Should we classify this differently?
-
It is obvious this is probably a substantial object in space, but I don't think this can really be classified as a galaxy. It appears more as a gravitationally bound dust cloud, or possibly an old galaxy of just dust and dead stars. It seems like most of the light from this is being reflected when you compare it to objects around it. Do you think we should classify this as a galaxy, or a different more dusty variety of an intergalactic object?
Posted
-
by
ElisabethB
moderator
Hi 404KyleNotFound and welcome to the Zoo,
It is definitely a galaxy, just a faint and fuzzy one.
Happy hunting ! 😄
Posted
-
by
JeanTate
in response to 404KyleNotFound's comment.
As it's an Illustris sim, it cannot be a 'dust cloud' ('dust' is not self-luminous in the simulated optical bands used in Illustris, and in any case is not depicted as having a spatial structure). The 'objects around it' are not, actually, nearby; they are an added 'background', derived from random SDSS fields, and have nothing to do - physically - with the sim.
The colors suggest, as you say, that it's "an old galaxy of [...] dead stars"; IMHO it's unusual for being so small, for such an old galaxy.
You can read more about Illustris in this recent GZ blog post; it's a fascinating project! 😃
Posted
-
by
KWillett
scientist, admin, translator
Good explanations, Jean and Els. In a more general sense - the surveys are designed to include only galaxies as the center object. If you ever see something you don't think is a galaxy (a star, or a nebula, or asteroid, or artifact, etc), we'd usually suggest clicking "star or artifact" at the beginning and then discussing it in Talk if you want. But everything else should definitely be classified "as a galaxy".
- cheers,
Kyle
Posted
- cheers,
