HEAPOW: Connecting the Bubbles (2021 Jan 18)

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HEAPOW: Connecting the Bubbles (2021 Jan 18)

Post by bystander » Mon Jan 18, 2021 7:24 pm

HEAPOW: Connecting the Bubbles (2021 Jan 18)
Image HEAPOW: Connecting the Bubbles (2021 Jan 18)

One of the most surprising structures associated with our home galaxy, the Milky Way, are the gamma-ray emitting, bubble-like structures extending more than 25,000 light years above and below the center of the Galaxty. These bubbles were discovered by the Fermi Gamma-Ray Space Telescpe about a decade ago, and now affectionately known as the "Fermi Bubbles" by astronomers. Clearly the result of some remarkable outpouring of energy near the center of the Milky Way, the event (or series of events) that blew the "Fermi Bubbles" is still not entirely understood. A new all-sky X-ray map obtained by the eROSITA telescope on the Spektr-RG spacecraft may help solve this problem. The image above shows composite all-sky maps centered on the center of the Milky Way (so that the disk of the Milky Way stretches from left to right at the middle of the image, and the center of the Milky Way is at the center of the image). The gamma-ray map from Fermi is shown in red, while the X-ray map from eROSITA is shown in blue. The Fermi image shows the Fermi Bubbles emanating from the center of the Milky Way above and below the disk of the Galaxy. The X-ray image from eROSITA also shows similar X-ray bubbles above and below the Galaxy, but about twice as large as the Fermi bubbles, each having a diameter of about 45,000 lightyears. Analysis of the X-ray "eROSITA Bubbles" suggest that these bubbles are probably the remnants of an enormous but temporary burst of energy from Sgr A*, the 4-million solar mass black hole at the center of the Milky Way, about a Fermi bubble diameter away from us. The outburst might have happened if Sgr A* swallowed a massive cloud of gas (or perhaps some unfortunate star or group of stars) a few million years ago, and, for a million years or two, formed a disk of accreting matter and shot a particle beam into space perpendicular to the Galaxy's disk, blowing out material that we seen now as the Fermi/eROSITA bubbles. Sometime after this feeding frenzy, the monster black hole afterwards fell into its current sleepy state.

Quanta: Galaxy-Size Bubbles Discovered Towering over the Milky Way
MPE: eROSITA Finds Large-Scale Bubbles in the Halo of the Milky Way

Detection of Large-Scale X-ray Bubbles in the Milky Way Halo ~ P. Predehl et al

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Re: HEAPOW: Connecting the Bubbles (2021 Jan 18)

Post by Ann » Tue Jan 19, 2021 12:47 pm

The Fermi and eRosita bubbles, centered on "nothing" (because there is no activity in Milky Way's central black hole), remind me of Hanny's Voorwerp.

The Milky Way Fermi and eRosita bubbles are likely remnants of past activity in Sgr A*, our galaxy's central black hole. Sgr A* has since gone quiet, but the Fermi and eRosita bubbles remain.

Likewise, Hanny's Voorwerp remains, even though the quasar activity in galaxy IC 2497 that likely ionized Hanny' Voorwerp in the first place has since gone quiet.

These things are a bit like humongously large supernova remnants. The supernova is gone, but its ionized shell of debris remains.

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Re: HEAPOW: Connecting the Bubbles (2021 Jan 18)

Post by neufer » Wed Jan 20, 2021 3:36 am

Click to play embedded YouTube video.
Ann wrote:
Tue Jan 19, 2021 12:47 pm

The Fermi and eRosita bubbles,
centered on "nothing"
Nothing will come
of nothing: speak again.
Art Neuendorffer