Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The HII Regions of the Damped Lyman alpha Absorber SBS 1543+593   We report new imaging and spectroscopic observations of the damped Ly alpha
(DLA) galaxy SBS 1543+593, a nearby dwarf galaxy whose stellar disk is
intersected by the sightline to the bright background QSO HS 1543+5921. Hubble
Space Telescope imaging observations with WFPC2 in the F450W and F702W bands
are used to measure the DLA galaxy's properties and compile a catalog of its
(candidate) HII regions. Ground-based long-slit spectroscopy of the brightest
HII region in the galaxy yields estimates of the star formation rate (SFR) and
of chemical abundances in the galaxy's interstellar medium. We find that SBS
1543+593 exhibits a SFR $\approx 0.006 h^{-2}_{70} M_{\odot}$ yr$^{-1}$, or a
SFR per unit area of $\approx 1.4 \times 10^{-4} h^{-2}_{70} M_\odot$ yr$^{-1}$
kpc$^{-2}$. We derive gas-phase abundances in the ionized gas of $12 + \log
{\rm (O/H)} = 8.2 \pm 0.2$, which is about 1/3 of the solar value, and $\log
{\rm (N/O)} = -1.40^{+0.2}_{-0.3}$. These values are consistent with the
morphologial appearance of SBS 1543+593, an Sm dwarf of $M_B -5 \log h_{70} =
-16.8\pm0.2$ and of intermediate surface brightness. SBS 1543+593 is the first
{\it bona fide} DLA for which abundances have been measured using emission-line
diagnostics. When compared with future, high-resolution, ultraviolet
spectroscopy, our results should prove key for interpreting abundance
determinations in high redshift DLAs.

31
The categories of this paper are: ao-sci
3
The categories of this paper are: physics
32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int
2
The categories of this paper are: math
8
The categories of this paper are: hep-ex
29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc
21
The categories of this paper are: adap-org
11
The categories of this paper are: hep-lat
36
The categories of this paper are: cmp-lg
15
The categories of this paper are: nucl-ex
1
The categories of this paper are: cs
18
The categories of this paper are: econ