I few points, for what they're worth:
- Polishing out a scratch requires abrasives as you're effectively removing the damaged material and cutting the surface back to undamaged material beneath.
- The existing surface appears to be a brushed finish running across the length of the tubes.
- If the finish is raw (unlacquered) you may get away with just polishing it, if it's had some form of coating applied during production (lacquer / clear coat) you're going to want to re-apply this afterwards, which adds complexity / hassle.
- Any polishing you do is going to want to run only in the same direction as the brushed "grain" - i.e. across the tubes to maintain the existing finish.
- You're going to want to match the abrasive coarseness to that of the existing finish; with paper abrasives such as wet and dry this is defined by the "grit" number - the lower the number the more coarse the abrasive.
- You're going to want to mask off the logos (which look media blasted..?) before treatment or you'll polish these out too and it'll look bloody terrible.
Ultimately, potentially do-able but you want to ensure you're approaching it properly to avoid making it worse. In your position I'd probably look to source some fairly gentle abrasives (such as scotch pad type stuff as alredy mentioned) in a number of coarsenesses, carefully mask off any adjacent bits of logo and give one spot a gentle polish across the tube with maybe a 400 grit equivalent pad to see how that turns out; noting how the scratch is reacting and how the resultant finish compares to what's already there. You may wish to use a flat backer / block on the pad (rather than your finger) to reduce the chance of getting a dip in the finish because you're concentrating on one specific area.
The last thing to remember is that (personally speaking) it's often easier to accept damage than to accept the results of imperfect attempts to rectify if