I'm wondering if anyone noticed what appears to be a pretty interesting lensing event in the upper-left corner of the picture. It is small, but in a dark location and encircles a dim blob that is clearly a very, very distant galaxy. The lensed image is almost an arc of 180 degrees around that dim galaxy, and this (apparently) lensed object appears to have more detail than just another faint, spherical blob - it looks like it is a background galaxy being magnified significantly. And the fact that it is being lensed by this very faint, clearly singular, dim blob would tend to indicate that that blob doing the lensing is very, very massive. Also, the lensing is very sharp, seemingly indicating that it might, just possibly, be so distant and violently lensed that very small changes in relative position of the lensing blob may cause a visible change in the lensed image of the background galaxy - meaning that periodic re-imaging might lead to a visible change in the lensed shape of the distant galaxy.... Now that is a "movie" I would like to see.
The object doing the apparent lensing is located at (in the hi-res image APOD links to - the 8000 x 6074 pixel image) pixel (1523,893). The apparent lensed arc runs from pixel (1540,882) to (1503,923). It looks like a hair fell onto a photographic plate - and maybe that really is what it is - but if that filament is really out there and really is a lensing event, it's a pretty incredible one.
Another tantalizing explanation is that what I've called the blob (galaxy?) doing the apparent lensing might not actually be doing the lensing - it is significantly off-center relative to the lensed arc. And if it isn't doing the lensing, then you have an incredibly large amount of mass there doing the lensing - but it is completely dark. Is it a black hole?
Suppose it really is a black hole, and the faint blob is just an off-center (ie not significantly lensed) background galaxy, or is a foreground dwarf galaxy or cluster. Where in the line of sight is the black hole? Could it be a black hole that was flung out of the distended, bright Markarian galaxy just to the lower left of it in this image? That galaxy is clearly recovering from a galactic collision - and/or is experiencing tidal forces from something.
I checked the 2007 APOD image of Markarian's Eyes linked to in this one's description -
http://apod.nasa.gov/apod/ap070608.html - it doesn't quite have the resolution to show if the lensed arc is present or not. I'm very curious to hear if any other images show the arc, and if so, is it changing at all?
That 2007 APOD, however, shows slightly better what appear to be large molecular clouds darkening regions of the picture. Note another apparent lensing center-of-mass roughly near (1543,421) and/or (1522,507) - the distant galaxies at (1537,292), (1670,342), (1802,654), and (1294,497) all appear to be lensed. The center of that lensing event is a strangely dark field that seems to have significantly less background light noise than most of the other "empty"/"black" areas of this photo. It's as if there is a gigantic molecular cloud there centered around (1627,479), a dark circle with a diameter of almost 200 pixels where significantly fewer distant light sources are present, compare to most other fields in the photo. This "giant dark cloud" seems to continue (or have companions) - such as (1830,1406). There are a quite a few more where it seems the distant background galaxies have been uniformly shaded. Is that an artifact introduced later? Or just a coincidence? It looks to me like there really is some kind of cloud blocking the view (maybe it's a nearby cloud...).
Some more squiggles that - if they are actually more lensing events - would be extraordinary to monitor for changes: (2574,5926), (2709,5945) - this one has a circular curve to it like the larger one - implying a very compact (in radial diameter), dim mass..., (1035,2933).
The seemingly dark mass apparently doing the lensing here - over vast parts of the image - may suggest the presence of a large quantity of dark matter, which would also explain the co-location of so many galaxies. Suppose those dark or shady regions are relatively dense concentrations of dark matter, flung around chaotically during the recent galactic collision. Even as such a collection of dark matter can facilitate lensing and amplification of distant galaxies, it might also explain the darkness of these regions if the dark matter is essentially defracting much of the other light (those not being amplified along our sight-line) away from our sight-line - just as happens when you focus a beam of light onto a surface using a lens - the lens concentrates much of the light to a point, but all around that point is a dark shadow being apparently cast by the lens - but, in fact, the lens is just shifting light to the focal point, and scattering all other mis-aligned rays. If that's what's going on here, it suggests that detailed, repeated observations of those dark fields of (possibly) concentrated, high-velocity dark matter might be a location where otherwise infrequent dark-matter collisions are happening at a higher rate. Maybe we can catch a few photons and shed some light on what dark matter is?