ESO: Dazzling Spiral with an Active Heart (M77)

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bystander
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ESO: Dazzling Spiral with an Active Heart (M77)

Post by bystander » Wed Jul 05, 2017 3:34 pm

Dazzling Spiral with an Active Heart
ESO Photo Release | VLT | 2017 Jul 05
[img3="Credit: ESO VLT"]https://cdn.eso.org/images/screen/eso1720a.jpg[/img3][hr][/hr]
ESO’s Very Large Telescope (VLT) has captured a magnificent face-on view of the barred spiral galaxy Messier 77. The image does justice to the galaxy’s beauty, showcasing its glittering arms criss-crossed with dust lanes — but it fails to betray Messier 77’s turbulent nature.

This picturesque spiral galaxy appears to be tranquil, but there is more to it than meets the eye. Messier 77 (also known as NGC 1068) is one of the closest active galaxies, which are some of the most energetic and spectacular objects in the Universe. Their nuclei are often bright enough to outshine the whole of the rest of the galaxy. Active galaxies are among the brightest objects in the Universe and emit light at most, if not all, wavelengths, from gamma rays and X-rays all the way to microwaves and radiowaves. Messier 77 is further classified as a Type II Seyfert galaxy, characterised by being particularly bright at infrared wavelengths.

This impressive luminosity is caused by intense radiation blasting out from a central engine — the accretion disc surrounding a supermassive black hole. Material that falls towards the black hole is compressed and heated up to incredible temperatures, causing it to radiate a tremendous amount of energy. This accretion disc is thought to be enshrouded by thick doughnut-shaped structure of gas and dust, called a “torus”. Observations of Messier 77 back in 2003 were the first to resolve such a structure using the powerful VLT Interferometer (eso0319).

This image of Messier 77 was taken in four different wavelength bands represented by blue, red, violet and pink (hydrogen-alpha) colours. Each wavelength brings out a different quality: for example, the pinkish hydrogen-alpha highlights the hotter and younger stars forming in the spiral arms, while in red are the fine, thread-like filamentary structures in the gas surrounding Messier 77 [1]. A foreground Milky Way star is also seen beside the galaxy centre, displaying tell-tale diffraction spikes. Additionally, many more distant galaxies are visible; sitting at the outskirts of the spiral arms, they appear tiny and delicate compared to the colossal active galaxy. ...
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Ann
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Re: ESO: Dazzling Spiral with an Active Heart (M77)

Post by Ann » Thu Jul 06, 2017 5:00 am

ESO wrote:

..the pinkish hydrogen-alpha highlights the hotter and younger stars forming in the spiral arms, while in red are the fine, thread-like filamentary structures in the gas surrounding Messier 77
I hadn't seen those red filaments in M77 before! They are very suggestive of outflows and possibly jets from an active black hole.

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Jets from an active black hole?

Post by neufer » Thu Jul 06, 2017 3:01 pm

Ann wrote:
ESO wrote:

..the pinkish hydrogen-alpha highlights the hotter and younger stars forming in the spiral arms,
while in red are the fine, thread-like filamentary structures in the gas surrounding Messier 77
I hadn't seen those red filaments in M77 before!

They are very suggestive of outflows and possibly jets from an active black hole.
http://www.spacetelescope.org/images/heic0817a/ wrote:

Click to play embedded YouTube video.
Magnetic monster NGC 1275
NASA, ESA and Andy Fabian (University of Cambridge, UK)

<<This stunning image of NGC 1275 was taken using the NASA/ESA Hubble Space Telescope's Advanced Camera for Surveys in July and August 2006. It provides amazing detail and resolution of the fragile filamentary structures, which show up as a reddish lacy structure surrounding the central bright galaxy NGC 1275. These filaments are COOL despite being surrounded by gas that is around 55 million degrees Celsius hot. They are suspended in a magnetic field which maintains their structure and demonstrates how energy from the central black hole is transferred to the surrounding gas.

By observing the filamentary structure, astronomers were, for the first time, able to estimate the magnetic field's strength. Using this information they demonstrated how the extragalactic magnetic fields have maintained the structure of the filaments against collapse caused by either gravitational forces or the violence of the surrounding cluster during their 100-million-year lifetime.

This is the first time astronomers have been able to differentiate the individual threads making up such filaments to this degree. Astonishingly, they distinguished threads a mere 200 light-years across. By contrast, the filaments seen here can be a gaping 200 000 light-years long. The entire image is approximately 260 000 light-years across.

Also seen in the image are impressive lanes of dust from a separate spiral galaxy. It lies partly in front of the giant elliptical central cluster galaxy and has been completed disrupted by the tidal gravitational forces within the galaxy cluster. Several striking filaments of blue newborn stars are seen crossing the image.>>
Art Neuendorffer

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Re: Jets from an active black hole?

Post by Ann » Thu Jul 06, 2017 8:50 pm

neufer wrote:
http://www.spacetelescope.org/images/heic0817a/ wrote:

Magnetic monster NGC 1275
NASA, ESA and Andy Fabian (University of Cambridge, UK)

<<This stunning image of NGC 1275 was taken using the NASA/ESA Hubble Space Telescope's Advanced Camera for Surveys in July and August 2006. It provides amazing detail and resolution of the fragile filamentary structures, which show up as a reddish lacy structure surrounding the central bright galaxy NGC 1275. These filaments are COOL despite being surrounded by gas that is around 55 million degrees Celsius hot. They are suspended in a magnetic field which maintains their structure and demonstrates how energy from the central black hole is transferred to the surrounding gas.

By observing the filamentary structure, astronomers were, for the first time, able to estimate the magnetic field's strength. Using this information they demonstrated how the extragalactic magnetic fields have maintained the structure of the filaments against collapse caused by either gravitational forces or the violence of the surrounding cluster during their 100-million-year lifetime.
Ah! So we're not talking jets from a black hole, but energy from the black hole being transferred to the surrounding gas and somehow becoming trapped in magnetic field lines?

Ann
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