1. An Introduction to Simdata Scott Schnee (NRAO) Victoria Workshop – Jan 18, 2011

2. What is Simdata Good For? Number of antennas Antenna configuration Length of observation Noise Take a model image and find out how it would look if observed with ALMA

3. Model Image 30Dor Spitzer IRAC 8um image from SAGE

4. Model Image Resized and now at 230 GHz

5. Fourier Transforms of Images From http://carmilumban-ap186.blogspot.com

6. Scales Measured by ES Configuration Antenna Placement uv-coverage synthesized beam 2 hour observation

7. Scales Measured by FS Compact Antenna Placement uv-coverage synthesized beam 2 hour observation

8. Scales Measured by FS Extended Antenna Placement uv-coverage synthesized beam 2 hour observation

9. Model Image in ES Configuration Model ImageConvolved Model“Observed” Image 2 hour observation

10. Model Image in FS Compact Model ImageConvolved Model“Observed” Image 2 hour observation

11. Model Image in FS Extended Model ImageConvolved Model“Observed” Image 2 hour observation

12. Basic Simdata Inputs Image / model of target Observing time Antenna configuration

13. Basic Simdata Inputs

14. FITS Image Basics Coordinates Brightness Observing Frequency Resolution (angular and spectral) Polarization (if needed)

15. modifymodel modifymodel = True skymodel = “30dor.fits” inbright = ”0.1mJy/pixel” indirection = "J2000 10:00:00 -40:00:00” incell = "0.25arcsec” incenter = "230GHz” inwidth = '2GHz'

16. setpointings integration = '600s’ mapsize = "” pointingspacing = ""

17. predict repodir = os.getenv("CASAPATH").split(' ')[0] antennalist = repodir+"/data/alma/simmos/alma.early.250m.cfg"

18. Simdata Output analyze = True showarray = True showconvolved = True showdifference = False showfidelity = False

19. Simdata Output

21. Simdata Output - Viewer

22. Other Simdata Options Thermal Noise thermalnoise = ‘tsys-atm’ image = True vis=‘$project.noisy.ms’

23. Other Simdata Options Thermal Noise Convolved ModelThermal NoiseNo Thermal Noise

24. Other Simdata Options Phase Noise Convolved ModelNo Phase NoisePhase Noise

25. Other Simdata Options Phase Noise Create measurement set with simdata Use the “toolkit” to add phase noise – http://casa.nrao.edu/docs/CasaRef/CasaRef.html http://casa.nrao.edu/docs/CasaRef/CasaRef.html – http://casaguides.nrao.edu/index.php?title=Corrupt http://casaguides.nrao.edu/index.php?title=Corrupt – sm.openfromms("simPN.ms") – sm.settrop(mode='screen',pwv=1.0,deltapwv=0.15) – sm.corrupt() – sm.done() Use clean (in CASA) to make the image

26. Your Turn Find a fits file of an object you want to image Use simdata to see how it would look if observed with ALMA – Rescale image if necessary – Try different antenna configurations – Add noise if interested Don’t be afraid to ask for help!