Detalles de publicación
PP 013064
Morphological Parameters of Spitzer Survey of Stellar Structure in Galaxies (S4G)
(1) European Space Agency Research Fellow (ESTEC), Ke- plerlaan 1, 2200 AG Noordwijk, The Netherlands
(2) National Radio Astronomfy Observatory/NAASC, 520 Edgemont Road, Charlottesville, VA 22903, USA
(3) Astronomy Division, Department of Physical Sciences, FIN- 90014 University of Oulu, P.O. Box 3000, Oulu, Finland
(4) Max-Planck-Institut fu ̈r Astronomie / K ̈onigstu ̈hl 17 D- 69117, Heidelberg, Germany
(5) Spitzer Science Center, 1200 East California Boulevard, Pasadena, CA 91125, USA
(6) Spitzer Science Center, Mail Stop 220-6, 1200 East Califor- nia Boulevard, Pasadena, CA 91125, USA
(7) Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721, USA
(8) Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
(9) Departamento de Astrof ́ısica, Universidad Complutense de Madrid, 28040 Madrid, Spain
(10) The Observatories of the Carnegie Institution of Washing- ton, 813 Santa Barbara Street, Pasadena, CA 91101, USA
(11) Astronomy Program, Department of Physics and Astron- omy, Seoul National University, Seoul 151-742, Republic of Ko- rea
(12) Finnish Centre of Astronomy with ESO (FINCA), Univer- sity of Turku, Vislntie 20, FI-21500, Piikki, Finland
(13) European Southern Observatory, Casilla 19001, Santiago 19, Chile
(14) Instituto de Astrof ́ısica de Canarias, V ́ıa La ́ctea s/n 38205 La Laguna, Spain
(15) Departamento de Astrof ́ısica, Universidad de La Laguna, Avda. Astrof ́ısico Francisco S ́anchez s/n 38206 La Laguna, Spain
(16) Aix Marseille Universit ́e, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, 13388, Marseille, France
The morphology of galaxies can be quantified to some degree using a set of scale-invariant parame- ters. Concentration (C), Asymmetry (A), Smoothness (S), the Gini index (G), relative contribution of the brightest pixels to the second order moment of the flux (M20), ellipticity (E), and the Gini index of the second order moment (GM ) 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 (S4G), a volume-limited near-infrared imaging survey of nearby galaxies using the 3.6 and 4.5 μm channels of the IRAC camera onboard Spitzer Space Telescope. Our goal is to provide a reference catalog of near-infrared 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 (C82) and M20 for normal galaxies. M20 can be used to classify galaxies into earlier and later types (e.g., to separate spirals from irregu- lars). 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 near-infrared imaging. We find that four relations, based on the parameters A and S, G and M20, GM, and C and M20, respectively, select outliers in the morphological parameter space, but each selects different subsets of galaxies. Two criteria (GM > 0.6, G > −0.115 × M20 + 0.384) seem most appropriate to identify possible mergers and the merger fraction in near-infrared surveys. We find no strong relation between lopsidedness and most of these morphological parameters, except for a weak dependence of lopsidedness on Concentration and M20.