The subject of Naked Active Galactic nuclei is theoretically and observationally connected to the papers that assert that BHs do not have an event horizon.

As noted in this thread,
(Black Holes don't exist! ) one piece of evidence to support the assertion that BHs do not have an event horizon is the discovery of quasar structures that would require a very strong magnetic field to create. The papers quoted in this BAUT thread comment, assert that an accretion disk is not capable of generating the strong magnetic field that would be required to create the observed quasar structure. In the same BAUT comment, there is a link to a paper that notes a BH without an event horizon is theoretically in agreement with GR. (i.e. New physics is not required, to support the hypothesis that BH do not an event horizon.)

The observation of Naked AGN may provide additional support for the assertion that BHs, do not have an event horizon.

This paper provides an introduction to the observations and the issues concerning naked AGN.

Naked active galactic nuclei By M.Hawkins

http://arxiv.org/pdf/astro-ph/0406163

Hawkins provides below the classical explanation of Naked AGN which is: "These naked AGN therefore would represent a period in the duty cycle intermediate between activity and dormancy. They would survive on the fuel reserves present in the accretion disc.". (See below for context of that short quote.)

I am not sure, however, how an AGN coasting period could generate the Naked AGN spectrum. i.e. If the accretion disk stops falling into the BH, what is left to generate the Naked AGN spectrum?

There are other papers that provide data that questions the hypothesis that Naked AGN is the coasting period in the duty cycle of AGN.

The following are observations that may be close to providing definite proof for the existence of a Naked AGN.

“Discovery of a bright quasar without a massive host galaxy”, By Magain, Letawe, Courbin, Jablonka, Jahnke, Meylan & Wisotzki

http://arxiv.org/pdf/astro-ph/0509433


http://www.nature.com/nature/journal...ture04013.html

The following is the authors' attempt to explain the observations using the standard quasar disk accretion model. First how did the quasar become separated from its companion galaxy? And second if there is a mechanism to separate a quasar from its host galaxy, Why is the quasar still luminous? It must be coasting, producing radiation using remnant gas or some other process. For with the standard model BH have "no hair" and hence can only produce radiation through the accretion mechanism.

If two galaxies, each with a supermassive black hole, merge, then the black holes may interact strongly with each other. In some circumstances, one of the black holes may be ejected from the center of the galaxy. There are a number of groups working on the numerical solutions to interacting black holes (one of them here at RIT where I work), and some of the astronomers here are searching for more examples of supermassive black holes which have left their host galaxies.

Absolutely right. There must still be some gas in the general vicinity for the black hole to be accreting.

I imagine at least one such interacting black hole would have to have had a previous 'minor' encounter to give it enough relative velocity for a closer 'fly-by' with the other supermassive black hole to give it a good fling rather than a merge.

__________________
Everyone is entitled to his own opinion, but not his own facts.

Stupendous Man,

I believe there is currently no theoretical explanation for the Naked AGN spectrum. (i.e. It is not simply a matter of stripping a host galaxy from a BH to produce the observed naked AGN spectrum.) Note also that basic fundamental components of AGN currently do not have physical explanation. (See quoted below) i.e. The AGN/quasar models are black box models as opposed to a physical model. The black box model may be completely theoretical, a blind alley.) I will repeat the comment concerning radio active AGN and MECCO hypothesis.

A Chandra view of naked active galactic nuclei, By Gliozzi, Sambruna, & Foschini

http://arxiv.org/pdf/astro-ph/0703269

Hi Stupendous Man,

Here is something to think about.

There is observational evidence that supports the assertion that the BHs which drives Quasars do not have an event horizon. If the BH does not have a event horizon it can emit its own spectrum which may explain quasar spectrum observations.

The following are two of a set of three papers that provide observational evidence and theoretical support for the existence of eternally collapsing "black" holes. As the hypothesized eternally collapsing "black holes" do not have an event horizon, they are not black and they are hypothesized to produce an intrinsic extremely strong magnetic field. As noted below the "black hole's" intrinsic extremely strong magnetic field is required to explain quasar features which require an extremely strong magnetic field to produce. The authors note the quasar accretion disk mechanism is theoretically not capable of generating the observed quasar magnetic field.


Observations supporting the existence of an intrinsic magnetic moment inside the central compact object with in the Quasar Q0957+561 by Schild, Leiter, and Roberston.

http://arxiv.org/pdf/astro-ph/0505518

The Magnetospheric Eternally Collapsing Object (MECO) Model of Galactic Black Hole Candidates and Active Galactic Nuclei by Stanley Robertson and Darryl Leiter.

http://arxiv.org/pdf/astro-ph/0602453

Nope. Counter-intuitive, I admit. See "Ejection of Supermassive Black Holes from Galaxy Cores", by Gualandris and Merritt, http://arxiv.org/abs/0708.0771. Here's the abstract:

Stupendous Man,

It should be noted there are theoretical issues which the AGN accretion disk hypothesis does not as of yet theoretically explain, in addition to: How does the accretion disk mechanism produce the observed spectrum of naked AGN? I do not see how a classic hairless BH can produce the Naked AGN spectrum.


Stupendous Man or anyone else, do you way any ideas, how an accretion disk could produce the Naked AGH spectrum? Also see my quoted concerning detail quasar structures that require a massive magnetic field to produce. (Similar to a magnstar or a pulsar.) I repeat, it seems that a hairless classical BH cannot produce the observed spectrum for quasars or AGN.

It should be noted that very fundamental issues concerning the accretion disk mechanism have not been resolved and may not be resolvable. For example, see this paper January 2007 and the comment “Yet we still do not understand how gas gets down to the black hole.” (See below for a fuller quote for context.)

“Fuelling Active Galactic Nuclei”, By King and Pringle January, 2007

http://arxiv.org/pdf/astro-ph/0701679

Wow.

__________________
Everyone is entitled to his own opinion, but not his own facts.

So the glass is part empty?

I thought S-Man answered that, in general terms: "There must still be some gas in the general vicinity for the black hole to be accreting." I'm no spectral specialist, but less disk => narrower lines, seems reasonable to me.

Whirling disks around SMBHs are going to be producing massive magnetic fields. What's the question?

Why wouldn't they be resolvable?

"It is rather ironic that the job of a scientist is to understand nature, and if the scientist completely succeeds, the reward is unemployment. But of the many things that concern me in the day-to-day existence of a scientist, waking up one morning and discovering that there are no problems to solve is rather low on the list." -- Rocky Kolb, Blind Watchers of the Sky

__________________
Everyone is entitled to his own opinion, but not his own facts.

Guys, look up "MECOs", we've discussed them here before. Proponents of Mitra's ECO/MECO ideas claim some quasar observations support their model.

Oh, and the merging black holes do indeed give us a very non-Newtonian result. The (huge honking amounts of) gravitational radition is aniostropic and gives the merged result a linear radiation kick, which as mentioned above, can be quite enormous. That's very strange looking, as the center of mass flies off, something that would not happen in Newton. But that's the system pushing off against its own gravitational radiation field.

-RIchard

And the kicks are biggest when the two black holes each start out spinning really, really fast, _and_ have an initial orbit which also involves a good deal of angular momentum. I didn't mention the spinning bit in my earlier message --- sorry.

The Naked AGN spectrum is flat. Less gas does not produce a flat spectrum. The emission source for the AGN appears to be unconnected with the accretion disk. i.e. No quasar company galaxy, very luminous quasar with a very different spectrum and no accretion disk. (Also note the lack of absorption lines in the Naked AGN spectrum. Please see Hawkins paper. The Naked AGN spectrum is at the end of the paper.)

The quasar spectrum is generated by a compact source illuminating the accretion disk. Call that hypothesis "2".


If hypothesis "1", thats the hypothesis that the accretion disk is the source of the illumination is incorrect, a couple of centuries more of model tweaking will not fix the fundamentally incorrect hypothesis.

Now on to the dusty quasar problem. Please note that as of yet the Naked Quasar illumination problem does not as yet have a solution. The theoretical problems appear to be plying up.

Quasar Winds as Dust Factories at High Redshift by Martin Elvis, Massimo Marengo & Margarita Karovska

http://arxiv.org/pdf/astro-ph/0311454

Quasars seem to be a general purpose astronomical object. Would not have thought the accretion disk mechanism could also be a "dust" factory. But as there is an observed massive amount of "dust" around high red shifted quasars, obviously with a little theoretical work, the accretion disk can also become a dust factory. Please read on and judge for yourself.

Is it just, me. I would not have thought quasar winds would create carbon dust. Early universe, hydrogen and helium? What the heck, perhaps a good strong wind could change hydrogen or helium to carbon. Let's not forget the issue with super solar metallicity in high red shift quasars. Perhaps the super solar metallicity can also be attributed to quasar winds.

Why quasar winds and not say fairies? Could the massive amount of carbon and oxygen (forgot to mention the O2), be a hint that the quasar compact object is generating the dust? No the all purpose accretion disk is clearly the best and only hypothesis to consider.

Publius’s comment concerning classical hairless BH.

Publius, is it just me or does the hairless BH that is sort of a super vacuum and the hairless BH that can be a BH propellant seem to be sort of a kludge?

http://en.wikipedia.org/wiki/Kludge

MECCO’s may have been discussed before, however something must have missed in the discussion. Hairless BH appear to the only hypothesis that gets air time in the forum and frankly they seems to be having a couple of problems.

Hawkins says:

....it is argued that the central star cluster fuelling the accretion disc has ceased supplying gas, and the naked AGN represent a transition stage between activity and a dormant phase, in which the disc draws on its internal resources to maintain its energy output.

And before that he said:

"...it would thus appear that for those AGN where broad emission lines are not present, the source of inflowing material has dried up. These naked AGN therefore would represent a period in the duty cycle intermediate between activity and dormancy. They would survive on the fuel reserves present in the accretion disc." .

This seems to contradict Hawkins' quotes above.