APOD: M64: The Black Eye Galaxy Close Up (2023 Jul 20)

[APOD Robot]

M64: The Black Eye Galaxy Close Up

Explanation: This magnificent spiral galaxy is Messier 64, often called the Black Eye Galaxy or the Sleeping Beauty Galaxy for its dark-lidded appearance in telescopic views. The spiral's central region, about 7,400 light-years across, is pictured in this reprocessed image from the Hubble Space Telescope. M64 lies some 17 million light-years distant in the otherwise well-groomed northern constellation Coma Berenices. The enormous dust clouds partially obscuring M64's central region are laced with young, blue star clusters and the reddish glow of hydrogen associated with star forming regions. But imposing clouds of dust are not this galaxy's only peculiar feature. Observations show that M64 is actually composed of two concentric, counter-rotating systems. While all the stars in M64 rotate in the same direction as the interstellar gas in the galaxy's central region, gas in the outer regions, extending to about 40,000 light-years, rotates in the opposite direction. The dusty eye and bizarre rotation are likely the result of a billion year old merger of two different galaxies.

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[Sa Ji Tario]

Friends! Hapy day !!

[Ann]

Core of galaxy M64. Image Credit: NASA, ESA, Hubble, HLA; Processing: Jonathan Lodge

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Core of galaxy M100. Credit: ESA/Hubble & NASA

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What's the difference between the cores of galaxies M64 and M100? Well, apart from the fact that we see M64 "mostly sideways" and M100 "almost face on", the swirling dust lane around the core of M64 is strongly dominated by dust rather than stars, whereas the dust lane surrounding the core of M100 is "bursting with brilliant stars".

In other words: If M64 is the "Black-Eye Galaxy", then M100 is the "Bright-Eye Galaxy".

Let's look at the general makeup and the brightness distribution of disk vs. core in M64 and M100:

Image credit: Isaac Newton Group of Telescopes, La Palma; Nik Szymanek

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Image credit: FORS/VLT/ESO

We can see that the disk of M64 is "softly undulating", apparently dust-free, and generally very, very smooth. M100, by contrast, sports well-formed spiral arms full of star clusters and emission nebulas.

M64 is a very unusual galaxy. Today's caption explained it well:

Observations show that M64 is actually composed of two concentric, counter-rotating systems. While all the stars in M64 rotate in the same direction as the interstellar gas in the galaxy's central region, gas in the outer regions, extending to about 40,000 light-years, rotates in the opposite direction. The dusty eye and bizarre rotation are likely the result of a billion year old merger of two different galaxies.

It seems likely that all the dust in the center of M64 is created by the collision and friction of the two "bodies of gas" in this galaxy, rotating in different directions. But the dust does not give rise to a frenzy of star formation.

I’m not sure that the inner and outer disks rotate in the directions I have suggested. I just wanted to show what it might look like when they rotate in opposite directions, and I wanted to suggest that the strange dust in M64 may have formed as a consequence of the ”friction” between these two gas masses.


I'm reminded of the galactic weirdo of NGC 4622, which has two sets of arms winding in opposite directions!

NGC 4622. Credit: NASA and The Hubble Heritage Team (STScI/AURA)

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Arms in NGC 4622 winding in different directions.

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Fancy that! Read more about NGC 4622 here, if you are interested.

Ann

[dBerch]

I would love see an animation of this counter-rotating galaxy!

[Chris Peterson]

I would love see an animation of this counter-rotating galaxy!

I think it rotates like any other spiral galaxy.

[Ann]

I would love see an animation of this counter-rotating galaxy!

I think it rotates like any other spiral galaxy.

Its stars do. Not its gas.

Ann

[Chris Peterson]

I would love see an animation of this counter-rotating galaxy!

I think it rotates like any other spiral galaxy.

Its stars do. Not its gas.

Ann

I don't understand. The stars and the gas move together.

[Ann]

I think it rotates like any other spiral galaxy.

Its stars do. Not its gas.

Ann

I don't understand. The stars and the gas move together.

Not according to the caption:

Observations show that M64 is actually composed of two concentric, counter-rotating systems. While all the stars in M64 rotate in the same direction as the interstellar gas in the galaxy's central region, gas in the outer regions, extending to about 40,000 light-years, rotates in the opposite direction. The dusty eye and bizarre rotation are likely the result of a billion year old merger of two different galaxies.

Ann

[johnnydeep]

For the full extent of M64 (this APOD shows only the central region), see https://apod.nasa.gov/apod/ap150618.html

Also, the first (probably not) pentagonal (or perhaps hexagonal, if you count the one much shorter edge) dust eye?

[Chris Peterson]

Its stars do. Not its gas.

Ann

I don't understand. The stars and the gas move together.

Not according to the caption:

Observations show that M64 is actually composed of two concentric, counter-rotating systems. While all the stars in M64 rotate in the same direction as the interstellar gas in the galaxy's central region, gas in the outer regions, extending to about 40,000 light-years, rotates in the opposite direction. The dusty eye and bizarre rotation are likely the result of a billion year old merger of two different galaxies.

Ann

Interesting. Collisions do weird things.

[orin stepanek]

Pretty colorful; I like it!