Dark Energy Survey finds more celestial neighbors

Dark Energy Survey finds more celestial neighbors
The Dark Energy Survey has now mapped one-eighth of the full sky (red shaded region) using the Dark Energy Camera on the Blanco telescope at the Cerro Tololo Inter-American Observatory in Chile (foreground). This map has led to the discovery of 17 dwarf galaxy candidates in the past six months (red dots), including eight new candidates announced today. Several of the candidates are in close proximity to the two largest dwarf galaxies orbiting the Milky Way, the Large and Small Magellanic Clouds, both of which are visible to the unaided eye. By comparison, the new stellar systems are so faint that they are difficult to “see” even in the deep DES images and can be more easily visualized using maps of the stellar density (inset). Fourteen of the dwarf galaxy candidates found in DES data are visible in this particular image. Credit: Dark Energy Survey Collaboration

Scientists on the Dark Energy Survey, using one of the world's most powerful digital cameras, have discovered eight more faint celestial objects hovering near our Milky Way galaxy. Signs indicate that they, like the objects found by the same team earlier this year, are likely dwarf satellite galaxies, the smallest and closest known form of galaxies.

Satellite galaxies are small celestial objects that orbit larger galaxies, such as our own Milky Way. Dwarf galaxies can be found with fewer than 1,000 stars, in contrast to the Milky Way, an average-size galaxy containing billions of stars. Scientists have predicted that larger galaxies are built from smaller galaxies, which are thought to be especially rich in dark matter, the substance that makes up about 25 percent of the total matter and energy in the universe. Dwarf , therefore, are considered key to understanding dark matter and the process by which larger galaxies form.

The main goal of the Dark Energy Survey (DES), as its name suggests, is to better understand the nature of , the mysterious stuff that makes up about 70 percent of the matter and energy in the universe. Scientists believe that dark energy is the key to understanding why the expansion of the universe is speeding up. To carry out its dark energy mission, DES takes snapshots of hundreds of millions of distant galaxies. However, some of the DES images also contain stars in dwarf galaxies much closer to the Milky Way. The same data can therefore be used to probe both dark energy, which scientists think is driving galaxies apart, and dark matter, which is thought to hold galaxies together.

Scientists can only see the faintest dwarf galaxies when they are nearby, and had previously only found a few of them. If these new discoveries are representative of the entire sky, there could be many more galaxies hiding in our cosmic neighborhood.

"Just this year, more than 20 of these dwarf satellite galaxy candidates have been spotted, with 17 of those found in Dark Energy Survey data," said Alex Drlica-Wagner of the U.S. Department of Energy's (DOE) Fermi National Accelerator Laboratory, one of the leaders of the DES analysis. "We've nearly doubled the number of these objects we know about in just one year, which is remarkable."

In March, researchers with the Dark Energy Survey and an independent team from the University of Cambridge jointly announced the discovery of nine of these objects in snapshots taken by the Dark Energy Camera, the extraordinary instrument at the heart of the DES, an experiment funded by the DOE, the National Science Foundation and other funding agencies. Two of those have been confirmed as dwarf satellite galaxies so far.

Prior to 2015, scientists had located only about two dozen such galaxies around the Milky Way.

"DES is finding galaxies so faint that they would have been very difficult to recognize in previous surveys," said Keith Bechtol of the University of Wisconsin-Madison. "The discovery of so many new galaxy candidates in one-eighth of the sky could mean there are more to find around the Milky Way."

The closest of these newly discovered objects is about 80,000 light-years away, and the furthest roughly 700,000 light-years away. These objects are, on average, around a billion times dimmer than the Milky Way and a million times less massive. The faintest of the new dwarf galaxy candidates has about 500 stars.

Most of the newly discovered objects are in the southern half of the DES survey area, in close proximity to the Large Magellanic Cloud and the Small Magellanic Cloud. These are the two largest satellite galaxies associated with the Milky Way, about 158,000 light-years and 208,000 light-years away, respectively. It is possible that many of these new objects could be satellite galaxies of these larger satellite galaxies, which would be a discovery by itself.

"That result would be fascinating," said Risa Wechsler of DOE's SLAC National Accelerator Laboratory. "Satellites of satellites are predicted by our models of dark matter. Either we are seeing these types of systems for the first time, or there is something we don't understand about how these satellite galaxies are distributed in the sky."

Since are thought to be made mostly of dark matter, with very few stars, they are excellent targets to explore the properties of dark matter. Further analysis will confirm whether these new objects are indeed dwarf satellite galaxies and whether signs of can be detected from them.

The 17 dwarf satellite galaxy candidates were discovered in the first two years of data collected by the Dark Energy Survey, a five-year effort to photograph a portion of the southern sky in unprecedented detail. Scientists have now had a first look at most of the survey area, but data from the next three years of the survey will likely allow them to find objects that are even fainter, more diffuse or farther away. The third survey season has just begun.

"This exciting discovery is the product of a strong collaborative effort from the entire DES team," said Basilio Santiago, a DES Milky Way Science Working Group coordinator and a member of the DES-Brazil Consortium. "We've only just begun our probe of the cosmos, and we're looking forward to more exciting discoveries in the coming years."

View the Dark Energy Survey analysis online.


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Scientists find rare dwarf satellite galaxy candidates in Dark Energy Survey data

Citation: Dark Energy Survey finds more celestial neighbors (2015, August 17) retrieved 22 October 2019 from https://phys.org/news/2015-08-dark-energy-survey-celestial-neighbors.html
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Aug 17, 2015
So lets compare a oil tank on fire next to a match. With that small patch of sky there could be millions around us we didn't find yet. So maybe just maybe we found that gravity field we were sure was dark matter, because it doesn't have to be clumps of 100% active stars. The match goes out long before the oil gets going and It doesn't have to filled with star sized objects at all. Maybe just maybe a Galactic Oort Cloud or as I'll call it a .... GOC We should send a probe.

Aug 17, 2015
http://phys.org/n...axy.html

Boto,

Above link is what you're looking for. Basically you've already guessed it right. The DM hypothesis is that it envelopes Spiral galaxies providing countervailing gravitational forces to keep the radial arms from being sucked into the central bulge.

The above linked giant halos of ordinary matter that stretch almost half the distances between galaxies could not exist as they do because the DM Envelope that supposedly surrounds Spiral galaxies would prevent the formation of the detectable halo.

Aug 17, 2015
Ha..and thanks...and maybe the next big find will be the changes in light we do see that make us think the universe is expanding ever faster may just be a optical effect on light changing in the halo(s). Still I also like my idea that its the effect of space time and energy replacing it self from what gets sucked into black holes. The larger the distance the smaller the effect we see. Much like an oil film on water. We may be only able to measure the change that is close enough to see (within reason) much for the same reason we can only measure the halo of Andromeda. Then again what do I know for I hold no degree to speak of....I only enjoy the puzzle and making it work with what I know. In much the same way I once gave comment a black hole could be a ball of Gluons because they fit the space requirements to pack tight enough create a event horizon. Just because the math says it could be a point doesn't mean it is. N.G. Tyson never responded to my e-mail on that....oh well

Aug 18, 2015
@Benni: "The DM hypothesis".

The rest is correct, but there is no separate DM hypothesis any longer. It is an indelible part of modern cosmology and its theory, and has been observed to ~ 20 sigma (IIRC) in the latest Planck data release. It is better to speak of the observed DM content's properties.

Speaking of DM's role, Astrobites (the professional blog for astronomy students) have a recent article on how DM now is necessary - best - to predict spiral galaxies, the very area that it did badly before (due to the cusp core problem). http://astrobites...er-halo/

So now it is the best mechanism where it should be (structure formation from cosmological filaments down to dwarf galaxies). I, for one, welcome our new Dark Matter Overlords!


Aug 18, 2015
@Benni: "The DM hypothesis".

The rest is correct, but there is no separate DM hypothesis any longer. It is an indelible part of modern cosmology and its theory, and has been observed to ~ 20 sigma (IIRC) in the latest Planck data release. It is better to speak of the observed DM content's properties.


You don't know what you're talking about, just the usual marrative of the DM Hypotheses talking points. If there were all this Cosmic Fairy Dust pervading every recess of the universe, then Einstein in 1915 in General Relativity would never have been able to calculate the exact angle that starlight bends as it passes the visible peripheral disc of the sun.

You DM Enthusaists never seem to get it. Einstein did not need to include 75-90% missing matter gravity into his Gravitational Lensing calculations in General Relativity, but none of you understand why he didn't need to. Go to that section of GR & actually study it, that is if the math isn't too arduous for you.

Aug 18, 2015
With that small patch of sky there could be millions around us we didn't find yet. So maybe just maybe we found that gravity field we were sure was dark matter, because it doesn't have to be clumps of 100% active stars.


These dwarf galaxies are luinous, they contain stars. If the whole dark matter halo was made out of dwarf galaxies it would be as bright as the regular stellar halo. It's not observed so it isn't stars. If you could "inactive stars" whatever you mean by that then they would need to appear in microlensing projects which ruled out stellar mass objects as the major component of the dark matter halo. As Torbjorn_Larsson_OM correctly points out there is additional evidence for dark matter not simply being normal matter, namely the CMB powerspectrum, primordial nucleosynthesis and the amplitude of the baryon acoustic oscillation in the modern universe.

Aug 18, 2015
If there were all this Cosmic Fairy Dust pervading every recess of the universe, then Einstein in 1915 in General Relativity would never have been able to calculate the exact angle that starlight bends as it passes the visible peripheral disc of the sun.


A claim you repeat even though it has been shown to you to be wrong. The expected dark matter content of the solar system out to Pluto is on the order of a mid sized asteroid, a rounding error for the aberration of starlight.

Aug 18, 2015
If there were all this Cosmic Fairy Dust pervading every recess of the universe, then Einstein in 1915 in General Relativity would never have been able to calculate the exact angle that starlight bends as it passes the visible peripheral disc of the sun.


A claim you repeat even though it has been shown to you to be wrong. The expected dark matter content of the solar system out to Pluto is on the order of a mid sized asteroid, a rounding error for the aberration of starlight.
......if you're so much smarter than Einstein when it comes to calculating Gravitational Lensing, then I want to see your Differential Equations. Ya got'em? You promised a couple of weeks ago to produce them & we're all still waiting to see "IMP9 Field Equations".

Aug 18, 2015
The expected dark matter content of the solar system out to Pluto is on the order of a mid sized asteroid
.....an "asteroid" sized quantity of DM? Must be an asteroid far bigger than the Sun to account for the Universe to be composed of 75-90% of this stuff, you realize of course there is supposed to be a 5/1 ratio of this stuff?

a rounding error for the aberration of starlight.
Do you even know what is meant by "rounding error"? Rounding errors do not fall into the 75-90% range, more like about 5% max.

I still want to see those vaunted "IMP9 Field Equations", you know, that math that's beyond GR that you incessantly harp about.

Aug 18, 2015
you realize of course there is supposed to be a 5/1 ratio of this stuff?


You know the Sun makes up 99.9% of the mass of the solar system and yet when you weigh some flour on a set of scales you don't have to add 99.9% solar material. Why is that? Maybe it's because the Sun isn't uniformly distributed in the solar system in some sort of fixed mass fraction. Similarly why would you expect dark matter to fixed in a fraction? You wouldn't. Cold dark matter doesn't collapse into stars so it is much less dense than the Sun. If dark matter really was simply an additional fixed fraction of all mass in the universe then it wouldn't be dark matter, regular matter would just be heavier (or change G).

This has all been explained to you, more than once.

And please don't invent things I've said, it's incredibly childish. You look mad enough already.

Aug 18, 2015
Cold dark matter doesn't collapse into stars but hot regular matter even less.

Aug 18, 2015
This has all been explained to you, more than once.
Yep, by the entire Funny Farm Science crowd populating this site who've never seen a Differential Equation they could solve.

And please don't invent things I've said
Don't need to crickey mate, you are doing well enough on your own.

it's incredibly childish. You look mad enough already.
Just an impish chuckle old man, everytime I see you download a new tantrum.

Aug 18, 2015
This has all been explained to you, more than once.
Yep, by the entire Funny Farm Science crowd populating this site who've never seen a Differential Equation they could solve.

And please don't invent things I've said
Don't need to crickey mate, you are doing well enough on your own.

it's incredibly childish. You look mad enough already.
Just an impish chuckle old man, everytime I see you download a new tantrum.


Hey, Benni,
Publish this sh*t , or shut the f*ck up. Yes? You don't have a clue what you are talking about.

Aug 18, 2015
If the whole dark matter halo was made out of dwarf galaxies it would be as bright as the regular stellar halo.
Actually it would be brighter; there's more dark matter than bright matter. But that's just a quibble; your point holds, and is in fact bolstered by this.

Aug 18, 2015
If there were all this Cosmic Fairy Dust pervading every recess of the universe, then Einstein in 1915 in General Relativity would never have been able to calculate the exact angle that starlight bends as it passes the visible peripheral disc of the sun.


A claim you repeat even though it has been shown to you to be wrong. The expected dark matter content of the solar system out to Pluto is on the order of a mid sized asteroid, a rounding error for the aberration of starlight.
This is evidence of a common delusion among non-astronomers. The planets are huge and close together. Galaxies are just beyond that.

They don't get that the entire mass of the Solar System is only infinitesimally larger than the Sun, if it were all packed into the Sun.

contd

Aug 18, 2015
OK, the scales of things:

The Sun is a beachball on the goal line of a football field in San Francisco.
The Earth is a pea on the 20-yard-line.
Jupiter is an orange on the 60-yard-line.
Pluto is across the street from the ball park.
Alpha Centauri is in New York.

That's how dense the galaxy is. And we're in a fairly dense part of it.

There's hardly any bright matter in galaxies compared to the dark matter, but it's clumped together in solar systems. Actually mostly into stars.

Aug 18, 2015
I always get disappointed when people maybe smarter then me (and I say that only because I couldn't afford to attend school as much as I would have liked to) in an area of science such as this; act like little kids, None of you try to resolve anything, you don't really explain anything but what your own views are centered on. I don't see anyone helping to bring out anyone gifts here but and the only outstanding gifts i do see are related to rudeness and self pride. I've totally lost all interest in all of you and your views on the subject. You all act like the only thing you learned for sure is how to act like snot nosed ass-holes.

Aug 19, 2015
Fellow commenters, although arguing with Benni is totally in vain, I appreciate you efforts very much. It is also often amusing.
If you are bored and want to have a laugh, check out a few of us trying to explain the BB to Benni,

http://phys.org/n...rth.html

Aug 19, 2015
As someone who posts here a lot, discussing Alfven's ideas on galaxy formation and possible cathode/anode models of the Sun, I'm not sure what you're trying to talk about Benni. Are referring to this? http://www.eso.or...eso1217/

If you are, then I think the issue may be that you're confusing the wording in the article when they talk about "in the neighborhood of the Sun" with "within the solar system." Within the neighborhood of the Sun was a region of ~13,000 light years, whereas the solar system itself, at least out to the Oort Cloud, is ~1.87 light years in distance.

There's nothing necessarily wrong with the fact of dark matter not being found in the solar system, the distribution at that scale would be negligible regardless. If I were you, I'd find it much more interesting that no discernible dark matter was found in a fairly sizable portion of our own galaxy. Which reminds me to ask, does anyone know of a more recent survey than the one I posted?

Aug 19, 2015
There's hardly any bright matter in galaxies compared to the dark matter, but it's clumped together in solar systems. Actually mostly into stars.

.......so Einstein was wrong when he did the calculations for the exact angle of gravitational lensing as starlight passes the visible peripheral disc of the Sun. This was was 20 years before Zwickey came up with his funny farm science of DM Cosmic Fairy Dust. Poor Einstein, he didn't realize how he missed 75-90% of the gravity of the Universe because his Differential Equations couldn't account for what Zwickey would hypothesize 20 years later.

If you're to believe the DM Narrative, none of the Einstein Field Equations should work. IMP & Schneib, why do you guys think you're so much smarter than Einstein? I want to see your Field Equations that you're claiming are so far beyond General Relativity that only DM Enthusiasts are capable of comprehending. Got'em handy? Get'em up.....

Aug 19, 2015
Fellow commenters, although arguing with Benni is totally in vain, I appreciate you efforts very much. It is also often amusing.
If you are bored and want to have a laugh, check out a few of us trying to explain the BB to Benni,

http://phys.org/n...rth.html


You're not arguing with Benni, you're arguing with Einstein's General Relativity & the Einstein Field Equations. Go give it some study time & maybe you'll understand why.

Aug 19, 2015
Again, calculations based on the measured properties of the particle please, otherwise, theoretical bullshit until proven.


Succinctly, here's the problem DM Enthusiasts are confronted with. The Hadron Collider in Cern claims to have discovered everything particle that exists in the Universe, meaning the god-particle, the Higgs-Boson.

If indeed the particle that makes up everything else that exists has been discovered, then that means they've also discovered the particle that makes up DM. Is this a conundrum?

Aug 19, 2015
Well, if they keep finding more and more "regular" matter, they'll need to extrapolate less and less "dark" matter...:-)

Aug 19, 2015
Straw man argument.
Scientists, including Einstein, never claimed that the Higgs boson "makes up everything else that exists".


@ bschott, 5 Star for this......
Straw man? His logic is flawless, yours needs major tweaking. The Higgs, according to the mainstream is exactly as he states. If the hypothesis about the Higgs is correct, DM would have to house at least one Higgs boson...and thus have a detectable, measurable energy component.

So once again....produce a particle, or stop giving it theoretical properties that would cause what we observe and using the observations as proof that the particle exists.
.......I mistakenly tagged you with a 1 Star on this response above, it of course should have been a 5 Star. Heck, you're explaining this science better than I am, I should just start following you & do nothing but vote 5s.




Aug 19, 2015
Hi all. :) Taking another quick break to look through PO discussions. This thread is about dark ENERGY survey using digital cameras to locate matter-energy features/distributions via light spectrum received, with a side-purpose of using discovered energy-mass concentrations/distributions as input for analytical 'inputs' to subsequent 'interpretive work' based on assumptions and hypotheses of dark Matter and Dark ENERGY hypotheses and theoretical constructs. No-one has found either dark ENERGY or Dark Matter in this survey. Only regularly detectable matter features such as dwarf galaxies etc. The subsequent analysis of what 'normal matter' features/distributions they found will tell whether the assumptions/expectations re DE and/or DM hypotheses hold any water. Take it easy, everyone. Let's wait until they have something to present after this 'survey' is completed and properly analysed and explained as to what was/was not involved/assumed when drawing 'conclusions'. Cheers. :)

Aug 19, 2015
Well, if they keep finding more and more "regular" matter, they'll need to extrapolate less and less "dark" matter...:-)
This is spit in the ocean, or like adding five grains of sand to a beach.

Aug 20, 2015
Fellow commenters, although arguing with Benni is totally in vain, I appreciate you efforts very much. It is also often amusing.
If you are bored and want to have a laugh, check out a few of us trying to explain the BB to Benni,

http://phys.org/n...rth.html


At least refer to the asshole as returners and stop indulging his sock puppets. He's created yet another for this discussion.

This study is having excellent knock-on effects. Is anybody going to discuss that or just argue with a mentally ill self-deluded troll? This site is worthless.

Aug 20, 2015
What you call "theoretical bullshit" is actually science.


LOL...no, what you call science is actually theoretical bullshit.
So is there anything about science that you DO understand ?

Yeah. He knows how to kill real discussion. You have to understand the mindset of someone that sits in his mother's basement jerking off all day. He is feckless beyond imagining. Cheap shots, self-deluded pronouncements and interfering with actual discussion is his one proud achievement in life. This is the only life he has. Think about that. Ignore returners and all his sock puppets and his virtual life is over. You have the power in your hands. "Ignore user" and he ceases to be.

Even if you find his mental illness entertaining, he's like an incontinent old sheepdog that keeps getting lost. Time to put 'im down.

Aug 20, 2015
For those of us that are professionals and having been working on local dwarf galaxies since the '90s, this is fantastic!!!

I long ago blocked that fucktard returners...and then benni, but now he's created Botopfbber. Hey, what kind of site allows someone that's never average above a 2 on comments the ability to create unlimited sock puppets??? And then just what kind of person would argue with him? If I ever said anything to him directly I'd feel as though I'd need to go shower.

AGW, you're wrong about the sheepdog metaphor. You humanely euthenize an old dog. Returners, you paint his testicles with honey and sit him on a fire ant mound and then kick him in the nuts until he stops babbling!

Sep 19, 2015
You appear to consider it possible that such a particle or such matter exists.


No, it is not possible

That would make DM a viable hypothesis in your POV.


Wrong again

Formulating a viable hypothesis is not "complete bullshit" at any moment, it is science.


Viable being the key word

Only if would be _impossible_ to find such matter, DM would be "complete bullshit".
If that is your POV, what evidence do you have for it?


So far it is proving impossible to find. You understand how that constitutes evidence right?


He obviously understands it better than you understand what a complete moron you are.

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