Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Does the AGN Continuum Shape Change with Luminosity?   We test the general wisdom that AGN continua vary with larger amplitude at
shorter wavelengths, through a re-analysis of historical data from the optical
and UV (IUE) monitoring campaign on the Seyfert 1 galaxy NCG 5548 by the AGN
Watch Consortium. We assume that the only non-varying component of the optical
continuum is the integrated light from the host galaxy, which does not affect
the UV continuum. Therefore, we expect any curvature in a linear plot of the UV
continuum flux versus the simultaneous optical flux to represent a true change
in the spectral index alpha; the y-intercept provides an estimate of the host
galaxy contribution in the optical region. We measured the continuum fluxes at
1350A (rest frame) from the NEWSIPS-extracted spectra and adopted the optical
continuum determinations of Wanders & Peterson (1996). The data confirm that
the curvature in the F_{lambda}(5100) -- F_{lambda}(1350) plot is real, and
that the spectral index is a function of luminosity. Hence for NGC 5548, the
continuum does get harder as it gets brighter. However, the relationship
between the optical and UV continuum flux is more complicated than the models
we tested would indicate.

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The categories of this paper are: math-ph
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The categories of this paper are: adap-org
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The categories of this paper are: bayes-an
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The categories of this paper are: cmp-lg
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The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc
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The categories of this paper are: q-bio
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The categories of this paper are: funct-an
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The categories of this paper are: plasm-ph
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The categories of this paper are: math
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The categories of this paper are: acc-phys
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The categories of this paper are: patt-sol
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The categories of this paper are: alg-geom
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The categories of this paper are: chao-dyn
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The categories of this paper are: eess
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The categories of this paper are: cond-mat