University of Oulu

Fuentes-Carrera, I., Rosado, M., Amram, P., Laurikainen, E., Salo, H., Gómez-López, J., Castañeda, H., Bernal, A., Balkowski, C. (2018) Kinematics and dynamics of the luminous infrared galaxy pair NGC 5257/58 (Arp 240). Astronomy and Astrophysics, 621, A25.

Kinematics and dynamics of the luminous infrared galaxy pair NGC 5257/58 (Arp 240)

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Author: Fuentes-Carrera, I.1; Rosado, M.2; Amram, P.3;
Organizations: 1Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional (ESFM-IPN), U.P. Adolfo López Mateos, edificio 9, Zacatenco, 07730 Mexico City, Mexico
2Instituto de Astronomía, Universidad Nacional Autónoma de México (UNAM), Apdo. Postal 70-264, 04510 Mexico City, Mexico
3Aix-Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille), 13388 Marseille, France
4Department of Physical Sciences, Division of Astronomy, University of Oulu, 90570 Oulu, Finland
5GEPI, Observatoire de Paris, CNRS, Université Paris Diderot, 5 Place Jules Janssen, 92190 Meudon, France
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.2 MB)
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Language: English
Published: EDP Sciences, 2019
Publish Date: 2019-02-22


Context: Encounters between galaxies modify their morphology, kinematics, and star formation history. The relation between these changes and external perturbations is not straightforward. The great number of parameters involved requires both the study of large samples and individual encounters where particular features, motions, and perturbations can be traced and analysed in detail.

Aims: We analysed the morphology, kinematics, and dynamics of two luminous infrared spiral galaxies of almost equal mass, NGC 5257 and NGC 5258, in which star formation is mostly confined to the spiral arms, in order to understand interactions between galaxies of equivalent masses and star-forming processes during the encounter.

Methods: Using scanning Fabry–Perot interferometry, we studied the contribution of circular and non-circular motions and the response of the ionized gas to external perturbations. We compared the kinematics with direct images and traced the star-forming processes and gravitational effects due to the presence of the other galaxy. The spectral energy distribution of each member of the pair was fitted. A mass model was fitted to the rotation curve of each galaxy.

Results: Large, non-circular motions detected in both galaxies are associated with a bar, spiral arms, and HII regions for the inner parts of the galaxies, and with the tidal interaction for the outer parts of the discs. Bifurcations in the rotation curves indicate that the galaxies have recently undergone pericentric passage. The pattern speed of a perturbation of one of the galaxies is computed. Location of a possible corotation seems to indicate that the gravitational response of the ionized gas in the outer parts of the disc is related to the regions where ongoing star formation is confined. The spectral energy distribution fit indicates slightly different star formation history for each member of the pair. For both galaxies, a pseudo-isothermal halo better fits the global mass distribution.

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Series: Astronomy and astrophysics
ISSN: 0004-6361
ISSN-E: 1432-0746
ISSN-L: 0004-6361
Volume: 621
Article number: A25
DOI: 10.1051/0004-6361/201834159
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Copyright information: © ESO 2018.