Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Outlying H$\alpha$ emitters in SDSS IV MaNGA   We have carried out a systematic search for outlying H$\alpha$ emitters in
the entire data release 14 of the Sloan Digital Sky Survey (SDSS) IV Mapping
Nearby Galaxies at APO (MaNGA) survey. We have discovered six outlying
H$\alpha$ emitters with no bright underlying optical continuum emission in the
imaging data release 5 from the Dark Energy Camera Legacy Survey (DECaLS) and
data release 6 of the Mayall $z$-band Legacy Survey (MzLS) + Beijing-Arizona
Sky Survey (BASS). They also show a velocity field which is different from that
of the host galaxy. These outlying H$\alpha$ emitters all have extended
structure in the H$\alpha$ image. Their emission line ratios show that they are
photoionised due to an active galactic nucleus (AGN) or a mixture of both an
AGN and star formation. Some of them are very likely to be fainter counterparts
of Hanny's Voorwerp like objects.

36
The categories of this paper are: cmp-lg
2
The categories of this paper are: math
25
The categories of this paper are: patt-sol
30
The categories of this paper are: q-alg
24
The categories of this paper are: dg-ga
5
The categories of this paper are: gr-qc
8
The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con
16
The categories of this paper are: stat
33
The categories of this paper are: plasm-ph
7
The categories of this paper are: hep-th
21
The categories of this paper are: adap-org
0
The categories of this paper are: hep-ph
29
The categories of this paper are: funct-an
19
The categories of this paper are: eess
23
The categories of this paper are: solv-int