Autor(es):
Edgar, S. Brian 
; Ramos, M. P. Machado
Data: 2007
Identificador Persistente: http://hdl.handle.net/1822/7701
Origem: RepositóriUM - Universidade do Minho
Assunto(s): Pure radiation; Invariant formalism
Detalhes do Documento
Type O pure radiation metrics with a cosmological constant
Descrição
In this paper we complete the integration of the conformally flat pure radiation spacetimes with a non-zero cosmological constant $\Lambda$, and $\tau \ne 0$, by considering the case $\Lambda +\tau\bar\tau \ne 0$. This is a further demonstration of the power and suitability of the generalised invariant formalism (GIF) for spacetimes where only one null direction is picked out by the Riemann tensor. For these spacetimes, the GIF picks out a second null direction, (from the second derivative of the Riemann tensor) and once this spinor has been identified the calculations are transferred to the simpler GHP formalism, where the tetrad and metric are determined. It is straightforward to deduce the Karlhede classification, and the Karlhede algorithm terminates at the fourth derivative order; the whole class of spacetimes (those found in this paper, together with those found earlier for the case $\Lambda +\tau\bar\tau = 0$) have a rich variety of subclasses with zero, one, two, three, four or five Killing vectors.
In this paper we complete the integration of the conformally flat pure radiation spacetimes with a non-zero cosmological constant $\Lambda$, and $\tau \ne 0$, by considering the case $\Lambda +\tau\bar\tau \ne 0$. This is a further demonstration of the power and suitability of the generalised invariant formalism (GIF) for spacetimes where only one null direction is picked out by the Riemann tensor. For these spacetimes, the GIF picks out a second null direction, (from the second derivative of the Riemann tensor) and once this spinor has been identified the calculations are transferred to the simpler GHP formalism, where the tetrad and metric are determined. It is straightforward to deduce the Karlhede classification, and the Karlhede algorithm terminates at the fourth derivative order; the whole class of spacetimes (those found in this paper, together with those found earlier for the case $\Lambda +\tau\bar\tau = 0$) have a rich variety of subclasses with zero, one, two, three, four or five Killing vectors.
Tipo de Documento
Artigo
Idioma Inglês
Idioma Inglês
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