Physics GRE Discussion Forums

After visiting a school and meeting with a few of the astro professors, I received an email with an offer letter, listing two of the professors I met as having research positions available. I had really good discussions with them, and they both emailed me after I got the offer, stating how they would like to have me in their respective research groups. I haven't fully made up my mind, but I'm leaning towards accepting the school's offer, and in that case, I know which of the professors I'd like to work with. Does anyone have some tips on politely informing the other professor of my choice, if I do decide to attend this school?

Unless you're going somewhere outside the U.S. where it might be different, from what I've come to understand you don't really have to commit to a specific advisor for another couple years after getting to know them better. This doesn't preclude you from working with either before choosing an advisor, but it also shouldn't necessarily restrict you to that advisor (though obviously there would be advantages to sticking with them).

I've been accepted for the master's program as a transfer student, and since I'll have completed one year of my master's at my current school, I'll likely be finished in one year, so I'll want to start very early in the semester. I already know which of the two I'd like to work with, so I was really just wondering if anyone else had been in a similar situation and had any tips on informing the other professor.