So there is a website where you can sort through a 100 billion photos of galaxies taken by autonomous space robots and classify them for science. For no pay.
So I was clicking through and found this galaxy, which doesn't look like anything else I've ever seen or heard of.
Any ideas on why an otherwise boring, pleb-tier elliptical galaxy is shitting out stars in that C-shape pattern? It makes no sense to me whatsoever.
>tfw you don't know what you're doing on your first time and you label wrongly what is actually a reachable alien civilization
>the course of humanity is irrevocably changed by one man as the most important galactic discovery is discarded from future research
I'd categorize it as two-arm spiral, obvious bulge, and irregular or disturbed. Probably a recent merger, yeah. Most spiral galaxies I looked at are fucked up irregular ones with no bar.
I know, right? It's not very pretty looking but it's weird as fuck. It can't be an overlap or artifact or a star and nothing is around to account for the tidal debris, no spin to it, so it's some asshole elliptical trying to merge into nothingness for no reason whatsoever.
If it was the result of a long-ago merging galaxy, I don't see how the center would be perfectly round and undisturbed, with no spin, while still having arms derping out like that.
I like it. I like perturbed galaxies. Increases wonderment levels.
Astronomer here who works on galaxy surveys like the data that goes into GalaxyZoo.
The first thing I would do is check where the image came from. Currently GalaxyZoo galaxies come from either DeCALs (a big, deep survey in the southern hemisphere like the one I work with), the rest come from a simulation called Illustris. Illustris has done many things well but their galaxies look shit. This looks like real data (the simulated ones are supposed to as well) so I'll assume it's real but if it's not don't be surprised it's weird, their super massive black hole physics fucks up their galaxy shapes.
I'm no expert at morphology but to me that looks like a sort of polar-ring galaxy (like pic related, google it for other examples). Polar-ring galaxies are the results of galaxy mergers where a spiral galaxy has been swallowed by another galaxy at a steep angle (to the disk) and the disk has been thrown out as a polar-ring. The merger can trigger star formation in the disk causing it to be blue. It's thought they don't last very long, and eventually settle into more elliptical galaxies.
It could also just be a tidal tail for a previous major galaxy merger.
It's a nice galaxy, flag it as interesting.
What this guy says:>>7803183
Also please don't be afraid to guess on GalaxyZoo if you don't know. It's a statistical project so if you disagree from the average classification it doesn't matter but can help point to it not being totally obvious.
What I see there is a blue disk which is slightly clumpy. Disks in spirals are usually bluer than the core because they have active star formation. It's clumpy so it's a good sign of a disk, maybe a dwarf spiral. There is a redder core where you can see the older stars which make up the bulge, it looks slightly barred to me. There is maybe the think of two arms but it's ambiguous. Bear in mind not all galaxies have clear spiral arms, many have flocculent arms (pic related). In fact only a small fraction (~15%) are grand spirals like famous NGC1300.
Yes, it's an image from DECaLS. The stupid C-shaped thing is an actual real object and the references show it looking exactly the same.
I posted it on the forums on that website just now, Maybe the weird moderator woman there will know what it is.
>If it was the result of a long-ago merging galaxy, I don't see how the center would be perfectly round and undisturbed, with no spin, while still having arms derping out like that.
So one thing to remember about mergers is that the orbit time in the core is a small fraction of that far out in the "disk". The core may settle into equilibrium quickly simply because it's had time. The disk however needs more orbits which takes longer.
It could also be that the larger galaxy pre-merge was a an elliptical like you said in which case they can be quite compact and thus not easily disrupted by the merge.
Eh, yeah maybe. All the spiral galaxies that I've seen merge looked fucked up, amazing, awe-inspiring. Ellipticals merge and kinda just look... boring.
Still, that's a seemingly unnatural shape for a static elliptical galaxy to have, especially if it was recently merged.
I don't even know. Maybe the galatic core of that object is being orbited by a galactic core-type supermassive black hole with a slow but very eccentric orbit and the stars get spread out along the orbital trajectory path but the galaxy's central supermassive keeps all the core stars around in immediately in perfect formation.
I dunno. Sounds good, right? I'm not about to right a thesis paper on this shit I'm just curious and assumed somebody more knowledgeable than me can sate my curiosity.
Then I would guess it's a ring galaxy or a polar ring galaxy.
The same galaxy is in a survey called SDSS which was used for the original galaxyZoo. SDSS isn't as deep as DECaLS but it had more filters and spectroscopy. If you care to see a spectrum here it is:
A typical transitional galaxy with strong absorption lines from old stars and bright emission lines from star formation.
Another fun service is NASA's Extragalactic Database where you will find wealth of past observations on this object.
It's only really been referenced in surveys but it was in the original galaxyZoo too. Sadly there doesn't seem to be any better images from either Hubble or ESO telescopes.
Ellipticals are definitely boring to look at but they are also quite interesting in how they formed. It's thought generally that they form though the massive collisions of big spiral galaxies and go though stages of being the most luminous galaxies in the universe for a while. There is evidence for this now in the motions of stars inside them. At the same time however the very most massive ones like M87 are very hard to explain, you can find objects of similar stellar mass at reasonably early epochs but denser. It's curious.
Generally the supermassive black hole only really affects the very core of the galaxy through gravity at least. They can be ejected in mergers but I'm not sure if one could ever settle into an orbit. Although huge they are actually a very small portion of the overall mass in a merger like this so they tend not to be a critical component gravitationally. But if you replace the central SMBH with the central bulge I would start to agree. It's shear density will keeps it somewhat undisturbed perhaps.
It's good fun to take a punt at a formation hypothesis. When faced with just an image all you can do is guess really, there's nothing wrong with that. Unfortunately for this galaxy we lack better data to take a closer look and see if we can tell what it's doing.
I know. I looked through those databases too, but those are generated by said space robots, it doesn't actually say why it looks like that or what the fuck is going on, that's why I posted here.
That and the other website is way slow and the shit will not upload an image nomatter how hard I try.
If it wasn't so asymmetrical I'd agree polar ring galaxy, but I dunno. It's obviously unusual but I seriously doubt I'm the first asshole on earth to ever notice something like that.
The benefit of NED however is that it links you to papers and to observation notes. If anyone has done a detailed analysis and found out what it actually is then you will find it there. But you clearly know your stuff.
There's nothing wrong with disagreeing. You see an image like that and you try to build a picture, not everyone gets the same one and that's why GalaxyZoo uses statistics.
An interesting thing would be to see how it was classified in the old GalaxyZoo but that would be a task for tomorrow for me.
Yeah, I have no idea how a supermassive black hole would ever get stuck in the orbit of something else.
Also, blackholes shit out a ton of ultra-hot gas and radiation and bullshit at right-angles to everything, so the galaxy would look a mess, it'd be perturbed and disturbed and all fucked up looking. It looks perfectly tidy minus the stupid arms.
Cause they don't make any fuckin sense! It's not doing what a galaxy is supposed to do, it's obviously stupid.
You work for free but your reward is looking at vast cosmic objects nobody, or maybe only a few other people, or up to 40 other people, has ever looked at before. Besides the robot that took the picture.
Then, you fucking classify that thing, some 50 billion suns, for the glory of mankind and science. Why the fuck not?
>Classifying objects we will never visit in the entire lifetime of the human race
Op here, if anymore cares anymore, so I brought the image it to the attention of somebody knowledgeable and they looked at the spectrometer and EM readings and whatnot from other surveys. The object is a 'starburst galaxy' and the new stars forming and the long arms are likely the result of a collision with another galaxy.
So it's similar in construction to the more famous 'antenna galaxy' here, only with a weirdly more symmetrical center.