Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Physics of the central region in the quasar 0850+581   The apparent position of the origin (core) of extragalactic radio jets shifts
with the observing frequency, owing to synchrotron self-absorption and external
absorption. One of the largest core shifts was detected by us in the quasar
0850+581 between 2 and 8 GHz. We have followed this up recently by a dedicated
VLBA experiment at 5, 8, 15, 24, and 43 GHz. First results from this study
enabled estimating the absolute geometry and physical conditions in the
parsec-scale jet origin.

22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
12
The categories of this paper are: nucl-th
33
The categories of this paper are: plasm-ph
14
The categories of this paper are: math-ph
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
24
The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
21
The categories of this paper are: adap-org
26
The categories of this paper are: bayes-an
16
The categories of this paper are: stat
2
The categories of this paper are: math
20
The categories of this paper are: acc-phys
4
The categories of this paper are: cond-mat