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NGC 4565: Galaxy on Edge

Explanation: Magnificent spiral galaxy NGC 4565 is viewed edge-on from planet Earth. Also known as the Needle Galaxy for its narrow profile, bright NGC 4565 is a stop on many telescopic tours of the northern sky, in the faint but well-groomed constellation Coma Berenices. This sharp, colorful image reveals the galaxy's bulging central core cut by obscuring dust lanes that lace NGC 4565's thin galactic plane. An assortment of other background galaxies is included in the pretty field of view, with neighboring galaxy NGC 4562 at the upper left. NGC 4565 itself lies about 40 million light-years distant and spans some 100,000 light-years. Easily spotted with small telescopes, sky enthusiasts consider NGC 4565 to be a prominent celestial masterpiece Messier missed.

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A pretty shot and very well done I think.

I recommend that APODs be chosen more frequently from the detailed shots of Mars taken from orbit; we don't see very many of them here and they are fascinating.

APOD Robot wrote:
Easily spotted with small telescopes,
sky enthusiasts consider NGC 4565
to be a prominent celestial masterpiece Messier missed.

• "The sharp edge of a razor is difficult to pass over;
  thus the wise say the path to Salvation is hard,"

Kramer: It's a story about love, deception,
greed, lust and...unbridled enthusiasm.

Elaine: unbridled enthusiasm...?

Kramer: Well , that's what led to Billy Mumphrey's downfall.

Elaine: Oh! boy.

Kramer: You see Elaine, Billy was a simple country boy. You might say a cockeyed optimist,
who got himself mixed up in the high stakes game of world diplomacy and international intrigue.

Elaine: Oh! my God.

All they did was take the APOD picture from October 15th, 2011 and flipped the orientation. The description is exactly the same.

http://apod.nasa.gov/apod/ap111015.html

/disappoint

This is a very fine picture of a fascinating galaxy.

I'd like to call attention to the large size of the disk. Note, too, that although the disk is slightly warped, the warp is not at all pronounced. For the most part, the disk looks "undisturbed".

Also note that although there are some bluish knots in the dust lane, indicative of young star clusters and recent star formation, these blue knots are neither bright nor numerous.

There are faint hints of pink in the dust lane, and there appears to be one definite emission nebula in the dust lane to the right of the bulge. But like the blue knots, the pink emission nebulae are faint and few.

There are signs of some activity in the dust lane. To the left of the bulge there are a pair of obvious "chimneys", where dust is blown up into the thick disk or possibly even into the halo of the galaxy by energetic processes in the dust lane. A likely cause would be past supernovae.

But again, the activity in the dust lane is not great. To me it seems that the activity in the dust lane of NGC 4565 is somewhat but not much greater than the activity in the dust lane of M104, seen here in a large Hubble picture.
Compare the activity in the dust lane of NGC 4565 with the activity in the dust lane of similarly edge-on galaxy NGC 891. Clearly the activity in NGC 891 is much greater.



NGC 4565 is a considerably larger galaxy than NGC 891. It is a galaxy that must have seen huge amounts of star formation and also growth by cannibalization of smaller galaxies. More of the latter is to come, since there are still dwarf galaxies in the vicinity. But for now NGC 4565 is semi-retired, and it has "quieted down", settling itself on its throne like a fat old king.

Ann

Does anyone happen to know what the blue fuzzy blob directly below the galaxy is? Is it one of the background galaxies?

Trb7074 wrote:
All they did was take the APOD picture from October 15th, 2011 and flipped the orientation.

The description is exactly the same. http://apod.nasa.gov/apod/ap111015.html

It's a different image by Bob Franke rather than Ken Crawford.

And the description is not exactly the same: NGC 4562 is at "the upper left" rather than "the lower right."

Ann wrote:
NGC 4565 is semi-retired, and it has "quited down",
settling itself on its throne like a fat old king.

All Quite on the Western Front.

Cello wrote:Does anyone happen to know what the blue fuzzy blob directly below the galaxy is? Is it one of the background galaxies?

A blue fuzzy blob close to a large galaxy is unlikely to be a background galaxy. A background galaxy will have its light reddened by redshift, and in order to look blue in spite of being a background galaxy it has to be ultraviolet-bright (so that the ultraviolet light can be redshifted into the blue part of the spectrum). But ultraviolet-bright galaxies usually have sharply defined bright regions of star formation, and such galaxies will therefore not look fuzzy.

A small, rather faint, fuzzy bluish blob of light close to a large relatively nearby galaxy is very likely to be a small satellite galaxy trapped in the gravitational field of that galaxy.

It should be noted that the blue color of the small fuzzy blob isn't likely to be produced by very hot ultraviolet-bright stars. If that had been the case, the small galaxy should have been clumpy in appearance. The blue color of the galaxy likely comes from more modest stars, similar to Sirius and Vega.

Ann

Ann wrote:A blue fuzzy blob close to a large galaxy is unlikely to be a background galaxy. A background galaxy will have its light reddened by redshift, and in order to look blue in spite of being a background galaxy it has to be ultraviolet-bright (so that the ultraviolet light can be redshifted into the blue part of the spectrum). But ultraviolet-bright galaxies usually have sharply defined bright regions of star formation, and such galaxies will therefore not look fuzzy...

While what you say makes sense in principle, we should note that this galaxy is only 40 million ly distant, corresponding to a redshift of z=0.003. For such a small z, the actual wavelength shift is dominated by relative motion. That is, Doppler redshift swamps cosmological redshift, and the galaxy may even be blueshifted. Even if there is no relative motion, however, z=0.003 tells us that the cosmological redshift for blue light will be about 1nm (that is, we'll see a 450nm source as 451nm, which is measurable but not visually apparent).

Chris Peterson wrote:

Ann wrote:A blue fuzzy blob close to a large galaxy is unlikely to be a background galaxy. A background galaxy will have its light reddened by redshift, and in order to look blue in spite of being a background galaxy it has to be ultraviolet-bright (so that the ultraviolet light can be redshifted into the blue part of the spectrum). But ultraviolet-bright galaxies usually have sharply defined bright regions of star formation, and such galaxies will therefore not look fuzzy...

While what you say makes sense in principle, we should note that this galaxy is only 40 million ly distant, corresponding to a redshift of z=0.003. For such a small z, the actual wavelength shift is dominated by relative motion. That is, Doppler redshift swamps cosmological redshift, and the galaxy may even be blueshifted. Even if there is no relative motion, however, z=0.003 tells us that the cosmological redshift for blue light will be about 1nm (that is, we'll see a 450nm source as 451nm, which is measurable but not visually apparent).

Please note that I didn't suggest that the fuzzy bluish blob next to NGC 4565 should have its light very reddened by the redshift imparted by a 40 million ly distance. What I meant was that if this blue blob had been a large (similar in size to NGC 4565) background galaxy, then it would have been sufficiently distant to have its light noticeably redshifted, and then it should be intrinsically at least relatively ultraviolet-bright in order to look blue. Its ultraviolet nature, in turn, would have changed its morphology into something other than a fuzzy blob.

Ann

Chris Peterson wrote:

Ann wrote:
A blue fuzzy blob close to a large galaxy is unlikely to be a background galaxy. A background galaxy will have its light reddened by redshift, and in order to look blue in spite of being a background galaxy it has to be ultraviolet-bright (so that the ultraviolet light can be redshifted into the blue part of the spectrum). But ultraviolet-bright galaxies usually have sharply defined bright regions of star formation, and such galaxies will therefore not look fuzzy...

While what you say makes sense in principle, we should note that this galaxy is only 40 million ly distant, corresponding to a redshift of z=0.003. For such a small z, the actual wavelength shift is dominated by relative motion. That is, Doppler redshift swamps cosmological redshift, and the galaxy may even be blueshifted. Even if there is no relative motion, however, z=0.003 tells us that the cosmological redshift for blue light will be about 1nm (that is, we'll see a 450nm source as 451nm, which is measurable but not visually apparent).

• NGC 4562, itself, has a z=0.004513.

Art wrote:

NGC 4562, itself, has a z=0.004513.

The blue fuzzy blob I'm referring to isn't NGC 4562. NGC 4562 is the elongated galaxy seen in the upper left corner of today's APOD. I wouldn't describe it a fuzzy blob.

I'm referring to the fuzzy blob seen below the disk of NGC 4565, at six o'clock. Its designation is IC 3571.

Ann

neufer wrote:NGC 4562, itself, has a z=0.004513.

Thanks. That means its cosmological redshift isn't well known, since the Doppler shift scatter on measurements is on the order of z=0.01.

So what you guys are saying is that it could be something small and close, or it could be something less small but farther away. It's been given a designation but is too insignificant for anyone to have bothered classifying it. Poor blob. You know what that means, right? It's probably where the elusive god-being we can neither prove nor disprove lives.

geckzilla wrote:So what you guys are saying is that it could be something small and close, or it could be something less small but farther away. It's been given a designation but is too insignificant for anyone to have bothered classifying it. Poor blob. You know what that means, right? It's probably where the elusive god-being we can neither prove nor disprove lives.

Hmm... Perhaps then, it should be called BosonVille

geckzilla wrote:
So what you guys are saying is that it could be something small and close, or it could be something less small but farther away. It's been given a designation but is too insignificant for anyone to have bothered classifying it. Poor blob. You know what that means, right? It's probably where the elusive god-being we can neither prove nor disprove lives.

neufer wrote:

geckzilla wrote:
So what you guys are saying is that it could be something small and close, or it could be something less small but farther away. It's been given a designation but is too insignificant for anyone to have bothered classifying it. Poor blob. You know what that means, right? It's probably where the elusive god-being we can neither prove nor disprove lives.

IC 3571 : z = 0.004203

Or more simply, it's another galaxy and is about the same distance away as NGC 4565.

Ok, blob. Today is your day. You are now a full-fledged galaxy.

<< the faint but well-groomed constellation Coma Berenices >>

[humorous smily] Berenices' tresses have always seemed rather dishevelled to me. [/humorous smily]

geckzilla wrote:So what you guys are saying is that it could be something small and close, or it could be something less small but farther away. It's been given a designation but is too insignificant for anyone to have bothered classifying it. Poor blob. You know what that means, right? It's probably where the elusive god-being we can neither prove nor disprove lives.

Are you sure? Because I think he already lives at the north celestial pole, according to a legend.

Anthony Barreiro wrote:

<< the faint but well-groomed constellation Coma Berenices >>

[humorous smily]

Berenices' tresses have always seemed rather dishevelled to me.