Magnetospheric eternally collapsing object
Magnetospheric Eternally Collapsing Objects or MECOs represent a viable alternative to black holes that were initally proposed in 2002 by Darryl Leiter and Stan Robertson. The MECO model was further developed and successfully applied to the observational data associated with astrophysical scenarios in a series of papers from 2002 to 2006. [1] [2] [3] [4] [5] The MECOs are an intrinsically magnetic variant of eternally collapsing objects or ECOs that were first proposed by Abhas Mitra in 1998 and then later developed within a more general and consistent framework in 2006. [6]
In these papers physical arguments, based on preservation of the "Strong Principle of Equivalence"
in General Relativity, were given that showed that black holes were dynamically prevented from
froming in the context of the spherically symmetric gravitational collapse of a star. There
it was shown that the development of "trapped surfaces" leading to the development of event horizons horizons in gravitationally collapsing hot compact objects could be halted by Eddington limited radiation pressure trapped deep inside of its photon sphere and thus form into either an ECO or a MECO.
Because of an emphasis on questions about whether Black Holes with non-zero mass can proven to mathematically exist in the Einstein equations, much controversy and criticism has been focused on the 1998 to 2000 papers by Abhas Mitra, and for this reason the existence of the ECO has not yet been widely accepted by the astrophysics community.
However it is important to note that these criticisms do not apply to the MECO model developed in the 2002 to 2006 papers quoted in the references below because in them the mathematical existence of Black Hole solutions with non-zero mass, associated with the structure and form of the left hand side of the Einstein equations, was not an issue. Instead these papers took a different approach entirely. Since the left-hand side of the Einstein equation cannot not by itself dynamically enforce the preservation of the "Strong Principle Of Equivalence", it was argued that for hot gravitationally collapsing objects there must exist non-gravitational processes in Nature which "dynamically" preserve the "Strong Principle of Equivalence" and for this reason must always be included in the energy–momentum tensor on the right-hand side of the Einstein equation. In this manner it was found that the formation of "Trapped Surfaces" leading to Black Holes with event horizons was prevented by the "dynamic preservation" of the "Strong Principle Of Equivalence" which can spontaneously occur for a hot, magnetic, gravitationally collapsing MECO under the influence of both gravitational forces and non-gravitational forces in a hot collapsing Plasma under the influence of Radiation Pressure and strong equipartition Magnetic Fields at very high levels of Luminosity/Size compactness where the physical effects of Quantum Electrodynamics must be taken into account.
It is interesting to note that for the physically plausible case of the MECO advocated by Robertson and Leiter a distinct observable difference between MECO's and black holes can be found. This is because, in addition the magnetic field produced by its accretion disc environment, the MECO produces its own intrinsic magnetic field which can generate observable physical effects on its accretion environment. What is even more interesting is the the fact that in support of the viabliity of the MECO model for active galactic nuclei Harvard Astronomer Rudolph Schild, in collaboration with Darryl Leiter and Stan Robertson, have found evidence of such MECO intrinsic magnetic fields emanating from the central supermassive compact objects in the two quasars Q0957+561 and Q2237.
[7]
See also
External links
Research Sheds New Light On Quasars] (SpaceDaily) Jul 26, 2006
References
- ^ Robertson, S. and Leiter, D., Astrophysical Journal, v565, p447 (2002).
- ^ Robertson, S. and Leiter, D., Astrophysical Journal, v596, L203, (2003).
- ^ Robertson, S. and Leiter, D., MNRAS, v350, p1391, (2004).
- ^ Robertson, S. and Leiter, D., arXiv:astro-phys/0602543 (2006).
- ^ Robertson, S. and Leiter, D., arXiv:astro-phys/0603746 (2006).
- ^ "Sources of Stellar Energy, Einstein-Eddington Timescale of Gravitational Contraction and Eternally Collapsing Objects", A. Mitra, arXiv:astro-ph/0608178 (2006).
- ^ "Observations Supporting the Existence of an Intrinsic Magnetic Moment inside the Central Compact Object within the Quasar Q0957+561", R. Schild, D. Leiter, and S. Robertson, The Astronomical Journal, 132(1), 420-432, arXiv:astro-ph/0505518.
- ^ "Direct Microlensing-Reverberation Observations of the Intrinsic Magnetic Structure of Active Galactic Nuclei In Different Spectral States: A Tale of Two Quasars", R. Schild, D. Leiter, and S. Robertson, The Astronomical Journal, 135(1), 947-956,.