Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Kinematic Distance of Galactic Planetary Nebulae   We construct \HI~absorption spectra for 18 planetary nebulae (PNe) and their
background sources using the data from the International Galactic Plane Survey.
We estimate the kinematic distances of these PNe, among which 15 objects'
kinematic distances are obtained for the first time. The distance uncertainties
of 13 PNe range from 10% to 50%, which is a significant improvement with
uncertainties of a factor two or three smaller than most of previous distance
measurements. We confirm that PN G030.2-00.1 is not a PN because of its large
distance found here.

15
The categories of this paper are: nucl-ex
3
The categories of this paper are: physics
35
The categories of this paper are: mtrl-th
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio
5
The categories of this paper are: gr-qc
2
The categories of this paper are: math
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph
28
The categories of this paper are: alg-geom
7
The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
37
The categories of this paper are: supr-con
13
The categories of this paper are: quant-ph
4
The categories of this paper are: cond-mat