Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: High-resolution polarization imaging of the Fermi blazar 3C 279   Ever since the discovery by the Fermi mission that active galactic nuclei
(AGN) produce copious amounts of high-energy emission, its origin has remained
elusive. Using high-frequency radio interferometry (VLBI) polarization imaging,
we could probe the magnetic field topology of the compact high-energy emission
regions in blazars. A case study for the blazar 3C 279 reveals the presence of
multiple gamma-ray emission regions. Pass 8 Fermi-Large Area Telescope (LAT)
data are used to investigate the flux variations in the GeV regime; six
gamma-ray flares were observed in the source during November 2013 to August
2014. We use the 43 GHz VLBI data to study the morphological changes in the
jet. Ejection of a new component (NC2) during the first three gamma-ray flares
suggests the VLBI core as the possible site of the high-energy emission. A
delay between the last three flares and the ejection of a new component (NC3)
indicates that high-energy emission in this case is located upstream of the 43
GHz core (closer to the black hole).

13
The categories of this paper are: quant-ph
26
The categories of this paper are: bayes-an
2
The categories of this paper are: math
19
The categories of this paper are: eess
24
The categories of this paper are: dg-ga
9
The categories of this paper are: nlin
32
The categories of this paper are: atom-ph
7
The categories of this paper are: hep-th
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg
1
The categories of this paper are: cs