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astrothesaurus / UAT

The Unified Astronomy Thesaurus is an open, interoperable and community-supported thesaurus of astronomical and astrophysical concepts and their relationships.
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Circumgalactic Medium #108

Closed jegpeek closed 5 years ago

jegpeek commented 5 years ago

We need a term called Circumgalactic Medium (CGM). This describes the material typically neither considered the gas "in" a galaxy, but surrounding it and associated with it. It could be considered a term in Extragalactic astronomy, or within Intergalactic medium. It comes up in the literature 1500 times. It looks like it was coined in 1969 by Solinger.

usage is dramatically accelerating:

https://www.dropbox.com/s/kbmto7r6khegawz/Screenshot%202018-08-07%2009.38.29.png?dl=0

I would use the term "gaseous galaxy halo" interchangably, as in

Putman, M E, J E G Peek, and M R Joung. “Gaseous Galaxy Halos.” Annual Review of Astronomy and Astrophysics 50 (September 2012): 491–529. doi:10.1146/annurev-astro-081811-125612.

though the term is a bit out of favor. Some people use the term "galactic corona" interchangeably, but typically that refers to uniformly hot media, closer to the milky way disk, and it is an older term:

Spitzer, L J. “On a Possible Interstellar Galactic Corona..” \Apj 124 (1956): 20–. doi:10.1086/146200.

katieefrey commented 5 years ago

Hm, if "Circumgalactic medium" is a synonymous with "gaseous galaxy halo," is it also a synonym with the currently existing concept "Galaxy halos"? Currently found at...

Galaxy physics -> Galaxy structure -> Galaxy components -> Galaxy halo

It doesn't necessarily have to stay at that location, but is it already covering the same topic?

jegpeek commented 5 years ago

It could. In that context I think we mean a galaxy stellar halo. It’s a bit weird. People wouldn’t say that a galaxy stellar halo, gaseous halo, and dark matter halo are all narrower terms of galaxy halo, but rather that galaxy halo itself is an ambiguous term without context. The cgm is sort of a component of a galaxy, but sort of the context of a galaxy.

katieefrey commented 5 years ago

Galaxy components is a weird and ambiguous term too... this issue is bringing up more issues!

hierarchy thoughts... removing galaxy components and moving its children to direct children of galaxy structure

Galaxy physics -> Galaxy structure -> Galaxy bulges Galaxy physics -> Galaxy structure -> Galaxy disks -> Stellar disks [maybe... galaxy stellar disks?] Galaxy physics -> Galaxy structure -> Galaxy disks Galaxy physics -> Galaxy structure -> Galaxy stellar halos [instead of "galaxy halos"] Galaxy physics -> Galaxy structure -> Galaxy dark matter halos [new concept] Galaxy physics -> Galaxy structure -> Galaxy nuclei -> Active galactic nuclei Galaxy physics -> Galaxy structure -> Galaxy nuclei -> Active galactic nuclei -> [a lot of other subconcepts] Galaxy physics -> Galaxy structure -> Galaxy nuclei -> Galaxy circumnuclear disk Galaxy physics -> Galaxy structure -> Galaxy nuclei Galaxy physics -> Galaxy structure -> Spiral arms Galaxy physics -> Galaxy structure -> Tidal tails Extragalactic astronomy -> Circumgalactic medium [npt: gaseous galaxy halo]

jegpeek commented 5 years ago

I like this. @peeples , do you think Circumgalactic medium [npt: gaseous galaxy halo] should be a in Galaxy Structure? Or directly in extragalactic structure?

katieefrey commented 5 years ago

it can also live in both, if that makes sense!

peeples commented 5 years ago

If I had to choose one, I'd pick "galaxy structure", but if it can be both, then great!

jegpeek commented 5 years ago

We are asking a bunch of other CGM folks over Slack now.

katieefrey commented 5 years ago

slightly revised hierarchy:

Galaxy physics -> Galaxy structure -> Galaxy bulges Galaxy physics -> Galaxy structure -> Galaxy disks -> Galaxy stellar disks [npt: stellar disks] Galaxy physics -> Galaxy structure -> Galaxy disks Galaxy physics -> Galaxy structure -> Galaxy stellar halos Galaxy physics -> Galaxy structure -> Galaxy dark matter halos [new concept] Galaxy physics -> Galaxy structure -> Galaxy nuclei -> Active galactic nuclei Galaxy physics -> Galaxy structure -> Galaxy nuclei -> Active galactic nuclei -> [a lot of other subconcepts] Galaxy physics -> Galaxy structure -> Galaxy nuclei -> Galaxy circumnuclear disk Galaxy physics -> Galaxy structure -> Galaxy nuclei Galaxy physics -> Galaxy structure -> Spiral arms Galaxy physics -> Galaxy structure -> Tidal tails Galaxy physics -> Galaxy structure -> Circumgalactic medium [npt: gaseous galaxy halo] Extragalactic astronomy -> Circumgalactic medium [npt: gaseous galaxy halo]

Planning to deprecate "galaxy components," but I'll make a separate issue for it since it is a larger change. See #110

adding scope notes as follows...

Galaxy disks: Refers to the disk part of a galaxy. Does not refer to a specific shape and form of a particular classification of galaxies (see "Disk galaxies").

Galaxy stellar disks: Refers to the disk of stars that make up part of the disk of the galaxy. This concept would specific exclude the dust and gas components of the galaxy's disk.

Disk galaxy: Refers to the specific shape and form of a particular classification of galaxies. Does not refer to the disk part of a galaxy (see "Galaxy disk").

peeples commented 5 years ago

OK, our super unscientific poll definitely prefers "both", but if forced to choose, "Galaxy Structure", with no votes for "Extragalactic".

katieefrey commented 5 years ago

Glad to hear the outcome of your slack discussion! Luckily, the UAT is a polyhierarchy so it can be a child of both concepts. I'll implement the structure as laid out in my most recent comment above.