Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: IRAS 0421+0400: jets crossing an ISM/IGM interface?   The emission lines in the active galaxy IRAS 0421+0400 show a dramatic (~ 900
km/s) increase in the velocity spread at the position of radio hotspots which
are located at the beginning of extended radio lobes. We study a model which
explains this phenomenon as the result of a jet emerging through the boundary
between the interstellar and intergalactic media. A similar scenario has
previously been suggested as an explanation for wide angle tail radio sources
(WATs). Based on our model, we simulate the longslit spectra of these regions
and compare the results with the observations and find that it can explain most
of the details in the observed longslit spectra.

15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol
17
The categories of this paper are: q-fin
5
The categories of this paper are: gr-qc
23
The categories of this paper are: solv-int
11
The categories of this paper are: hep-lat
14
The categories of this paper are: math-ph
13
The categories of this paper are: quant-ph
4
The categories of this paper are: cond-mat
32
The categories of this paper are: atom-ph
31
The categories of this paper are: ao-sci
19
The categories of this paper are: eess
27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th
9
The categories of this paper are: nlin
16
The categories of this paper are: stat