APOD: The Vertical Magnetic Field of NGC 5775 (2021 Jan 27)

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Expand view Topic review: APOD: The Vertical Magnetic Field of NGC 5775 (2021 Jan 27)

Re: APOD: The Vertical Magnetic Field of NGC 5775 (2021 Jan 27)

by Ann » Fri Jan 29, 2021 8:08 pm

VictorBorun wrote: Fri Jan 29, 2021 5:52 pm
Ann wrote: Wed Jan 27, 2021 7:52 pm Don't have much to say about NGC 5775, but I guess it has been active in the past, if it isn't active now. It has two companions, and the larger one, NGC 5774, is fluffy, almost certainly gas-rich, and possibly tidally distorted. This galaxy may have fed gas into the black hole of NGC 5775 in the past and possibly caused activity that is now seen as both a magnetic field and a radio halo.

Ann
Tried to overlay the posted pic with this with thermal radio cloud (3.5° rotation, 89/72 stretch)
Magnetic synchrotron lanes look strikingly similar to smoke streaks from red-hot ashes (starring star-forming regions here) and thermal radio halo to a diffuse haze after extinguishing the fire with a bucket of water
Thanks, Victor! I like your picture overlays.

Ann

Re: APOD: The Vertical Magnetic Field of NGC 5775 (2021 Jan 27)

by VictorBorun » Fri Jan 29, 2021 5:52 pm

Ann wrote: Wed Jan 27, 2021 7:52 pm Don't have much to say about NGC 5775, but I guess it has been active in the past, if it isn't active now. It has two companions, and the larger one, NGC 5774, is fluffy, almost certainly gas-rich, and possibly tidally distorted. This galaxy may have fed gas into the black hole of NGC 5775 in the past and possibly caused activity that is now seen as both a magnetic field and a radio halo.

Ann
Tried to overlay the posted pic with this with thermal radio cloud (3.5° rotation, 89/72 stretch)
Magnetic synchrotron lanes look strikingly similar to smoke streaks from red-hot ashes (starring star-forming regions here) and thermal radio halo to a diffuse haze after extinguishing the fire with a bucket of water

Re: APOD: The Vertical Magnetic Field of NGC 5775 (2021 Jan 27)

by neufer » Fri Jan 29, 2021 1:34 am

bystander wrote: Thu Jan 28, 2021 10:33 pm
vaster wrote: Thu Jan 28, 2021 9:05 pm
Are you going to create a Spanish or Frech version, for example?
Are you volunteering to administer it?
  • I'm in charge of the frech version.
https://en.wiktionary.org/wiki/frech wrote:
frech (German)

1) cheeky, barefaced, rude
2) (of a child also) naughty

Re: APOD: The Vertical Magnetic Field of NGC 5775 (2021 Jan 27)

by bystander » Thu Jan 28, 2021 10:33 pm

vaster wrote: Thu Jan 28, 2021 9:05 pm Are you going to create a Spanish or Frech version, for example?
Are you volunteering to administer it?

Re: APOD: The Vertical Magnetic Field of NGC 5775 (2021 Jan 27)

by bystander » Thu Jan 28, 2021 3:47 pm

Sérgio wrote: Wed Jan 27, 2021 5:15 am E o cometa em rota de colisão com a terra, como está o cálculo ?
heehaw wrote: Wed Jan 27, 2021 10:42 am É calculado usando a lei da gravidade de Newton
Huh? wrote: Thu Jan 28, 2021 1:01 am ¿A qué cometa te refieres?
heehaw wrote: Thu Jan 28, 2021 10:54 am Todos os cometas seguem a mesma lei da gravidade de Newton
RJN wrote: Mon Jan 18, 2010 7:40 pm
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Re: APOD: The Vertical Magnetic Field of NGC 5775 (2021 Jan 27)

by neufer » Thu Jan 28, 2021 3:10 pm

heehaw wrote: Thu Jan 28, 2021 10:54 am
Todos os cometas seguem a mesma lei da gravidade de Newton
https://en.wikipedia.org/wiki/Halley%27s_Comet#Computation_of_orbit wrote:
<<Halley's Comet, officially designated 1P/Halley, is a short-period comet visible from Earth every 75–76 years. Some scholars have proposed that first-century Mesopotamian astronomers already had recognized Halley's Comet as periodic. This theory notes a passage in the Bavli Talmud, tractate Horayot#Aggada that refers to "a star which appears once in seventy years that makes the captains of the ships err."

Halley has probably been in its current orbit for 16,000–200,000 years, although it is not possible to numerically integrate its orbit for more than a few tens of apparitions, and close approaches before 837 AD can only be verified from recorded observations. The non-gravitational effects can be crucial; as Halley approaches the Sun, it expels jets of sublimating gas from its surface, which knock it very slightly off its orbital path. These orbital changes cause delays in its perihelion of four days, average.

In 1989, Boris Chirikov and Vitold Vecheslavov performed an analysis of 46 apparitions of Halley's Comet taken from historical records and computer simulations. These studies showed that its dynamics were chaotic and unpredictable on long timescales. Halley's projected lifetime could be as long as 10 million years. These studies also showed that many physical properties of Halley's Comet dynamics can be approximately described by a simple symplectic map, known as the Kepler map. More recent work suggests that Halley will evaporate, or split in two, within the next few tens of thousands of years, or will be ejected from the Solar System within a few hundred thousand years. Observations by D. W. Hughes suggest that Halley's nucleus has been reduced in mass by 80 to 90% over the last 2,000 to 3,000 revolutions.>>

Re: APOD: The Vertical Magnetic Field of NGC 5775 (2021 Jan 27)

by khjalmarj@gmail.com » Thu Jan 28, 2021 2:37 pm

I gotta check my memory and understanding with you folks. How do the blue lines/patterns get determined? I think this is synchrotron radiation, right? Relativistic electrons spiraling around magnetic field lines? You determine whether this is so by mapping the galaxy in at least two different radio frequencies. If the spectrum is fairly flat, meaning you get close to the same strength in each frequency, that's synchrotron radiation. If the two differ by quite a bit, it's something else, like thermal emission. Does that sound anywhere close to right?
(I did some work on radio spectra back in grad school, but that was many years ago, so I've probably misremembered a lot.)

Re: APOD: The Vertical Magnetic Field of NGC 5775 (2021 Jan 27)

by heehaw » Thu Jan 28, 2021 10:54 am

Todos os cometas seguem a mesma lei da gravidade de Newton

Re: APOD: The Vertical Magnetic Field of NGC 5775 (2021 Jan 27)

by Huh? » Thu Jan 28, 2021 1:01 am

heehaw wrote: Wed Jan 27, 2021 10:42 am
Sérgio wrote: Wed Jan 27, 2021 5:15 am E o cometa em rota de colisão com a terra, como está o cálculo ?
É calculado usando a lei da gravidade de Newton
¿A qué cometa te refieres?

Re: APOD: The Vertical Magnetic Field of NGC 5775 (2021 Jan 27)

by heehaw » Wed Jan 27, 2021 11:09 pm

Chris Peterson wrote: Wed Jan 27, 2021 3:08 pm
orin stepanek wrote: Wed Jan 27, 2021 2:50 pm Interesting that a galaxy has so much magnetism!
Does it? The imaging style used to display the lines certainly makes for an impressive appearance, but we need to remember that these fields are incredibly weak. Orders of magnitude smaller than the magnetic fields of planets like the Earth, for instance.
I do so wish that we were allowed 'likes' on this, our dear APOD!!

Re: APOD: The Vertical Magnetic Field of NGC 5775 (2021 Jan 27)

by neufer » Wed Jan 27, 2021 10:33 pm

ptahhotep wrote: Wed Jan 27, 2021 6:13 pm
APOD Robot wrote: Wed Jan 27, 2021 5:08 am
For decades astronomers knew only that some spiral galaxies had magnetic fields.
Do all spirals have magnetic fields? Do non-spirals have magnetic fields?
https://www.nasa.gov/feature/magnetic-highway-channels-material-out-of-cigar-galaxy wrote:
Magnetic fields in Messier 82, or the Cigar galaxy, are shown as lines over a visible light and infrared composite image of the galaxy from the Hubble Space Telescope and the Spitzer Space Telescope. Stellar winds streaming from hot new stars form a galactic super wind that is blasting out plumes of hot gas (red) and a huge halo of smoky dust (yellow/orange) perpendicular to the narrow galaxy (white). Researchers used the Stratospheric Observatory for Infrared Astronomy magnetic field data and tools that have been used extensively to study the physics around the Sun to extrapolate the magnetic field’s strength 20,000 lights-years around the galaxy. They appear to extend indefinitely into intergalactic space, like the Sun’s solar wind, and may help explain how the gas and dust have traveled so far away from the galaxy. Credits: NASA, SOFIA, L. Proudfit; NASA, ESA, Hubble Heritage Team; NASA, JPL-Caltech, C. Engelbracht

Magnetic ‘Highway’ Channels Material Out of Cigar Galaxy
NASA, Jan. 14, 2021

<<What’s fueling the massive ejection of gas and dust out of the Cigar galaxy, otherwise known as Messier 82?

We know that thousands of stars bursting into existence are driving a powerful super-wind that’s blowing matter into intergalactic space. New research shows that magnetic fields are also contributing to the expulsion of material from Messier 82, a well-known example of a starburst galaxy with a distinctive, elongated shape [classified as an irregular galaxy].

The findings from NASA’s Stratospheric Observatory for Infrared Astronomy, or SOFIA, help explain how dust and gas can move from inside galaxies into intergalactic space, offering clues to how galaxies formed. This material is enriched with elements like carbon and oxygen that support life and are the building blocks for future galaxies and stars. The research was presented at the meeting of the American Astronomical Society.

SOFIA, a joint project of NASA and the German Aerospace Center, DLR, previously studied the direction of magnetic fields close to the core of Messier 82, as the Cigar galaxy is officially known. This time the team applied tools that have been used extensively to study the physics around the Sun, known as heliophysics, to understand the magnetic field’s strength surrounding the galaxy at a distance 10 times larger than before.

“This is old physics for studying the Sun, but new for galaxies,” said Joan Schmelz, a director at the Universities Space Research Association based at NASA’s Ames Research Center in Silicon Valley, and co-author of the upcoming paper about this research. “It’s helping us understand how the space between stars and galaxies became so rich with matter for future cosmic generations.”

Located 12 million light-years from Earth in the constellation Ursa Major, the Cigar galaxy is undergoing an exceptionally high rate of star formation called a starburst. The star formation is so intense that it creates a “super wind” that blows material out of the galaxy. As SOFIA previously found using the instrumented called the High-Resolution Airborne Wideband Camera, or HAWC+, the wind drags the magnetic field near the galaxy’s core so that it’s perpendicular to the plane of the galaxy across 2,000 light-years.

Researchers wanted to learn if the magnetic field lines would extend indefinitely into intergalactic space like the magnetic environment in the solar wind, or turn over to form structures similar coronal loops that are found in active regions of the Sun. They calculate that the galaxy’s magnetic fields extend out like the solar wind, allowing the material blown by the super wind to escape into intergalactic space.

These extended magnetic fields may help explain how gas and dust spotted by space telescopes have traveled so far away from the galaxy. NASA’s Spitzer Space Telescope detected dusty material 20,000 lightyears beyond the galaxy, but it was unclear why it had spread so far away from the stars in both directions instead of in a cone-shaped jet.

“The magnetic fields may be acting like a highway, creating lanes for galactic material to spread far and wide into intergalactic space,” said Jordan Guerra Aguilera, a postdoctoral researcher at Villanova University in Pennsylvania and co-author on the upcoming paper.

With rare exceptions, the magnetic field in the solar corona cannot be measured directly. So, about 50 years ago, scientists developed methods to accurately extrapolate magnetic fields from the Sun’s surface into interplanetary space, known in heliophysics as the potential field extrapolation. Using SOFIA’s existing observations of central magnetic fields, the research team modified this method to estimate the magnetic field about 25,000 light-years around the Cigar galaxy.

“We can’t easily measure the magnetic fields at scales this large, but we can extrapolate it with these tools from heliophysics,” said Enrique Lopez-Rodriguez, a Universities Space Research Association scientist for SOFIA based at Ames and lead author on the study. “This new, interdisciplinary method gives us the larger perspective that we need to understand starburst galaxies.”>>

Re: APOD: The Vertical Magnetic Field of NGC 5775 (2021 Jan 27)

by Ann » Wed Jan 27, 2021 7:52 pm

Don't have much to say about NGC 5775, but I guess it has been active in the past, if it isn't active now. It has two companions, and the larger one, NGC 5774, is fluffy, almost certainly gas-rich, and possibly tidally distorted. This galaxy may have fed gas into the black hole of NGC 5775 in the past and possibly caused activity that is now seen as both a magnetic field and a radio halo.

Ann

Re: APOD: The Vertical Magnetic Field of NGC 5775 (2021 Jan 27)

by Alanh » Wed Jan 27, 2021 7:37 pm

I am guessing that in real life the colors are not there but it looks like the northern lights.

Re: APOD: The Vertical Magnetic Field of NGC 5775 (2021 Jan 27)

by ptahhotep » Wed Jan 27, 2021 6:13 pm

APOD Robot wrote: Wed Jan 27, 2021 5:08 am For decades astronomers knew only that some spiral galaxies had magnetic fields.
Apart from the extensions, what else has the VLA revealed? Do all spirals have magnetic fields? Do non-spirals have magnetic fields?

Re: APOD: The Vertical Magnetic Field of NGC 5775 (2021 Jan 27)

by orin stepanek » Wed Jan 27, 2021 4:24 pm

Chris Peterson wrote: Wed Jan 27, 2021 3:08 pm
orin stepanek wrote: Wed Jan 27, 2021 2:50 pm Wow! :shock: If we could ride these fields; we could travel near the speed pf light!
That's like saying that if we could ride our highways, we could travel near the speed of light. Riding magnetic field lines does not imply any particular speed. At least, unless you happen to be an electron.
Interesting that a galaxy has so much magnetism!
Does it? The imaging style used to display the lines certainly makes for an impressive appearance, but we need to remember that these fields are incredibly weak. Orders of magnitude smaller than the magnetic fields of planets like the Earth, for instance.
Yeah; I guess I dream too much! :mrgreen:

Re: APOD: The Vertical Magnetic Field of NGC 5775 (2021 Jan 27)

by Chris Peterson » Wed Jan 27, 2021 3:08 pm

orin stepanek wrote: Wed Jan 27, 2021 2:50 pm Wow! :shock: If we could ride these fields; we could travel near the speed pf light!
That's like saying that if we could ride our highways, we could travel near the speed of light. Riding magnetic field lines does not imply any particular speed. At least, unless you happen to be an electron.
Interesting that a galaxy has so much magnetism!
Does it? The imaging style used to display the lines certainly makes for an impressive appearance, but we need to remember that these fields are incredibly weak. Orders of magnitude smaller than the magnetic fields of planets like the Earth, for instance.

Re: APOD: The Vertical Magnetic Field of NGC 5775 (2021 Jan 27)

by orin stepanek » Wed Jan 27, 2021 2:50 pm

Wow! :shock: If we could ride these fields; we could travel near the speed pf light!
NGC5775_NraoEnglish_1080.jpg
Interesting that a galaxy has so much magnetism!
APOD says unexpectedly discovered
which reveals another pretty but surprised cat!
MwLMgEJ.jpg
OK; OK! I like today's remittance by APOD! :D

Re: APOD: The Vertical Magnetic Field of NGC 5775 (2021 Jan 27)

by Tszabeau » Wed Jan 27, 2021 12:36 pm

For some reason... me want cookie.

Re: APOD: The Vertical Magnetic Field of NGC 5775 (2021 Jan 27)

by heehaw » Wed Jan 27, 2021 10:42 am

Sérgio wrote: Wed Jan 27, 2021 5:15 am E o cometa em rota de colisão com a terra, como está o cálculo ?
É calculado usando a lei da gravidade de Newton

Re: APOD: The Vertical Magnetic Field of NGC 5775 (2021 Jan 27)

by XgeoX » Wed Jan 27, 2021 8:59 am

What a wonderful image.

Eric

Re: APOD: The Vertical Magnetic Field of NGC 5775 (2021 Jan 27)

by Sérgio » Wed Jan 27, 2021 5:15 am

E o cometa em rota de colisão com a terra, como está o cálculo ?

APOD: The Vertical Magnetic Field of NGC 5775 (2021 Jan 27)

by APOD Robot » Wed Jan 27, 2021 5:08 am

Image The Vertical Magnetic Field of NGC 5775

Explanation: How far do magnetic fields extend up and out of spiral galaxies? For decades astronomers knew only that some spiral galaxies had magnetic fields. However, after NRAO's Very Large Array (VLA) radio telescope (popularized in the movie Contact) was upgraded in 2011, it was unexpectedly discovered that these fields could extend vertically away from the disk by several thousand light-years. The featured image of edge-on spiral galaxy NGC 5775, observed in the CHANG-ES (Continuum Halos in Nearby Galaxies) survey, also reveals spurs of magnetic field lines that may be common in spirals. Analogous to iron filings around a bar magnet, radiation from electrons trace galactic magnetic field lines by spiraling around these lines at almost the speed of light. The filaments in this image are constructed from those tracks in VLA data. The visible light image, constructed from Hubble Space Telescope data, shows pink gaseous regions where stars are born. It seems that winds from these regions help form the magnificently extended galactic magnetic fields.

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