Absorption spectra not appearing correctly

[Andy Cook]

Hello,

I've been using Trident recently to get absorption spectra in an AREPO simulation. I followed the annotated example on the Trident documentation and managed to produce a plot (attached) but it appears to have slightly weirdly shaped absorption lines. In addition, when my script begins creating a ray for this dataset a warning comes up:

"yt : [WARNING  ] 2021-09-10 13:57:05,714 Setting negative densities for field O_p2_number_density to 0! Bad!"

It does this for every element and produces the plot attached. If anyone can give any advice or help that would be greatly appreciated.

Many thanks,

Andrew Cook

[Andy Cook]

I forgot to add I'm using the current versions of yt and Trident