Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: RadioAstron gravitational redshift experiment: status update   A test of a cornerstone of general relativity, the gravitational redshift
effect, is currently being conducted with the RadioAstron spacecraft, which is
on a highly eccentric orbit around Earth. Using ground radio telescopes to
record the spacecraft signal, synchronized to its ultra-stable on-board
H-maser, we can probe the varying flow of time on board with unprecedented
accuracy. The observations performed so far, currently being analyzed, have
already allowed us to measure the effect with a relative accuracy of
$4\times10^{-4}$. We expect to reach $2.5\times10^{-5}$ with additional
observations in 2016, an improvement of almost a magnitude over the 40-year old
result of the GP-A mission.

8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
13
The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg
29
The categories of this paper are: funct-an
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga
11
The categories of this paper are: hep-lat
23
The categories of this paper are: solv-int
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
7
The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
37
The categories of this paper are: supr-con