Quantum Stabilization of a Relativistic Degenerate Star Beyond the Chandrasekhar Mass Limit

Silverman, Mark P.

doi:10.1142/s0218271804006334

Cited by 4 publications

(4 citation statements)

References 3 publications

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“…The total AGN space density presented by these authors shows an apparent decline above z ∼ 1, although this becomes less certain when the effects of spectroscopic incompleteness are taken into account. These results are very similar to those presented by Silverman et al (2005), in a shallower but wider survey, showing a peak of MLAGN activity at z ∼ 1 and a strong apparent decline at higher redshifts. Such a conclusion would be fundamental, and apparently at odds with the presumed linkage between black hole growth, galaxy formation and mergers.…”

Section: Introductionsupporting

confidence: 90%

“…They are also relatively unbiased, compared with optical or soft X‐ray surveys, against obscured objects. The first attempts at determining AGN evolution from deep Chandra surveys (C03; Ueda et al 2003, hereafter U03; Silverman et al 2005; Barger et al 2005) confirm a rapid rise in the number of high‐luminosity AGN ( L X > 10 44 erg s −1 ) towards high redshift. This evolution is consistent with results from optical and soft X‐ray surveys (e.g.…”

Section: Introductionmentioning

confidence: 99%

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The space density of moderate-luminosity active galaxies at z = 3

Nandra¹,

Laird²,

Steidel³

2005

Monthly Notices of the Royal Astronomical Society: Letters

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We present an estimate of the space density of active galactic nuclei (AGN) at z= 3. Combining deep X‐ray data with Lyman break galaxy (LBG) colour selection in the rest‐frame ultraviolet makes for highly efficient identification of AGN in a narrow redshift range (z∼ 2.5–3.5). Using Chandra data from the Groth–Westphal Strip (GWS) and the Hubble Deep Field North (HDF‐N), we find a total of 15 X‐ray‐detected LBGs at z∼ 3, the majority of which are unlikely to have been identified in blanket follow‐up surveys of X‐ray‐detected objects. We find the comoving space density of moderate‐luminosity AGN (MLAGN; LX= 1043–44.5 erg s−1) at z= 3 to be a factor of ∼10 higher than that of the most powerful objects. The available data are consistent with a roughly constant space density of MLAGN from z= 0.5 to 3, and they are also consistent with a mild decline in the space density above z= 1 as predicted by the luminosity‐dependent density evolution models of Ueda et al. This strong AGN activity at z= 3 argues against previous suggestions that the majority of black hole accretion occurs at low redshift. A further implication of our investigation is that, as far as can be determined from current data, the majority of the AGN population at z∼ 3 is selected by the LBG dropout technique. Although this is sensitive to AGN with an ultraviolet excess arising from an accretion disc, it predominantly identifies star‐forming galaxies. A significant fraction of X‐ray sources seem likely to be hosted by these more typical LBGs, further strengthening the starburst–AGN connection at high redshift.

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Section: Introductionsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

The space density of moderate-luminosity active galaxies at z = 3

Nandra¹,

Laird²,

Steidel³

2005

Monthly Notices of the Royal Astronomical Society: Letters

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“…I have previously shown that long-range magnetic coupling of neutrons changes the spatial dependence of the internal energy function in such a way that a self-gravitating system of relativistic degenerate neutrons over the OV mass limit may achieve a stable equilibrium at a macroscopic radius (comparable to that of a neutron star) and finite density. (55) What effects ultra-strong magnetic fields can have on the condensation of ultra-dense nuclear matter is a question that has hardly been explored.…”

Section: Concluding Commentsmentioning

confidence: 99%

“…During the past few years there have been several attempts to stabilize the collapse of a degenerate star beyond the OV mass limit by (1) taking account of long-range magnetic interactions among nucleons, (8) which, among other things, affects the spatial dependence of the internal energy, (2) by recognition of a vacuum quantum field process referred to as particle resorption, (9) which is complementary to the process responsible for Hawking radiation (10) and affects the fermion number density, and (3) by appeal to loop quantum gravity to suppress the formation of an event horizon. (11) However, very recent advances in the investigation of degenerate atomic Fermi gases at ultra-low temperature (12)(13)(14)(15) suggest a new possibility by means of which known physical laws, in contrast to as yet hypothetical quantizations of gravity, may prevent the singular collapse of a degenerate star.…”

Section: Introduction: the Stellar End Statementioning

confidence: 99%

Condensates in the Cosmos: Quantum Stabilization of the Collapse of Relativistic Degenerate Stars to Black Holes

Silverman

2007

Found Phys

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According to prevailing theory, relativistic degenerate stars with masses beyond the Chandrasekhar and Oppenheimer-Volkoff (OV) limits cannot achieve hydrostatic equilibrium through either electron or neutron degeneracy pressure and must collapse to form stellar black holes. In such end states, all matter and energy within the Schwarzschild horizon descend into a central singularity. Avoidance of this fate is a hoped-for outcome of the quantization of gravity, an as-yet incomplete undertaking. Recent studies, however, suggest the possibility that known quantum processes may intervene to arrest complete collapse, thereby leading to equilibrium states of macroscopic size and finite density. I describe here one such process which entails pairing (or other even-numbered association) of neutrons (or constituent quarks in the event of nucleon disruption) to form a condensate of composite bosons in equilibrium with a core of degenerate fermions. This process is analogous to, but not identical with, the formation of hadron Cooper pairs that give rise to neutron superfluidity and proton superconductivity in neutron stars. Fermion condensation to composite bosons in a star otherwise destined to collapse to a black hole facilitates hydrostatic equilibrium in at least two ways: (1) removal of fermions results in a decrease in the Fermi level which stiffens the dependence of degeneracy pressure on fermion density, and (2) phase separation into a fermionic core surrounded by a self-gravitating condensate diminishes the weight which must be balanced by fermion degeneracy pressure. The outcome is neither a black hole nor a neutron star, but a novel end state, a "fermicon star," with unusual physical properties.

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Gravitationally-Induced Particle Resorption Into the Vacuum: A General Solution to the Problem of Black Hole Collapse

Silverman¹

2005

Int. J. Mod. Phys. D

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The process of gravitationally-induced particle creation (Hawking radiation), if it exists, necessitates, in accordance with general thermodynamic principles, a corresponding process of gravitationally-induced particle resorption into the vacuum. Although the former process occurs in the external vicinity of the Schwarzschild surface where matter density is relatively low, the latter process would be expected to occur inside the Schwarzschild surface where the stellar material is enormously compressed and fermions fill all quantum states up to the Fermi level. I show that the occurrence of particle resorption provides a general mechanism, irrespective of the interactions of the constituent particles, which halts the collapse of a black hole to a singular point and leads to an equilibrium state of macroscopic extent.

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Quantum Stabilization of a Relativistic Degenerate Star Beyond the Chandrasekhar Mass Limit

Cited by 4 publications

References 3 publications

The space density of moderate-luminosity active galaxies at z = 3

The space density of moderate-luminosity active galaxies at z = 3

Condensates in the Cosmos: Quantum Stabilization of the Collapse of Relativistic Degenerate Stars to Black Holes

Gravitationally-Induced Particle Resorption Into the Vacuum: A General Solution to the Problem of Black Hole Collapse

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