Dwarf galaxy metallurgy, NGC 1569 Starburst (2008 Dec 29)

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neufer
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Dwarf galaxy metallurgy, NGC 1569 Starburst (2008 Dec 29)

Post by neufer » Mon Dec 29, 2008 5:47 am

http://apod.nasa.gov/apod/ap081229.html
http://antwrp.gsfc.nasa.gov/apod/ap020725.html

<<Explanation: For astronomers, elements other than hydrogen and helium are sometimes considered to be simply "heavy elements". It's understandable really, because even lumped all together heavy elements make up an exceedingly small fraction of the Universe. Still, heavy elements can profoundly influence galaxy and star formation ... not to mention the formation of planets and people. In this tantalizing false-color x-ray image from the orbiting Chandra Observatory, small dwarf galaxy NGC 1569 is surrounded by x-ray emitting clouds of gas thousands of light-years across. The gas has recently been observed to contain significant concentrations of astronomers' heavy elements such as oxygen, silicon, and magnesium, supporting the idea that dwarf galaxies, the most common type of galaxy in the Universe, are largely responsible for heavy elements in intergalactic space. A mere 7 million light-years distant toward the long-necked constellation Camelopardalis, NGC 1569 has undergone a recent burst of star formation and stellar supernova explosions. The furious cosmic activity has heated the expanding gas clouds to temperatures of millions of degrees while enriching them with newly synthesized heavy elements.>>
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Image
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http://en.wikipedia.org/wiki/Dwarves

<<A dwarf is a creature from Germanic mythology. It usually has magical talents, often involving metallurgy. As their mythology evolved, the most notable changes have had them become more comical and more mysterious. They adopted the modern image of short height and ugliness. Their associations with the underground became more predominant. Dwarves were magical creatures with huge skill at metallurgy, taking fame for making great artifacts of legend. The typical modern dwarf has distinctive features such as short stature, excessive hair, and skill at mining and metallurgy. However, modern literature draws from a wide range, and dwarves vary in fidelity to historical notions. Many fantasists devise new powers or images for dwarves. Modern dwarves have no strict definition.>>
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Art Neuendorffer

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Re: Hi, Ho: Dwarf galaxy metallurgy (APOD 2008 December 29)

Post by flamencoprof » Mon Dec 29, 2008 7:59 am

Off the metallic subject I know, but..... I am astounded to hear that dwarf galaxies are the most common of galaxies. I had perhaps by popular images of spiral ones been led to believe they were the "standard" galactic formation. Now I wonder that since another factoid I remember, that we have found many galaxies have a black hole at the centre, and if as I assume from this pic there is no strong gravitational centre to it, could it be that the dwarves are too young to have a black hole accumulate? Does the eventual gravitational collapse of one star to a BH start a gravitational well that produces a larger spiral galaxy?
Hofstadter's Law: "It always takes longer than you
expect, even if you take into consideration Hofstadter's Law"

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Re: Hi, Ho: Dwarf galaxy metallurgy (APOD 2008 December 29)

Post by flamencoprof » Mon Dec 29, 2008 8:18 am

Another question: - Is it likely that the presence of the two smaller "massive star clusters" (massive stars, or massive clusters?) suggests the presence of a galaxy forming influence in the area that tails off a bit in their direction?
Hofstadter's Law: "It always takes longer than you
expect, even if you take into consideration Hofstadter's Law"

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Hubble Resolves Puzzle About Loner Starburst Galaxy NGC 1569

Post by bystander » Mon Dec 29, 2008 1:26 pm

Hubble Resolves Puzzle About Loner Starburst Galaxy
NASA Mission News - HST - 2008 Nov 20 - STScI-PRC08-38

http://www.nasa.gov/mission_pages/hubbl ... 81120.html

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Re: Hi, Ho: Dwarf galaxy metallurgy (APOD 2008 December 29)

Post by neufer » Mon Dec 29, 2008 2:22 pm

flamencoprof wrote:Off the metallic subject I know, but..... I am astounded to hear that dwarf galaxies are the most common of galaxies. I had perhaps by popular images of spiral ones been led to believe they were the "standard" galactic formation. Now I wonder that since another factoid I remember, that we have found many galaxies have a black hole at the centre, and if as I assume from this pic there is no strong gravitational centre to it, could it be that the dwarves are too young to have a black hole accumulate? Does the eventual gravitational collapse of one star to a BH start a gravitational well that produces a larger spiral galaxy?
Only a handful of galactic stars are even aware of the the existence of a small or moderate sized black hole at the galactic center:
http://antwrp.gsfc.nasa.gov/apod/ap081211.html

And many elliptical galaxies have very large black holes:
http://antwrp.gsfc.nasa.gov/apod/ap060520.html
http://antwrp.gsfc.nasa.gov/apod/ap060427.html
http://antwrp.gsfc.nasa.gov/apod/ap050628.html

Very large black holes are more likely to destroy a spiral galaxy than to help form it:
http://antwrp.gsfc.nasa.gov/apod/ap080110.html
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<<Most identified dwarf spiral galaxies are located outside clusters. Strong gravitational interactions between galaxies and interactions between galaxies and intracluster gas are expected to destroy the disks of most dwarf spiral galaxies. Nonetheless, dwarf galaxies with spiral-like structure have been identified within the Virgo Cluster and Coma Cluster.>>
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Dwarf spiral galaxy
http://en.wikipedia.org/wiki/Dwarf_spiral_galaxy

<<A dwarf spiral galaxy is the dwarf version of a spiral galaxy. Dwarf galaxies are characterized as having low luminosities, small diameters (less than 5 kpc), low surface brightnesses, and low hydrogen masses. The galaxies may be considered a subclass of low surface brightness galaxies. Dwarf spiral galaxies, particularly the dwarf counterparts of Sa-Sc type spiral galaxies, are quite rare. In contrast, dwarf elliptical galaxies, dwarf irregular galaxies, and the dwarf versions of Sm type galaxies (which may be considered transitory between spiral and irregular in terms of morphology) are very common.>>
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<<There are many dwarf galaxies in the Local Group: these small galaxies frequently orbit around larger galaxies, such as the Milky Way, the Andromeda Galaxy and the Triangulum Galaxy. A recent paper has suggested that many dwarf galaxies were created by tidal forces during the early evolution of the Milky Way and Andromeda. The Milky Way has 14 known dwarf galaxies orbiting it, and recent discoveries have also led astronomers to believe the largest globular cluster in the Milky Way, Omega Centauri, is in fact the core of a dwarf galaxy with a black hole in its center, which was at some time absorbed by the Milky Way.>>
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Dwarf galaxy
http://en.wikipedia.org/wiki/Dwarf_galaxy

<<A dwarf galaxy is a small galaxy composed of up to several billion stars, a small number compared to our own Milky Way's 200-400 billion stars. The Large Magellanic Cloud, containing over 30 billion stars, is sometimes classified as a dwarf galaxy while others consider it a full-fledged galaxy going around the Milky Way galaxy.
.
. Hobbit galaxies
.
The recently coined term, hobbit galaxy has been used to describe galaxies smaller and dimmer than dwarf galaxies.
.
. Ultra Compact Dwarfs
.
Ultra Compact Dwarf galaxies (UCD) are a recently discovered class of very compact galaxies with very high stellar population counts. They are thought to be on the order of 200 light years across, with a hundred million stars. It is theorized that these are the cores of nucleated dwarf elliptical galaxies, that have been stripped of gas and outlying stars by tidal interactions, travelling through the hearts of rich clusters. UCDs have been found in the Virgo Cluster, Fornax Cluster, Abell 1689, amongst other clusters.>>
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Re: Hi, Ho: Dwarf galaxy metallurgy (APOD 2008 December 29)

Post by neufer » Mon Dec 29, 2008 4:42 pm

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http://www.britannia.com/history/arthur/excalibur.html

<<Legendary figures throughout the World are associated with
. magical swords, often the symbol of their Kingship.
Such swords were usually said to have been forged by an elfan SMITH.
In Saxon mythology his name is WAYLAND (= Gofannon to the Celts).
He is also to be identified with (the lame) Vulcan or Hephaestus
who made magical weapons for the Muses to give to Perseus,
. and for Thetis to give to Achilles.>>
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Art Neuendorffer

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NGC 1569: Starburst in a Dwarf Irregular (2008 Dec 29)

Post by Case » Tue Dec 30, 2008 5:04 am

It seems that image rotation hasn't been verified with the text: "Two massive star clusters [...] are seen left of center in the gorgeous Hubble Space Telescope image." If I am correct, then that should be "right of center", as I have marked in the image below?
Image

The Hubble site even mentions that one of them is actually two clusters close together. How does one know, if this (warning: 15 MB) is the best image, and it still looks like one clump in there?
I, for one, like Roman numerals.

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Re: NGC 1569: Starburst in a Dwarf Irregular (2008 Dec 29)

Post by neufer » Tue Dec 30, 2008 5:22 pm

Case wrote:It seems that image rotation hasn't been verified with the text: "Two massive star clusters [...] are seen left of center in the gorgeous Hubble Space Telescope image." If I am correct, then that should be "right of center", as I have marked in the image below?
Image

The Hubble site even mentions that one of them is actually two clusters close together.
How does one know, if this (warning: 15 MB) is the best image,
and it still looks like one clump in there?
Maybe from spectral redshift measurements or a differences in star population.
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http://en.wikipedia.org/wiki/NGC_1569

<<NGC 1569 contains two prominent super star clusters with different histories. Both clusters have experienced episodic star formation. Super star cluster A, located in the northwest of the galaxy, contains young stars (including Wolf-Rayet stars) that formed less than 5 million years ago as well as older red stars. Super star cluster B, located near the center of the galaxy, contains an older stellar population of red giants and red supergiants. Both of these star clusters are thought to have masses equivalent to the masses of the globular clusters in the Milky Way. Numerous smaller star clusters with relatively young ages have also been identified. These results, along with the results from other dwarf galaxies such as the Large Magellanic Cloud and NGC 1705, demonstrate that star formation in dwarf galaxies does not occur continuously but instead occurs in a series of short, nearly instantaneous bursts.

NGC 1569 is exceptional in that its spectrum is blueshifted. This means that the galaxy is moving towards the Earth. In contrast, the spectra of most other galaxies are redshifted because of the expansion of the universe.>>
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Re: NGC 1569: Starburst in a Dwarf Irregular (2008 Dec 29)

Post by bystander » Tue Dec 30, 2008 5:53 pm

Case wrote:It seems that image rotation hasn't been verified with the text: "Two massive star clusters [...] are seen left of center in the gorgeous Hubble Space Telescope image." If I am correct, then that should be "right of center" ...
I think you are correct. It seems the text was copied from APOD: 2004 Feb 5 - NGC 1569: Starburst in a Small Galaxy, but that image appears rotated 180 from APOD: 2008 Dec 29 - NGC 1569: Starburst in a Dwarf Irregular Galaxy and the text was not corrected for the rotation.

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