC 2574 Integrated intensityVelocity Field Explore effects of different array configurations with the galaxy in the local neighbourhood and then try moving it further away.