Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Evolution of the Cosmic Microwave Background   We discuss the time dependence and future of the Cosmic Microwave Background
(CMB) in the context of the standard cosmological model, in which we are now
entering a state of endless accelerated expansion. The mean temperature will
simply decrease until it reaches the effective temperature of the de Sitter
vacuum, while the dipole will oscillate as the Sun orbits the Galaxy. However,
the higher CMB multipoles have a richer phenomenology. The CMB anisotropy power
spectrum will for the most part simply project to smaller scales, as the
comoving distance to last scattering increases, and we derive a scaling
relation that describes this behaviour. However, there will also be a dramatic
increase in the integrated Sachs-Wolfe contribution at low multipoles. We also
discuss the effects of tensor modes and optical depth due to Thomson
scattering. We introduce a correlation function relating the sky maps at two
times and the closely related power spectrum of the difference map. We compute
the evolution both analytically and numerically, and present simulated future
sky maps.

12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
18
The categories of this paper are: econ
21
The categories of this paper are: adap-org
22
The categories of this paper are: chao-dyn
20
The categories of this paper are: acc-phys
24
The categories of this paper are: dg-ga
27
The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
3
The categories of this paper are: physics
5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph
33
The categories of this paper are: plasm-ph
32
The categories of this paper are: atom-ph
2
The categories of this paper are: math