Very faint structures refered to as "jets" associated with NGC 1097 are thought to be streams
of stars left behind after a smaller galaxy passed through its inners regions billions of years ago.

There are 4 jets in total with the brightest shinning at about 26mag/sqr arc sec but the fourth one
is extremely faint and I really only see hints of it in this capture, try using averted vision :-)
I would suspect it shines at closer to 28mag/sqr arc sec!

You can read about measuring the brightness of these jets here:
http://adsabs.harvard.edu/full/1984MNRAS.211..707C