Galaxy with Double Nucleus

We all assume that every galaxy has a nucleus at its center. But astronomers have discovered that the nearby galaxy NGC-4486B has a double nucleus, which they hadn’t seen before. NGC-4486B is located close to the Virgo Cluster’s central region. This discovery gives new insight into the end stages of supermassive black hole (SMBH) mergers. When such things happen, they shape galaxies across cosmic time.

Using advanced methods of observation, the team found two distinct bright regions at NGC-4486B’s center. This strongly suggests that the galaxy has two compact stellar components. Each would potentially be associated with an SMBH remnant.

Detailed measurements revealed slight differences in the brightness and motion of stars near its galactic core. These differences would be consistent with the gravitational influence of a pair of black holes that had recently merged.

Galaxies with dual nuclei are rarely observed. Although once considered a calm and ancient elliptical system, NGC-4486B now seems to bear the scars of a recent cosmic event. This event could redefine our understanding of black hole mergers in mature galaxies.

Not long ago on a cosmic timescale, indications are that two supermassive black holes at the core of NGC-4486B. Despite its proximity to the massive M87 in the Virgo cluster and the age of the galaxy, the data says that final relaxation is incomplete, which leaves a record of this violent past. Since its SMBH have merged relatively recently, its nucleus is a rare change for studying post-merger SMBH dynamics.

NGC-4486B is one of a handful of galaxies that can be directly probed as to the aftermath of black hole mergers. This stage is usually hidden by dust, distance, or time. This galaxy’s proximity gives astronomers an opportunity to redress models of gravitational wave emission as well as stellar dynamics in post-merger systems.

Obviously, black hole activity can persist even in old, staid galaxies. A supermassive black hole merger releases horrendous amounts of energy, which can reshape surrounding stellar orbits and alter the galaxy’s form and structure.

Using the signatures of this merger, scientists can test theoretical models. NGC-4486B could be used as a benchmark for studying these types of mergers and could bridge the gap between simulations and observation.

Observing a double nucleus system may prove how galaxies like our Milky Way might evolve after their central black holes merge. In addition, next-generation observatories may soon detect low-frequency gravitational waves from other similar, nearby systems.

NGC-4486B reminds us that even tranquil galaxies can hide the echoes of cosmic violence.

 

https://www.msn.com/en-us/news/technology/astronomers-uncover-mysterious-double-nucleus-at-the-heart-of-galaxy-ngc-4486b/ar-AA1T83Ox?ocid=hpmsn&cvid=69504ba802754e8997779ac7d601a875&ei=55

How Black is a Black Hole?

Have you seen the Disney movie, Black Hole, from 1979? It was typical Disney fare; clueless good guy, camouflaged bad guy, comic relief characters… And all the action happened on a ship that sat in space, just outside the ‘point of no return’ of a Black Hole, which was depicted as a whirlpool of light.

Even then, I knew a black hole was ‘a region of space having a gravitational field so intense that no matter or radiation can escape.’ So that depiction of a black hole bothered me. If light can’t escape, then the black hole would not appear as a whirlpool of light. It should be black. Even light from stars beyond the black hole shouldn’t be seen; it would be bent and swallowed before it reached the observer. Right?

That’s what I was thinking, anyway.

These days, the idea of a Black Hole is not quite so… black and white.

NASA says a black hole is a place in space where the gravity is so intense, light cannot escape. In the same article, they say that if a black hole is located close to a star, high-energy (invisible) light is released. I suppose this is a special case, but I think they should have started by saying no visible light can escape.

Another NASA webpage states that black holes cannot be seen, because (visible) light cannot escape. But anything in the vicinity is effected. Dust bits will fall into the black hole, getting closer and closer until they hit that ‘point of no return’, when the light reflecting off them can no longer escape. The gravity will tug at any stars and planets in the area, making them wobble as they try to resist. Stars might even be pulled apart, and slurped up. As the star matter accelerates toward the hole, it emits x-rays, which can be detected by the proper equipment.

But something can and does escape from black holes, in a way. Some matter that is falling into a black hole ricochets off the event horizon (point of no return) instead of going through it. It bounces away at a speed so great, the jet of material can be detected relatively easily.

If that’s not enough for you, then consider a super-black hole that spins really, really fast. This spin creates a charge-separated magnetosphere, which forms parallel electrical charges around the poles. Particles accelerate to very close almost the speed of light and are thrown out into space as gamma radiation bursts. Bursts have been observed from the massive black hole at the center of Galaxy IC310. However, the description of how they are created is just a theory, since no one can see inside the event horizon to see what’s going on.

So, Black Holes are pretty black, unless something is escaping.

www.nasa.gov/audience/forstudents/k-4/stories/nasa-knows/what-is-a-black-hole-k4.html

https://science.nasa.gov/astrophysics/focus-areas/black-holes

http://www.space.com/15421-black-holes-facts-formation-discovery-sdcmp.html

Black and White

This last week, I’ve been reading about Black Holes. If you’ve seen the movie ‘Interstellar’, that involved a Black Hole that they were trying to avoid while skirting around the edges. Neil deGrasse Tyson applauded the science in that movie, so it’s educational as well as entertaining, right?

I’ve been reading science fiction for several decades, so I’m pretty well acquainted with what little is known about Black Holes. But theories grow and change, so I periodically read up on the subject, just to tweak my ‘knowledge’.

Most of what I read I already knew: Black Holes have so much gravity that nothing can escape once it’s entrapped, not even light, so they appear black. The gravity field of a Black Hole is so massive, that it even warps time, making it go slower. Black Holes are created when a star dies and collapses in on itself. And current theory is that there’s a super-Black Hole in the center of each galaxy.

But there were a couple things that made me pause and think. Such as the current theory that each Black Hole has a universe inside it. Therefore, this universe we live in must be inside a Black Hole. It makes me wonder what a Black Hole looks like from the other side. Where is the opening into our universe, and why haven’t we found it yet? How does that fit in with the theory of parallel universes? Are all the universes inside other Black Holes parallel universes to ours? Or am I trying to smash too much into one theory?

There was also the idea that since Black Holes exist, then there must be an opposite counterpart, a White Hole, where stuff would be spewing into our universe. Wow! And would a White Hole have negative gravity, the opposite of a Black Hole’s massive gravity? And would a White Hole spew lots of light and radiation, just like a Black Hole swallows up that stuff? Sounds like they’d be easy to spot. In fact, in my mind, a White Hole sounds like the other side of a Black Hole. So how come we haven’t found any? Well, just be patient. In 2006, an unusual burst of gamma radiation was detected, and currently being studied as a potential White Hole event.

And most of these facts and theories have been used in science fiction during the time I’ve been reading it. I can’t remember the name of the book(s), nor the author(s), but I can remember a scene or two that used each fact/theory. Except one. I don’t remember any books about Black Holes containing universes, but maybe I just didn’t get my hands on that one.

What about you? Read any good Black Hole books lately?