Starship Asterisk*

by **Chris Peterson** » Sat May 05, 2018 4:52 am

Patherat wrote: ↑Sat May 05, 2018 4:12 am What blows my mind is the fact that the stars on the far side of the disk are 50,000 years older then the one's on the near side. What is the measurement that is used to confirm this. Are the stars on the far side measurably shifted to account for their rotation around the axis of the galaxy?

The stars take millions of years to orbit the galaxy. 50,000 years represents much too small a part of that orbit to see in an image of this scale.

by **Patherat** » Sat May 05, 2018 4:12 am

What blows my mind is the fact that the stars on the far side of the disk are 50,000 years older then the one's on the near side. What is the measurement that is used to confirm this. Are the stars on the far side measurably shifted to account for their rotation around the axis of the galaxy?

by **fes352** » Tue Feb 10, 2015 5:45 am

The photo shown is a reversed mirror image

by **rcolombari** » Mon Feb 09, 2015 10:20 pm

I would have been really happy to have a more noble version/excuse but unfortunately this is an artifact

by **Deathcon** » Mon Feb 09, 2015 9:50 pm

I was scanning around the image when I noticed some striking symmetry.

I cropped and broke the image down, as well as sharpened up and adjusted the light levels to see the objects better. The symmetry was even more evident.

In the next few pictures I made a copy of one side of the supposed symmetry and made it a transparent mask over the original image, which I then color inverted. When I take the transparent mask over either of the two sides the result is a uniform color indicating the two sets of stars are virtually identical in brightness and position from one another.

I made the copy of the bottom group of stars here and placed the mask to the right for comparison.

I placed the mask over the same group I copied to illustrate the effect.

Then placed the mask over the other group, showing it is identical as the first.

Can anyone try to explain this? Gravitational lensing, or some sort of post-processing mirror artifact?

by **Chris Peterson** » Fri Feb 06, 2015 3:13 pm

BMAONE23 wrote:Like dancing ballerinas acting out M104's swan song

Don't be so sure. It's gravitationally bound to at least one other galaxy, probably several. So eventually it will probably experience a collision or strong interaction, which means a new round of active star formation. Probably better to think of this galaxy as dormant.

by **BMAONE23** » Fri Feb 06, 2015 2:34 pm

Like dancing ballerinas acting out M104's swan song

by **Ann** » Fri Feb 06, 2015 5:14 am

Boomer12k wrote:OK...OFFICIALLY my favorite picture!!!! Orion not withstanding...this is just amazing!!!

I don't know if it is the cameras or processes, or lack of filters, or what...but where are the star forming regions???

I think Ann's observation of an Elliptical galaxy that has a ring of dust is interesting...

I also find it interesting that the dust appears to have been blown out from the middle...
Spectacular job!!!!!

:---[===] *

There are no star forming regions in this galaxy, although there appear to be some stars hot enough to register (weakly) by the now-defunct ultraviolet-detecting space telescope GALEX. Such stars would likely be spectral class A, I think.

There is an interesting article here about M104 being two galaxies in one, one elliptical galaxy and one flat double ring structure not totally unlike the rings of Saturn, except that the one ring is made of stars only and the other one is made of stars and dust.

http://www.universetoday.com/94800/spit ... es-in-one/ wrote:

Although it might seem that the Sombrero is the result of a collision between two separate galaxies, that’s actually not thought to be the case. Such an event would have destroyed the disk structure that’s seen today; instead, it’s thought that the Sombrero accumulated a lot of extra gas billions of years ago when the Universe was populated with large clouds of gas and dust. The extra gas fell into orbit around the galaxy, eventually spinning into a flattened disk and forming new stars.

But that star formation must have ended long ago, and the Sombrero galaxy does not seem to be receiving any substantial new helpings of gas. In any case, its supermassive black hole may heat the gas that is there so that it loses its ability to form stellar nurseries of dense cool dusty gas. This galaxy is on a fast track toward the red and dead stage.

Yes, but take a look at those nice background interacting spiral galaxies! They are aglow with brilliant clusters of new stars. I think they look so beautiful. And it is fascinating that they are so similar in appearance too, both in size, structure and apparent stellar populations.

Ann

by **Mactavish** » Fri Feb 06, 2015 2:36 am

The last pint I had was about the same as all the others before it. But it was just as good. Think I’ll have another!

by **Boomer12k** » Thu Feb 05, 2015 11:50 pm

OK...OFFICIALLY my favorite picture!!!! Orion not withstanding...this is just amazing!!!

I don't know if it is the cameras or processes, or lack of filters, or what...but where are the star forming regions???

I think Ann's observation of an Elliptical galaxy that has a ring of dust is interesting...

I also find it interesting that the dust appears to have been blown out from the middle...
Spectacular job!!!!!

:---[===] *

by **BMAONE23** » Thu Feb 05, 2015 10:17 pm

geckzilla wrote:
foresthillsbob wrote:Can anyone identify what appears to be a pair of interacting galaxies just below and to the right (see arrow in this picture)?
http://i.imgur.com/BAhnRIO.png
2MASX J12400754-1140015
CXOU J124007.15-114001.8

Not much to go on. They aren't studied beyond noting that one exists and the other has an x-ray source within it. Most of these small/distant galaxies are anonymous.

Here is the best image of the pair that I have found

: Click to view full size image

by **Chris Peterson** » Thu Feb 05, 2015 10:07 pm

ta152h0 wrote:does the direction of the spin axis of these things remain forever, since birth ?

You have to consider what the spin axis even is for a non-rigid body like a galaxy. Some galaxies have no common spin axis at all- their constituent stars orbit in random inclinations (as with a globular cluster). Some have weak commonality (as with many ellipticals). Some have an apparent planar structure, although the majority of the mass in the central bulge still shares no common inclination.

That said, I'd expect the disc plane of an isolated spiral to remain pretty constant. But if it were to interact with another galaxy- even without an actual collision- the plane could be significantly altered.

by **geckzilla** » Thu Feb 05, 2015 10:01 pm

foresthillsbob wrote:Can anyone identify what appears to be a pair of interacting galaxies just below and to the right (see arrow in this picture)?
http://i.imgur.com/BAhnRIO.png

2MASX J12400754-1140015
CXOU J124007.15-114001.8

Not much to go on. They aren't studied beyond noting that one exists and the other has an x-ray source within it. Most of these small/distant galaxies are anonymous.

by **ta152h0** » Thu Feb 05, 2015 9:18 pm

does the direction of the spin axis of these things remain forever, since birth ?

by **foresthillsbob** » Thu Feb 05, 2015 9:09 pm

Can anyone identify what appears to be a pair of interacting galaxies just below and to the right (see arrow in this picture)?
http://i.imgur.com/BAhnRIO.png

by **tubeydude** » Thu Feb 05, 2015 9:08 pm

There are some "filaments" in the image that look like what you would see if you scanned a picture that has a lot of dust on it. Above the Galactic disk, over tot he right 1/2 galactic radius and up one radius. They look like little filaments. I'm sure these are artifacts of some sort, but they are also all different, so it not a "camera shake" type thing.

Love the images, thanks for doing this!

by **BMAONE23** » Thu Feb 05, 2015 8:12 pm

Did anyone notice or appreciate that this image of M104 is obviously from the other side of the galaxy

Or is it that the image was just mirrored from the regular orientation

by **geckzilla** » Thu Feb 05, 2015 8:11 pm

starsurfer wrote:Isn't this galaxy supposed to have a really high number of globular clusters?

Yeah. You can see a lot of them in the image, but most people would guess that those small dots are foreground stars.

by **eksgabe** » Thu Feb 05, 2015 7:10 pm

Joe Nobody wrote:It's like you guys have run out of things to show us. Is this all there is? Why are there hardly any NEW images on APOD? I've been following this site since it began, and have seen a bunch of cool pics, but I also have noticed, the same images over and over. Are there no NEW images? Has Hubble stopped working since APOD started? What gives???
It's like you have so many, then, just repeat them... Why are you not showing new images? New galaxies? You can't tell me there aren't any left to show.

Come on, Joe. Though your experience may be extensive, what about young ones, both in age and experience, that may be seeing this for the first time?

Also, do you get tired of your favorite foods? Do you completely appreciate all the nuances in the first experience? There is so much more to many of the APOD images we see. You yourself learn more with each day, which then helps you to see each image from a fresh perspective. Seeing other people's perspectives in the comments for that day also brings uniqueness (Ann, Geck, B Daniel Mayfield, Neufer, Chris Peterson to name a few), and with the occasional exception of disgruntled viewers or the occasional snooty remark by the Abominable Snowman (which also make me smile, I must admit), every day is a fresh day.

APOD staff and posters: thank you for all the hard work! Even "repeats" are appreciated.

-Gabe

by **Chris Peterson** » Thu Feb 05, 2015 6:30 pm

BDanielMayfield wrote:
Chris Peterson wrote:Unknown. There are models for both scenarios. Evidence leans towards the black holes forming very early in the life of the galaxy, however, and not being the seed of galaxy formation.
What about central BHs and their surrounding galaxies growing together over time?

A thought occurred to me (I'm sure that others must have thought of this too): The most efficient way for a BH to grow is by merger with other BHs.

Yes. Mergers are definitely one of the preferred explanations for the growth of SMBs.

The biggest theoretical problems are at the earlier stages. The energy released when black holes feed tends to push material away, which stops the feeding. It's not obvious how you get over that bump. Mergers are one solution. But it's interesting that we don't find a continuum of black holes massing from stellar to SMBs.

by **BDanielMayfield** » Thu Feb 05, 2015 6:25 pm

Chris Peterson wrote:
Ron-Astro Pharmacist wrote:Is it known which came first; the black hole or the galaxy?
Unknown. There are models for both scenarios. Evidence leans towards the black holes forming very early in the life of the galaxy, however, and not being the seed of galaxy formation.

What about central BHs and their surrounding galaxies growing together over time?

A thought occurred to me (I'm sure that others must have thought of this too): The most efficient way for a BH to grow is by merger with other BHs.

by **BMAONE23** » Thu Feb 05, 2015 6:10 pm

geckzilla wrote:
Joe Nobody wrote:It's like you guys have run out of things to show us. Is this all there is? Why are there hardly any NEW images on APOD? I've been following this site since it began, and have seen a bunch of cool pics, but I also have noticed, the same images over and over. Are there no NEW images? Has Hubble stopped working since APOD started? What gives???
It's like you have so many, then, just repeat them... Why are you not showing new images? New galaxies? You can't tell me there aren't any left to show.
If you think that there are no new images, you haven't been paying very much attention. Today's is a new image of the Sombrero Galaxy. Yesterday? New image of sprites. Before that? Brand new image of 67p. And before that? Brand new, never before featured composite of Titan. It practically can't get any newer. Reruns are primarily on weekends to give the editors a break (there are only two of them doing the whole thing).

It really only appears to be old images. As Geck stated, these are new Images but of the same things. M104 has been imaged countless times but each unique image is of the same thing giving the appearance of being the same image.
Since Nov 1995 a search for M104 gets 19 hits on the APDO search and although some are Sunday repeats many are new though ALL are M104.
I am certain that when CERES is fully resolved there will be a series of APODs containing images and similar for Pluto.
Repeats will forever happen on Sundays because Sunday is for them. Many astronomical images will appear to be repeats even if they are new simply because the object has been images before.

by **Chris Peterson** » Thu Feb 05, 2015 4:07 pm

Ron-Astro Pharmacist wrote:Is it known which came first; the black hole or the galaxy?

Unknown. There are models for both scenarios. Evidence leans towards the black holes forming very early in the life of the galaxy, however, and not being the seed of galaxy formation.

by **Ron-Astro Pharmacist** » Thu Feb 05, 2015 3:59 pm

Here's a chicken or the egg scenario-

Is it known which came first; the black hole or the galaxy? Being centrally located one might think it was there first, afterwards attracting the matter which surrounds. But then again perhaps it formed from as a result of the abundance of matter; collapsing to form a black hole which grew larger?

My first inclination was the latter. Then again, they might be: the former of galaxies. Do we know for sure?

by **leon.l7027@gmail.com** » Thu Feb 05, 2015 3:45 pm

The last statement implies that M104 is a member of the Virgo Cluster. But at the link it is clearly stated that it is a foreground galaxy, 2/3 of the way between us and Virgo.

Starship Asterisk*

APOD: M104: The Sombrero Galaxy (2015 Feb 05)

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