Astronomers Pinpoint The Origin of Huge Gas Bubbles Flowing Out of The Milky Way
There’s an unusual paradox hampering research into parts of the Milky Way. Dense gas blocks observations of the galactic core, and it can be difficult to observe in visible light from our vantage point.
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Tau.Neutrino said:
Astronomers Pinpoint The Origin of Huge Gas Bubbles Flowing Out of The Milky WayThere’s an unusual paradox hampering research into parts of the Milky Way. Dense gas blocks observations of the galactic core, and it can be difficult to observe in visible light from our vantage point.
more…
In what way is that a paradox?
The Rev Dodgson said:
Tau.Neutrino said:
Astronomers Pinpoint The Origin of Huge Gas Bubbles Flowing Out of The Milky WayThere’s an unusual paradox hampering research into parts of the Milky Way. Dense gas blocks observations of the galactic core, and it can be difficult to observe in visible light from our vantage point.
more…
In what way is that a paradox?
Hence it’s unusual!
The Rev Dodgson said:
Tau.Neutrino said:
Astronomers Pinpoint The Origin of Huge Gas Bubbles Flowing Out of The Milky WayThere’s an unusual paradox hampering research into parts of the Milky Way. Dense gas blocks observations of the galactic core, and it can be difficult to observe in visible light from our vantage point.
more…
In what way is that a paradox?
They use the word “paradox” here because “annoyance” sounds non-technical.
These are the Fermi bubbles, right? Right.
> Wisconsin H-Alpha Mapper (WHAM)
Gotta love the acronym.
> In an H-Alpha atom, an electron has jumped from the third energy level to the second energy level. That leaves a spectral line that’s the brightest hydrogen spectral line in optical light.
So why isn’t that blocked, or is it?
> Astronomers think that whatever happened at the Milky Way’s core to create the Fermi Bubbles, it happened several millions of years ago.
That recently? I suppose it could be. It’s 100,000 light years to the Milky Way’s core so a fast moving jet could travel a significant fraction of the distance in a million years.
Tau.Neutrino said:
Astronomers Pinpoint The Origin of Huge Gas Bubbles Flowing Out of The Milky WayThere’s an unusual paradox hampering research into parts of the Milky Way. Dense gas blocks observations of the galactic core, and it can be difficult to observe in visible light from our vantage point.
more…
From technical paper:
“Spectroscopic studies before 1977 towards Galactic Center, primarily focusing on the 21-cm neutral HI line, revealed the presence of many high velocity emission features near the plane of the Galaxy, suggesting that explosive phenomena were at play”. By 1988, this was explained as due to elliptical orbits in the plane of the galaxy and the presence of a bar making the Mily Way a barred-spiral, and not due to explosion.
“The discovery of the Fermi Bubbles, large lobes extending ∼55 degrees above and below the Galactic midplane visible in gamma-ray emission has rekindled interest in the possibility of Galactic outflows” from the centre.
“Here, we present new WHAM observations of Hα and towards the quasar PDS 456, where high-velocity UV absorption-lines have previously been seen with HST”
Oh, is that all. A single line of sight.
“We have discovered high-velocity optical emission in the vicinity of the Fermi Bubbles at the same velocity as previously observed UV absorption features”
What speed?
“We detect no significant Hα emission around vLSR ∼ +135 km s−1 where UV absorption is observed.”
That contradicts claims of discovering a high speed components that confirmed the previous UV absorption results.
Summary, this paper is extremely limited (one sight line) and self-contradictory.