A CRJ700 crew believed they struck a bird during a night IMC takeoff from ORD. The flight continued to its scheduled destination because all systems appeared normal.

Narrative

During takeoff while rotating we heard a loud bang coming from the right nose area; as flying pilot I had already called for the gear up. All engine indications appeared normal; the gear went up without problem. The airplane responded correctly. In the mean time ORD approach kept relentlessly feeding us new instructions while the Flight Attendants were calling us to know what was happening. While dealing with all of the above; the First Officer and I were busy trying to figure out what is going on; trying to assess if something threatening our safety had occurred; if an immediate landing was warranted or not. Since all indications remained in the green; no EICAS messages showed up; the airplane responded and pressurized normally on schedule I decided an immediate overweight landing in icing IMC condition in ORD was not prudent. Further discussion with the First Officer once the adrenaline returned to normal levels focused on a possible bird strike on rotation. I had not seen anything while transitioning from outside references to instruments; the First Officer did not remember seeing a bird either but night and rain made it more difficult. During the process of prioritizing; ATC radio calls and clearances were missed; we were unable to speak to the flight attendants right away. And since we could not state with certainty what our problem was; keeping ATC in the loop would have burdened us further. Once at higher altitude; we went systematically through scenarios; cross checking engine instruments; synoptic pages and listening for noise or vibrations. I spoke with the #1 Flight Attendant. She reported she had also heard the bang and thought it came from the main passenger door area. She also reported the #2 Flight Attendant had mentioned the right door area but she checked them both and everything was normal. The First Officer reported he was hearing a different air noise from the right nose area; I could not hear it. During the flight all gauges stayed in the green with no EICAS messages. The only engine indication was a slightly elevated N1 vibration (I saw it reached 1.4 for a short time then it went back down to reach almost parallel value with the left engine once we exited icing condition). In order to land below maximum landing weight; holding would have had to take place. Low altitude was out of the question due to icing. I estimated 30 minutes to bring the weight within reasonable range also if the situation degraded many suitable airports were available along the route. Thus after consulting with the First Officer; I decided to continue to our destination. On post flight we found evidence of a possible bird strike on the radome. I entered it in the maintenance log. I also gave as much info to the maintenance team as I knew. They assure me they would do a thorough bird strike inspection.