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mfouesneau / pyphot

suite to deal with passband photometry
https://mfouesneau.github.io/pyphot/
MIT License
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The difference of wise-w3 transmit curve with SVO #60

Open zhang-zhixiang opened 2 months ago

zhang-zhixiang commented 2 months ago

I found there is an obvious difference in W3 transmit curves between pyphot and SVO. This difference affects the conversion from spectrum to synthetic photometry. I don't know which curve is correct. Could anyone please explain this problem?

The SVO W3 transmit curve is from http://svo2.cab.inta-csic.es/theory/fps/index.php

The difference between pyphot and SVO is as follows: WX20240913-150217@2x

mfouesneau commented 2 months ago

SVO reports WISE to be an energy counter while pyphot has it as photon counter. By eye, it seems that SVO has defined their transmission as wavelength * pyphot transmission, which would explain the slope while the features seem the same.

https://www.researchgate.net/figure/WISE-photon-counting-relative-system-response-RSR-curves-lRl-normalized-to-unity_fig14_231135277

But I do not know which one is the original definition. As long as they are consistently used, that should work.

What differences in the magnitudes do you get?