MaNGA and galaxy spectroscopy

31:24>> Very cool. And then I guess MaNGA was nearby galaxies. >> Yeah. >> What was the what was the question cuz I I I imagine with red shift you're trying to answer in a Hubble's constant expansion of the universe. >> Yep. >> Cosmology at the biggest scales kind of thing. >> Pretty much. >> What was MaNGA's prerogative? >> MaNGA was and MaNGA's tagline was the galaxy survey for people who love galaxies. >> Okay. >> So so it was getting so it was this much smaller number of galaxies. I think by the time we finished the SDSS red shift surveying at the end of eBOSS we had maybe somewhere between three and four million galaxy red shifts. MaNGA observed 10,000 galaxies. It was much smaller number.

32:05But for each galaxy you are observing not just you know, the the the red shift survey just takes the spectrum of the center of the galaxy. >> Right, it's like the mean. >> It's just get one red shift and get and you get more information. You get something about the overall age of the stars, the metallicity of the stars, something about the gas in the galaxy. But MaNGA you had these fiber bundles where you put the whole fiber bundle they're not this big though, like that big. >> Yeah. >> But um >> Optic These are optic fibers. >> Optical fibers. >> Not the string theory fiber bundles, just >> That is, yeah, there's no Lee algebra here in the creation of these fiber bundles.

32:46Um the uh, the these fiber bundles are pieces of glass, um, and and and they're put on the galaxy in the focal plane of the telescope, and we would do 17 of them at a time, uh, and get information across the face of the galaxy. >> Oh, very cool. I >> So, you could get a rotation curve, you could get, you know, the gradients of the gas distribution and the metallicity distribution. >> Right. >> Uh, much more information about, uh, you like if there was an active galactic nucleus, which is like a supermassive black hole at the center of the galaxy, you could get that separately from the rest of the galaxy.

33:27>> Yeah. So, before there was just one spectrum, and the entire galaxy, all of its spectrum was coming through, and you're getting this thing. >> Yeah. >> Now, you're sort of like pixelating a galaxy and tiling it. >> Yeah. >> Because the spectrum over here, because it's moving, you know, the it maybe it's rotating this way, is different from the spectrum over here, is different from the center if there's some black hole that's acting up. >> Yeah. Very cool. >> I see. Yeah. That's that's that's super fascinating. Um, I wanted to wrap up with two questions. >> Okay. >> One was, you know, with your with your tenure coming up in Carnegie, what is like one mystery of the universe that you personally are super, you know, curious about, and you

34:08hope that your efforts can can lead to an answer? >> I mean, uh, there are many. >> Yeah. If you were to pick, you know, one that >> If I'm going to pick one, personally, >> Personally. >> Yeah. >> then I I grew up as a galaxy person, uh, and I'm still fascinated by galaxies, and I well, it's really two things. One one is that we which is really just about the galaxies, which is that and this has been a mystery since I was a graduate student. >> Okay. >> Uh and it's still as far as I'm concerned still mysterious if we even if we have some

34:50better knowledge. Um which is that the most massive galaxies in the universe are not forming any stars. They're no stars forming in them. They are They are They are filled with old stars that mostly formed billions of years ago. >> Okay. >> And although you would think they would have available gas and some cases you see the available gas >> Mhm. >> uh which is normally what new stars form out of, they're not actually doing that.