Bibcode
Buta, R. J.; Laurikainen, E.; Salo, H.; Block, D. L.; Knapen, J. H.
Bibliographical reference
American Astronomical Society Meeting 207, #188.01; Bulletin of the American Astronomical Society, Vol. 37, p.1481
Advertised on:
12
2005
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Description
The Near-Infrared S0 Survey (NIRS0S; Laurikainen, Salo, and Buta 2005,
MNRAS, 362, 1319) is an attempt to obtain a statistically well-defined
database of images of S0s from which the properties of S0 bars may be
fairly compared to those of spirals. The main goal of the survey is to
provide information on the the distribution of bar strengths in S0
galaxies, derived using a recently developed gravitational torque
indicator (Buta and Block 2001, ApJ, 550, 243; Laurikainen et al. 2004,
MNRAS, 355, 1251). S0 bars, and their strengths, have not been studied
in much detail before, even though these bars contain important
`fossilized' information about the evolutionary history of S0 galaxies,
particularly about the evolutionary connection, if any, between spirals
and S0s. Previous studies have focussed more on basic properties of S0s,
such as thick and thin disks, bulge-to-disk ratios, luminosities, star
formation history, gas content, and environment.
The Ohio State University Bright Galaxy Survey (Eskridge et al. 2002,
ApJS, 143, 73) provides a valuable dataset for studying the properties
of spiral galaxies, and has been used to show that the distribution of
bar strengths in spirals is an approximately exponentially declining
function of bar strength (Buta et al. 2005, AJ, 130, 506). The questions
we ask are: (1) how strong do S0 bars get compared to spiral bars? (2)
how does the distribution of bar strengths in S0 galaxies compare with
that for spirals? and (3) what characterizes the morphology of bars in
S0 galaxies?
In this paper, we describe the rationale for the survey, its status, and
present results of 2D bulge/disk/bar decompositions and of detailed
analysis of the relative Fourier intensity amplitudes that characterize
early-type galaxy bars. Our main findings are that, when bars are fitted
simultaneously with bulges and disks, bulge-to-total luminosity ratios
of S0s at 2.2 μ m come out much less (0.24 vs. 0.6) than previously
thought, and that relative Fourier intensity profiles, Im/I_o
(m=integer) versus radius, of bars may be described by one or more
gaussian components. We also confirm the approximate validity of the
symmetry assumption of Im/I_0 profiles when used in
bar-spiral separation analyses (Buta, Block, and Knapen 2003, AJ, 126,
1148).
This work was supported by NSF Grants AST-0205143 and AST-0507140 to the
University of Alabama. Funding for the OSU Bright Galaxy Survey was
provided by NSF grants AST-9217716 and AST-9617006, with additional
funding from the Ohio State University.