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Eli Kasai          NASSP Masters 2011                UCT               SAAOThesis: SN Ia Rate in Intermediate-Redshift    ...
OUTLINE   SN Ia rate measurement    •   Importance   Physical Processes    •   Single and Double degenerate   Image Sub...
Importance SN Ia rate measurements   Progenitor Models       Delay Time Distribution   Iron Abundance in the ICM   Int...
Physical Processes
Image Subtraction Algorithm – IRAF   Measure FWHM of few stars   Convolve images to seeing of worst frame       tw05.R1...
Image Subtraction Algorithm – IRAF cont...   tw05.R128.1004.fits > conv_tw05.R128.1004.s23.fits
Image Subtraction Algorithm – IRAF cont...   Scale flux of convolved reference frame to match the rest    of the convolve...
Image Subtraction Algorithm – IRAF cont...   Subtract scaled convolved reference from each convolved image   Normalize d...
Automated Subtraction Algorithm – ISIS   Measure FWHM of few stars - IRAF   Crop out common area > 3600 x 3600 - Python ...
Automated Subtraction Algorithm – ISIS cont...   Produce 900 x 900 cutouts (for MS0451) – Python script   Apply automate...
Automated Subtraction Algorithm – ISIS cont...   interp.csh       image registration – match coordinates to reference fr...
Automated subtraction steps – ISIS cont...   Mosaic the sub-images to produce complete difference    image – Python script
Automated Subtraction Algorithm – ISIS cont...   Left: difference sub-image   Centre: difference sub-image normalized by...
Transients found by both Algorithm in the same imagesTop row: Iraf AlgorithmBottom row: ISIS algorithm
Comparison of the algorithms,                 Left – IRAF; Right – ISIS   Time span from image convolution to differencin...
THANK YOU
References   Alard C. & Lupton, R. H. 1998, ApJ, 503, 325   Alard, C. 2000, A&A, 144, 363   Barbary et al. 2011, arXiv:...
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SN Ia Rate in Intermediate-Redshift Galaxy Clusters - Eli Kasai

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Transcript of "SN Ia Rate in Intermediate-Redshift Galaxy Clusters - Eli Kasai"

  1. 1. Eli Kasai NASSP Masters 2011 UCT SAAOThesis: SN Ia Rate in Intermediate-Redshift Galaxy Clusters Supervisor: Dr Steve Crawford Co-supervisor: Prof Bruce Bassett
  2. 2. OUTLINE SN Ia rate measurement • Importance Physical Processes • Single and Double degenerate Image Subtraction Algorithm • IRAF Automated Image Subtraction Algorithm • ISIS (Alard & Lupton, 1998)
  3. 3. Importance SN Ia rate measurements Progenitor Models  Delay Time Distribution Iron Abundance in the ICM Intra-cluster stellar component tracer Cosmology • Improved cosmological parameters
  4. 4. Physical Processes
  5. 5. Image Subtraction Algorithm – IRAF Measure FWHM of few stars Convolve images to seeing of worst frame  tw05.R186.1001.fits > conv_tw05.R186.s23.fits
  6. 6. Image Subtraction Algorithm – IRAF cont... tw05.R128.1004.fits > conv_tw05.R128.1004.s23.fits
  7. 7. Image Subtraction Algorithm – IRAF cont... Scale flux of convolved reference frame to match the rest of the convolved frames  Flux conv_tw05.R186.1001.s23.fits = Flux conv_tw05.R128.1004.s23.fits
  8. 8. Image Subtraction Algorithm – IRAF cont... Subtract scaled convolved reference from each convolved image Normalize difference image with Poisson fluctuations > S/N image
  9. 9. Automated Subtraction Algorithm – ISIS Measure FWHM of few stars - IRAF Crop out common area > 3600 x 3600 - Python script
  10. 10. Automated Subtraction Algorithm – ISIS cont... Produce 900 x 900 cutouts (for MS0451) – Python script Apply automated subtraction steps
  11. 11. Automated Subtraction Algorithm – ISIS cont... interp.csh  image registration – match coordinates to reference frame ref.csh  composite reference frame subtract.csh  mrj_phot C code, convolution kernel modeling, difference images detect.csh  normalize subtracted images with photon noise find.csh  positions of candidate transients phot.csh  light curve production
  12. 12. Automated subtraction steps – ISIS cont... Mosaic the sub-images to produce complete difference image – Python script
  13. 13. Automated Subtraction Algorithm – ISIS cont... Left: difference sub-image Centre: difference sub-image normalized by poisson fluctuations Right: positions of variables located by “find.csh”
  14. 14. Transients found by both Algorithm in the same imagesTop row: Iraf AlgorithmBottom row: ISIS algorithm
  15. 15. Comparison of the algorithms, Left – IRAF; Right – ISIS Time span from image convolution to differencing  IRAF algorithm ~ 1 week  ISIS automated algorithm ~ 3 - 4 hours
  16. 16. THANK YOU
  17. 17. References Alard C. & Lupton, R. H. 1998, ApJ, 503, 325 Alard, C. 2000, A&A, 144, 363 Barbary et al. 2011, arXiv:1010.5786v3 Dilday et al. 2010, ApJ, 715, 1021 Maoz & Avishay 2004, MNRAS, 347, 951 Sand et al. 2008, AJ, 135, 1917 Sharon et al. 2010, ApJ, 718, 876
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