Tuesday, 1 November 2011

Wikipedia Article Vandalized by some Anonymous editor

Abhas Mitra

Abhas Mitra is a noted Indian astrophysicist and is known for his trait of novel thinking on several frontline astrophysics problems. He is the first astrophysicist to suggest that photo-meson process rather than proton-proton collision process could be the leading mechanism for Ultra High Energy gamma-ray production in ultra-compact X-ray binaries.[1] As far as India based astrophysicists are concerned, he was the first to carry out research on various theoretical aspects of modern Gamma Ray Burst paradigm,[2][3][4][5],.[6] In particular, it was he who first pointed out that the so-called Fireball model may not work unless the presence of an ambient magnetic field, much stronger than the typical interstellar value, would be assumed.[2] Accordingly, he was the first astrophysicist, based in India, who got an oral slot for presentation on the `Theory and Models' of cosmic gamma ray bursts in a prestigious international scientific conference.[7]
One of his recent papers claims to contain an exact mathematical proof that the true/exact Schwarschild Black Holes have zero gravitational mass: M=0.[8] This paper claims that no objects with a finite gravitational mass can be true/exact black holes. If so, the so-called Black Hole candidates cannot be true black holes even though they may resemble `black holes' in many respects.
Recently, Mitra and Norman Glendenning[9] have shown that continued gravitational collapse of massive objects should result in a radiation pressure supported quasi-static hot ball of plasma rather than a true black hole.[10] Such a quasi-static self-gravitating hot ball of plasma has been termed as `Eternally Collapsing Object' in view of the fact it is ever shrinking to asymptotically attain the true Schwarzschild black hole state having M=0.[11]
He may be first author to suggest that some of the unidentified high energy gamma-ray sources detected by the Energetic Gamma Ray Experiment Telescope of NASA are associated with the wind shock of massive Wolf-Rayet stars.[12] And this paper happens to be the only one, written on Indian soil, cited in the science brochure [13] of the space borne latest Fermi Gamma-ray Space Telescope.
Relativistic astrophysicists have struggled for ages to find an exact general relativistic counterpart of the Newtonian Virial theorem : 2T+V=0  for a quasi-spherical system. And Mitra found such an exact GR version of Virial Theorem in 2006.[14]
Similarly, it has generally been believed that inclusion of fluid pressure increases the Active Gravitational Mass Density in general relativity. However, he has shown that pressure eventually decreases the same and pressure gradient indeed opposes gravitational collapse.[15]
The total energy of the universe, inclusive of matter, radiation and gravitation in the Big Bang has been worked out by Mitra by directly using Einstein's original prescription (i.e., without using any super-potential).[16] This maiden direct computation claims to show that the principle of energy conservation is indeed violated in the Big- Bang model. And only way the principle of energy conservation would be valid here would be if the model would degenerate into a Newtonian one with zero mean matter density!
He has introduced a new astrophysical term - `Einstein - Eddington Time Scale' in the honor of Albert Einstein and Arthur Stanley Eddington. This time scale is based on the fact that in the context of General Relativity, the total available energy of an object in the rest frame of a distant observer is : E= M c^2 , and the maximum rate at which this energy can be radiated out is given by the general relativistic Eddington luminosity. The relevant paper where this concept got developed was selected as one of the highlight publications of Max Planck Society.[17]
Apart from astrophysics, his interest in physics ranges from Classical Mechanics[18] to Quantum Computing.[19]
Although he is basically a theoretical physicist, he evinces keen interest in experimental Gamma-ray Astronomy and is associated with the `Himalayan Gamma Ray Observatory'[20] being set up at Hanle[21] jointly by Tata Institute of Fundamental Research and Bhabha Atomic Research Centre.
He initiated research in Theoretical Astrophysics in Bhabha Atomic Research Centre, India's equivalent of Los Alamos National Laboratory. And he has been heading the Theoretical Astrophysics Section of this premier national research organization since 2004. Presently, he happens to be the lone member of International Astronomical Union from this institute.
In 1989, he won the `Best Young Physicist' Prize from the Indian Physical Society.
See als



  1.  http://adsabs.harvard.edu/abs/1990A%26A...234L...5M Towards a proper ultra-high-energy gamma-ray production mechanism in Cygnus X-3
  2. ↑ a b http://adsabs.harvard.edu/abs/1996A%26A...313L...9M Do fireballs in the interstellar medium necessarily imply blast wave propagation?
  3.  http://adsabs.harvard.edu/abs/1998ApJ...492..677M The Expected Duration of Gamma-Ray Bursts in the Impulsive Hydrodynamic Models
  4.  http://adsabs.harvard.edu/abs/1998A%26A...340..447M On the true energy budget of GRB970508 and GRB971214
  5.  http://adsabs.harvard.edu/abs/2000astro.ph.10311M General Relativistic Collapse of Neutron Stars to Strange Stars: A Mechanism for Gamma Ray Bursts
  6.  http://adsabs.harvard.edu/abs/2000InJPB..74..175M
    The ultra nova model of cosmic gamma ray bursts
  7.  http://www.batse.msfc.nasa.gov/events/3hgrbs/abstracts/models.html 3rd Huntsville Symposium on Gamma-Ray Bursts
  8.  http://adsabs.harvard.edu/abs/2009JMP....50d2502M Comments on The Euclidean gravitational action as black hole entropy, singularities, and space-time voids [J. Math. Phys. 49, 042501 (2008)
  9.  http://www-nsdth.lbl.gov/~nkg/
  10.  http://adsabs.harvard.edu/abs/2010MNRAS.404L..50M Likely formation of general relativistic radiation pressure supported stars or eternally collapsing objects
  11.  http://www.scitopics.com/Eternally_Collapsing_Object.html Eternally Collapsing Objects
  12.  http://adsabs.harvard.edu/abs/1997AIPC..410.1271K
    Possible identification of unidentified EGRET sources with Wolf-Rayet stars
  13.  http://fermi.gsfc.nasa.gov/public/resources/pubs/gsd/GSD_web.pdf GLAST/FERMI Science Brochure
  14.  http://adsabs.harvard.edu/abs/2006PhRvD..74b4010M Why gravitational contraction must be accompanied by emission of radiation in both Newtonian and Einstein gravity
  15.  http://adsabs.harvard.edu/abs/2010PhLB..685....8M
    Does pressure increase or decrease active gravitational mass density
  16.  http://adsabs.harvard.edu/abs/2010GReGr..42..443M Einstein energy associated with the Friedmann-Robertson-Walker metric
  17.  http://www.mpg.de/english/researchResults/researchPublications/researchReports/AST/200648_084.shtml Max Planck Research Highlights 2006
  18.  http://adsabs.harvard.edu/abs/1985AmJPh..53.1175M Role of integrals of motion in closing an orbit
  19.  http://adsabs.harvard.edu/abs/2002PhLA..301..125P
    Quantum limit on computational time and speed
  20.  http://adsabs.harvard.edu/abs/2005ICRC....5..243K The Himalayan Gamma Ray Observatory
  21.  http://adsabs.harvard.edu/abs/2008ICRC....3.1361A The Status of Himalayan Gamma Ray Observatory

External links==

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