Regional Jet 200 ER/LR (CRJ200)
Flight Crew Air Transport Pilot (ATP)
Situational Awareness; Distraction
Deviation / Discrepancy - Procedural Landing Without Clearance; Inflight Event / Encounter Wake Vortex Encounter
General None Reported / Taken
Procedure; Environment - Non Weather Related; Human Factors
While being vectored to the runway 10 approach into Atlanta we were cleared for the visual approach and told to slow to 180 until ZMANN and contact tower at ZMANN 119.5.  Just prior to reaching ZMANN we began to get configured.  The Captain called for gear down flaps thirty.  We intercepted the glideslope just prior to ZMANN and started to feel some wake off the 757 ahead of us.  The Captain opted to switch from approach mode to navigation mode and fly the approach using Vertical Speed mode for descent.  He wanted to stay about one dot above the glideslope to avoid the wake from the 757 ahead.  We made a normal touchdown in the touchdown zone and tower instructed us to taxi via the gold west hold short of 9R. I repeated that back to him and no other communications were exchanged.  Prior to that I remember keying the mike but do not recall hearing anything back.  I had switched frequencies at ZMANN; but got distracted with the changing of the flight profile to adjust for the wake turbulence and cannot recall if I got a reply from tower.Threats that occurred were primarily the wake turbulence from the 757 ahead along with configuration changes and descent changes.  Another potential threat can be when a time elapses from the time approach tells you to call tower at a given fix until you reach that fix; this can sometimes be several minutes and then many things happen at once.  I need to find a way to remind myself to make sure we have clearance
A CRJ-200 First Officer reported possibly landing without a clearance when a wake turbulence encounter distracted him at a critical time.