Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Model Atmosphere Analysis of the Weakly Magnetic DZ White Dwarf G165-7   A reanalysis of the strongly metal-blanketed DZ white dwarf G165-7 is
presented. An improved grid of model atmospheres and synthetic spectra is used
to analyze BVRI, JHK, and ugriz photometric observations as well as a high
quality Sloan Digital Sky Survey spectrum covering the energy distribution from
3600 to 9000 A. The detection of splitting in several lines of Ca, Na, and Fe,
suggesting a magnetic field of Bs~650 kG, is confirmed by spectropolarimetric
observations that reveal as much as +/- 7.5% circular polarization in many of
the absorption lines, most notably Na, Mg, and Fe. Our combined photometric and
spectroscopic fit yields Teff = 6440 K, log g=7.99, log H/He=-3.0 and log
Ca/He=-8.1. The other heavy elements have solar ratios with respect to calcium,
with the exception of Na and Cr that had to be reduced by a factor of two and
three, respectively. A crude polarization model based upon the observed local
spectral flux gradient yields a longitudinal field of 165 kG, consistent with
the mean surface field inferred from the Zeeman splitting. The inclusion of
this weak magnetic field in our synthetic spectrum calculations, even in an
approximate fashion, is shown to improve our fit significantly.

31
The categories of this paper are: ao-sci
26
The categories of this paper are: bayes-an
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol
14
The categories of this paper are: math-ph
37
The categories of this paper are: supr-con
15
The categories of this paper are: nucl-ex
33
The categories of this paper are: plasm-ph
34
The categories of this paper are: chem-ph
2
The categories of this paper are: math
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
19
The categories of this paper are: eess
28
The categories of this paper are: alg-geom
13
The categories of this paper are: quant-ph
27
The categories of this paper are: comp-gas