$\star$ Photometry with solved galaxy

In the case of 2001go and more still for 2001gy, the galaxy host is well solved and is spread out over more pixels than the supernova. Moreover, the shape of the galaxy is such as its contribution in the aperture is weak. Lastly, subjacent flux in each pixel of the galaxy is weak in comparison with the supernova.

We thus decided for these two supernovæ to carry out the subtraction pixel with pixel. The galaxy in these two cases present of the slow space variations and the error introduced by bad alignment are relatively weak.

Flux is then estimated on a ray of opening more significant than for 2001gn. The flux of the supernova is very largely higher than the fluctuations of the bottom of sky, a larger aperture involves only one relatively weak increase in the error.

The estimate of the fluctuations is made directly on the withdrawn image what allows a direct estimate of the error.

Once again, we check that the increase in the rays of opening does not change the result.