Formation ideas: failed giant vs ram-pressure stripping

32:17and then early star formation makes the globular clusters around it but then star formation somehow abruptly just like stops and so you just get a bunch of dark matter a few stars and these globular clusters around >> if I recall there's like some threshold where it's right in the sweet spot where it it will maintain versus continuing to >> generate though the weird thing is this is bigger than that threshold though >> I did check >> and this 10 the 10 um solar masses. So 10 billion solar masses is larger than the threshold that we had over there. >> So it shouldn't just be like cloud 9. >> Yeah. It's not like cloud 9. Otherwise, it would be a relic and there'd be no stars. There's still a few stars. Fair, right? Um the other thing could be like something called a quenching mechanism. There's something called RAM pressure.

32:59So this is a photo of the Perseus cluster. You can see a lot of the um starlight is coming from these large galaxies and the blue sort of haze is from the dark matter that we've mapped out because of all of the velocity measurements that we've taken. And one can imagine that in this really vibrant cluster, you had this early dark matter halo with a bunch of dark matter and it was like it had a bunch of cold gas is what we call because cold gas is like the gases are moving around so it can clump in and form stars. So, it was destined to be a galaxy kind of like the large melanic cloud, but maybe like some other galaxy just rammed into it and then stripped it of all of the star

33:40making material. So, now it didn't have any star making material and it's just stuck being like this dark galaxy. >> That's actually interesting. >> Okay, so there's these there's these like theories and you know more testing and more observation is going to tell which one is correct. What I'm really excited about is what I was telling earlier, which is this cusp and core model, right? Like which one why why do >> why does dark matter not form a cusp, >> right?