APOD: The Galactic Center in Stars, Gas,... (2021 Jun 02)

[APOD Robot]

The Galactic Center in Stars, Gas, and Magnetism

Explanation: What's going on near the center of our galaxy? To help find out, a newly detailed panorama has been composed that explores regions just above and below the galactic plane in radio and X-ray light. X-ray light taken by the orbiting Chandra Observatory is shown in orange (hot), green (hotter), and purple (hottest) and superposed with a highly detailed image in radio waves, shown in gray, acquired by the MeerKAT array. Interactions are numerous and complex. Galactic beasts such as expanding supernova remnants, hot winds from newly formed stars, unusually strong and colliding magnetic fields, and a central supermassive black hole are all battling in a space only 1000 light years across. Thin bright stripes appear to result from twisting and newly connecting magnetic fields in colliding regions, creating an energetic type of inner galactic space weather with similarities to that created by our Sun. Continued observations and study hold promise to not only shed more light on the history and evolution of our own galaxy -- but all galaxies.

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[Ann]

The Galactic Center in Stars, Gas, and Magnetism. Note the outline in purple of two enormous bubbles, one above the plane of our galaxy and one below it. Image Credit: X-ray: NASA/CXC/UMass/Q.D. Wang; Radio: NRF/SARAO/MeerKAT.

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X-ray outflow bubbles from the core of the Milky Way.

The core of the Milky Way in X-rays. ESA.

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The Fermi Bubbles are two enormous orbs of gas and cosmic rays that tower over the Milky Way, covering a region roughly as large as the galaxy itself. These giant space bubbles may be fueled by a strong outflow of matter from the center of the Milky Way. (Image credit: NASA Goddard)

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Outflows from the core of the Milky Way. ESA.

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The X-ray outflows from the core of the Milky Way appears to be tied to the enormous gamma ray bubbles, the Fermi Bubbles, that are found above and below the plane of the Milky Way, centered on the core of the Milky Way and its supermassive central black hole, Sagittarius A*.

The X-ray outflows could be the mechanism that maintains the Fermi Bubbles and keeps them hot.

Ann

[JohnD]

Quote this APOD description, "Galactic beasts such as expanding supernova remnants, hot winds from newly formed stars, unusually strong and colliding magnetic fields, and a central supermassive black hole are all battling in a space only 1000 light years across."

I've asked this before, and been reassured, because 'Space is big,it's really big!" and the extraordinarily energetic parts are too far away to be a danger to life. But a " a space only 1000 light years across" isn't that big, is it? Full of the "hottest" X-rays that we can 'see' from 25,000 LY away. Does that mean that we can forget about 'life' on planets in that part of the Galaxy?

John

[orin stepanek]

All I can say is wow! I'm glad we don't live near there! We are still bombarded by radiation though; enough so that we are gradually evolving as a species; hopefully for the better! :shock

Aww; poor kitty!

[Ann]

Quote this APOD description, "Galactic beasts such as expanding supernova remnants, hot winds from newly formed stars, unusually strong and colliding magnetic fields, and a central supermassive black hole are all battling in a space only 1000 light years across."

I've asked this before, and been reassured, because 'Space is big,it's really big!" and the extraordinarily energetic parts are too far away to be a danger to life. But a " a space only 1000 light years across" isn't that big, is it? Full of the "hottest" X-rays that we can 'see' from 25,000 LY away. Does that mean that we can forget about 'life' on planets in that part of the Galaxy?

John

If you ask me, the complete amateur, I'd say, Yes, it does!

Ann

[Chris Peterson]

Quote this APOD description, "Galactic beasts such as expanding supernova remnants, hot winds from newly formed stars, unusually strong and colliding magnetic fields, and a central supermassive black hole are all battling in a space only 1000 light years across."

I've asked this before, and been reassured, because 'Space is big,it's really big!" and the extraordinarily energetic parts are too far away to be a danger to life. But a " a space only 1000 light years across" isn't that big, is it? Full of the "hottest" X-rays that we can 'see' from 25,000 LY away. Does that mean that we can forget about 'life' on planets in that part of the Galaxy?

John

It's questionable just how many planets there even are in that part of the galaxy. When the stars are so close together, they will be passing within sub-light-year distances of each other on million-year timescales, or less. That means that planetary systems will be getting regularly perturbed. Eventually, most (or all) planets will be ejected. And any that find themselves in Goldilocks zones will not be there for long. If there is life on planets in that region, it is unlikely to be more complex than single-celled organisms, living in water. For such life, the local radiation environment is not a problem. Atmospheres and oceans are excellent at blocking x-rays.

[neufer]

Outflows from the core of the Milky Way. ESA.

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The X-ray outflows from the core of the Milky Way appears to be tied to the enormous gamma ray bubbles, the Fermi Bubbles, that are found above and below the plane of the Milky Way, centered on the core of the Milky Way and its supermassive central black hole, Sagittarius A*. The X-ray outflows could be the mechanism that maintains the Fermi Bubbles and keeps them hot.

Click to play embedded YouTube video.

[VictorBorun]

I am confused as to what bright spots does the Chandra site label with lime circles?

And I failed to find the legend of X-ranges mapping to orange green blue purple

[neufer]

I am confused as to what bright spots does the Chandra site label with lime circles?

<<Also labeled in the main image are X-rays reflected from dust around bright X-ray sources (green circles), Sagittarius A*, and, in purple circles and ellipses, the Arches and Quintuplet Clusters, DB00-58 and DB00-6, 1E 1743.1-28.43, the Cold Gas Cloud and Sagittarius C.>>

And I failed to find the legend of X-ranges mapping to orange green blue purple

• blue

Chandra's High Resolution Camera (HRC) has two micro-channel
plate components and images over the range of 0.1–10 keV ... so maybe:

• orange: 0.1–0.45 keV
  green: 0.45–2.2 keV
  purple: 2.2–10 keV

[VictorBorun]

<<Also labeled in the main image are X-rays reflected from dust around bright X-ray sources (green circles), Sagittarius A*, and, in purple circles and ellipses, the Arches and Quintuplet Clusters, DB00-58 and DB00-6, 1E 1743.1-28.43, the Cold Gas Cloud and Sagittarius C.>>

Got it. Thanks!

[VictorBorun]

Chandra's High Resolution Camera (HRC) has two micro-channel
plate components and images over the range of 0.1–10 keV ... so maybe:

• orange: 0.1–0.45 keV
  green: 0.45–2.2 keV
  purple: 2.2–10 keV

blue must be there:
Color Code X-ray: orange, green, blue, purple; Radio: lilac, gray;

[neufer]

Chandra's High Resolution Camera (HRC) has two micro-channel
plate components and images over the range of 0.1–10 keV ... so maybe:

• orange: 0.1–0.45 keV
  green: 0.45–2.2 keV
  purple: 2.2–10 keV

blue must be there:
Color Code X-ray: orange, green, blue, purple; Radio: lilac, gray;

• orange: 0.1–0.3 keV
  green: 0.3–1.55 keV
  blue: 1.55–3.34 keV
  purple: 3.34–10 keV

<<X-rays with high photon energies above 5–10 keV (below 0.2–0.1 nm wavelength) are called hard X-rays, while those with lower energy (and longer wavelength) are called soft X-rays. The intermediate range with photon energies of several keV is often referred to as tender X-rays.

Due to their penetrating ability, hard [5–10 keV] X-rays are widely used to image the inside of objects, e.g., in medical radiography and airport security. Since the wavelengths of hard X-rays are similar to the size of atoms, they are also useful for determining crystal structures by X-ray crystallography.

By contrast, soft X-rays are easily absorbed in air; the attenuation length of 0.6 keV (~2 nm) X-rays in water is less than 1 micrometer.>>

[VictorBorun]

• orange: 0.1–0.3 keV
  green: 0.3–1.55 keV
  blue: 1.55–3.34 keV
  purple: 3.34–10 keV

<<X-rays with high photon energies above 5–10 keV (below 0.2–0.1 nm wavelength) are called hard X-rays, while those with lower energy (and longer wavelength) are called soft X-rays. The intermediate range with photon energies of several keV is often referred to as tender X-rays.

Due to their penetrating ability, hard [5–10 keV] X-rays are widely used to image the inside of objects, e.g., in medical radiography and airport security. Since the wavelengths of hard X-rays are similar to the size of atoms, they are also useful for determining crystal structures by X-ray crystallography.

By contrast, soft X-rays are easily absorbed in air; the attenuation length of 0.6 keV (~2 nm) X-rays in water is less than 1 micrometer.>>

So what do we make of this:

Click to view full size image

X-ray
4 Color[/img2]
?

The many little purple dots must be hot objects like neutron stars or black holes.

The northern and southern orange with a little hint of green chimneys' interiors must be relatively cold gas heated by massive BHs' jets.
But how do we get to see the X ray photons that soft? Where we can't see the light behind all the dust in the core of the Milky Way.

And the regions around the central BH and a few non-central supermassive BHs are bluish. I guess the image of the central clouds:
1) is depleted of its soft X rays by the dust in front of it
2) lacks the hard X rays because it's not hot enough

By the way, is every blindingly bright white globe here a supermassive BH in a moment of active feeding?
Why is there 3 of the largest ones to the South of Saggitarius A* and none to the North?
Is it why the Southern chimney is way denser than the Northern one?

[Chris Peterson]

• orange: 0.1–0.3 keV
  green: 0.3–1.55 keV
  blue: 1.55–3.34 keV
  purple: 3.34–10 keV

<<X-rays with high photon energies above 5–10 keV (below 0.2–0.1 nm wavelength) are called hard X-rays, while those with lower energy (and longer wavelength) are called soft X-rays. The intermediate range with photon energies of several keV is often referred to as tender X-rays.

Due to their penetrating ability, hard [5–10 keV] X-rays are widely used to image the inside of objects, e.g., in medical radiography and airport security. Since the wavelengths of hard X-rays are similar to the size of atoms, they are also useful for determining crystal structures by X-ray crystallography.

By contrast, soft X-rays are easily absorbed in air; the attenuation length of 0.6 keV (~2 nm) X-rays in water is less than 1 micrometer.>>

So what do we make of this:

Click to view full size image

X-ray
4 Color[/img2]
?

The many little purple dots must be hot objects like neutron stars or black holes.

The northern and southern orange with a little hint of green chimneys' interiors must be relatively cold gas heated by massive BHs' jets.
But how do we get to see the X ray photons that soft? Where we can't see the light behind all the dust in the core of the Milky Way.

And the regions around the central BH and a few non-central supermassive BHs are bluish. I guess the image of the central clouds:
1) is depleted of its soft X rays by the dust in front of it
2) lacks the hard X rays because it's not hot enough

By the way, is every blindingly bright white globe here a supermassive BH in a moment of active feeding?
Why is there 3 of the largest ones to the South of Saggitarius A* and none to the North?
Is it why the Southern chimney is way denser than the Northern one?

An image like this is largely aesthetic, not scientific. If you were considering the science, you'd be studying monochrome images of each data channel separately. An image like this has been corrupted by converting it to a color output. "Orange" is a mix of the display primaries red and green. "Purple" is a mix of the display primaries red and blue. So when you look at a pixel's content, which consists of only three values: red, green, and blue, there is no way to reliably determine which source bands are mixed together there.

[VictorBorun]

Is there a 50 ly disk at an angle to the Milky Way plane?

Click to view full size image

Here I played down the red and blue of RGB.
The center of my yellow dot elipse is at Saggitarius A*, it's tilted clockwise by 9.7° to fit the radiowaves chimney frames.
May Southern Chimney be relativistically brightened because it jets partially toward us?
May radiowaves frames of both chimneys be equally bright because radiowaves are generated by cooled down non-relativistic fraction of media?