Astronomers find new details in first known spiral galaxy

February 3, 2015, Case Western Reserve University
Case Western Reserve University astronomers found new features on the first-known spiral galaxy, M51a, which has been sketched and photographed for 170 years. Credit: Aaron Watkins

Case Western Reserve University astronomers peered deep into space to discover new features of a galaxy that's been sketched and photographed for 170 years.

The researchers were able to see faint plumes extending from the northeast and south of the nearby spiral galaxy M51a, also called the "Whirlpool Galaxy," by taking what is essentially a photograph made by a 20-hour exposure.

The image also provides new details of the linear northwest plume, which itself is nearly 120,000 light-years long, and reveals a lack of in a portion of the southeast tail.,

"These features can be used in future modeling to understand the history of M51, when it and its first started to interact," said Aaron Watkins, a PhD student in the department of astronomy at Case Western Reserve and lead author of the study.

Modeling that's already been done fails to match the structures of the system, ages and more.

Watkins worked with the CWRU astronomy professor Chris Mihos and Observatory Manager Paul Harding. The research is published in Astrophysical Journal Letters.

M51a is the first known spiral galaxy, identified and sketched by William Parsons, the Earl of Rosse, in 1845. The whirlpool and its small companion, M51b, are in the hunting dogs constellation, Canes Venatici, about 31 million light years away.

"No professional astronomer we know of has ever taken such a deep image of this galaxy," Watkins said. The images were taken from the CWRU's Burrell Schmidt telescope at Kitt Peak National Observatory near Tucson during February, March and April in 2010 and 2012.

The team aimed the telescope at M51 on moonless nights and exposed its digital camera to the light from the galaxy at 20-minute intervals, recalibrating in between. For a total of 10 hours, light was filtered to reveal younger stars. For anther 10 hours, light was filtered to reveal older stars. These 10-hour images were merged to create the 20-hour final image.

The northwest plume was seen in the 1970s, but the technology provided limited detail. The astronomers found it's dominated by older, redder stars and has little gas, found in small patches. Due to the age of the stars and the extreme length of the plume, they suggest the plume was created by the interaction of an outer disk of M51 with another galaxy 200 million years ago or more.

The southern plume is an oddity. It has no morphological similarities with the surrounding parts of M51 and no gas. The plume has comparatively few stars and, therefore, mass, and little total light. One possibility, the researchers suggest, is the plume could be the remnants of a third satellite or body in the M51 system.

The northeast plume has about the same total light as the southern one. It may be an extension of the north side of the galaxy, but that is impossible to tell, Watkins said.

Other researchers discovered the southeastern gas tail in 1990 and assumed it was pulled out during an interaction with another galaxy. This new, deeper view still found no stars. That's unusual for such a tail, but it provides a clear test for future interaction models.

The astronomers are now devising other ways to look at M51, particularly to gather more detail from the faint plumes. The northwest is bright enough that it may be a good candidate for further study using the Hubble telescope, Watkins said.

Explore further: Chandra captures galaxy sparkling in X-rays

More information: Astrophysical Journal Letters, http://iopscience.iop.org/2041-8205/800/1/L3/article

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Humbled1
1.5 / 5 (8) Feb 03, 2015
Modeling that's already been done fails to match the structures of the system, ages and more.


The Dark Matter particle used in models behaves like a non-interacting point gravitational mass. This is functionally indistinguishable from ordinary matter, with the exception that it can pass through ordinary matter. This means it would tend to collect in the cores of stars and black holes via momentum transfer from the gravitational force.

Even an electrically non-interactive particle in a N-body system can be robbed of relative momentum until it comes to relative rest with respect to one of the other particles.

Therefore the electrically non-interactive particle would not produce dark matter halos.

Why does the model work then? Because they are modeling Newton's Law, which actually describes the phenomenon exactly. The particle they model is just another newtonian mass, and doesn't even go where they expect it to go in the model, which I predicted.
Humbled1
1.4 / 5 (9) Feb 03, 2015
For those who didn't understand that, it turns out that Dark Matter really is just unknown ordinary matter plus the Disk shape of the Galaxy.
Humbled1
1.4 / 5 (9) Feb 03, 2015
Additionally, no one particle would ever produce the fantasized dark matter halos anyway, because you actually require multiple types of "charges" in order to sustain that structure (Halos, filaments, etc) over time in and between galaxies.

And here I don't use "Charge" in an electric sense.

The problem I ran into is one type of DM ends up inside of black holes anyway,and still doesn't behave the way the alleged halos need to behave.
Uncle Ira
2.6 / 5 (5) Feb 03, 2015
For those who didn't understand that, it turns out that Dark Matter really is just unknown ordinary matter plus the Disk shape of the Galaxy.


@ Not-So-Humbled-Returnering-Skippy. I put this on one of the other comment places but thought I'd put him here too because you write so many postums on so many subjects you might miss him there..

@Returnering-Skippy. How you are Cher? I am still good me. Thanks.

I am glad the doctors let you out to try again seeing if your mental condition is getting under control. But did you forget that the too many postums is what caused them to lock you away last time? And the times before that too.

Where they put you this time? Back in Mandeville again or back in Jackson again? Maybe you should try Brentwood if it isn't to far from where you are, it is way up there almost in Texas at Shreveport. I heard they got real good food there.
Humbled1
1.8 / 5 (5) Feb 03, 2015
I actually wasn't banned on the other account.

I forgot my password because I hadn't re-entered it in a very long time, and my hard drive on that computer failed.

My solution of the problem works, and it works so well that as the number of objects simulated increases it acts more and more like the observations, and you don't have to invent invisible, intangible mass to do it.
Shootist
5 / 5 (1) Feb 03, 2015
Shreveport. I heard they got real good food there.


Ralph and Kacoo's, I guarantee.
Uncle Ira
3 / 5 (4) Feb 03, 2015
I actually wasn't banned on the other account.

I forgot my password because I hadn't re-entered it in a very long time,


Well it's going to be a long time again Cher if that is not the lie. You did not have much trouble remembering Not-So-Humbled-Skippy's password all the way back to when you started him. And the brand new hard drive did not have any trouble remembering him either.

My solution of the problem works, and it works so well that as the number of objects simulated increases it acts more and more like the observations, and you don't have to invent invisible, intangible mass to do it.


Well you better be careful, your solutions might work so well that the doctors take you back to Mandeville again so they can study it more closely.
Uncle Ira
3 / 5 (4) Feb 03, 2015
Shreveport. I heard they got real good food there.


Ralph and Kacoo's, I guarantee.


He'll have to settle for Brentwood's food. If they take him there instead of back to Mandeville or Jackson
Benni
1.8 / 5 (5) Feb 03, 2015
@ Not-So-Humbled-Returnering-Skippy. I put this on one of the other comment places but thought I'd put him here too because you write so many postums on so many subjects you might miss him there..

@Returnering-Skippy. How you are Cher? I am still good me. Thanks.

I am glad the doctors let you out to try again seeing if your mental condition is getting under control. But did you forget that the too many postums is what caused them to lock you away last time? And the times before that too.

Where they put you this time? Back in Mandeville again or back in Jackson again? Maybe you should try Brentwood if it isn't to far from where you are, it is way up there almost in Texas at Shreveport. I heard they got real good food there.


Ira, I see you've got your contrived spelling accent back..........you have credibility again. Now, what was it you wanted to say about this galaxy?
Uncle Ira
2.6 / 5 (5) Feb 03, 2015
Now, what was it you wanted to say about this galaxy?


Well hey Bennie-Skippy. How you are Cher? I'm real good, thanks for asking.

I do not have so much to say about this galaxy. Except he sure is a pretty one. What you think about him?
Benni
2.3 / 5 (6) Feb 03, 2015
Now, what was it you wanted to say about this galaxy?


Well hey Bennie-Skippy. How you are Cher? I'm real good, thanks for asking.

I do not have so much to say about this galaxy. Except he sure is a pretty one. What you think about him?


Sounds like you have a gender attachment...........to this galaxy
Whydening Gyre
4.3 / 5 (6) Feb 03, 2015
FTA
M51a is the first known spiral galaxy, identified and sketched by William Parsons, the Earl of Rosse, in 1845. The whirlpool and its small companion, M51b, are in the hunting dogs constellation, Canes Venatici, about 31 million light years away.

Waitaminut.... I thought we didn't even know about other galaxies before 1920s...
Did the Earl think it was a spiral star?
Uncle Ira
2.6 / 5 (5) Feb 03, 2015
Now, what was it you wanted to say about this galaxy?


Well hey Bennie-Skippy. How you are Cher? I'm real good, thanks for asking.

I do not have so much to say about this galaxy. Except he sure is a pretty one. What you think about him?


Sounds like you have a gender attachment...........to this galaxy


I do not know what that is. I'm not the galaxy expert like you aren't either. So is that all you have to say about him? I am attached to him?
cantdrive85
1.6 / 5 (7) Feb 03, 2015
The researchers were able to see faint plumes extending from the northeast and south of the nearby spiral galaxy M51a,


Those "plumes" extending from the galaxy are most likely the inter-galactic Birkeland currents powering the the galaxy. The third plume likely connected to the companion galaxy near the end of the arm of the large galaxy.

Modeling that's already been done fails to match the structures of the system, ages and more.


Failed models equate to failed theories, astrophysicists won't likely realize this for another 50 years or so. Billions wasted on more snipe hunts...
PhotonX
5 / 5 (8) Feb 03, 2015
FTA
M51a is the first known spiral galaxy, identified and sketched by William Parsons, the Earl of Rosse, in 1845. The whirlpool and its small companion, M51b, are in the hunting dogs constellation, Canes Venatici, about 31 million light years away.

Waitaminut.... I thought we didn't even know about other galaxies before 1920s...
Did the Earl think it was a spiral star?
Not definitely, but if I recall correctly it was either Voltaire or Goethe who suggested that those fuzzy bits that bothered Messier so much might be other galaxies (or other 'universes', depending on the exact terminology used). Kind of like Wegener suggested plate tectonics in the 1920's or so but it wasn't proven to be so until long after his death. Hubble just put the icing on the galactic cake.
.
.
Whydening Gyre
3.3 / 5 (7) Feb 04, 2015
Failed models equate to failed theories, astrophysicists won't likely realize this for another 50 years or so. Billions wasted on more snipe hunts...

It's called "filling in the holes.". Not an exciting job, but necessary...
bluehigh
2 / 5 (4) Feb 04, 2015
I wish I knew what you are looking for.
Might have known what you would find

Perhaps its the absence of something that triggers a belief that a dark presence is causitive,

A bit like the effect of some white background showing through a canvas when painting. Is the background seeking attention of its own accord? Or because it's highlighted by surrounds?

Shadows ?

bluehigh
2.3 / 5 (6) Feb 04, 2015
Is it only dark outside because it's bright inside?

It's dark outside because there's an absence. Not because there's a presence.

bluehigh
2.3 / 5 (6) Feb 04, 2015
Looking for Dark Stuff you can't find?

Maybe go look for some Light Stuff that's not there!!
bluehigh
2.6 / 5 (5) Feb 04, 2015
And it's something quite peculiar
Something shimmering and white
Leads you here despite your destination
Under the Milky Way tonight
Whydening Gyre
4.2 / 5 (5) Feb 04, 2015
And it's something quite peculiar
Something shimmering and white
Leads you here despite your destination
Under the Milky Way tonight

That Church song was one of my faves from the 80s...
Humbled1
1.8 / 5 (5) Feb 07, 2015
Failed models equate to failed theories, astrophysicists won't likely realize this for another 50 years or so. Billions wasted on more snipe hunts...


There still isn't a computer powerful enough to model a galaxy correctly even just using Newtonian Dynamics. They use approximations, but it is possible to show using just a dozen masses or so that the approximations are not correct.

The correct N-body correctly predicts a flattening orbital curve because objects that are close to one another affect one another much more powerfully than the total mass of the galaxy affects one another. A star that is 5 light-years away has 100 times more influence on you than a star that is 50 light years away and a million times more than a star that is 5000 light years away. Thus the core of a galaxy has negligible attraction power on stars in the disk of the galaxy when compared to other stars in the disk.
Humbled1
1 / 5 (4) Feb 07, 2015
Here is a "good" galaxy simulation, but even it uses faulty assumptions, including DM I believe.

http://www.youtub...UDWhPB_E

Here's a galaxy merger ran by NASA:

http://www.youtub...uujaldZk

This is one of the most violent results I've seen from there models. The eruption of the AGNs pretty much disintegrated both galaxies.

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