Starship Asterisk*

Virgo Cluster Galaxies

Explanation: Well over a thousand galaxies are known members of the Virgo Cluster, the closest large cluster of galaxies to our own local group. In fact, the galaxy cluster is difficult to appreciate all at once because it covers such a large area on the sky. Spanning about 5x3 degrees, this careful mosaic of telescopic images clearly records the central region of the Virgo Cluster through faint foreground dust clouds lingering above the plane of our own Milky Way galaxy. The cluster's dominant giant elliptical galaxy M87, is just below center in the frame. Above M87 is the famous interacting galaxy pair NGC 4438, also known as The Eyes. A closer examination of the image will reveal many Virgo cluster member galaxies as small fuzzy patches. Sliding your cursor over the image will label the larger galaxies using NGC catalog designations. Galaxies are also shown with Messier catalog numbers, including M84, M86, and prominent colorful spirals M88, M90, and M91. On average, Virgo Cluster galaxies are measured to be about 48 million light-years away. The Virgo Cluster distance has been used to give an important determination of the Hubble Constant and the scale of the Universe. (Editor's Note: Labels courtesy of Astrometry.net.)

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What a fabulous, wonderful image; I'm so glad it's an APOD!

Congratulations Rogelio, It is a beautiful image.
Greetings
César

This is another great astroimage by Rogelio Bernal Andreo.

The picture is a great portrait of a relatively massive galaxy cluster. Typically, the great majority of the galaxies are ellipticals. Rogelio Bernal Andreo has put M87 in the center of his image, which is fitting, since this supermassive elliptical galaxy with its relativistic jet is the dominant member of the entire Virgo Cluster.

Note how the biggest elliptical galaxies, M87, M86, M84 and M89 are surrounded by huge diffuse haloes. This is in sharp contrast to the few spiral galaxies here.

You can easily find the spiral galaxies by looking out for their blue disks. In reality, though, the spiral galaxies in this image are not so blue. Or rather, the spiral galaxies here are certainly blue compared with the elliptical galaxies in the cluster, so Rogelio's image does the color difference between the ellipticals and the spirals full justice.

But the spirals here are not so blue compared with typical spirals that are not located in big galaxy clusters. That's because the large galaxy cluster environment clearly impairs star formation. M90, for example, the bluest-looking of the galaxies in today's APOD, is an "anemic" galaxy with a large population of A-type stars, but very few B- or O-type stars. This image by Adam Block shows the true nature of M90:
The galaxy has a large yellow bulge, surrounded by a dusty ring with some, but not a lot of, star formation. Outside this ring there are smooth rather neutral-colored mostly dust-free broad arms whose light comes mainly from A-, F- and G-type stars. The presence of a large population of A-type stars does give this part of the galaxy a bluish tinge.

Interestingly, the Hubble Telescope recently took an image of a galaxy that resembles M90 in that it is situated in a large galaxy cluster, has broad smooth arms and has mostly shut down its star formation. The galaxy in question is NGC 4921 in the Coma Cluster:
The filters used by Hubble to produce the image don't bring out the color difference between the yellow bulge of NGC 4921 and its slightly bluish but fairly neutral-colored arms. But here is another image that does just that:

This former APOD does show you the slightly enhanced color difference between the arms and the bulge of NGC 4921. The galaxy is on the far left in this image.

Ann

It's a great image and that was a great addition Ann. Thank you.

What a gorgeous image!
Kinda makes me want to reach out and touch those beautiful jewels hanging there! Of course, I'd need some really loooooong arms!

The description is extremely interesting, too, with all the excellent links included. And thanks Ann, for some extra info!

This image gets a 10 out of 10!

Wouldn't it be fun to be able to explore all the galaxies and all the worlds they must contain! Of course it would take forever.

Stare at that image long enough, it's guaranteed to cure excessive dignity.
--
Obquote: "...billions and billions..." -Dr. Carl Sagan.

Cluster, n. [AS. cluster, clyster; cf. LG. kluster (also Sw. & Dan. klase a cluster of grapes, D. klissen to be entangled?.)]

1. A number of things of the same kind growing together; a bunch.

Her deeds were like great clusters of ripe grapes, Which load the bunches of the fruitful vine. Spenser.

• [Finnegans Wake 249.9] A grape cluster of lights hangs therebeneath
  and all the house is filled with the breathings of her fairness, the
  fairness of fondance and the fairness of milk and rhubarb and the
  fairness of roasted meats and uniomargrits and the fairness of
  promise with consonantia and avowals.

2. A number of similar things collected together or lying contiguous; a group; as, a cluster of islands. Cluster of provinces." Motley.

3. A number of individuals grouped together or collected in one place; a crowd; a mob.

• _____ Coriolanus Act 4, Scene 6
  
  MENENIUS: How! Was it we? we loved him but, like beasts
  . And cowardly nobles, gave way unto your clusters,
  . Who did hoot him out o' the city.
  
  MENENIUS: Here come the clusters.
  . And is Aufidius with him? You are they
  . That made the air unwholesome, when you cast
  . Your stinking greasy caps in hooting at
  . Coriolanus' exile. Now he's coming;
  . And not a hair upon a soldier's head
  . Which will not prove a whip: as many coxcombs
  . As you threw caps up will he tumble down,
  . And pay you for your voices. 'Tis no matter;
  . if he could burn us all into one coal,
  . We have deserved it.

The image, published at the illumination level shown, doesn't do justice to Rogelio's effort. The depth in this image is MAGNIFICENT! The galaxies! The DUST!

Many astroimages are limited by our atmosphere. With enhancement, this one seems limited only by the interstellar dust. I'm awestruck. Great job Rogelio!
-Noel

So which part is the dust, the darker parts or the lighter parts? My eyes are playing tricks on me.

I believe that the lighter brown parts are the dust and the darker parts are clear

I agree BMAONE23. Dust, faintly lit by ambient starlight.

I've just been looking at this image again, at full size, across both my monitors... Wow again! This image ranks right up there with the Hubble Ultra Deep Field.

-Noel

It was on my desktop minutes after I saw it this morning. Wonderful image Rogelio!

So how big is that central galaxy? Wkipedia tells me M87 has a radius of almost 10 times that of the Milky Way, and a mass of roughly 200 times our home galaxy. Zounds!

Rob

rstevenson wrote:
So how big is that central galaxy? Wikipedia tells me M87 has a radius of almost 10 times that of the Milky Way,
and a mass of roughly 200 times our home galaxy. Zounds!

These numbers don't seem consistent with much of the M87 Wikipedia article:

http://en.wikipedia.org/wiki/Messier_87 wrote:
<<The extended stellar envelope of [Messier 87] reaches a radius of about 150 kpc, compared to about 100 kpc for the Milky Way.

Within a radius of 32 kpc, the [Messier 87] mass is double the mass of the Milky Way galaxy.
However [only] about one part in six of the galaxy's mass is in the form of stars that are radiating energy.>>

Interesting. I found this on http://en.wikipedia.org/wiki/Messier_87:

The galactic envelope extends out to a radius of about 490 kly

and

The total mass of Messier 87 may be 200 times that of the Milky Way.

Ann

Ann wrote:
Interesting. I found this on http://en.wikipedia.org/wiki/Messier_87:

The total mass of Messier 87 may be 200 times that of the Milky Way.

The 200 number doesn't seem consistent with the rest of the M87 Wikipedia article:

http://en.wikipedia.org/wiki/Messier_87 wrote:
<<Within a radius of 32 kpc, the [Messier 87] mass is double the mass of the Milky Way galaxy.
However [only] about one part in six of the galaxy's mass is in the form of stars that are radiating energy.>>

Perhaps it should have been 20 rather than 200.

Just make up the difference in dark matter and call it a wash.

-Noel

neufer wrote:

Cluster, n.

Andy Costello wrote:The Tides of Manaunaun (1912), No. 1 of Three Irish Legends, by Henry Cowell (1897-1965)

The Tides of Manaunaun is based on a Irish myth by John Osborne Varian. The quote (taken from Varian) on the top of the score reads:

"Manaunaun was the god of motion, and long before the creation he sent forth tremendous tides, which swept to and fro through the universe, and rhythmically moved the particles and materials of which the gods were later to make the suns and the worlds."

Cowell claimed that he wrote this when he was only fifteen years old (1912), however, it was not published until 1917.

The piece is one of the first of piano literature to use the technique of tone clusters played with fists and arms. Rumor has it that Bela Bartok asked Cowell for permission to "steal" this piano technique for his own compositions.

---
Sam

That's an incredibly suggestive piece of music, Sam. Thanks for posting it!

Ann

Great image, one of best showing the immensity of things outside our galaxy. By removing all foreground objects, I'd like to see this image showing only what's outside our galaxy. Could give us an even better feel of what's out and out there, at least from this angle.

Sam wrote:Cowell claimed that he wrote this when he was only fifteen years old (1912), however, it was not published until 1917.

I'll be the first to admit that perhaps I am not particularly cultured, but I would have guessed more like 3 years old. To me that was just so much noise to try to tune out while straining to hear far too little melody. Kind of a SETI piece, I guess.

-Noel

NoelC wrote:...noise...

----
Sam