scholarly journals Effects of Higher Order Retarded Gravity

Universe ◽  
2021 ◽  
Vol 7 (7) ◽  
pp. 207
Author(s):  
Asher Yahalom
Keyword(s):  
Taylor Expansion ◽  
Temporal Change ◽  
Higher Order ◽  
Second Order ◽  
Galactic Rotation ◽  
Retardation Time ◽  
Rotation Curves ◽  
Order Analysis ◽  
Galactic Rotation Curves ◽  
Higher Order Terms

In a recent paper, we have a shown that the flattening of galactic rotation curves can be explained by retardation. However, this will rely on a temporal change of galactic mass. In our previous work, we kept only second order terms of the retardation time in our analysis, while higher terms in the Taylor expansion where not considered. Here we consider analysis to all orders and show that a second order analysis will indeed suffice, and higher order terms can be neglected.

scholarly journals Effects of Higher Order Retarded Gravity

2021 ◽  
Author(s):  
Asher Yahalom
Keyword(s):  
Taylor Expansion ◽  
Temporal Change ◽  
Higher Order ◽  
Second Order ◽  
Galactic Rotation ◽  
Retardation Time ◽  
Rotation Curves ◽  
Order Analysis ◽  
Galactic Rotation Curves ◽  
Higher Order Terms

In a recent paper we have a shown that the flattening of galactic rotation curves can be explained by retardation. However, this will rely on a temporal change of galactic mass. In our previous work we have kept only second order terms of the retardation time in our analysis, while higher terms in the Taylor expansion where not considered. Here we consider analysis to all orders and show that indeed a second order analysis will suffice, and higher order terms can be neglected.

scholarly journals Galactic rotation curves inspired by a noncommutative-geometry background

2011 ◽  
Vol 44 (4) ◽  
pp. 905-916 ◽  
Author(s):  
F. Rahaman ◽  
Peter K. F. Kuhfittig ◽  
K. Chakraborty ◽  
A. A. Usmani ◽  
Saibal Ray
Keyword(s):  
Noncommutative Geometry ◽  
Galactic Rotation ◽  
Rotation Curves ◽  
Galactic Rotation Curves

scholarly journals Possible formation of wormholes from dark matter in an isothermal galactic halo and void

2019 ◽  
Vol 34 (23) ◽  
pp. 1950188
Author(s):  
Nayan Sarkar ◽  
Susmita Sarkar ◽  
Farook Rahaman ◽  
P. K. F. Kuhfittig ◽  
G. S. Khadekar
Keyword(s):  
Dark Matter ◽  
Galactic Halo ◽  
Energy Condition ◽  
Null Energy Condition ◽  
Galactic Rotation ◽  
Einstein Field Equations ◽  
Field Equations ◽  
Rotation Curves ◽  
Galactic Rotation Curves ◽  
Traversable Wormholes

It is well-known that traversable wormholes are valid solutions of the Einstein field equations, but these structures can only be maintained by violating the null energy condition. In this paper, we have obtained such wormhole solutions in an isothermal galactic halo, as well as in a void. We have shown that the null energy condition is violated, with the help of a suitable redshift function obtained from flat galactic rotation curves.

Higher‐order moveout spectra

Geophysics ◽  
1979 ◽  
Vol 44 (7) ◽  
pp. 1193-1207 ◽  
Author(s):  
Bruce T. May ◽  
Donald K. Straley
Keyword(s):  
Fourth Order ◽  
Seismic Reflection ◽  
Order Term ◽  
Higher Order ◽  
Second Order ◽  
Equation Modeling ◽  
Fourth Order Term ◽  
Higher Order Terms ◽  
Velocity Spectra

Higher‐order terms in the generalized seismic reflection moveout equation are usually neglected, resulting in the familiar second‐order, or hyperbolic, moveout equation. Modeling studies show that the higher‐order terms are often significant, and their neglect produces sizable traveltime residuals after correction for moveout in such cases as kinked‐ray models. Taner and Koehler (1969) introduced velocity spectra for estimating stacking velocity defined on the basis of second‐order moveout. Through the use of orthogonal polynomials, an iterative procedure is defined that permits computation of fourth‐order moveout spectra while simultaneously upgrading the previously computed, second‐order spectra. Emphasis is placed on the fourth‐order term, but the procedure is general and can be expanded to higher orders. When used with synthetic and field recorded common‐midpoint (CMP) trace data, this technique produces significant improvements in moveout determination affecting three areas: (1) resolution and interpretability of moveout spectra, (2) quality of CMP stacked sections, and (3) computation of velocity and depth for inverse modeling.

Study of galactic rotation curves in wormhole spacetime

2016 ◽  
Vol 361 (3) ◽  
Author(s):  
Farook Rahaman ◽  
Banashree Sen ◽  
Koushik Chakraborty ◽  
G. C. Shit
Keyword(s):  
Galactic Rotation ◽  
Rotation Curves ◽  
Galactic Rotation Curves
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