Anybody have had troubles with spectroscpic data from GMOS?

[jorge]

Hello:

I wonder if anybody have had problems with spectroscopic data taken with GMOS?... I took data in NOD&SHUFFLE mode and I realiced that my bright spectra have fake features in the 550-650nm range, specifically two bumps with broad emission line shape. I checked the sensfunction, but it can't deal with this problem, thinking that the spectroscopic standard stars also have this problems but shifted in wavelength range, and every each with different shift... I don't know how to fix this problems.

anybody has an idea?

thank