APOD: Spiral Galaxy M66 (2010 Nov 13)

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APOD: Spiral Galaxy M66 (2010 Nov 13)

Post by APOD Robot » Sat Nov 13, 2010 5:02 am

Image Spiral Galaxy M66

Explanation: Big beautiful spiral galaxy M66 lies a mere 35 million light-years away. About 100 thousand light-years across, the gorgeous island universe is well known to astronomers as a member of the Leo Triplet of galaxies. In M66, pronounced dust lanes and young, blue star clusters sweep along spiral arms dotted with the tell-tale glow of pink star forming regions. This colorful and deep view also reveals faint extensions beyond the brighter galactic disk. Of course, the bright, spiky stars lie in the foreground, within our own Milky Way Galaxy, but many, small, distant background galaxies can be seen in the cosmic snapshot. Gravitational interactions with its neighboring galaxies have likely influenced the shape of spiral galaxy M66.

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Ann
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Re: APOD: Spiral Galaxy M66 (2010 Nov 13)

Post by Ann » Sat Nov 13, 2010 6:58 am

That is a beautiful picture of spiral galaxy M 66.

M66 is one member of the Leo Triplet:
In the picture of the Leo Triplet, you can see M 66 at bottom right. M 65 is at top right, and edge-on NGC 3628 is at top left.

This galaxy trio shows signs of having danced around each other for such a long time that they have spent most of their star forming material. It is typical of galactic interaction that it tends to compress the gas inside the galaxies and cause this gas to start forming stars at a high rate. Famous examples of galactic interaction that leads to intense star formation are the Antennae interacting galaxies and M 51 with companion NGC 5195:


M 51 and NGC 5195. Note the blue color of M 51, which results from huge numbers of newly formed hot stars. Also note the much more neutral-colored arcs and loops surrounding NGC 5195. They are streams of mostly old stars that have been thrown out of NGC 5195 because of tidal interaction with M 51. NGC 5195 has no star formation itself.

Like NGC 5195, M 66 is surrounded by arcs and loops of old to intermediate stars that have been thrown out of the galaxy because of tidal interaction with M 65 and NGC 3626. Like M 51, M 66 has star formation, too. There are obvious blue patches inside M 66, which are sites of recent star formation. There are also pink patches of emission nebulosity in M 66. They are not so obvious in this (otherwise very beautiful and colorful) image, but they show up better in other color pictures of M 66.

So M 66 has a large population of old stars, but it has ongoing star formation too. This sets it apart from its "Messier neighbour", M 65. Although one bluish cluster or association is visible in high resolution images of M 65, no emission nebulae are detected. Star formation appears to have ceased in this galaxy. Typically, M 66 and M 65 have noticably different color indexes: +0.70 for M 66 versus +0.90, which is much yellower, for M 65.

Edge-on Leo Triplet member NGC 3628 has no detectable bluish clusters or associations at all, and no emission nebulae. It is however possible that such clusters and associations exist, which are hidden from our perspective deeper in the disk of the galaxy. But we can see that NGC 3628 has a very puffed-up disk and a long tidal tail of stars emanating from one end of its disk:

http://astronomy.qteaser.com/images/NGC-3628-LRGB.jpg

The Leo Triplet creates an environment with a lot of tidal tugging and stretching. The Leo Triplet is a galaxy group with a small total amount of star formation. It is also a part of the sky where most of the gas and dust has already been spent, and there is little star formatin material left to set up stellar maternity wards. M 66 is the member that won't give up, and which keeps producing young blue stars born in rose-colored emission nebulae.

Image

Sleep, blue little star baby (or rather, big blue star baby, and I don't know what the pink star is doing there) in your lovely pink crib!

Ann
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Re: APOD: Spiral Galaxy M66 (2010 Nov 13)

Post by Squinting » Sat Nov 13, 2010 1:10 pm

A suggestion. It would be nice if every deep space photo had a small legend underneath comparing the angular size of the photo to the average full moon size, to help us instantly understand the scale of these beautiful shots. Something simple and easy like this:

Full Moon _________________________________________________________________________

Photo _________

or

Full Moon __

Photo ___________________________________________________________________________________________________________________________

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Re: APOD: Spiral Galaxy M66 (2010 Nov 13)

Post by orin stepanek » Sat Nov 13, 2010 1:44 pm

Wonderful photo; way to go APOD. 8-)
Orin

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Re: Size Info.

Post by nstahl » Sat Nov 13, 2010 1:48 pm

Or how about as ang. si. = 0.002 afm (average full moon)? That's not a bad idea.

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Re: APOD: Spiral Galaxy M66 (2010 Nov 13)

Post by cmflyer » Sat Nov 13, 2010 3:20 pm

Do the foreground "spikey" stars have the spikes added, or is it a natural result of optics?
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Re: APOD: Spiral Galaxy M66 (2010 Nov 13)

Post by Chris Peterson » Sat Nov 13, 2010 3:29 pm

cmflyer wrote:Do the foreground "spikey" stars have the spikes added, or is it a natural result of optics?
They are diffraction spikes from the vanes that support the secondary mirror of the telescope.
Chris

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Re: APOD: Spiral Galaxy M66 (2010 Nov 13)

Post by cliffhardin67 » Mon Nov 15, 2010 1:30 am

its a priviledge to see images of our universe with so much resolution !!! I cant wait to see the image results from the james webb telescope in 2014 !!! one of these days we may witness the beginning of time in the early universe,thats hard for the imagination to even try and grasp. i would like to thank apod, nasa,and everyone who had any part in making this possible .

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Re: APOD: Spiral Galaxy M66 (2010 Nov 13)

Post by rstevenson » Mon Nov 15, 2010 2:53 am

cliffhardin67 wrote:its a priviledge to see images of our universe with so much resolution !!! I cant wait to see the image results from the james webb telescope in 2014 !!! ...
You may have to wait a little longer. Just saw in the BBC news site that the James Webb Telescope budget has gone from $5B to $6.5B USD, and the launch is now possible in 2015 but likely to be later still.

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