APOD: NGC 4676: The Mighty Mice (2019 Jun 14)

[APOD Robot]

NGC 4676: The Mighty Mice

Explanation: These two mighty galaxies are pulling each other apart. Known as The Mice because they have such long tails, each large spiral galaxy has actually passed through the other. Their long tails are drawn out by strong gravitational tides rather than collisions of their individual stars. Because the distances are so large, the cosmic interaction takes place in slow motion -- over hundreds of millions of years. They will probably collide again and again over the next billion years until they coalesce to form a single galaxy. NGC 4676 lies about 300 million light-years away toward the constellation of Bernice's Hair (Coma Berenices) and are likely members of the Coma Cluster of Galaxies. Not often imaged in small telescopes, this wide field of view catches the faint tidal tails several hundred thousand light-years long.

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[Ann]

The main interest of today's APOD is that it underscores what a dedicated amateur armed with a small telescope and endless amounts of patience can achieve today when it comes to photographing faint 13th magnitude objects at a distance of 300 million light-years. It is impressive, to say the least.

Bruce Waddington's picture reminds me of the portrait of this pair in James D Wray's 1988 book, The Color Atlas of Galaxies. Wray photographed "The Mice" (NGC 4676) in 1979 with a 2.7 meter telescope, but in spite of the big telescope that he had access to, he captured fewer details of the mighty cosmic mice than Waddington did (last year?) with a telescope likely a fraction of that size.

I want to quote what Wray wrote about NGC 4676a, the galaxy with the long straight tail:

The morphological nature of the inner region of NGC 4676a is nothing less than baffling.

Good point. But Hubble has shown us that the "inner darkness" of NGC 4676a, where its bright core ought to be, is due to the fact that a thick dust lane is located in front of the core from our point of view, hiding the core from us.

Note, by the way, that NGC 4676b appears to have a twisted inner dust lane, somewhat reminiscent of the weird inner dust lane in M96.

Ann

[Boomer12k]

Isn't that sweet? Their getting married... The "Happy Couple"...one BIG happy family...

:---[===] *

[orin stepanek]

Be Nice, Mice! It is a nice photo!

[jisles]

Berenice's hair - not Bernice's, though that's a modern variant of the name.

John

[AVAO]

Click to view full size image

Click to view full size image

Interesting duo ...

Does anyone have a good idea what the bubbles could be in NGC 4676A?
Are these stars in the foreground or are they part of the Galaxy?

Jack from the AVAO team

[Ann]

Click to view full size image

Click to view full size image

Interesting duo ...

Does anyone have a good idea what the bubbles could be in NGC 4676A?
Are these stars in the foreground or are they part of the Galaxy?

Jack from the AVAO team

Thanks for the closeups, Jack!

An interesting aspect of the blue-green "bubbles" in NGC 4676A is that they don't seem to light up the dust in their apparent galactic vicinity (much), which suggests that they are foreground objects. On the other hand, it would be a rather amazing coincidence if they really were an incredibly tight group of stars located in our own galaxy, just by chance located in front of the dust lane of NGC 4676A, at an extremely comparable apparent distance from the core of NGC 4676A as the obvious region of star formation on the other side of the core of NGC 4676A.

In other words, if I didn't make myself clear, I find it unlikely in the extreme that these objects would not belong to NGC 4676A.

What are these things, then? Is it at all possible that they are huge Hα bubbles surrounding hotspots of star formation?

Note that the weird "bubbles" are located at what might be the end of a galactic bar. There are examples of barred galaxies that form a lot of stars at their bar ends, like NGC 6217, seen here in a picture from ESA/Hubble.

Ann

[AVAO]

Interesting duo ...

Does anyone have a good idea what the bubbles could be in NGC 4676A?
Are these stars in the foreground or are they part of the Galaxy?

Jack from the AVAO team

Thanks for the closeups, Jack!

An interesting aspect of the blue-green "bubbles" in NGC 4676A is that they don't seem to light up the dust in their apparent galactic vicinity (much), which suggests that they are foreground objects. On the other hand, it would be a rather amazing coincidence if they really were an incredibly tight group of stars located in our own galaxy, just by chance located in front of the dust lane of NGC 4676A, at an extremely comparable apparent distance from the core of NGC 4676A as the obvious region of star formation on the other side of the core of NGC 4676A.

In other words, if I didn't make myself clear, I find it unlikely in the extreme that these objects would not belong to NGC 4676A.

What are these things, then? Is it at all possible that they are huge Hα bubbles surrounding hotspots of star formation?

Note that the weird "bubbles" are located at what might be the end of a galactic bar. There are examples of barred galaxies that form a lot of stars at their bar ends, like NGC 6217, seen here in a picture from ESA/Hubble.

Ann

Thanks Ann

....for the inspiring thoughts. I took a closer look at the Hubble high resolution wide-angle image ( http://imgsrc.hubblesite.org/hvi/upload ... ll_tif.tif ). So it is interesting that a similar bubble cluster is also on the other end of the galactic bridge. Both gatekeeper clusters see themselves as bipolar in the center, which could possibly point to two simultaneous novas like in Eta Carinae. So it would be exciting to look at this details on a different wavelength ...

Jack/AVAO

[AVAO]

... on te other side of the bridge...

Click to view full size image

[neufer]

Click to play embedded YouTube video.