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Astronomy Picture of the Day -- NGC 4449: Star Stream for a Dwarf Galaxy
NASA ^ | January 25, 2012 | (see photo credit)

Posted on 01/26/2012 4:31:42 AM PST by SunkenCiv

Explanation: A mere 12.5 million light-years from Earth, irregular dwarf galaxy NGC 4449 lies within the confines of Canes Venatici, the constellation of the Hunting Dogs. About the size of our Milky Way's satellite galaxy the Large Magellanic Cloud, NGC 4449 is undergoing an intense episode of star formation, evidenced by its wealth of young blue star clusters, pinkish star forming regions, and obscuring dust clouds in this deep color portrait. It's also holds the distinction of being the first dwarf galaxy with an identified tidal star stream, faintly seen at the lower right. Placing your cursor over the image reveals an inset of the stream resolved into red giant stars. The star stream represents the remains of a still smaller infalling satellite galaxy, disrupted by gravitational forces and destined to merge with NGC 4449. With relatively few stars, small galaxies are thought to posses extensive dark matter halos. But since dark matter interacts gravitationally, these observations offer a chance to examine the significant role of dark matter in galactic merger events. The interaction is likely responsible for NGC 4449's burst of star formation and offers a tantalizing insight into how even small galaxies are assembled over time.

January 25, 2012

(Excerpt) Read more at 129.164.179.22 ...


TOPICS: Astronomy; Astronomy Picture of the Day; Science
KEYWORDS: apod; astronomy; ngc4449; science
[Credit & Copyright: R Jay Gabany (Blackbird Obs.); Insert: Subaru/Suprime-Cam (NAOJ); Collaboration: David Martinez-Delgado (MPIA, IAC), et al.]

1 posted on 01/26/2012 4:31:48 AM PST by SunkenCiv
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To: SunkenCiv

I lived there for a while but everything was too short for me.


2 posted on 01/26/2012 4:32:49 AM PST by Larry Lucido (Six months ago I was all "Go away Newt." Now I'm "Eh, he's the best we got, so 'Go Newt.'")
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To: brytlea; cripplecreek; decimon; bigheadfred; KoRn; Grammy; married21; steelyourfaith; Mmogamer; ...

3 posted on 01/26/2012 4:33:02 AM PST by SunkenCiv (FReep this FReepathon!)
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To: Larry Lucido

Those colorfully dressed (gay) singers drove me right out of there. No wonder they need a coroner.


4 posted on 01/26/2012 4:37:57 AM PST by SunkenCiv (FReep this FReepathon!)
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To: SunkenCiv

Beautiful, SunkenCiv!


5 posted on 01/26/2012 4:38:27 AM PST by momtothree
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Comment #6 Removed by Moderator

To: SunkenCiv

http://129.164.179.22/apod/ap120126.html


7 posted on 01/26/2012 5:15:16 AM PST by WSGilcrest (/s)
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To: Larry Lucido

I prefer the term “height-challenged galaxy”.


8 posted on 01/26/2012 5:42:53 AM PST by 6SJ7 (Meh.)
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To: SunkenCiv

“It was the best of times; it was the worst of times...”


9 posted on 01/26/2012 7:19:07 AM PST by pabianice (")
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To: SunkenCiv

Hey! It’s on the list for the February Star Party!

Thanks!


10 posted on 01/26/2012 7:53:49 AM PST by Conan the Librarian (The Best in Life is to crush my enemies, see them driven before me, and the Dewey Decimal System)
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To: pabianice

That’s what Spock told me on my birthday.


11 posted on 01/26/2012 4:54:33 PM PST by fieldmarshaldj
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