AR_final file_2018-19

ance calculations during the entire evolution of the galaxy. This simulation has been done in collabo- ration with Tejpreet Kaur. Thermal evolution of the early Moon The early thermal evolution of Moon has been numerically simulated to understand the magni- tude of the impactinduced heating and the ini- tially stored thermal energy of the accreting moon- lets. The main objective of the present study was to understand the nature of processes leading to coremantle differentiation, and the production and cooling of the initial convective magma ocean. The accretion of Moon was commenced over a time scale of 100 yr after the giant impact event around 30100 million years in the early solar system. We stud- ied the dependence of the planetary processes on the impact scenarios, the initial average temper- ature of the accreting moonlets, and the size of the protomoon that accreted rapidly beyond the Roche limit within the initial 1 yr after the giant impact. The simulations indicate that the accret- ing moonlets should have a minimum initial av- eraged temperature around 1600 K. The impacts would provide additional thermal energy. The ini- tial thermal state of the moonlets depends upon the environment prevailing within the Roche limit that experienced episodes of extensive vapouriza- tion and recondensation of silicates. The initial convective magma ocean of depth more than 1000 km is produced in the majority of simulations along with the global coremantle differentiation in case the melt percolation of the molten metal through porous flow from bulk silicates was not the major mode of coremantle differentiation. The possibility of shallow magma oceans cannot be ruled out in the presence of the porous flow. This simulations indicate the coremantle differentiation within the initial 10 2 to 10 3 yr of the Moon accretion. The ma- jority of the convective magma ocean cooled down for crystallization within the initial 10 3 to 10 4 yr. This simulation has been done in collaboration with Vishal Goyal. Asoke Kumar Sen The variation of photon speed with photon fre- quency in quantum gravity An expression for Planck mass or Planck energy is derived by equating the Compton wavelength with the gravitational radius of the Kerr rotating body. Using the modified photon energymomentum dis- persion relation, the variation of the photon prop- agation speed with photon frequency is derived. It is found that, the photon propagation speed, de- pends on the frequency of the photon, the rota- tion parameter of the Kerr rotating body, and also on the polarization state of the photon. Quantum gravity effect could be seen from the derived re- sults for the photon propagation speed. This work has been done in collaboration with Anuj Kumar Dubey, and Sonarekha Nath. T.R. Seshadri Generation of helical magnetic field in a viable sce- nario of inflationary magnetogenesis The generation of helical magnetic fields during in- flation, which is free from the strong coupling and backreaction problems has been investigated. The helical fields are generated by considering a term f 2 ˜ F µν F µν in the Lagrangian. It has been shown that the standard difficulties in most models of inflationary magneto genesis (strong coupling and backreaction problems) can be addressed in a sce- nario, in which f increases during inflation and de- creases post inflation to reheating. If the evolution of f is chose to be of the form, f ∝ a 2 during infla- tion, a fully helical magnetic field with a blue spec- trum is obtained. The reheating scale, for this to be achieved, should be less than 4000 GeV. Bounds from the γ -ray observations are satisfied. For re- heating scale of 100 GeV, magnetic field strength of 4 × 10 − 11 G with a coherence length of 70 kpc is ob- tained. If the reheating takes place at QCD scales of 150 MeV, the fields of nano Gauss strength, with coherence scale of 0.6 Mpc is obtained. This inves- tigation has been done in collaboration with Ramk- ishor Sharma, and Kandaswamy Subramanian. Mohit Kumar Sharma Suggestion for search of 2-aminoethanol in a cos- mic object The 2-aminoethanol is considered as a precursor to amino acid in the interstellar space. Thus, the scientists, searching for life in the universe, have great interest in its investigation, and therefore, its laboratory spectrum has been analyzed from time to time. It has a large electric dipole mo- ment with components along all the three princi- pal inertial axes: µ a = 2.75 D, µ b = 1.07 D, and µ c ( 213 )