Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantitative Spectroscopy of 24 A supergiants in the Sculptor galaxy NGC
  300: Flux weighted gravity luminosity relationship, metallicity and
  metallicity gradient   A quantitative spectral analysis of 24 A supergiants in the Sculptor Group
spiral galaxy NGC 300 at a distance of 1.9 Mpc is presented. A new method is
introduced to analyze low resolution (~5 AE) spectra, which yields
metallicities accurate to 0.2 dex including the uncertainties arising from the
errors in Teff (5%) and log g (0.2 dex). For the first time the stellar
metallicity gradient based on elements such as titanium and iron in a galaxy
beyond the Local Group is investigated. Solar metallicity is measured in the
center and 0.3 solar in the outskirts and a logarithmic gradient of -0.08
dex/kpc. An average reddening of E(B-V)~0.12 mag is obtained, however with a
large variation from 0.07 to 0.24 mag. We also determine stellar radii,
luminosities and masses and discuss the evolutionary status. Finally, the
observed relationship between absolute bolometric magnitudes M_{bol} and flux
weighted gravities g_{F} = g/Teff^4 is investigated. At high temperatures the
strengths of the Balmer lines depends solely on the flux-weighted gravity,
which allows a precise direct determination of log g_{F} with an accuracy of
0.05 to 0.1 dex. We find a tight relationship between M_{bol} and log g_{F} in
agreement with stellar evolution theory. Combining these new results with
previous work on Local Group galaxies we obtain a new flux weighted gravity
luminosity relationship (FGLR), which is very well defined and appears to be an
excellent alternative tool to determine distances to galaxies.

37
The categories of this paper are: supr-con
19
The categories of this paper are: eess
10
The categories of this paper are: q-bio
0
The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph
16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
13
The categories of this paper are: quant-ph
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys
4
The categories of this paper are: cond-mat
5
The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph
18
The categories of this paper are: econ
7
The categories of this paper are: hep-th
28
The categories of this paper are: alg-geom