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Fraser
2005-Jun-17, 05:10 PM
SUMMARY: Which came first, galaxies or the supermassive black holes at their centre? Most cosmologists now think the two are inextricably linked, each depending on the other. And according to researchers, including famed astronomer Sir Martin J Rees, these supermassive black holes got big, fast. By reviewing quasar data in the Sloan Digital Sky Survey (SDSS), the team has calculated that many supermassive black holes had reached 1 billion times the mass of our Sun in a very short period of time. Even for the largest, most voracious black holes in the Universe, that's an amazing feat.

View full article (http://www.universetoday.com/am/publish/early_black_holes_grew_quickly.html)

What do you think about this story? Post your comments below.

Guest
2005-Jun-17, 06:23 PM
This is an important step in the right direction.

Was early matter mostly

a.) dispersed in the form of atomic Hydrogen? Or

b.) highly compressed in the form of neutron stars and black holes?

Historically, cosmology has favored a.) but is slowly turning in the direction of b.)

With kind regards,

Oliver
http://www.umr.edu/~om

antoniseb
2005-Jun-17, 06:49 PM
Rees et al. have done some nice work here describing a plausible mechanism for how the early SMBHs and galaxies formed, and probably formed simultaneously from the Hydrogen and Helium that abounded thousands of times more densely in the early universe.

wstevenbrown
2005-Jun-17, 08:29 PM
Rees et. al. have done a bang-up job laying out the constraints on bottom-up growth of baryonic matter concentrations. It may not be enough. If the early matter concentrtions are still too high to be possible within this model, they may have to consider top-down structuring; i.e., that some portion of the SMBH's were primordial. This means they were present during and after the Bang, were never composed of baryonic matter, and from the beginning were simply mass-energy concentrations which did not participate in the general expansion/inflation which produced the H-He-Li which drove the evolution of the rest of the universe. It isn't surprising that the authors did not explicitly consider this, as the scenarios are highly model-dependent. How many Primordial BH's, and what sizes, are both dependent on physics not yet proven-- branes, supersymmetry, scalar fields, and the like.

Great article, Jeff! Best regards-- Steve

Guest
2005-Jun-17, 09:46 PM
Originally posted by wstevenbrown@Jun 17 2005, 08:29 PM
1. . . . . they may have to consider top-down structuring; i.e., that some portion of the SMBH's were primordial. This means they were present during and after the Bang, were never composed of baryonic matter, and from the beginning were simply mass-energy concentrations which did not participate in the general expansion/inflation which produced the H-He-Li which drove the evolution of the rest of the universe.

2. Great article, Jeff!
I agree, Steve.

1. It is even possible that the primary source of energy in the universe today is the spontaneous emission of particles from a highly compressed state (like neutron stars) into ordinary nuclear matter (like neutrons, protons and electrons).

2. I agree. Jeff did a superb job in writing this article.

With kind regards,

Oliver
http://www.umr.edu~om

dragonmaster_us@hotmail.com
2005-Jun-17, 10:43 PM
Beautiful story. It started off pastoral and progressed to the turbulence expected in cosmology, then back to pastoral. It certainly could explain several points in the expansion theories. I loved it as an excellent piece of writing. Then wstevenbrown comes up with the additional idea that SMBH's could be remnants of the pre-bang system. I like the imaginings that generates for me. I can visualize a SMBH as a fragment of pre-universe "material" being blown away from the epi-center of "All," and then returning captured matter back to it's original form.

The Near-Sighted Astronomer
2005-Jun-18, 04:17 AM
Hi All,

Thank you for the positive comments on the article - i had very good material to work with...

I like Steve's notion that primordial black holes probably formed very early in the Universe - even before the breeder stars blew up. Why, bcause the original paper points out that the metals from these stars would tend to cool the hydrogen and helium causing them to de-ionize which would change the growth rate of the MBH's and slow progress toward SMBH status. So assuming that seed black holes preceded massive breeder stars then the MBH's would have an opportunity to rapidly condense out of ionized gases - even before the ISM was flooded with metals.

My own intuitive sense is that the seed black holes formed in the transition preiod between the expression of the four forces and baryonic matter as a critical phase transition - but what dio i know - i'd rather have been frolicking with some virgin material that early on in the scheme of things...

jeff

gofree
2005-Jun-18, 05:19 AM
How could this law that, 'Black holes Grew up Quickly" be broken or not occur in its time?

Guest
2005-Jun-18, 02:04 PM
Originally posted by The Near-Sighted Astronomer@Jun 18 2005, 04:17 AM
I like Steve's notion that primordial black holes probably formed very early in the Universe - even before the breeder stars blew up. ...... So assuming that seed black holes preceded massive breeder stars then the MBH's would have an opportunity to rapidly condense out of ionized gases - even before the ISM was flooded with metals.

jeff
Systematic properties of nuclei demonstrate the validity of the question, which came first - the chicken or the egg, condensed or dispersed nuclear matter ?.

a.) The first source of nuclear energy recognized was the transformation,

Condensed nuclear matter -> Dispersed nuclear matter

Uranium -(fission)-> 2 Light Elements, e.g., Ba + Sr

This is the basis for the Atomic bomb and nuclear power reactors.

b.) The next source of nuclear energy recognized was the transformation,

Dispersed nuclear matter -> Condensed nuclear matter

Light elements -(fusion)-> Heavy Elements, e.g., H -> He -> Fe

This is the basis for the Hydrogen bomb and popular models of stellar energy. Modern cosmology assumes that the energy of the universe comes from this transformation.

c.) The third source of nuclear energy recognized was again the transformation,

Condensed nuclear matter -> Dispersed nuclear matter
Neutron star -(neutron-emission)-> n -(neutron-decay)-> H

This is now the greatest known source of nuclear energy.

The fraction of rest mass converted to energy is
about 0.1% in process a.)
about 0.7-8% in process b.)
about 1.1-2.4% in process c.)

Process c.) may also generate the Hydrogen pouring from the surfaces of stars if their cores are condensed nuclear matter.

The question now facing cosmologists is whether the main source of energy in the universe is b.) or c.)

Nuclear systematics seem to favor c.). Recent astronomical observations by people like Sir Martin J Rees seem to be pointing cosmologists in that direction.

With kind regards,

Oliver
http://www.umr.edu/~om

wstevenbrown
2005-Jun-18, 03:16 PM
c.) The third source of nuclear energy recognized was again the transformation,

Condensed nuclear matter -> Dispersed nuclear matter
Neutron star -(neutron-emission)-> n -(neutron-decay)-> H

This is now the greatest known source of nuclear energy.


Oliver, YOU are the only one saying this, and the appropriate place to say it is in the Alternate Theories section. It is not a mainstream idea, and you have not provided any plausible mechanism by which
1) An isolated neutron star can accelerate neutrons to escape velocity.
2) A main-sequence star may contain a neutron star.
3) A mechanism by which neutron stars of less than 1.4 solar masses may form,
so as to be contained in ordinary main-sequence stars

Regarding point 2 above, an accreting neutron star may display jet behavior, some portion of which may be hadronic, but this is reprocessing of infalling material, not ejection from the star itself.

In short, please do not present your unique flights of fancy as if they were mainstream science.

Best regards-- Steve

The Near-Sighted Astronomer
2005-Jun-19, 04:39 AM
Hi Gofree,


How could this law that, 'Black holes Grew up Quickly" be broken or not occur in its time?

Im not exactly sure of the thrust of your question but the key to understanding the Rees-Volontari idea has to do with the radiative efficiency of a medium-sized black hole. That efficiency relates to the percentage of matter that gets converted to radiation before it falls into the MBH's (Massive Black Hole) event horizon.

In late period quasars with SMBHs (Super MBHs) that efficiency approaches 10% - such a low mass to energy conversion factor means that SMBH's take on weight at a relatively high rate - but only once they become SMBH's...

Meanwhile nearby galaxies with Massive Black Holes have a mass-energy conversion rate of 30%. Because of this far less material falling toward a MBH ends up in it than in SMBH's.

Rees-Voluntari are saying that things were different in the early Universe (for reasons stated in the article) that allowed MBHs to accumulate mass much quicker than they do today do to lower mass-energy conversion rates...

Cheers,

jeff

untrained but curious
2005-Jun-19, 05:29 AM
I get the relationship between super massive black holes and the galaxies they core (sort of). But what about stellar mass black holes? Are they in galaxies, orbiting around galaxies, or would the be more likely in intergalactic space? Likewise, how are they temporally related to their neighbor stars. If they form from stellar collapse only are old galaxies the only candidate locations? Do we have nearby (relatively) stellar mass black holes or are the only to be found far away?

wstevenbrown
2005-Jun-19, 08:47 PM
Stellar mass (roughly, 3-10 solar masses) BH's tend to follow OB associations. Since these BH's are the result of core-collapse in a very massive star, the progenitor star must have formed from a very dense molecular cloud. From the instant in which core fusion begins until the appearance of that energy at the surface of the star is an uncertain interval whose OOM is about 750000 years. The upper limit on stellar masses is determined by how much additional mass can be accreted during that time. Very shortly thereafter, the solar wind and radiation pressure from the ferociously luminous massive star blow away the infall wind and forbid further accretion.

Because of its extreme mass, the star then burns very brightly, but very briefly-- somewhere between 50K and 1M years-- ending in a core-collapse supernova.

To return to your original question, wherever one such hypermassive star can form, many can form. These dense clusters of massive stars are referred to as OB associations, since their luminosity is dominated by massive, hot stars of spectral types O and B (with a few W's and many dwarf A's and F's that we notice less because of their faintness). The Orion Nebula is an OB association, nested within a larger one. Eta Carinae is the central object in another-- and might have exploded by the time I finish this post. Deneb (Alpha Cygni) is the centerpiece of yet another OB association.

In general, the OB associations tend to be in the disk of the galaxy, as does starburst activity generally. An important exception to this may be The Arches cluster, which seems to be within 150pc or so of Galactic Center. There is difficulty observing near GC due to obscuration by intervening dust.

Stellar-mass BH's can also arise from mergers of less massive objects, but there is 'spirited discussion' about the evolutionary paths, the statistical likelihood, and so forth. Hope this has been of help-- Steve

The Near-Sighted Astronomer
2005-Jun-20, 02:35 AM
But this does point to the crux of a discussion among astronomers - did the seed black holes that eventually centered themselves in quasars originate as supernovae or as primordial black holes formed even before the massive breeder stars in OB associations found in he early universe?

The fact that Ress-Volontari tend to see heavy metals acting in a manner contrary to rapid BH growth (because they cool virgin matter and cause it to de-ionize) suggests that there is a strong possibility that seed black holes existed before the massive heavy-metal breeder stars went supernovae and enriched the ISM with their by-products...

wstevenbrown
2005-Jun-20, 12:24 PM
... there is a strong possibility that seed black holes existed before the massive heavy-metal breeder stars went supernovae and enriched the ISM with their by-products...

Both options need to be held open. Both scenarios date from an epoch when physics was different from what the universe currently manifests.

WRT Primordial BH's, we can derive some rather general limits on size and size distribution, both from the CMB and from the mass distribution in the modern universe. The initial seconds of the BB was the only era in which mini-BH's (larger than a dust grain, smaller than 1.5 solar masses) could form. The specifics of formation and evolution, tho, are model-dependent. BH's smaller than Ceres should have undergone explosive evaporation by now (it's an accelerating process) unless, for some reason, accretion was faster than evaporation. Alternatively, and this is very speculative, there may be stable structures in that intermediate mass range that we don't know about, that inhibit further decay. Imagine WIMPs with the mass of a mountain or small moon!

WRT the no-metal, ultramassive stars, I call these Population IV objects, because nothing like them does or can exist in the modern universe. In the absence of metals (none had formed yet), they have to be extremely massive , on the order of 70 solar masses, in order to fuse at all, using only the proton-proton cycle to produce helium. Beyond this, we don't know much-- how much more mass could they accrete in the interval between the onset of fusion and the creation of a stellar wind strong enough to prevent further accretion? What are the upper limits on stellar mass? What are their lifetimes? Would such an object fuse only in its core, or perhaps more than one core? Would it have a magnetic field, starspots, or convection zones? We can only guess. The biggest mystery, from my point of view is: why did they ever condense at all? At that epoch, no metals = no dust, no nucleation centers for condensation. Neither H nor He is much inclined to stick to anything-- with space itself expanding between the atoms, most of the H would form H2 as it cooled, but why would it ever concentrate further?

If the James Webb Space Telescope ever gets off the ground, we'll at least get enough data to stay confused with, but I doubt whether most of these questions will be settled in the next 30 years. It'll be fun to watch, tho! Best regards-- Steve

Greg
2005-Jun-20, 11:36 PM
This is a nice article. I have not heard of the concept of primordial black holes created in the first few seconds after the big bang. It is an interesting idea, but I would think difficult to prove right or wrong since the evidence for them would be long gone by now and we can't see back that far. I could see how this theoretical concept might aid in clustering matter in the early universe. But do we really need to invoke this notion to explain what we see today, in other words is this a moot concept? Eventually, with more powerful and sensitive intruments, we may be able to find observational evidence to answer this question.
I still prefer to think that the first progenitor stars formed the first round of black holes, as their life span would have been unusually short being composed of so few heavy elements.

Guest
2005-Jun-21, 01:21 PM
Originally posted by The Near-Sighted Astronomer@Jun 20 2005, 02:35 AM
. . . . there is a strong possibility that seed black holes existed before the massive heavy-metal breeder stars went supernovae and enriched the ISM with their by-products...
I agree with The Near-Sighted Astronomer.

This seems a more likely source for the condensed nuclear matter at the centers of galaxies.

With kind regards,
Oliver (in Dubna)
http://www.umr.edu/~om

Nick4
2005-Jul-06, 05:03 AM
What do you think would happen if we sent a satillite or something into a black hole? :huh:

The Near-Sighted Astronomer
2005-Jul-11, 10:30 PM
WRT the no-metal, ultramassive stars, I call these Population IV objects, because nothing like them does or can exist in the modern universe. In the absence of metals (none had formed yet), they have to be extremely massive , on the order of 70 solar masses, in order to fuse at all, using only the proton-proton cycle to produce helium.

This is a notion i had not considered before. Apparently carbon is needed in the current crop of stars to facilitate fusion and the ABG workup on the Big Bang only admits of Hydrogen, Helium and Lithium - no carbon...

Meanwhile matter was very hot in the early universe and because of this it lacked "stickyness" and was less likely to condense to form stars.

The conundrum is obvious - current models of star formation don't really apply to the progenitor - metal-breeding stars. From my perspective there are two ways of addressing this.

1. Carbon formed along with the ABG non-metals.
2. All breeder stars formed around primordial black holes.

Neither is very tenable. The former can not be accounted for based on the physics and the latter suggests that any black holes in the cores of stars would eventually 'lunch out' on the accumulated matter or blow it away with radiation pressure...


What do you think would happen if we sent a satillite or something into a black hole?

This is probably best answered on a thread related to black hole phenomenology however let's be gracious here...

As a probe approaches a black hole its telemetry (radio-signals) would red-shift out as though it were accelerating at a high rate of speed away from us. Meqnahile as the probe approached the event horizon it is likely that the gravitational tidal forces would tear it apart (if a low mass black hole) or if a supermassive black hole it would appear to just hang there motionless while paradoxically any data from it would take longer and longer to be accumulated by our instruments - effectively it would seem frozen in place while paradoxically moving away from us at an incredible rate of speed...

Cheers,

jeff

wstevenbrown
2005-Jul-12, 01:48 PM
black holes in the cores of stars

Jeff: I wasn't suggesting this at all. A BH adding matter only makes a more massive BH. But, as in the present day, stars do form within the dense portions of the accretion disk-- infalling matter which has been 'stalled' by collision with previously infallen matter. The SNe from these stars would create superbubble shock waves, which would further densify infalling matter at more distant radii from the BH. Star formation would propagate outward locally, first in a thickening discoid; and later, as a result of collisions and interactions amongst the BH's, spherically outward on a global (universal?) scale.

The period dominated by discoids may have been very brief-- OTOO 50Kyr. In the much denser environment of the early universe, such pure geometries may not have been allowed at all. The key concept really, is that star formation propagated as a deflagration wave; i.e., it was shock-driven. The role of the PBH's was merely to provide the centers of density (and, paradoxically, cooling) necessary to allow star formation to happen at all. ;)

Best regards-- Steve