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Summary:
The CFHTLS ugriz filter set is described and contrasted with the SDSS ugriz filters. |
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Note:
Obviously, most the information presented in this page is available elsewhere. However, although I was able to find the CFHTLS filter transmission function without the telescope (mirrors, optics, detector) response function, I was unable to find files describing the filter set with multiplication with the system response (which are necessary for a number of things, notably photometric redshifts), so I have presented them here. |
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The figure at right show the CFHTLS ugriz filter set.
The light coloured lines show the filters responses
as obtained
here.
(Note that earlier versions of this page had the filter curves taken from
this file)
The labeled black lines show the response of the
primary mirror,
the
optics
and the QE of the
CCD's
as obtained from the CFHT website.
The filter responses were multiplied by the telescope (mirror+optics+CCD) response to obtaion total transmissions for the whole system. These total transmissions are shown as the heavy coloured lines The final response curves are given in text format here: |
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The figure at right shows the final CFHTLS filter transmission functions.
The same data for the SDSS ugriz filter set is shown in heavier lines.
Note the CFHTLS u and g filters are slightly redder than their
SDSS counterparts.
The transformation between the Vega and AB magnitude system is
different for the SDSS and MegaCam filters, particularly for the U.
This is shown in the following table:
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