Astronomers discover a primordial dark matter galaxy that seems to contain no stars!

www.universetoday.com...

There’s a galaxy out there without apparent stars but largely chock full of dark matter. What’s that you say? A galaxy without stars? Isn’t that an impossibility? Not necessarily, according to the astronomers who found it and are trying to explain why it appears starless. “What we do know is that it’s an incredibly gas-rich galaxy,” said Green Bank Observatory’s Karen O’Neil, an astronomer studying this primordial galactic object. “It’s not demonstrating star formation like we’d expect, probably because its gas is too diffuse.”

That's quite a remarkable finding and something I haven't come across before. The name of the galaxy is J0613+52 and is classified as a dwarf and low surface brightness galaxy located relatively close to the milky way.

There appears to be no stars in this galaxy which is made up completely of primordial cold gas (mostly hydrogen) and if true this is the first ever discovery of a galaxy containing no stars at all.

There is a numbers of reasons on why there appears to be no star formation, such as the gas is too diffuse, the galaxy is isolated and so no other nearby galaxies to affect it through gravity, which resulted in an undisturbed and underdeveloped galaxy.

The other possibility is for stars to exist but we can't see them for some reason.

a reply to: Venkuish1


Ummm…that’s uncanny…

I wonder why this galaxy hasn’t ingested any stray dead stars or passing debris from galactic collisions…


One would think that the dark matter would affect the gases gravitationally…and cause at the very least a galactic center dark matter black hole…

I haven’t read the article…because I wanted to speculate first…

I also wonder if the gas and dark matter rotate around a central axis…






YouSir

Wait so we proved dark matter exists? I thought that was just a way of filling in our lack of understanding of the universe with some thing that fits. We have no evidence, never been observed just our calculations don’t work therefore dark matter. Dubious at best.


Maybe there is just…nothing there. Maybe it’s all been mined already.
a reply to: Venkuish1

originally posted by: Athetos
Wait so we proved dark matter exists? I thought that was just a way of filling in our lack of understanding of the universe with some thing that fits. We have no evidence, never been observed just our calculations don’t work therefore dark matter. Dubious at best.


Maybe there is just…nothing there. Maybe it’s all been mined already.
a reply to: Venkuish1

No yet we haven't proved it but there is a lot of indirect evidence for its existence. See one of my other threads.

I have so it’s not proven.

a reply to: Venkuish1

originally posted by: YouSir
a reply to: Venkuish1


Ummm…that’s uncanny…

I wonder why this galaxy hasn’t ingested any stray dead stars or passing debris from galactic collisions…


One would think that the dark matter would affect the gases gravitationally…and cause at the very least a galactic center dark matter black hole…

I haven’t read the article…because I wanted to speculate first…

I also wonder if the gas and dark matter rotate around a central axis…

YouSir

The galaxy is very isolated and there haven't been any galactic collisions with other galaxies. As a result of this isolation the galaxy seems undisturbed and underdeveloped according to the researchers.

originally posted by: Athetos
I have so it’s not proven.

a reply to: Venkuish1

That's true it's not proven.
But there is plenty of indirect evidence for its existence and we assume to be the most likely explanation.

The movement of galaxies within clusters, the movement of stars in galaxies, galaxy rotation curves, gravitational lensing, are some of the strong evidence for the existence of dark matter.

Link:

greenbankobservatory.org...

a reply to: Venkuish1

If the galaxy was compact enough, perhaps a central black hole has consumed all its stars, leaving an outer halo of gas too thin to form further stars?

originally posted by: chr0naut
a reply to: Venkuish1

If the galaxy was compact enough, perhaps a central black hole has consumed all its stars, leaving an outer halo of gas too thin to form further stars?

According to the article the galaxy is classified as a dwarf galaxy and there is a limit in the amount of mass it can have. Many galaxies have a supermassive black hole at their center and I am not sure if this galaxy has a black hole in its center but if we assume it has then it should be much smaller than the supermassive black holes in spiral galaxies.

But a black hole can only suck material and stars that are nearby (in astronomical distances) and given the size of galaxies including dwarf galaxies that isn't possible. If star formation has occured then we will be able to 'see' a range of things including heavier elements (nuclear fusion)

originally posted by: Venkuish1

originally posted by: chr0naut
a reply to: Venkuish1

If the galaxy was compact enough, perhaps a central black hole has consumed all its stars, leaving an outer halo of gas too thin to form further stars?

According to the article the galaxy is classified as a dwarf galaxy and there is a limit in the amount of mass it can have. Many galaxies have a supermassive black hole at their center and I am not sure if this galaxy has a black hole in its center but if we assume it has then it should be much smaller than the supermassive black holes in spiral galaxies.

But a black hole can only suck material and stars that are nearby (in astronomical distances) and given the size of galaxies including dwarf galaxies that isn't possible. If star formation has occured then we will be able to 'see' a range of things including heavier elements (nuclear fusion)

A black hole can form in as little as 12x the mass of our Sun. A dwarf galaxy is way more massive than that, so I don't see galactic mass as a possible barrier to such a collapsed future. The issue is more one of density than total mass.

If we assume an unusual density in the 'quantum foam' just after the big bang (like an interstice of several 'bubble' boundaries) generating mainly early high mass hot stars in the region, then stellar life would be short and collapse into one or more black holes could occur in the first stellar generation (in as little as 20 million years).

The brightness of each supernova is dependent upon the rapidity of the collapse. If the star collapsed promptly (as is expected of high mass, short life hot stars), rather than in several stages, then much of the energy would be inside of the Schwarzschild Radius, rather than radiating. This would lead to a lower temperature in remnants and supernova ejecta.

Then the process of gravitational accumulation would sweep the area of all but supernova remnants from the collapse, leaving only a gaseous halo.

If it all happened in the first few billion years after the BB, then there would be little left that is detectable up to the present.

All entirely hypothetical, but plausible.

originally posted by: chr0naut

originally posted by: Venkuish1

originally posted by: chr0naut
a reply to: Venkuish1

If the galaxy was compact enough, perhaps a central black hole has consumed all its stars, leaving an outer halo of gas too thin to form further stars?

According to the article the galaxy is classified as a dwarf galaxy and there is a limit in the amount of mass it can have. Many galaxies have a supermassive black hole at their center and I am not sure if this galaxy has a black hole in its center but if we assume it has then it should be much smaller than the supermassive black holes in spiral galaxies.

But a black hole can only suck material and stars that are nearby (in astronomical distances) and given the size of galaxies including dwarf galaxies that isn't possible. If star formation has occured then we will be able to 'see' a range of things including heavier elements (nuclear fusion)

A black hole can form in as little as 12x the mass of our Sun. A dwarf galaxy is way more massive than that, so I don't see galactic mass as a possible barrier to such a collapsed future. The issue is more one of density than total mass.

If we assume an unusual density in the 'quantum foam' just after the big bang (like an interstice of several 'bubble' boundaries) generating mainly early high mass hot stars in the region, then stellar life would be short and collapse into one or more black holes could occur in the first stellar generation (in as little as 20 million years).

The brightness of each supernova is dependent upon the rapidity of the collapse. If the star collapsed promptly (as is expected of high mass, short life hot stars), rather than in several stages, then much of the energy would be inside of the Schwarzschild Radius, rather than radiating. This would lead to a lower temperature in remnants and supernova ejecta.

Then the process of gravitational accumulation would sweep the area of all but supernova remnants from the collapse, leaving only a gaseous halo.

If it all happened in the first few billion years after the BB, then there would be little left that is detectable up to the present.

All entirely hypothetical, but plausible.

Galaxies are massive in terms of size and if they have a central black hole then the size of it depends on the mass of the gas that has collapsed. In dwarf galaxies there is much less mass and hence the central black hole will be much smaller in terms of mass.

When stars are formed their location varies and given the size of galaxies it is not possible for central black holes to suck entire galaxies and all stars in them. It can only suck material from nearby stars.

The lowest mass black hole that has been found is around 3.3 Solar Masses and not 12 as you said.

www.universetoday.com...

You have made an assumption that all of the stars formed were massive (in a dwarf galaxy) and in a very close distance to a supermassive monstrous black hole. But this isn't possible. A dwarf galaxy doesn't behave this way and doesn't consists of only supernovae in a close distance. These massive stars will also leave some traces like heavier elements scattered around.

www.livescience.com...

Black holes are former massive stars that have collapsed back in on themselves to become incomprehensibly dense — so much so that even light can't escape them. The idea that a black hole could swallow the universe is based on the misconception that they work like vacuums, sucking space toward themselves, said Gaurav Khanna, a black hole physicist at the University of Rhode Island. But that's not the case.

They only swallow things that are extremely close Khanna said. In fact, black holes can only devour objects that venture into their event horizon — a black hole's point of no return, beyond which there is no escape.

originally posted by: Venkuish1

originally posted by: chr0naut

originally posted by: Venkuish1

originally posted by: chr0naut
a reply to: Venkuish1

If the galaxy was compact enough, perhaps a central black hole has consumed all its stars, leaving an outer halo of gas too thin to form further stars?

According to the article the galaxy is classified as a dwarf galaxy and there is a limit in the amount of mass it can have. Many galaxies have a supermassive black hole at their center and I am not sure if this galaxy has a black hole in its center but if we assume it has then it should be much smaller than the supermassive black holes in spiral galaxies.

There is no evidence to preclude the existence of a central black hole. All galaxies may have them. We only usually know of their existence by gravitational effects, such as lensing, or bright in-falling matter's x-ray emissions.

But a black hole can only suck material and stars that are nearby (in astronomical distances) and given the size of galaxies including dwarf galaxies that isn't possible. If star formation has occurred then we will be able to 'see' a range of things including heavier elements (nuclear fusion).

If galactic mass is discovered by perturbation in movements of nearby galaxies and stars, then there is a gravitational effect beyond the galactic rim, and most definitely inside of it. If there are numerous black holes (and in fact is the density was such that after the big bang, all stars were supermassive) and they have all swept the space near them, then even if they are in stable orbit around the galaxy, there could still be be no stars.

We are talking of an area of space unlike the norm by observation, so putting normal rules of stellar distribution and type onto it, isn't going to help make sense of it.

A black hole can form in as little as 12x the mass of our Sun. A dwarf galaxy is way more massive than that, so I don't see galactic mass as a possible barrier to such a collapsed future. The issue is more one of density than total mass.

If we assume an unusual density in the 'quantum foam' just after the big bang (like an interstice of several 'bubble' boundaries) generating mainly early high mass hot stars in the region, then stellar life would be short and collapse into one or more black holes could occur in the first stellar generation (in as little as 20 million years).

The brightness of each supernova is dependent upon the rapidity of the collapse. If the star collapsed promptly (as is expected of high mass, short life hot stars), rather than in several stages, then much of the energy would be inside of the Schwarzschild Radius, rather than radiating. This would lead to a lower temperature in remnants and supernova ejecta.

Then the process of gravitational accumulation would sweep the area of all but supernova remnants from the collapse, leaving only a gaseous halo.

If it all happened in the first few billion years after the BB, then there would be little left that is detectable up to the present.

All entirely hypothetical, but plausible.

Galaxies are massive in terms of size and if they have a central black hole then the size of it depends on the mass of the gas that has collapsed. In dwarf galaxies there is much less mass and hence the central black hole will be much smaller in terms of mass.

When stars are formed their location varies and given the size of galaxies it is not possible for central black holes to suck entire galaxies and all stars in them. It can only suck material from nearby stars.

The lowest mass black hole that has been found is around 3.3 Solar Masses and not 12 as you said.

www.universetoday.com...

I was talking about the size of the stars that led to the black holes, and specifically about stars that collapse in a single generation. Supermassive short lifespan hot stars.

If collapse to black holes occurred in more stages/generations, such as via magnetars and neutron stars, I would imagine the waste heat and ejecta would be more visible and be giving birth to subsequent stellar generations.

You have made an assumption that all of the stars formed were massive (in a dwarf galaxy) and in a very close distance to a supermassive monstrous black hole. But this isn't possible. A dwarf galaxy doesn't behave this way and doesn't consists of only supernovae in a close distance. These massive stars will also leave some traces like heavier elements scattered around.

www.livescience.com...

Black holes are former massive stars that have collapsed back in on themselves to become incomprehensibly dense — so much so that even light can't escape them. The idea that a black hole could swallow the universe is based on the misconception that they work like vacuums, sucking space toward themselves, said Gaurav Khanna, a black hole physicist at the University of Rhode Island. But that's not the case.

They only swallow things that are extremely close Khanna said. In fact, black holes can only devour objects that venture into their event horizon — a black hole's point of no return, beyond which there is no escape.

Which we could only observe of they were incandescent or were filtering the light from known specific stars in a direct line.

We do know there are clouds of Hydrogen gas there. First gen stars that die in collapse to black holes aren't going to have high abundance of the heavier elements, anyway.

We are talking about what is an observationally non-normal area of space.

originally posted by: chr0naut

originally posted by: Venkuish1

originally posted by: chr0naut

originally posted by: Venkuish1

originally posted by: chr0naut
a reply to: Venkuish1

If the galaxy was compact enough, perhaps a central black hole has consumed all its stars, leaving an outer halo of gas too thin to form further stars?

According to the article the galaxy is classified as a dwarf galaxy and there is a limit in the amount of mass it can have. Many galaxies have a supermassive black hole at their center and I am not sure if this galaxy has a black hole in its center but if we assume it has then it should be much smaller than the supermassive black holes in spiral galaxies.

There is no evidence to preclude the existence of a central black hole. All galaxies may have them. We only usually know of their existence by gravitational effects, such as lensing, or bright in-falling matter's x-ray emissions.

But a black hole can only suck material and stars that are nearby (in astronomical distances) and given the size of galaxies including dwarf galaxies that isn't possible. If star formation has occurred then we will be able to 'see' a range of things including heavier elements (nuclear fusion).

If galactic mass is discovered by perturbation in movements of nearby galaxies and stars, then there is a gravitational effect beyond the galactic rim, and most definitely inside of it. If there are numerous black holes (and in fact is the density was such that after the big bang, all stars were supermassive) and they have all swept the space near them, then even if they are in stable orbit around the galaxy, there could still be be no stars.

We are talking of an area of space unlike the norm by observation, so putting normal rules of stellar distribution and type onto it, isn't going to help make sense of it.

A black hole can form in as little as 12x the mass of our Sun. A dwarf galaxy is way more massive than that, so I don't see galactic mass as a possible barrier to such a collapsed future. The issue is more one of density than total mass.

If we assume an unusual density in the 'quantum foam' just after the big bang (like an interstice of several 'bubble' boundaries) generating mainly early high mass hot stars in the region, then stellar life would be short and collapse into one or more black holes could occur in the first stellar generation (in as little as 20 million years).

The brightness of each supernova is dependent upon the rapidity of the collapse. If the star collapsed promptly (as is expected of high mass, short life hot stars), rather than in several stages, then much of the energy would be inside of the Schwarzschild Radius, rather than radiating. This would lead to a lower temperature in remnants and supernova ejecta.

Then the process of gravitational accumulation would sweep the area of all but supernova remnants from the collapse, leaving only a gaseous halo.

If it all happened in the first few billion years after the BB, then there would be little left that is detectable up to the present.

All entirely hypothetical, but plausible.

Galaxies are massive in terms of size and if they have a central black hole then the size of it depends on the mass of the gas that has collapsed. In dwarf galaxies there is much less mass and hence the central black hole will be much smaller in terms of mass.

When stars are formed their location varies and given the size of galaxies it is not possible for central black holes to suck entire galaxies and all stars in them. It can only suck material from nearby stars.

The lowest mass black hole that has been found is around 3.3 Solar Masses and not 12 as you said.

www.universetoday.com...

I was talking about the size of the stars that led to the black holes, and specifically about stars that collapse in a single generation. Supermassive short lifespan hot stars.

If collapse to black holes occurred in more stages/generations, such as via magnetars and neutron stars, I would imagine the waste heat and ejecta would be more visible and be giving birth to subsequent stellar generations.

You have made an assumption that all of the stars formed were massive (in a dwarf galaxy) and in a very close distance to a supermassive monstrous black hole. But this isn't possible. A dwarf galaxy doesn't behave this way and doesn't consists of only supernovae in a close distance. These massive stars will also leave some traces like heavier elements scattered around.

www.livescience.com...

Black holes are former massive stars that have collapsed back in on themselves to become incomprehensibly dense — so much so that even light can't escape them. The idea that a black hole could swallow the universe is based on the misconception that they work like vacuums, sucking space toward themselves, said Gaurav Khanna, a black hole physicist at the University of Rhode Island. But that's not the case.

They only swallow things that are extremely close Khanna said. In fact, black holes can only devour objects that venture into their event horizon — a black hole's point of no return, beyond which there is no escape.

Which we could only observe of they were incandescent or were filtering the light from known specific stars in a direct line.

We do know there are clouds of Hydrogen gas there. First gen stars that die in collapse to black holes aren't going to have high abundance of the heavier elements, anyway.

We are talking about what is an observationally non-normal area of space.

If you remember what you said a few posts back, you argued there are stars because they have been eaten by a supermassive monstrous black hole but this hasn't happened and I explained why in the post above.

There appears to be no star formation at all. Not every star turns into a supernova! In fact the vast majority of stara don't turn into a supernova but all stars are powered by nuclear fusion and if they were stars of any type in the galaxy we would get
traces of other elements other than hydrogen and helium. But that hasn't happened either.