Abstract:  The issue here is:  Can a operating star that has 
accreted enough mass to retain radiation, collapse 
internally to a radiation retaining black hole 'neutron 
star' within its event horizon when it accrets to a certain 
critical threshold, a solar mass number or value, that would 
overwhelm its internal replusive forces that would keep the 
star burning under normal conditions? 

Consider a modest sized minimalist black hole of say, 550 
solar masses.  At this mass point, to a joe,  it is unclear 
that the core has already collapsed into a neutron star 
style core.

Let us assume that in the absence of any ultra high 
detectable magnetic fields that it hasn't.

Contrariwise, if there are strong magnetic (magnatar) type 
fields.



                        Restating...

If we keep adding mass to a very modestly sized black hole 
eventually the internal mass will increase to a point that 
will exert sufficient external pressures upon the core to 
effect a collapse of the presumably still 'burning' (ungoing 
fusion) mass into a neutron type 'star'.

According to the current party line, this similar type of 
collapse in a visible star at the end of its life would 
generate the classic release of radiation and mass into 
space, creating a spectacular visible nova type event.

BUT... Here we are dealing with a black hole.  And the 
spectacular novatic event now is completely concealed due to 
the escape velocity of the black hole.

The Joseph_Sixpackian hypothesis exists that:
All the normally ejected mass and radiation is totally 
contained within the event horizon of the black hole upon 
its collapse into neutron star densities.



That leaves us with a few things to figure out...

All the normally ejected mass is presumably looped back and 
re-accreted to the surface of the neutron core, as are any 
particles and possibly radiation that contains within it, 
voltage (mass).

The new density of the new (post internal collapse) neutron 
mass containing black hole will generate massive magnetic 
fields.

But the whole thing will be invisible with no visible 
announcement of collapse to astronomers.

The only event that might broadcast this concealed 
spectacular event is an increase in the warped spacetime 
(gravity) around the hidden mass.  That is a gravity wave 
may issue outward at supposedly the velocity of c announcing 
an internal collapse and the resultant increase in gravity 
(warped spacetime) from the now much denser, hidden object.



             A Sea awash in gravitational waves

This leaves us with the phenomenon of gravity waves 
apparently coming from nowhere!  Well, nowhere that is 
visible.  So an unknown number will be at least 
crisscrossing each other in the visible cosmos...



                   so restating yet again

Therefore of the many billions of invisible black holes, 
many (a sizeable percentage) will have very strong 
gravitational fields.  And if internally collapsed to 
neutron status, will have massive magnetic fields (magnetar 
characteristics) depending upon the actual physical validity 
of the above hypotheses being fact.



So when does a black hole have a high enough number of solar 
masses to go to a neutron star status?

Well... that is a good question...

If the black hole, by virtue of being a black hole 
hasn't already gone to neutron star status.  (i don't know 
the real solar mass threshold number)

And

If in fact the internally burning black hole object 
'star' can resist a neutron collapse until the numbers are 
very high, the collapsing mass threshold of an active star 
might have a different range of values depending upon the 
composition and fusion conditions of the star when it 
accrets the mass to its own unique threshold value.

In sum, it is anybody's guess...



unused related notes:  

For very large black holes, we presume the event horizon is 
a bit out from the surface of the actual collapsed hard 
neutron mass itself.

Let us further presume that the "black hole" star is still 
undergoing the "burning" (fusion) processes that stars do 
best, BUT its radiatitive light is being contained by an 
escape velocity of something in excess of c.  So it is still 
a star and still a black hole.

Now, let us add mass through gravitational accretion until 
the black hole star has reached a value that will, in spite 
of the ongoing fusion process, collapse the star internally 
to neutron star densities and status.

And this collapse to neutron star status occurs in spite of 
the ongoing fusion process internally due primarily to the 
extreme pressures induced by the added or accreted mass.


an afterthought...
                      Gamma Ray Bursts

The mysterious gamma ray bursts might have a connection to 
the internal collapse of black holes to an internal neutron 
type core.

Ummm... but how can a gamma ray burst escape an internal 
black hole collapse?

Well, since the detection of gamma ray bursts has been 
effected, it would seem that if the two are somehow related, 
a small gravitational wave would be generated roughly at the 
same time.  shouldn't be too hard to effect an investigation 
since equippment is already in place and being used for 
other purposes currently.

One of the issues is which indicator would arrive first,
the gravity wave? or the gamma ray burst?

restated otherwise, which has the higher energy that would 
be deflected the least in its passage to earth's indicators?