Grand design and flocculent spirals in the Spitzer survey of stellar structure in glaxies (S^4G)



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Gil de Paz, Armando and otros, ... (2011) Grand design and flocculent spirals in the Spitzer survey of stellar structure in glaxies (S^4G). Astrophysical journal, 737 (1). ISSN 0004-637X

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Spiral arm properties of 46 galaxies in the Spitzer Survey of Stellar Structure in Galaxies (S^4G) were measured at 3.6μm, where extinction is small and the old stars dominate. The sample includes flocculent, multiple arm, and grand design types with a wide range of Hubble and bar types. We find that most optically flocculent galaxies are also flocculent in the mid-IR because of star formation uncorrelated with stellar density waves, whereas multiple arm and grand design galaxies have underlying stellar waves. Arm–interarm contrasts increase from flocculent to multiple arm to grand design galaxies and with later Hubble types. Structure can be traced further out in the disk than in previous surveys. Some spirals peak at mid-radius while others continuously rise or fall, depending on Hubble and bar type. We find evidence for regular and symmetric modulations of the arm strength in NGC 4321. Bars tend to be long, high amplitude, and flat-profiled in early-type spirals, with arm contrasts that decrease with radius beyond the end of the bar, and they tend to be short, low amplitude, and exponential-profiled in late Hubble types, with arm contrasts that are constant or increase with radius. Longer bars tend to have larger amplitudes and stronger arms.

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© 2011. The American Astronomical Society. All rights reserved. Artículo firmado por 29 autores. We are grateful to the dedicated staff at the Spitzer Science Center for their help and support in planning and execution of this Exploration Science program. We also gratefully acknowledge support from NASA JPL/Spitzer grant RSA1374189 provided for the S^(4)G project. D. M. E. gratefully acknowledges Vassar College for student support for Andrew Yau, and thanks NASA/JPL/Caltech for grant 1368024. E. A. and A. B. thank the Centre National d'Etudes Spatiales for financial support. This research is based in part on archival data obtained with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA, and has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. D. M. E. thanks Fred Chromey for writing the script to transform images into polar coordinates. We thank the referee for helpful comments on statistics.

Uncontrolled Keywords:Infrared surface photometry; Dust-penetrated classification; Barred galaxies; Star-formation; Density waves; Disk galaxies; Band observations; Pattern speeds; Gravitational torques; Driving mechanisms
Subjects:Sciences > Physics > Astrophysics
Sciences > Physics > Astronomy
ID Code:35443
Deposited On:01 Feb 2016 15:50
Last Modified:10 Dec 2018 15:05

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