Starship Asterisk*

NGC 2403 in Camelopardalis

Explanation: Magnificent island universe NGC 2403 stands within the boundaries of the long-necked constellation Camelopardalis. Some 10 million light-years distant and about 50,000 light-years across, the spiral galaxy also seems to have more than its fair share of giant star forming HII regions, marked by the telltale reddish glow of atomic hydrogen gas. The giant HII regions are energized by clusters of hot, massive stars that explode as bright supernovae at the end of their short and furious lives. A member of the M81 group of galaxies, NGC 2403 closely resembles a galaxy in our own local galaxy group with an abundance of star forming regions, M33, the Triangulum Galaxy. Spiky in appearance, bright stars in this portrait of NGC 2403 are in the foreground, within our own Milky Way. Also in the foreground of the deep, wide-field, telescopic image are the Milky Way's dim and dusty interstellar clouds also known as galactic cirrus or integrated flux nebulae. But faint features that seem to extend from NGC 2403 itself are likely tidal stellar streams drawn out by gravitational interactions with neighboring galaxies.

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Wow, there is so much floof in the lower left part of the picture, and there are so many background galaxies there!


The tidal tail kings of the nearby cosmos are, of course, the Antennae Galaxies!


We can see that the tidal tails of NGC 2403, if that is what they are, can't be compared with the tidal tails of the Antennae Galaxies in any way. The Antennae tidal tails are elegantly arc-shaped, quite bright and very long, but the possible tidal tails of NGC 2403 are faint, gray, relatively short and somewhat haphazardly curved.

But it is sure interesting that the gray floofy clouds of whatever they are near NGC 2403 crowd together in the lower left part of the APOD, where we also find a lot of background galaxies!

Ann

That galaxies are meant to be inhabited by man in the near future as foretold by scientists when starships are ready to be piloted by future astronauts
like us, so live forever & prosper!

MelvzLuster wrote: ↑Mon Jun 03, 2024 4:31 pm That galaxies are meant to be inhabited by man in the near future as foretold by scientists when starships are ready to be piloted by future astronauts
like us, so live forever & prosper!

Please define "near", "foretold" and which "scientists".

Ann wrote: ↑Mon Jun 03, 2024 5:13 am Wow, there is so much floof in the lower left part of the picture, and there are so many background galaxies there!

The tidal tail kings of the nearby cosmos are, of course, the Antennae Galaxies!

We can see that the tidal tails of NGC 2403, if that is what they are, can't be compared with the tidal tails of the Antennae Galaxies in any way. The Antennae tidal tails are elegantly arc-shaped, quite bright and very long, but the possible tidal tails of NGC 2403 are faint, gray, relatively short and somewhat haphazardly curved.

But it is sure interesting that the gray floofy clouds of whatever they are near NGC 2403 crowd together in the lower left part of the APOD, where we also find a lot of background galaxies!

I don't think there are any tidal tails here. We're just seeing the foreground galactic cirrus.

I must say I don't like this image, other than the interesting wide view capturing the foreground dust. I've seen quite a lot of images lately that end up with these bizarre orange colors. Maybe the problem here was just too many scopes and cameras, but the color is weird and I don't think it's accurately capturing what's going on in the galaxy itself. I shot this recently, and comparing it to numerous other images as well as HST shots, I think it gives a much better view of the continuum galaxy and the H II regions. (And I don't think [O III] really adds anything to most galaxy images).
_

Halton Arp, in his book Seeing Red thinks the “tidal tail” Ann highlights could be ejection debris.

Roy wrote: ↑Mon Jun 03, 2024 7:11 pm Halton Arp, in his book Seeing Red thinks the “tidal tail” Ann highlights could be ejection debris.

Fringe science, rejected by virtually all cosmologists.

Chris Peterson wrote: ↑Mon Jun 03, 2024 7:26 pm

Roy wrote: ↑Mon Jun 03, 2024 7:11 pm Halton Arp, in his book Seeing Red thinks the “tidal tail” Ann highlights could be ejection debris.

Fringe science, rejected by virtually all cosmologists.

Now, in the case of Halton Arp, I would be a little cautious with such statements.
As an astronomer, he probably spent more time in front of telescopes than almost anyone else,
and unlike most cosmologists, he tried to derive his explanatory models from real observations and not the other way around.

In the case of NGC 2403, however, I am completely with you and very convinced
that these are neither tidal tails nor ejected debris.

Chris Peterson wrote: ↑Mon Jun 03, 2024 7:26 pm

Roy wrote: ↑Mon Jun 03, 2024 7:11 pm Halton Arp, in his book Seeing Red thinks the “tidal tail” Ann highlights could be ejection debris.

Fringe science, rejected by virtually all cosmologists.

For this galaxy though, the desc links to this paper https://arxiv.org/abs/2301.13526

We present new neutral hydrogen (HI) observations of the nearby galaxy NGC 2403 to determine the nature of a low-column density cloud that was detected earlier by the Green Bank Telescope. We find that this cloud is the tip of a complex of filaments of extraplanar gas that is coincident with the thin disk. The total HI mass of the complex is 2×107 M⊙ or 0.6% of the total HI mass of the galaxy. The main structure, previously referred to as the 8-kpc filament, is now seen to be even more extended, along a 20 kpc stream. The kinematics and morphological properties of the filaments are unlikely to be the result of outflows related to galactic fountains. It is more likely that the 20 kpc filament is related to a recent galaxy interaction. In this context, a ∼ 50 kpc long stellar stream has been recently detected connecting NGC 2403 with the nearby dwarf satellite DDO 44. Intriguingly, the southern tip of this stream overlaps with that of 20 kpc HI filament. We conclude that the HII anomalies in NGC 2403 are the result of a recent (∼2 Gyr) interaction with DDO 44 leading to the observed filamentary complex.

Is that not a reference to a tidal "tail"? Or is a "stream" not "always" a "tail"?

Hello Chris,

I dont understand your statement about the colors on this galaxy. If you noticed it well, 75h of data had been collected to reach this result, quite different than your image you mention, but I think this is a personal point of view, because with a less dark sky background in your image, could you maybe have detected something? Maybe ?

This galaxy has potential in OIII; that’s what makes it interesting when adding exposure time. There are a few articles on the Arxiv site on this subject, but also on the topic of tidal stream. Not wanting to get ahead of ourselves on the subject, we have asked professionals in the field who are currently verifying the hypotheses. In the meantime, wait and see.

Chris Peterson wrote: ↑Mon Jun 03, 2024 6:32 pm

Ann wrote: ↑Mon Jun 03, 2024 5:13 am Wow, there is so much floof in the lower left part of the picture, and there are so many background galaxies there!

The tidal tail kings of the nearby cosmos are, of course, the Antennae Galaxies!

We can see that the tidal tails of NGC 2403, if that is what they are, can't be compared with the tidal tails of the Antennae Galaxies in any way. The Antennae tidal tails are elegantly arc-shaped, quite bright and very long, but the possible tidal tails of NGC 2403 are faint, gray, relatively short and somewhat haphazardly curved.

But it is sure interesting that the gray floofy clouds of whatever they are near NGC 2403 crowd together in the lower left part of the APOD, where we also find a lot of background galaxies!

I don't think there are any tidal tails here. We're just seeing the foreground galactic cirrus.

I must say I don't like this image, other than the interesting wide view capturing the foreground dust. I've seen quite a lot of images lately that end up with these bizarre orange colors. Maybe the problem here was just too many scopes and cameras, but the color is weird and I don't think it's accurately capturing what's going on in the galaxy itself. I shot this recently, and comparing it to numerous other images as well as HST shots, I think it gives a much better view of the continuum galaxy and the H II regions. (And I don't think [O III] really adds anything to most galaxy images).
_
NGC2403_hrgb.jpg

johnnydeep wrote: ↑Mon Jun 03, 2024 8:31 pm

Chris Peterson wrote: ↑Mon Jun 03, 2024 7:26 pm

Roy wrote: ↑Mon Jun 03, 2024 7:11 pm Halton Arp, in his book Seeing Red thinks the “tidal tail” Ann highlights could be ejection debris.

Fringe science, rejected by virtually all cosmologists.

For this galaxy though, the desc links to this paper https://arxiv.org/abs/2301.13526

We present new neutral hydrogen (HI) observations of the nearby galaxy NGC 2403 to determine the nature of a low-column density cloud that was detected earlier by the Green Bank Telescope. We find that this cloud is the tip of a complex of filaments of extraplanar gas that is coincident with the thin disk. The total HI mass of the complex is 2×107 M⊙ or 0.6% of the total HI mass of the galaxy. The main structure, previously referred to as the 8-kpc filament, is now seen to be even more extended, along a 20 kpc stream. The kinematics and morphological properties of the filaments are unlikely to be the result of outflows related to galactic fountains. It is more likely that the 20 kpc filament is related to a recent galaxy interaction. In this context, a ∼ 50 kpc long stellar stream has been recently detected connecting NGC 2403 with the nearby dwarf satellite DDO 44. Intriguingly, the southern tip of this stream overlaps with that of 20 kpc HI filament. We conclude that the HII anomalies in NGC 2403 are the result of a recent (∼2 Gyr) interaction with DDO 44 leading to the observed filamentary complex.

Is that not a reference to a tidal "tail"? Or is a "stream" not "always" a "tail"?

Well. I think that the ARXIV article you quoted is not very usefull, since the referenced dwarf galaxy DDO 44 (the Hubble image section is the rectangle in the top right corner) is far away from the section of sky shown in the APOD.

...I would also like to point out that the APOD shown has very extreme image distortions, so I would not really describe the image as an astrophotography but rather as an image collage. Here is perhaps a tip for the creators of the image that this could have been relatively easily corrected with Photoshop, for example, if a distortion-free SDSS image had been referenced.

Chris Peterson wrote: ↑Mon Jun 03, 2024 6:32 pm
I don't think there are any tidal tails here. We're just seeing the foreground galactic cirrus.

I must say I don't like this image, other than the interesting wide view capturing the foreground dust. I've seen quite a lot of images lately that end up with these bizarre orange colors. Maybe the problem here was just too many scopes and cameras, but the color is weird and I don't think it's accurately capturing what's going on in the galaxy itself. I shot this recently, and comparing it to numerous other images as well as HST shots, I think it gives a much better view of the continuum galaxy and the H II regions. (And I don't think [O III] really adds anything to most galaxy images).
_

Click to view full size image

I must agree with you, Chris, at least partly. Many years ago I spent a lot of time at a 14-inch telescope just looking at stars to try to assess their color. Hardly any stars were as orange as the center of NGC 2403 in this APOD. Betelgeuse, the way I remember it, was about this color, ███. Mu Cephei, the Garnet Star, was a sort of pale copper, ███, but even that star was not quite as orange as the center of NGC 2403 in today's APOD. Only a few carbon stars were that orange - in fact, they were a lot redder, ███!

I'd say that the center of NGC 2403 in today's APOD is about this color, ███. But then there are a lot of pink Hα regions almost superimposed on the core. I found it hard to find a good match for the color of the Hα regions, but maybe their color was like this, ███, or like this, ███. Together, this creates a vibrant and - I must admit that I think so - a very pleasant color!

Ann

Makesimu wrote: ↑Mon Jun 03, 2024 9:11 pm Hello Chris,

I dont understand your statement about the colors on this galaxy. If you noticed it well, 75h of data had been collected to reach this result, quite different than your image you mention, but I think this is a personal point of view, because with a less dark sky background in your image, could you maybe have detected something? Maybe ?

This galaxy has potential in OIII; that’s what makes it interesting when adding exposure time. There are a few articles on the Arxiv site on this subject, but also on the topic of tidal stream. Not wanting to get ahead of ourselves on the subject, we have asked professionals in the field who are currently verifying the hypotheses. In the meantime, wait and see.

Chris Peterson wrote: ↑Mon Jun 03, 2024 6:32 pm

Ann wrote: ↑Mon Jun 03, 2024 5:13 am Wow, there is so much floof in the lower left part of the picture, and there are so many background galaxies there!

The tidal tail kings of the nearby cosmos are, of course, the Antennae Galaxies!

We can see that the tidal tails of NGC 2403, if that is what they are, can't be compared with the tidal tails of the Antennae Galaxies in any way. The Antennae tidal tails are elegantly arc-shaped, quite bright and very long, but the possible tidal tails of NGC 2403 are faint, gray, relatively short and somewhat haphazardly curved.

But it is sure interesting that the gray floofy clouds of whatever they are near NGC 2403 crowd together in the lower left part of the APOD, where we also find a lot of background galaxies!

I don't think there are any tidal tails here. We're just seeing the foreground galactic cirrus.

I must say I don't like this image, other than the interesting wide view capturing the foreground dust. I've seen quite a lot of images lately that end up with these bizarre orange colors. Maybe the problem here was just too many scopes and cameras, but the color is weird and I don't think it's accurately capturing what's going on in the galaxy itself. I shot this recently, and comparing it to numerous other images as well as HST shots, I think it gives a much better view of the continuum galaxy and the H II regions. (And I don't think [O III] really adds anything to most galaxy images).
_
NGC2403_hrgb.jpg

It's not just the weird color. It's the indecipherable mess in the core of the galaxy. I'm skeptical that I'm seeing actual structure.

johnnydeep wrote: ↑Mon Jun 03, 2024 8:31 pm

Chris Peterson wrote: ↑Mon Jun 03, 2024 7:26 pm

Roy wrote: ↑Mon Jun 03, 2024 7:11 pm Halton Arp, in his book Seeing Red thinks the “tidal tail” Ann highlights could be ejection debris.

Fringe science, rejected by virtually all cosmologists.

For this galaxy though, the desc links to this paper https://arxiv.org/abs/2301.13526

We present new neutral hydrogen (HI) observations of the nearby galaxy NGC 2403 to determine the nature of a low-column density cloud that was detected earlier by the Green Bank Telescope. We find that this cloud is the tip of a complex of filaments of extraplanar gas that is coincident with the thin disk. The total HI mass of the complex is 2×107 M⊙ or 0.6% of the total HI mass of the galaxy. The main structure, previously referred to as the 8-kpc filament, is now seen to be even more extended, along a 20 kpc stream. The kinematics and morphological properties of the filaments are unlikely to be the result of outflows related to galactic fountains. It is more likely that the 20 kpc filament is related to a recent galaxy interaction. In this context, a ∼ 50 kpc long stellar stream has been recently detected connecting NGC 2403 with the nearby dwarf satellite DDO 44. Intriguingly, the southern tip of this stream overlaps with that of 20 kpc HI filament. We conclude that the HII anomalies in NGC 2403 are the result of a recent (∼2 Gyr) interaction with DDO 44 leading to the observed filamentary complex.

Is that not a reference to a tidal "tail"? Or is a "stream" not "always" a "tail"?

I understand the reference to refer to tidal streams from the satellite galaxy, not NGC 2403.

johnnydeep wrote: ↑Mon Jun 03, 2024 8:31 pm

Chris Peterson wrote: ↑Mon Jun 03, 2024 7:26 pm

Roy wrote: ↑Mon Jun 03, 2024 7:11 pm Halton Arp, in his book Seeing Red thinks the “tidal tail” Ann highlights could be ejection debris.

Fringe science, rejected by virtually all cosmologists.

For this galaxy though, the desc links to this paper https://arxiv.org/abs/2301.13526

We present new neutral hydrogen (HI) observations of the nearby galaxy NGC 2403 to determine the nature of a low-column density cloud that was detected earlier by the Green Bank Telescope. We find that this cloud is the tip of a complex of filaments of extraplanar gas that is coincident with the thin disk. The total HI mass of the complex is 2×10⁷ M_⊙ or 0.6% of the total HI mass of the galaxy. The main structure, previously referred to as the 8-kpc filament, is now seen to be even more extended, along a 20 kpc stream. The kinematics and morphological properties of the filaments are unlikely to be the result of outflows related to galactic fountains. It is more likely that the 20 kpc filament is related to a recent galaxy interaction. In this context, a ∼ 50 kpc long stellar stream has been recently detected connecting NGC 2403 with the nearby dwarf satellite DDO 44. Intriguingly, the southern tip of this stream overlaps with that of 20 kpc HI filament. We conclude that the HII anomalies in NGC 2403 are the result of a recent (∼2 Gyr) interaction with DDO 44 leading to the observed filamentary complex.

How very interesting, Johnny! Could this be the dwarf galaxy?


If that is the dwarf galaxy, then that would explain all the gray fluff in the lower left corner of the APOD. Also note that there is a bridge, although a very thin one, between the possible dwarf galaxy and NGC 2403.

Ann

Ann wrote: ↑Tue Jun 04, 2024 4:34 am

johnnydeep wrote: ↑Mon Jun 03, 2024 8:31 pm

Chris Peterson wrote: ↑Mon Jun 03, 2024 7:26 pm

Fringe science, rejected by virtually all cosmologists.

For this galaxy though, the desc links to this paper https://arxiv.org/abs/2301.13526

We present new neutral hydrogen (HI) observations of the nearby galaxy NGC 2403 to determine the nature of a low-column density cloud that was detected earlier by the Green Bank Telescope. We find that this cloud is the tip of a complex of filaments of extraplanar gas that is coincident with the thin disk. The total HI mass of the complex is 2×10⁷ M_⊙ or 0.6% of the total HI mass of the galaxy. The main structure, previously referred to as the 8-kpc filament, is now seen to be even more extended, along a 20 kpc stream. The kinematics and morphological properties of the filaments are unlikely to be the result of outflows related to galactic fountains. It is more likely that the 20 kpc filament is related to a recent galaxy interaction. In this context, a ∼ 50 kpc long stellar stream has been recently detected connecting NGC 2403 with the nearby dwarf satellite DDO 44. Intriguingly, the southern tip of this stream overlaps with that of 20 kpc HI filament. We conclude that the HII anomalies in NGC 2403 are the result of a recent (∼2 Gyr) interaction with DDO 44 leading to the observed filamentary complex.

How very interesting, Johnny! Could this be the dwarf galaxy?


APOD 3 June 2024 annotated dwarf galaxy.png


If that is the dwarf galaxy, then that would explain all the gray fluff in the lower left corner of the APOD. Also note that there is a bridge, although a very thin one, between the possible dwarf galaxy and NGC 2403.

Ann

The blue cross marks DDO 44, the galaxy that has had tidal filaments detected that are hypothesized to have resulted from interacting with NGC 2403. That galaxy is seen at the bottom.
_

Chris Peterson wrote: ↑Tue Jun 04, 2024 4:52 am

Ann wrote: ↑Tue Jun 04, 2024 4:34 am

johnnydeep wrote: ↑Mon Jun 03, 2024 8:31 pm

For this galaxy though, the desc links to this paper https://arxiv.org/abs/2301.13526

How very interesting, Johnny! Could this be the dwarf galaxy?


APOD 3 June 2024 annotated dwarf galaxy.png


If that is the dwarf galaxy, then that would explain all the gray fluff in the lower left corner of the APOD. Also note that there is a bridge, although a very thin one, between the possible dwarf galaxy and NGC 2403.

Ann

The blue cross marks DDO 44, the galaxy that has had tidal filaments detected that are hypothesized to have resulted from interacting with NGC 2403. That galaxy is seen at the bottom.
_

Click to view full size image

Thanks, Chris!

Ann