APOD: Portrait of NGC 3628 (2020 Jun 04)

[APOD Robot]

Portrait of NGC 3628

Explanation: Sharp telescopic views of NGC 3628 show a puffy galactic disk divided by dark dust lanes. Of course, this deep portrait of the magnificent, edge-on spiral galaxy puts some astronomers in mind of its popular moniker, the Hamburger Galaxy. It also reveals a small galaxy nearby, likely a satellite of NGC 3628, and a faint but extensive tidal tail. The drawn out tail stretches for about 300,000 light-years, even beyond the right edge of the wide frame. NGC 3628 shares its neighborhood in the local universe with two other large spirals M65 and M66 in a grouping otherwise known as the Leo Triplet. Gravitational interactions with its cosmic neighbors are likely responsible for creating the tidal tail, as well as the extended flare and warp of this spiral's disk. The tantalizing island universe itself is about 100,000 light-years across and 35 million light-years away in the northern springtime constellation Leo.

<< Previous APOD

This Day in APOD

Next APOD >>

[Ann]

NGC 3628. Image Credit: Stefano Cancelli and Paul Mortfield.

---

NGC 3628 with tail. Photo: Stefano Cancelli and Paul Mortfield.

---

I was searching the Internet as usual to find another image of the APOD object to put it into perspective. Guess what. The picture I found, that I liked best, was another version of the APOD, a picture of the same galaxy by the same people, except in the picture I found on the net the galaxy isn't shown with its tail.

And I didn't even realize at first that the picture I found was basically the same as the APOD!

Ann

[orin stepanek]

Nice view showing the tail

Beautiful thrio

You ever wish we could go fast enough to visit!

[HeggieAstro]

Thank you for choosing this photo for today's APOD. Stef Cancelli, one of the two credited imagers, passed away recently. He was a gifted astro imager, polymath and a good friend. All who knew him miss him dearly.
Stuart

[sillyworm 2]

Let's say you had a solar system in one of these tidal fields...would life on a planet go on as normal? I know this would be an incredibly slow process.

[sillyworm 2]

Let's say you had a solar system in one of these tidal fields...would life on a planet go on as normal? I know this would be an incredibly slow process.

[Chris Peterson]

Let's say you had a solar system in one of these tidal fields...would life on a planet go on as normal? I know this would be an incredibly slow process.

The tidal forces are infinitesimally small on the scale of something the size of a planetary system. There would be no detectable impact.

[steve case]

Great post, I loved it.

[johnnydeep]

Let's say you had a solar system in one of these tidal fields...would life on a planet go on as normal? I know this would be an incredibly slow process.

The tidal forces are infinitesimally small on the scale of something the size of a planetary system. There would be no detectable impact.

Well, couldn't there be an increased chance of nearby star perturbations nudging Oort cloud objects inward and thereby increasing the likelihood of planetary impacts? Or are these tidal tails already less dense in stars than in the galaxy proper, and thereby safer places for life to begin with?

[Chris Peterson]

Let's say you had a solar system in one of these tidal fields...would life on a planet go on as normal? I know this would be an incredibly slow process.

The tidal forces are infinitesimally small on the scale of something the size of a planetary system. There would be no detectable impact.

Well, couldn't there be an increased chance of nearby star perturbations nudging Oort cloud objects inward and thereby increasing the likelihood of planetary impacts? Or are these tidal tails already less dense in stars than in the galaxy proper, and thereby safer places for life to begin with?

These kinds of gradients are distributed over thousands or even millions of light years. They simply aren't significant over one light year.

[johnnydeep]

It also reveals a small galaxy nearby, likely a satellite of NGC 3628

So, is this the nearby small galaxy being referred to?

[johnnydeep]

The tidal forces are infinitesimally small on the scale of something the size of a planetary system. There would be no detectable impact.

Well, couldn't there be an increased chance of nearby star perturbations nudging Oort cloud objects inward and thereby increasing the likelihood of planetary impacts? Or are these tidal tails already less dense in stars than in the galaxy proper, and thereby safer places for life to begin with?

These kinds of gradients are distributed over thousands or even millions of light years. They simply aren't significant over one light year.

Ok, but then how close are nearby stars getting to our sun to nudge Oort cloud objects as I've often seen posited as the cause of some mass extinctions on Earth? Or are you saying that the galactic tidal forces are swamped in magnitude by what I'll call "gravitational brownian motion" of nearby stars?

[Chris Peterson]

Well, couldn't there be an increased chance of nearby star perturbations nudging Oort cloud objects inward and thereby increasing the likelihood of planetary impacts? Or are these tidal tails already less dense in stars than in the galaxy proper, and thereby safer places for life to begin with?

These kinds of gradients are distributed over thousands or even millions of light years. They simply aren't significant over one light year.

Ok, but then how close are nearby stars getting to our sun to nudge Oort cloud objects as I've often seen posited as the cause of some mass extinctions on Earth? Or are you saying that the galactic tidal forces are swamped in magnitude by what I'll call "gravitational brownian motion" of nearby stars?

When stars pass within a few light years of the Solar System they might perturb the Oort cloud. A star that is a few light years away exerts many orders of magnitude greater tidal forces on the Solar System than a pair of interacting galaxies does on the scale of a stellar system. The gravitational gradient from the latter is so small that two stars separated by even hundreds of light years will not experience significantly different forces. So within local regions, not stars are going to be perturbed relative to other local stars. They all see essentially identical forces.

[johnnydeep]

These kinds of gradients are distributed over thousands or even millions of light years. They simply aren't significant over one light year.

Ok, but then how close are nearby stars getting to our sun to nudge Oort cloud objects as I've often seen posited as the cause of some mass extinctions on Earth? Or are you saying that the galactic tidal forces are swamped in magnitude by what I'll call "gravitational brownian motion" of nearby stars?

When stars pass within a few light years of the Solar System they might perturb the Oort cloud. A star that is a few light years away exerts many orders of magnitude greater tidal forces on the Solar System than a pair of interacting galaxies does on the scale of a stellar system. The gravitational gradient from the latter is so small that two stars separated by even hundreds of light years will not experience significantly different forces. So within local regions, not stars are going to be perturbed relative to other local stars. They all see essentially identical forces.

Ok, you convinced me

[Ann]

It also reveals a small galaxy nearby, likely a satellite of NGC 3628

So, is this the nearby small galaxy being referred to?

NGC3628.jpg

Yes, that must be it.

Ann

[johnnydeep]

It also reveals a small galaxy nearby, likely a satellite of NGC 3628

So, is this the nearby small galaxy being referred to?

NGC3628.jpg

Yes, that must be it.

Ann

Ok. I found this pic that better shows - at least to my mind - that blur of stars as a more convincingly distinct object. I can even imagine that it could be one of NGC 3628's "Magellanic clouds"!

NGC 3628, Spiral Galaxy in Leo Composite Image from Multiple Data Sources 8.2 Meter Subaru Telescope (NAOJ) Hubble Space Telescope Color data Marco Burali MTM OBSERVATORY ITALY (www.osservatoriomtm.it)

---

For a bigger image see here: http://www.robgendlerastropics.com/NGC3 ... u-HST.html

[Ann]

So, is this the nearby small galaxy being referred to?

NGC3628.jpg

Yes, that must be it.

Ann

Ok. I found this pic that better shows - at least to my mind - that blur of stars as a more convincingly distinct object: view the expanded image to see it clearly. I can even imagine that it could be one of NGC 3628's "Magellanic clouds"!

NGC 3628, Spiral Galaxy in Leo Composite Image from Multiple Data Sources 8.2 Meter Subaru Telescope (NAOJ) Hubble Space Telescope Color data Marco Burali MTM OBSERVATORY ITALY (www.osservatoriomtm.it)

---

Great picture, Johnny! I absolutely agree with you that the dwarf galaxy resembles the Large Magellanic Cloud. There is a grainy "body" that looks like a bar, similar to the bar of the LMC, and then there is what looks like a huge cyan-colored region of massive OIII-rich star formation - the NGC 3628 satellite galaxy's own Tarantula Nebula!

The picture you have posted is big, 1.04 MB, and I'm not sure you're allowed to post anything that big. I think the limit is 400 KB, although I myself certainly post pictures as big as, say, 450 KB. I don't dare post anything bigger than 500 KB, though, and I try to stay below 450 KB.

You can find smaller sizes of the picture you posted at this site. There are two versions of the image that are smaller than 400 KB. If I were you, I would post one of the two smaller versions, and then suggest that people should click to see the full size image.

Thanks for finding the picture for us!

Ann

[MarkBour]

Ok. I found this pic ...
[ NGC 3628, Spiral Galaxy in Leo
Composite Image from Multiple Data Sources
8.2 Meter Subaru Telescope (NAOJ)
Hubble Space Telescope
Color data Marco Burali
MTM OBSERVATORY ITALY (www.osservatoriomtm.it)"]
http://www.robgendlerastropics.com/NGC3 ... HST-LL.jpg ]

I agree with Ann, that's a very nice image. I especially enjoyed looking more closely at the dust pattern and also that there are sooo many beautiful background galaxies discernible in the image.

[johnnydeep]

Yes, that must be it.

Ann

Ok. I found this pic that better shows - at least to my mind - that blur of stars as a more convincingly distinct object: view the expanded image to see it clearly. I can even imagine that it could be one of NGC 3628's "Magellanic clouds"!

Great picture, Johnny! I absolutely agree with you that the dwarf galaxy resembles the Large Magellanic Cloud. There is a grainy "body" that looks like a bar, similar to the bar of the LMC, and then there is what looks like a huge cyan-colored region of massive OIII-rich star formation - the NGC 3628 satellite galaxy's own Tarantula Nebula!

The picture you have posted is big, 1.04 MB, and I'm not sure you're allowed to post anything that big. I think the limit is 400 KB, although I myself certainly post pictures as big as, say, 450 KB. I don't dare post anything bigger than 500 KB, though, and I try to stay below 450 KB.

You can find smaller sizes of the picture you posted at this site. There are two versions of the image that are smaller than 400 KB. If I were you, I would post one of the two smaller versions, and then suggest that people should click to see the full size image.

Thanks for finding the picture for us!

Ann

My pleasure! Yeah, I was slightly worried about the size of that pic, but I figured if it was too big, it would have been flagged as such and not let me use it. But, 1 MB isn't really that big these days, is it? That said, I did take your recommendation and edited my original post as you suggested. [EDIT: But wait a minute now. Aren't all these images just links to off-site data (except that is for any attachment pics that you uploaded from your own PC)?]

[Ann]

My pleasure! Yeah, I was slightly worried about the size of that pic, but I figured if it was too big, it would have been flagged as such and not let me use it. But, 1 MB isn't really that big these days, is it? That said, I did take your recommendation and edited my original post as you suggested. [EDIT: But wait a minute now. Aren't all these images just links to off-site data (except that is for any attachment pics that you uploaded from your own PC)?]

Actually, Johnny, you might be right. I know it has happened that images have been edited by bystander in the Recent Submissions thread because they were too large.

If you check out the images posted in the current Recent Submissions thread, most of them are smaller than 400 KB. Two are of unknown size, and one is definitively bigger.

So maybe you didn't have to edit your picture after all.

Ann

[aneedham]

Congratulations to the editors for saying that this object is in the constellation Leo. So much more sensible than describing objects as being towards a constellation.

[Danny]

If you lived on a planet in the ‘tail’ that extends from this galaxy, would the spiral part of the main galaxy fill your night sky?

[sillyworm 2]

If you lived on a planet in the ‘tail’ that extends from this galaxy, would the spiral part of the main galaxy fill your night sky?

One could certainly hope so!