THE UNUSUAL VERTICAL MASS DISTRIBUTION OF NGC 4013 SEEN THROUGH THE SPITZER SURVEY OF STELLAR STRUCTURE IN GALAXIES (S{sup 4}G)

Journal Article · Sat Sep 10 00:00:00 EDT 2011 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/738/2/L17· OSTI ID:21562437

Comeron, Sebastien ^[1]; Elmegreen, Bruce G ^[2]; Knapen, Johan H ^[3]; Sheth, Kartik; Munoz-Mateos, Juan-Carlos; Kim, Taehyun; Mizusawa, Trisha ^[4]; Hinz, Joannah L ^[5]; Regan, Michael W ^[6]; Gil de Paz, Armando ^[7]; Menendez-Delmestre, KarIn; Seibert, Mark; Ho, Luis C ^[8]; Laurikainen, Eija; Salo, Heikki; Laine, Jarkko ^[9]; Athanassoula, E; Bosma, Albert ^[10]; Buta, Ronald J ^[11]; Gadotti, Dimitri A ^[12]

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1. Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong-gu, Daejeon 305-348 (Korea, Republic of)
2. IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY 10598 (United States)
3. Instituto de Astrofisica de Canarias, E-38200 La Laguna (Spain)
4. National Radio Astronomy Observatory/NAASC, 520 Edgemont Road, Charlottesville, VA 22903 (United States)
5. Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
6. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
7. Departamento de Astrofisica, Universidad Complutense de Madrid, 28040 Madrid (Spain)
8. The Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
9. Astronomy Division, Department of Physical Sciences, University of Oulu, P.O. Box 3000, FIN-90014 Oulu (Finland)
10. Laboratoire d'Astrophysique de Marseille (LAM), UMR6110, Universite de Provence/CNRS, Technopole de Marseille Etoile, 38 rue Frederic Joliot Curie, 13388 Marseille Cedex 20 (France)
11. Department of Physics and Astronomy, University of Alabama, Box 870324, Tuscaloosa, AL 35487 (United States)
12. European Southern Observatory, Casilla 19001, Santiago 19 (Chile)

NGC 4013 is a nearby Sb edge-on galaxy known for its 'prodigious' H I warp and its 'giant' tidal stream. Previous work on this unusual object shows that it cannot be fitted satisfactorily by a canonical thin+thick disk structure. We have produced a new decomposition of NGC 4013, considering three stellar flattened components (thin+thick disk plus an extra and more extended component) and one gaseous disk. All four components are considered to be gravitationally coupled and isothermal. To do so, we have used the 3.6 {mu}m images from the Spitzer Survey of Stellar Structure in Galaxies. We find evidence for NGC 4013 indeed having a thin and a thick disk and an extra flattened component. This smooth and extended component (scale height z{sub EC} {approx} 3 kpc) could be interpreted as a thick disk or as a squashed ellipsoidal halo and contains {approx}20% of the total mass of all three stellar components. We argue it is unlikely to be related to the ongoing merger or due to the off-plane stars from a warp in the other two disk components. Instead, we favor a scenario in which the thick disk and the extended component were formed in a two-stage process, in which an initially thick disk has been dynamically heated by a merger soon enough in the galaxy history to have a new thick disk formed within it.

• OSTI ID: 21562437
• Journal Information: Astrophysical Journal Letters, Vol. 738, Issue 2; Other Information: DOI: 10.1088/2041-8205/738/2/L17; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
DECOMPOSITION
GALAXIES
MASS
MASS DISTRIBUTION
PHOTOMETRY
STARS
CHEMICAL REACTIONS
DISTRIBUTION
SPATIAL DISTRIBUTION