APOD: NGC 253: Close Up (2011 May 19)

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APOD: NGC 253: Close Up (2011 May 19)

Post by APOD Robot » Thu May 19, 2011 4:06 am

Image NGC 253: Close Up

Explanation: This dusty island universe is one of the brightest spiral galaxies in planet Earth's sky. Seen nearly edge-on, NGC 253 is only 13 million light-years away, the largest member of the Sculptor Group of galaxies, neighbor to our own local galaxy group. The detailed close-up view is a five frame mosaic based on data assembled from Hubble Legacy Archive data. Beginning on the left near the galaxy's core, the sharp panorama follows dusty filaments, interstellar gas clouds, and even individual stars toward the galaxy's edge at the right. The magnificent vista spans nearly 50,000 light-years. The frame at the far right has been compressed slightly to bring into view an intriguing interacting pair of background galaxies. Designated a starburst galaxy because of its frantic star forming activity, NGC 253 features tendrils of dust rising from a galactic disk laced with young star clusters and star forming regions. NGC 253 is also known to be a strong source of high-energy x-rays and gamma rays, likely due to massive black holes near the galaxy's center.

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Ann
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Re: APOD: NGC 253: Close Up (2011 May 19)

Post by Ann » Thu May 19, 2011 4:27 am

Check out the fantastic interacting pair of galaxies at the far right.

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Re: APOD: NGC 253: Close Up (2011 May 19)

Post by Beyond » Thu May 19, 2011 4:39 am

That's one heck-of-a-size difference in those two Galaxies. It looks like the little one is biting off more than it can chew :!: :lol:
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Re: APOD: NGC 253: Close Up (2011 May 19)

Post by Ann » Thu May 19, 2011 5:00 am

Beyond wrote:That's one heck-of-a-size difference in those two Galaxies. It looks like the little one is biting off more than it can chew :!: :lol:
Well put! :D

As for NGC 253 itself, it is one of the best-looking galaxies in the sky when you view it through a small telescope. Its nickname, the Silver Dollar Galaxy, tells you how beautiful it looks from afar. But close up, like in this Hubble picture, it is rather messy. There isn't much structure to be seen, but there is a lot of chaotic dust. I checked it with my software, and while its B magnitude is 8.147 ± 0.585, its far infrared magnitude (which is a signature of dust) is 5.632, about two and a half magnitudes brighter than the B light magnitude! That is indeed very dusty as galaxies go. The only nearby galaxy that I can think of which is comparably dusty is M82. Indeed, M82 is even dustier, because it is actually three and a half magnitudes brighter in the far infrared than in blue light. Most unusual. But M82 is a much smaller galaxy than NGC 253, so the total amount of dust in NGC 253 is much greater.
M82.

There are several interesting similarities between M82 and NGC 253. Both are characterized by an intense starburst close to the center of the galaxy. Both are very dusty. Both have rather small amounts of star formation and rather red colors away from the central region.

The biggest difference between the two galaxies is the amazing twin red outflows of ionized gas from the center of M82, of course!

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Re: APOD: NGC 253: Close Up (2011 May 19)

Post by leon.l7027@gmail.com » Thu May 19, 2011 11:47 am

For the first time I find myself disappointed with an APOD description: no link about those two interacting galaxies at the far right. And then from the link for the Sculptor Group, APOD has never had NGC 45, nor IC 5332. Hope these will forthcoming. :!: Leon

Judy

Re: APOD: NGC 253: Close Up (2011 May 19)

Post by Judy » Thu May 19, 2011 12:30 pm

leon.l7027@gmail.com wrote:For the first time I find myself disappointed with an APOD description: no link about those two interacting galaxies at the far right. And then from the link for the Sculptor Group, APOD has never had NGC 45, nor IC 5332. Hope these will forthcoming. :!: Leon
I like this part of the post (underlining is mine)..."only 13 million light years away". :lol: I get so amazed by the distances we can see.
To APOD..thanks so much for this site!

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Re: APOD: NGC 253: Close Up (2011 May 19)

Post by NGC3314 » Thu May 19, 2011 12:56 pm

The galaxy pair at far right was the subject of a Hubble image release in September 2008, dealing with analysis of the dust in the foreground galaxy. (I thought this had been an APOD itself, but can't find it with a quick search). They are not actually interacting - new H I data indicate that the foreground dusty one is far in the foreground. This gives the whole NGC 253 mosaic a deeply three-dimensional quality - we see stars in the Milky Way, NGC 253 itself with its brightest stars visible, the two different distances of this pair, and the deep background galaxies stretching away into the distance.

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Re: APOD: NGC 253: Close Up (2011 May 19)

Post by neufer » Thu May 19, 2011 12:59 pm

Judy wrote:
I like this part of the post (underlining is mine)..."only 13 million light years away". :lol:
NGC 253 is probably much closer than that:
http://en.wikipedia.org/wiki/NGC_253 wrote:
<<At least two techniques have been used to measure distances to Sculptor in the past ten years.

Using the planetary nebula luminosity function method,
an estimate of 10.89 (+0.85 −1.24) Mly was achieved in 2006.

Sculptor is close enough that the tip of the red giant branch (TRGB) method may also be used to estimate its distance.
The estimated distance to Sculptor using this technique in 2004 yielded 12.8 ± 1.2 Mly.

A weighted average of the most reliable distance estimates gives a distance of 11.4 ± 0.7 Mly.>>
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Re: APOD: NGC 253: Close Up (2011 May 19)

Post by orin stepanek » Thu May 19, 2011 1:26 pm

I was fascinated with the picture. It was almost like looking at a picture of the Milky Way! 8-)
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Re: APOD: NGC 253: Close Up (2011 May 19)

Post by BMAONE23 » Thu May 19, 2011 1:50 pm

Ann wrote:Check out the fantastic interacting pair of galaxies at the far right.

Ann
That was one of the first things I noticed in the full size image and panned to the right to view them. To my untrained eye, they don't appear to be interacting though. It looks like dust in outskirts of the much smaller foreground galaxy is blocking light from the much larger background galaxy.

For the structure imaged, I see the early MW galaxy and the galaxy that will become the LMC/SMC remnants just prior to first interaction

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Re: APOD: NGC 253: Close Up (2011 May 19)

Post by moonstruck » Thu May 19, 2011 2:34 pm

Just WOW!! 8-)

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Re: APOD: NGC 253: Close Up (2011 May 19)

Post by neufer » Thu May 19, 2011 3:24 pm

APOD Robot wrote:Image NGC 253: Close Up

Explanation: This dusty island universe is one of the brightest spiral galaxies in planet Earth's sky. Beginning on the left near the galaxy's core, the sharp panorama follows dusty filaments, interstellar gas clouds, and even individual stars toward the galaxy's edge at the right. Designated a starburst galaxy because of its frantic star forming activity, NGC 253 features tendrils of dust rising from a galactic disk laced with young star clusters and star forming regions. NGC 253 is also known to be a strong source of high-energy x-rays and gamma rays, likely due to massive black holes near the galaxy's center.
Click to play embedded YouTube video.
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Re: APOD: NGC 253: Close Up (2011 May 19)

Post by mexhunter » Thu May 19, 2011 4:46 pm

It's like watching the Milky Way, but in another galaxy. Beautiful !!!
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Re: APOD: NGC 253: Close Up (2011 May 19)

Post by Ann » Thu May 19, 2011 6:48 pm

This may the first time I post an infrared image. It does show off the bar structure in NGC 253.
The image is by the Spitzer Space Telescope.

Oh, and this is a Hubble image of the starburst region of NGC 253. It's not too easy to see the young clusters, I think.

Image

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