The center of our galaxy

I was reading on Space.com about our galaxy and it said that there is a bar of stars, mostly old and red, at the center and at a 45 degree angle from the plane the rest of us are on. In addition to this there is a super-massive black hole. How can the BH be there and the bar of stars, let alone, at a 45?
 
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heres the article by the way:
Milky Way’s central structure seen with fresh clarity


new infrared survey that claims to be the most comprehensive structural analysis of our galaxy confirms previous evidence for a central bar of stars.

The bar is embedded in the center of the galaxy's spiral arms and cuts across the heart of it all where a supermassive black hole resides. The survey found that the bar is longer than thought and sits at a sharp angle to the galaxy's main plane.

"This is the best evidence ever for this long central bar in our galaxy," said Ed Churchwell, a University of Wisconsin-Madison professor of astronomy.

The challenge

If you've ever been fortunate enough to see the Milky Way in the night sky, then you can appreciate the frustration astronomers face trying to probe the galaxy's center.

The milky swath of stars visible under a dark, rural, summertime sky represents a fraction of the millions upon millions of stars that crowd the center of the galaxy. We sit on the outskirts, looking in. Seeing through the glow to determine the galaxy's structure is hard.

Even more challenging is peering through all the dust between here there.

The survey was done with NASA's Spitzer Space Telescope, which records infrared light. All objects that emit any heat can be seen in infrared, and this wavelength penetrates dust, so the new survey revealed light from tens of millions of stars hidden to optical telescopes.

Bigger than expected

The bar is made of relatively old and red stars, the survey shows. It is about 27,000 light-years long, or roughly 7,000 light-years longer than previously thought. Churchwell's team also found that the bar is oriented at about a 45-degree angle relative to the main plane of the galaxy, in which the Sun and the other spiral-arm stars orbit.

A light-year is the distance light travels in a year, about 6 trillion miles (10 trillion kilometers).

Other stars exist outside the galaxy's main plane. The Milky Way, like many galaxies, is surrounded by a sparsely populated spherical halo of stars. The main galactic disk is about 100,000 light-years wide, and the Sun sits about 26,000 light-years from the center.

Bars are fairly common in large spiral galaxies, but some do not have them. Astronomers had glimpsed ours and were not sure if it was in fact a bar or perhaps an ellipse.
 

DaveC426913

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Echo 6 Sierra said:
I was reading on Space.com about our galaxy and it said that there is a bar of stars, mostly old and red, at the center and at a 45 degree angle from the plane the rest of us are on. In addition to this there is a super-massive black hole. How can the BH be there and the bar of stars, let alone, at a 45?
What is the source of your confusion?

image of a Bar galaxy


See attached (very) rough sketch:
 
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What he wants to know is how can the Bar of stars exist in such a straight (or what we currently percieve to be straight) co-exist with the presence of a super massive blackhole?

The one thing i can only think of is that BH's are messy eaters in that the Chew more than they can swallow, the excess material of whatever body they are consuming (in this case and as in most cases, Stars) form an acretion disk the cause for the "jet" that produces in a blackhole (or Pulsar) i dont know, maybe someone here can help me out on this one.
 

SpaceTiger

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Echo 6 Sierra said:
How can the BH be there and the bar of stars, let alone, at a 45?
There's no problem with having both a supermassive black hole and a bar of stars at the center of the galaxy. This is because the scales are completely different. The event horizon of a supermassive black hole is usually less than the radius of the earth's orbit (~0.00001 parsecs), while stellar bars are usually thousands of parsecs in size and thousands of times more massive. In other words, the bar won't notice that the supermassive black hole is there.

We think the black hole will notice, though. We're still very much unsure about the evolution of both supermassive black holes and bars, but the popular theories invoke gradual accretion onto the black holes, with the gas being periodically funnelled to the center of the galaxy by instabilities in the surrounding galactic disk. A bar is one such instability and likely plays a role in redistributing matter for accretion onto the supermassive black hole.
 
So, it's the enormous distances between the objects that keeps everything okey-doke, right? It's odd to look at the artists rendering of the galaxy and see our approximate location and ALL THE OTHER STUFF that I simply can't make out even on the darkest night. Humbling, but cool.
 

SpaceTiger

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Echo 6 Sierra said:
So, it's the enormous distances between the objects that keeps everything okey-doke, right?
That's right, and the fact that the surrounding stars have enough angular momentum that they won't be dragged into the center on any reasonable timescale. It's likely that supermassive black holes do disrupt (or "eat") some stars, but it probably isn't an amount that would have a noticable effect on the large-scale dynamics.
 

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