How about this: the Lightsaber Galaxy?

I second that. Very apt.

Lenticular/S0 galaxies are actually not that rare — probably about 10-15% of bright galaxies.

I’m not sure about an X structure in this particular galaxy; that may be (mostly) an optical illusion. In any case, while such structures could, in some cases, be the result of minor mergers, the majority of them (i.e., so-called “boxy” or “peanut-shaped” bulges) are internally generated: they are the inner, vertically thick parts of stellar bars, seen close to side-on. (And I suspect a significant past merger would not have left this galaxy’s disk as thin as it is.)

It could be that this galaxy is quite different looking from the diskside view.

When I saw this picture I for one thought, “Light Sabre”

Captn Tommy

You have to be careful not to overplay it. We DO understand that our galaxy’s disk is comprised of an inner and outer disk component, just like every other disk galaxy we see. And it is not very accurate to declare that our galaxy’s disk has a thickness of “2500 or so light years” when our Milky Way’s disk not only sports an inner and outer component, but also exhibits considerable warping from a given plane. The reality is always a might removed from a specific declaration of thickness. For example, many non-optical wavelength surveys of our galaxy plainly show our galaxy’s disk to be either considerably below or above that figure. But if a DIFFUSE distribution of stars alone determines it, one can’t put a figure to it other than by some distributive grounds, such as saying, for example, ’50% of the stars in the disk are confined within x light years of the midplane”. I do not think that our Milky Way would be significantly different from NGC 4452 in that particular respect.

But in this particular case with NGC 4452, you obviously discount the outer diffuse component of the disk, which is clearly evident in the image. THAT ratio exceeds 6:1. It’s probably similar to that of our galaxy, as well as any disk galaxy. It is probably NOT terribly special in that regard.

It is also interesting to see on scanning it horizontally to find vague but significant variations in brightness along the disk that appear to be symmetrically positioned with respect to the core. That indicates that, if viewed perpendicularly to this line of sight (so that we view it face-on), this galaxy would exhibit some structure departing from a smooth distribution with radius.

If one scans ones eyes slowly laterally along the horizontal, one will notice a very subtle but distinct “X” structure centered on the core region. That comes about from stars imported from another galaxy that have preferentially assumed orbits from some merger in the distant past of this system. The most extreme examples of the phenomenon create what astronomers dub ‘box-shaped’ cores. It’s quite easy to recreate the phenomenon with simple programs that are freely available on the net.

UFO enthusiasts may now commence declaring this marvelously symmetrical object to be an example of an artificial construct.

Rick

It’s meant to be :

The lack of central core bulge is odd. I’m going to naively as if it’s possible that there’s not a single black hole at the centre but two black holes orbiting each other around a central point?

*Then* my reply to that of :

Yes, I think that’s possible and I vaguely recall having seen / heard somewhere that the Andromeda galaxy has such a double nucleus with two black holes at its core.

***

Although that on checking here :

http://en.wikipedia.org/wiki/Andromeda_Galaxy#Nucleus

It looks like I was wrong about that anyhow.

Also, might I recomend you ask this on the Bad Astronomy Universe Today (BAUT) forum here :

http://www.bautforum.com/

as well? (If you haven’t already.) Folks there may be able to find an answer for those too.

Yes, I think that’s possible and I vaguely recall having seen / heard somewhere that the Andromeda galaxy has such a double nucleus with two black holes at its core.

Is such a formation of black holes even possible in Galaxy formation?

I’d think so given the idea that galaxies grow through merger and the consumption of smaller dwarf galaxies. If a galaxy engulfs a few others logically, the other galaxies core should fall inwards and eventually join up but there’d almost certainly be a stage where there’s more than one supermassive black hole in the galactic centre. These Supermasive Black Holes (SMBHs) would attract each other via gravity and likely end up orbiting each other and then merging to form one larger one although I haven’t immediately got any sources for you to confirm that, I’m afraid.

How far apart would they have to be to have such a minimal bulge effect on the central stars?

Sorry, this one I don’t know & won’t even venture a guess on.

I’d also guess two orbiting black holes in a Galaxy would make for unusual spiral arm arrangments if we viewed the Galactic disc from above but our view is obviously edge on.

Perhaps but not necessarily. If the second SMBH came from another galaxy it would be tidally disrupted and eventually intermingle with the original one and at the core the bulge would seme to hide the effect and the drama from the rest of the galaxy. Two orbiting SMBH’s close to each other would probably, I’d imagine, have as little effect on the surrounding arms as two stars in a tight binary have on orbiting planets – ie. outside of a zone where orbits are unstable or impossible the planets just orbit the centre of the systems mass (barycentre) normally.

But I could well be mistaken here.

Does anyone else know more here & care to enlighten us all please?

EDIT : Although I guess you do get tidal tails … so-oo .. I’d call tails!

Awesome image, excellent write-up. Thankyou BA.

This is just speculation on my part, but I think that a supermassive clump of gas and dust can never collapse straight into a black hole, because before that happens, the material will form a very high mass star, and at a certain ultra-high mass, a star is hot enough that its radiation pressure blows off its outer layers (and any other gas in the area – this is the Eddington Limit).
This would mean that even supermassive black holes would form first as “ordinary” large stars that just happened to be in very crowded surroundings, where there’s lots of gas (and stars and anything else) to slurp up once the black holes form at the end of the stars’ life.
The one thing about the binary black hole idea that I’m really unsure of is what happens to the angular momentum of the holes as they accrete more matter? Do they orbit more closely as they become more massive?
IIRC, one of the stated purposes of trying to identify gravitational waves through experiments like LIGO was to look for the gravitational disturbances caused by orbiting neutron stars or black holes, as these waves would presumably be extremely strong (as far as gravity waves go) and have an easily recognizable repeating signal.

Annnnnyway, my (uninformed layperson) opinion is that the answer to the first two questions is “probably definitely, with possible caveats” and my answer to the second two questions is “I have no freaking idea because I’m not a physicist and probably will never be one because I suck at math”

I’m going to naively as if it’s possible that there’s not a single black hole at the centre but two black holes orbiting each other around a central point?

Is such a formation of black holes even possible in Galaxy formation?

How far apart would they have to be to have such a minimal bulge effect on the central stars?

I’d also guess two orbiting black holes in a Galaxy would make for unusual spiral arm arrangments if we viewed the Galactic disc from above but our view is obviously edge on.

It’s humbling to think that even if we as a species manage to survive and explore and pull off an Asimovian feat of epic colonization, ultimately expanding across the whole Milky Way, exploring billions of worlds over hundreds of millions of years – even if our most hubris-filled sci-fi scenarios one day came true… Even then, we’d STILL only have managed to discover and occupy a few tiny parts of one single galaxy that exists among billions, stretching out further then we can reach or even see.

Even as gods, the universe would dwarf us utterly.