Zobrazeno 1 - 10
of 58
pro vyhledávání: '"Scharf, Günter"'
Autor:
Scharf, Günter
We study inhomogeneous perturbations away from the strongly homogeneous background cosmology previously studied. The problem is greatly simplified by using the mapping on the inner Schwarzschild solution. The resulting linear perturbation equations c
Externí odkaz:
http://arxiv.org/abs/1905.02526
Autor:
Scharf, Günter
We assume a one-to-one correspondence between comoving coordinates and the cosmic rest frame in a spherically symmetric inhomogeneous universe. This strongly restricts the solutions of Einstein's equations: (i) The pressure must be zero. (ii) The met
Externí odkaz:
http://arxiv.org/abs/1503.05878
Autor:
Scharf, Günter
We study Einstein's equations with an isotropic but inhomogeneous metric in the cosmic rest frame. The equations are solved perturbatively in the late Universe. The leading plus next-to-leading order results agree with observations without using a co
Externí odkaz:
http://arxiv.org/abs/1312.2695
Autor:
Scharf, Günter
Considering radial geodesics in the Robertson-Walker metric leads us to abandon the co-moving coordinates. Instead we work in the cosmic rest frame. Since then the matter is in motion, the solution of Einstein's equations is more complicated. We calc
Externí odkaz:
http://arxiv.org/abs/1309.5444
Autor:
Scharf, Günter
We revisit the Kerr metric in Boyer-Lindquist coordinates and construct the corresponding class of nonstandard solutions of Einstein's equations. These solutions can be used to describe the outer part of spiral galaxies without assuming dark matter.<
Externí odkaz:
http://arxiv.org/abs/1301.2140
Autor:
Scharf, Günter
We study Einstein's equations with matter in hydrostatic equilibrium in the nonstandard gauge which was recently investigated in the vacuum case. We obtain spherically symmetric solutions for any given rotation curve. These solutions can be used to d
Externí odkaz:
http://arxiv.org/abs/1210.1496
Autor:
Scharf, Günter
We show that the Schwarzschild solution can be embedded in a class of nonstandard solutions of the vacuum Einstein's equations with arbitrary rotation curves. These nonstandard solutions have to be taken as physical if dark matter as needed in the st
Externí odkaz:
http://arxiv.org/abs/1208.3749
Autor:
Scharf, Günter
We show that Einstein's equations in a non-standard gauge have vacuum solutions with an asymptotically flat rotation curve as it is observed in the dark halos of galaxies. Introducing a material disk into this model we find a matter density in accord
Externí odkaz:
http://arxiv.org/abs/1206.1912
Autor:
Scharf, Günter
We continue the study of the tensor-four-scalars theory which is a modification of general relativity. We include normal matter by applying the displace, cut, and reflect method to our previous vacuum solutions with dark halo. The resulting disklike
Externí odkaz:
http://arxiv.org/abs/1205.4309
Autor:
Scharf, Günter, Larere, Fabrice
We continue to study the spherically symmetric vacuum solutions of the tensor-four-scalars theory which is a modification of general relativity. Our aim is to construct vacuum solutions with asymptotically constant circular velocity curves which can
Externí odkaz:
http://arxiv.org/abs/1111.1166