The next time you hear thumps:
a. note what you’re doing at that moment that makes noise
b. do it less loudly
I would go and ask what’s up, prepared for the fact that the person might be like Mr. Heckles on “Friends” - i.e., an unreasonable nut-job. One of my neighbors is like this - she’s complained about the people in the units above, below, and to either side. Basically, if she hears anything, you’re being too loud.
Most people in the building are scared of confrontation, so contact building management, but all they can do is say “Hey, we got a noise complaint about you.” If the person says “it wasn’t me” they’ll drop it and when you follow-up that’s what they’ll tell you. They didn’t witness it, what can they do?
Personally, I accept that it’s part of apartment/condo living. Some previous neighbors had hardwood floors that conducted every sound and they didn’t want rugs everywhere - eh, I lived with it.
OK, so you’re saying that if your downstairs neighbour does think you are somehow being obnoxious (TV too loud, stomping on floor, wild yodelling orgies, whatever), you would want them to communicate their concern with you directly?
That’s reasonable.
Now go back and read your own OP and try to appreciate the irony.
This is probably just what your neighbour is thinking.
“Why should I have to go up there and tell him to stop tap-dancing on the floor in his bloody great big boots? I’ll just bang on the ceiling with this broom. That should get the message across.”
But to answer your question. I would have gone to the neighbour and asked them what the problem was.
However, since you’ve spoken to the management instead, just check back with them in a few days to find out what the issue is.
If this hasn’t been mentioned in all of this:
Thumping on the ceiling is a time-honored method in the US to inform the party above that they are making too much noise.
Living in an apartment means restricting your noise levels.
You don’t get to have that “thumpa-thumpa” bass anymore. disconnect the sub-woofer and keep it for when you have no others below you - they really do make the unit below sound like the interior of a bass drum.
Sorry, but this is a case where it is likely the OP was at fault.
Funny - since this thread started, one of my neighbors has been playing Gotye’s “Somebody That I Used To Know” over and over since they got home - doesn’t bode well for a confrontation, unless you like weeping. 
You don’t remember the episode where Mr. Heckles died? When people were walking around in the apartment it sounded like a herd of elephants and they realised he was actually being reasonable…
That isn’t unique to the US, that’s globally universal.
Universally global even.
It may have felt like the ceiling to you but it could have been an adjacent wall.
If this is just a one time thing, I’d let it go. It could have been lots of things. (like kids acting stupid with a broom handle)
I had nearly the same experience and its outcome would be a good lesson to Crumbled Bumble.
I play the guitar. After getting into my first new apartment out of college, I settled down for a practice session. This wasn’t shredding or heavy metal, it was jazz at a moderate volume. I heard this “thump, thump,” thought, WTF was that? And then started playing again. Thump. So I walked downstairs, knocked on the door, and asked if there was a problem. The resident said I was kind of loud, so I apologized sincerely. Two minutes later he came upstairs and knocked on my door offering to loan me his headphones.
It always pays to be the first one to reach out with an olive branch, even if you don’t think you’re at fault.
Flip side: I lived in a third-floor condo and had a downstairs neighbor who was blasting his stereo. I knocked on his door to ask him if he could turn it down. No answer. Knock knock. No answer. I return upstairs and fume for a while. I ran into him the next day and said I had knocked on his door because his stereo was really loud. He said, “Well, I don’t answer the door. It’s just my policy, I guess.” Fast forward a couple of weeks later. It was a beautiful day and I had my balcony door open. I was getting some kind of fumes coming into the condo. I walked onto the balcony and looked down to see flames. He was using a charcoal grill on his balcony. I knocked on his door. True to his “policy” he did not answer. So I called the fire department and explained what he was doing and they told me it was illegal and they would send someone out to take a look. They sent out a truck with sirens blazing. They did not storm his apartment but they were actually pretty pissed and yelled at him from the street not to do it again.
He and I never really got along after that. It could all have been avoided if he had simply answered his door.
That’s the thing - unless you go talk to them, you have no idea what just happened. You have no idea whether they were actually banging on the ceiling or high up on a wall, whether they were objecting to noise or hammering a nail, whether it was your noise they were objecting to or someone else’s, whether they *think *it’s your noise when it’s actually someone else’s…
When I lived in an apartment, one Saturday morning at 8am the people upstairs from us (we thought) started running something like a jackhammer. We all hauled ourselves furiously out of our hungover sleep and were bitching and complaining, when the people from upstairs came down to ask us to stop bloody jackhammering at 8am on a Saturday. Turns out it was actually the people upstairs from them, but because the noise carried oddly through the wall cavities, it sounded to each of us like it was coming from the other flat. If we hadn’t talked to each other, we’d have ended up loathing each other for no reason at all.
Basically, sound and vibrations carry very weirdly in apartment blocks, and even if you think you know what’s going on, you could be totally wrong. Talk to your neighbours.