Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Stellar Population and Kinematic Profiles in Spiral Bulges & Disks:
  Population Synthesis of Integrated Spectra   We present a detailed study of the stellar populations (SPs) and kinematics
of the bulge and inner disk regions of eight nearby spiral galaxies (Sa-Sd)
based on deep Gemini/GMOS data. The long-slit spectra extend to 1-2 disk scale
lengths with S/N/Ang>=50. Several different model fitting techniques involving
absorption-line indices and full spectrum fitting are explored and found to
weigh age, metallicity, and abundance ratios differently. The SPs of spiral
galaxies are not well matched by single episodes of star formation;
representative SPs must involve average SP values integrated over the star
formation history (SFH) of the galaxy. Our "full population synthesis" method
is an optimised linear combination of model templates to the full spectrum with
masking of regions poorly represented by the models. Our spiral bulges follow
the same correlations of increasing light-weighted age and metallicity with
central velocity dispersion as those of elliptical galaxies and early-type
bulges found in other studies, but when SFHs more complex and realistic than a
single burst are invoked, the trend with age is shallower and the scatter much
reduced. In a mass-weighted context, all bulges are predominantly composed of
old and metal-rich SPs. Bulge formation appears to dominated by early processes
that are common to all spheroids, whether they currently reside in disks or
not. While monolithic collapse cannot be ruled out in some cases, merging must
be invoked to explain the SP gradients in most bulges. Further bulge growth via
secular processes or "rejuvenated" star formation generally contributes
minimally to the stellar mass budget. (Abridged)

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The categories of this paper are: ao-sci
2
The categories of this paper are: math
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The categories of this paper are: bayes-an
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The categories of this paper are: solv-int
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The categories of this paper are: chao-dyn
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The categories of this paper are: chem-ph
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The categories of this paper are: patt-sol
1
The categories of this paper are: cs
9
The categories of this paper are: nlin
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The categories of this paper are: cmp-lg
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The categories of this paper are: supr-con
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The categories of this paper are: nucl-ex
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The categories of this paper are: math-ph
3
The categories of this paper are: physics
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The categories of this paper are: nucl-th
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The categories of this paper are: econ