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FIZIKA B 15 (2006) 3, 141-156
 
SPHERICALLY-SYMMETRIC NONSINGULAR MODELS WITH VARIABLE L
TERM IN RELATIVISTIC COSMOLOGY
ANIRUDH PRADHANa KASHIKA SRIVASTAVAa and R. P. SINGHb
aDepartment of Mathematics, Hindu Post-Graduate College, Zamania-232 331, Ghazipur, India
bDepartment of Mathematics, T. D. Post-Graduate College, Jaunpur- 222 002, India
E-addresses: pradhan@iucaa.ernet.in,
acpradhan@yahoo.com,
kash_gg@yahoo.co.uk
Received 8 May 2006; Revised manuscript received 7 December 2006
Accepted 13 December 2006 Online 23 February 2007
We discuss a class of nonsingular spherically-symmetric cosmological models
with radial heat flux and variable cosmological term L(t).
Three different exact solutions of the Einstein's field equations are obtained
for both perfect fluid and fluid with bulk viscosity. It turns out that the
cosmological term L(t) is a decreasing function of
time, what is consistent with recent observations of type Ia supernovae.
PACS numbers: 98.80.-k, 98.80.Es
UDC 524.83
Keywords: cosmology, variable cosmological term, nonsingular models, bulk
viscosity
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