Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Kinematics and Physical Conditions pf the Ionized Gas in Markarian
  509. II. STIS Echelle Observations   We present observations of the UV absorption lines in the luminous Seyfert 1
galaxy Mrk 509, obtained with the medium resolution (lambda/Delta-lambda ~
40,000) echelle gratings of the Space Telescope Imaging Spectrograph on the
Hubble Space Telescope. The spectra reveal the presence of eight kinematic
components of absorption in Ly-alpha, C IV, and N V, at radial velocities of
-422, -328, -259, -62, -22, +34, +124, and +210 km s^-1 with respect to an
emission-line redshift of z = 0.03440, seven of which were detected in an
earlier Far Ultraviolet Spectrographic Explorer (FUSE) spectrum. The component
at -22 km s^-1 also shows absorption by Si IV. The covering factor and velocity
width of the Si IV lines were lower than those of the higher ionization lines
for this component, which is evidence for two separate absorbers at this
velocity. We have calculated photoionization models to match the UV column
densities in each of these components. Using the predicted O VI column
densities, we were able to match the O VI profiles observed in the FUSE
spectrum. Based on our results, none of the UV absorbers can produce the X-ray
absorption seen in simultaneous Chandra observations; therefore, there must be
more highly ionized gas in the radial velocity ranges covered by the UV
absorbers.

35
The categories of this paper are: mtrl-th
19
The categories of this paper are: eess
2
The categories of this paper are: math
4
The categories of this paper are: cond-mat
0
The categories of this paper are: hep-ph
37
The categories of this paper are: supr-con
36
The categories of this paper are: cmp-lg
16
The categories of this paper are: stat
21
The categories of this paper are: adap-org
22
The categories of this paper are: chao-dyn
11
The categories of this paper are: hep-lat
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
12
The categories of this paper are: nucl-th
31
The categories of this paper are: ao-sci
10
The categories of this paper are: q-bio