Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: What drives the Balmer extinction sequence in spiral galaxies? Clues
  from the Sloan Digital Sky Survey   Using spectra of normal emission line galaxies from the First Data Release of
the Sloan Digital Sky Survey (SDSS) we have investigated the relations between
the extinction $C({\rm H}\beta)$ as derived from the \Ha/\Hb emission line
ratio and various global parameters of the galaxies. Our main findings are
that: 1) $C({\rm H}\beta)$ is linked with the galaxy spectral type and colour,
decreasing from early- to late-type spirals. 2) $C({\rm H}\beta)$ increases
with increasing metallicity. 3) $C({\rm H}\beta)$ is larger in galaxies with an
older stellar population. 4) $C({\rm H}\beta)$ is larger for more luminous
galaxies. 5) The extinction of the stellar light is correlated with both the
extinction of the nebular light and the intrinsic galaxy colours. We propose
phenomenological interpretations of our empirical results. We have also
cross-correlated our sample of SDSS galaxies with the IRAS data base. Due to
the lower redshift limit imposed to our sample and to the detection limit of
IRAS, such a procedure selected only luminous infrared galaxies. We found that
correlations that were shown by other authors to occur between optical and
infrared properties of galaxies disappear when restricting the sample to
luminous infrared galaxies. We also found that the optical properties of the
luminous infrared galaxies in our SDSS sample are very similar to those of our
entire sample of SDSS galaxies. This may be explained by the IRAS luminosity of
the galaxies originating in the regions that formed massive stars less than 1
Myr ago, while the opacity of galaxies as derived from the \Ha/\Hb emission
line ratio is due to diffuse dust.
  We show some implications of our empirical results on the determination of
global star formation rates and total stellar masses in normal galaxies.

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The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
12
The categories of this paper are: nucl-th
28
The categories of this paper are: alg-geom
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The categories of this paper are: solv-int
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The categories of this paper are: acc-phys
15
The categories of this paper are: nucl-ex
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
24
The categories of this paper are: dg-ga
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
0
The categories of this paper are: hep-ph
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The categories of this paper are: q-fin
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The categories of this paper are: funct-an