General question about the possibility of objective moral truth

[Pyrrho]

Hello to everyone

I have a general question about moral: The discussion between religious people and atheists often turns around the question if someone needs to be believer in order to follow moral rules.
In my opinion an atheist can be as much a person of high moral standards as a religious person (and some atheists can even have a higher moral standard than some religious people). Just to say that right at the beginning.

Now I would like to ask: Is from an atheistic point of view a moral conviction like "killing of people is morally wrong" an objective fact? Or is it a social convention, which means it is a subjective view?

Thanks for any answers!

The question of whether morality is objective or subjective is a separate question from whether there is a god or not.  One could take any combination of opinions on this subject.  Indeed, suggesting that morality depends on god strongly suggests that morality is merely a subjective whim of god, rather than something actually objective.