Changes between Initial Version and Version 1 of TestSN2009kf

Timestamp:

Oct 26, 2009, 1:18:23 AM (17 years ago)

Author:

m.botticella@…

Comment:

--

TestSN2009kf

@@ +1 @@
+= DRAVG test on SN 2009kf photometry (MT Botticella) =
+We are working on photometry of the the SN PS1-0609001 (2009kf) 
+and we have been looking at the newly released MD08 images (stacks for each epoch).
+
+Several  immediate problems :
+
+-'''masked areas'''
+
+the stacks have a lot of masked areas and 
+sometimes the SN host galaxy is
+hidden (see fig stacks, stacks_2,stacks_3 in the green circle the
+SN host galaxy).
+[[Image(stacks.png)]]
+[[Image(stacks_2.png)]]
+[[Image(stacks_3.png)]]
+
+If you look at some of the not saturated stars (for example the green ringed stars
+in fig Stars_ppStack.jpg) they have mask "blocks" sitting on top of them. The masks are not symmetrical, nor simply
+on the highest pixel value, but are irregular shapes, sitting over
+part of the psf. 
+[[Image(Stars_ppStack.png)]]
+
+These were several of the
+comparison stars for the SN photometry and we can not use them to
+calibrate the SN mag.
+There are masked areas all over the
+images. These masks are mostly (but not always) associated
+with moderately bright stars  - but the star cores are
+not saturated (we know this from comparisons with other images,
+and other stars in the field). The profiles of the same stars
+on
+stacked images obtained with IRAF with median
+combine and crreject are different 
+[[Image(Stars_imcombine.png)]]
+
+-'''background'''
+
+We are using the template
+subtraction technique to remove the signal of the host galaxy.  The  SN residual on difference image is nice but it is
+impossible to obtain an accurate measurement because of the background around the residual.
+[[Image(SNres.png)]]
+
+We collected some images from the Liverpool telescope and you can see the
+two difference images obtained with the same procedure (right images from the LT (stacked with IRAF) left images from PS1
+(stacked with IPP).
+[[Image(SN2009kf.png)]]
+We also found a bigger scatter between the zero points in the PS1 images
+with respect the LT images. Here some numbers relative to the same
+sequence stars
+
+13/10/09 z band  LT
+
+    id fwhm  ph_mag  fit_mag  fiterr zp
+
+   1  5.0   -4.379  -4.589  0.007 22.43
+   2  5.0   -2.990  -2.858  0.025 22.41
+   5  5.0   -5.597  -5.613  0.005 22.42
+   6  5.0   -5.043  -5.092  0.005 22.40
+   7  5.0   -5.350  -5.418  0.004 22.41
+   8  5.0   -5.168  -5.287  0.005 22.41
+
+PS1 (target and template are obtained stacking 8 PS1 images)
+
+16/06/09 z band
+
+  id fwhm  ph_mag  fit_mag  fiterr zp
+
+   1  7.0   -6.42  -6.45  0.006 24.30
+   2  7.0   -4.63  -4.62  0.006 24.10
+   5  7.0   -7.47  -7.49  0.003 24.29
+   6  7.0   -6.89  -6.91  0.002 24.15
+   7  7.0   -8.28  -7.19  0.003 24.19
+   8  7.0   -7.1   -7.13  0.003 24.25
+
+
+We tried to combine the warps available with IRAF and to obtain some
+measurements on these new stacks. In this case the measure is easier and
+the scatter is reduced.
+
+PS1 (target and template images are obtained stacking warps with IRAF)
+
+
+130609 z band
+
+     id fwhm  ph_mag  fit_mag  fiterr zp
+   
+   1  6.2   -6.466  -6.544  0.011 24.38
+   2  6.2   -4.657  -4.739  0.019 24.22
+   5  6.2   -7.451  -7.554  0.011 24.36
+   6  6.2   -6.783  -6.962  0.011 24.27
+   7  6.2   -7.892  -7.288  0.011 24.28
+
+
+160609 z band
+
+   id fwhm  ph_mag  fit_mag  fiterr zp
+
+   1  6.9   -6.421  -6.395  0.007 24.23
+   2  6.9   -4.402  -4.614  0.018 24.09
+   5  6.9   -7.453  -7.405  0.005 24.21
+   6  6.9   -6.871  -6.828  0.005 24.18
+   7  6.9   -7.158  -7.151  0.006 24.14
+   8  6.9   -7.107  -7.070  0.006 24.19