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Morphological Parameters of a Spitzer Survey of Stellar Structure in Galaxies

Holwerda, B. W. and Muñoz-Mateos, J.-C. and Comerón, S. and Meidt, S. and Sheth, K. and Laine, S. and Hinz, J. L. and Regan, M. W. and Gil de Paz, A. and Menéndez-Delmestre, K. and Seibert, M. and Kim, T. and Mizusawa, T. and Laurikainen, E. and Salo, H. and Laine, J. and Gadotti, D. A. and Zaritsky, D. and Erroz-Ferrer, S. and Ho, L. C. and Knapen, J. H. and Athanassoula, E. and Bosma, A. and Pirzkal, N. (2014) Morphological Parameters of a Spitzer Survey of Stellar Structure in Galaxies. Astrophysical Journal, 781 (1). Art. No. 12. ISSN 0004-637X.

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The morphology of galaxies can be quantified to some degree using a set of scale-invariant parameters. Concentration (C), asymmetry (A), smoothness (S), the Gini index (G), the relative contribution of the brightest pixels to the second-order moment of the flux (M_(20)), ellipticity (E), and the Gini index of the second-order moment (G_M) have all been applied to morphologically classify galaxies at various wavelengths. Here, we present a catalog of these parameters for the Spitzer Survey of stellar structure in Galaxies, a volume-limited, near-infrared (NIR) imaging survey of nearby galaxies using the 3.6 and 4.5 μm channels of the Infrared Array Camera on board the Spitzer Space Telescope. Our goal is to provide a reference catalog of NIR quantified morphology for high-redshift studies and galaxy evolution models with enough detail to resolve stellar mass morphology. We explore where normal, non-interacting galaxies—those typically found on the Hubble tuning fork—lie in this parameter space and show that there is a tight relation between concentration (C_(82)) and M_(20) for normal galaxies. M_(20) can be used to classify galaxies into earlier and later types (i.e., to separate spirals from irregulars). Several criteria using these parameters exist to select systems with a disturbed morphology, i.e., those that appear to be undergoing a tidal interaction. We examine the applicability of these criteria to Spitzer NIR imaging. We find that four relations, based on the parameters A and S, G and M_(20), G_M, C, and M_(20), respectively, select outliers in morphological parameter space, but each selects different subsets of galaxies. Two criteria (G_M > 0.6, G > –0.115 × M_(20) + 0.384) seem most appropriate to identify possible mergers and the merger fraction in NIR surveys. We find no strong relation between lopsidedness and most of these morphological parameters, except for a weak dependence of lopsidedness on concentration and M_(20).

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Holwerda, B. W.0000-0002-4884-6756
Meidt, S.0000-0002-6118-4048
Sheth, K.0000-0002-5496-4118
Laine, S.0000-0003-1250-8314
Gil de Paz, A.0000-0001-6150-2854
Menéndez-Delmestre, K.0000-0003-3153-5123
Seibert, M.0000-0002-1143-5515
Mizusawa, T.0000-0001-7182-5307
Zaritsky, D.0000-0002-5177-727X
Ho, L. C.0000-0001-6947-5846
Pirzkal, N.0000-0003-3382-5941
Alternate Title:Morphological Parameters of Spitzer Survey of Stellar Structure in Galaxies (S4G)
Additional Information:© 2014 American Astronomical Society. Received 2013 January 31; accepted 2013 September 5; published 2013 December 30. We thank the entire S4G team for their efforts on this project and the anonymous referee for his or her insightful comments that improved the manuscript. The lead author thanks the European Space Agency for the support of the Research Fellowship program. This work was co-funded under the Marie Curie Actions of the European Commission (FP7-COFUND). We acknowledge financial support to the DAGAL network from the People Programme (Marie Curie Actions) of the European Union’s Seventh Framework Programme FP7/2007-2013/ under REA grant agreement number PITN-GA-2011-289313. E.A. and A.B. acknowledge the Centre National d’Etudes Spatiales (CNES, France) for financial support. They also acknowledge support from the FP7 Marie Curie Actions of the European Commission, via the Initial Training Network DAGAL under REA grant agreement 289313. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. This research 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. This research has made use of NASA’s Astrophysics Data System. We acknowledge the usage of the HyperLEDA database (; Paturel et al. 2003).
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
European Space Agency (ESA)UNSPECIFIED
Marie Curie FellowshipPITN-GA-2011-289313
Centre National d'Études Spatiales (CNES)UNSPECIFIED
Subject Keywords:galaxies: elliptical and lenticular, cD; galaxies: general; galaxies: irregular; galaxies: spiral; galaxies: statistics; galaxies: stellar content; galaxies: structure
Issue or Number:1
Record Number:CaltechAUTHORS:20140211-114726941
Persistent URL:
Official Citation:Morphological Parameters of a Spitzer Survey of Stellar Structure in Galaxies B. W. Holwerda et al. 2014 ApJ 781 12
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:43779
Deposited By: Ruth Sustaita
Deposited On:11 Feb 2014 21:08
Last Modified:09 Mar 2020 13:18

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