Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Discovery of a dual AGN at z~3.3 with 20kpc separation   A prediction of the current paradigm of the hierarchical assembly of galaxies
is the presence of supermassive dual black holes at separations of a few kpc or
less. In this context, we report the detection of a narrow-line emitter within
the extended LyA nebula (~120kpc diameter) of the luminous radio-quiet
quasi-stellar object (QSO) LBQS0302-0019 at z=3.286. We identify several
high-ionization narrow emission lines (HeII, CIV, CIII]) associated with this
point-like source, which we have named "Jil", which is only ~20kpc (2.9") away
from the QSO in projection. Emission-line diagnostics confirm that the source
is likely powered by photoionization of an obscured active galactic nucleus
(AGN) three orders of magnitude fainter than the QSO. The system represents the
tightest unobscured/obscured dual AGN currently known at z>3, highlighting the
power of MUSE to detect these elusive systems.

34
The categories of this paper are: chem-ph
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
32
The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio
29
The categories of this paper are: funct-an
1
The categories of this paper are: cs
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
9
The categories of this paper are: nlin
23
The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph
14
The categories of this paper are: math-ph
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga
35
The categories of this paper are: mtrl-th