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Kinematic lopsidedness in the dwarf irregular galaxy WLM

Published online by Cambridge University Press:  30 October 2025

M. Khademi*
Affiliation:
School of Astronomy, Institute for Research in Fundamental Sciences (IPM), 19395-5531 Tehran, Iran GEPI, Observatoire de Paris, Universite PSL, CNRS, Place Jules Janssen 92195, Meudon, France Department of Physics, Shahid Beheshti University, 19839 Tehran, Iran
Y. Yang
Affiliation:
GEPI, Observatoire de Paris, Universite PSL, CNRS, Place Jules Janssen 92195, Meudon, France
F. Hammer
Affiliation:
GEPI, Observatoire de Paris, Universite PSL, CNRS, Place Jules Janssen 92195, Meudon, France
S. Nasiri
Affiliation:
Department of Physics, Shahid Beheshti University, 19839 Tehran, Iran

Abstract

To investigate whether an m = 1 perturbation in the halo potential could be a mechanism creating observed kinematical asymmetry in the rotation curve of the dwarf irregular galaxy WLM, we fit a theoretical rotational velocity associated with such a perturbation in the halo potential model to the observed data. We show that a lopsided halo potential model can explain the asymmetry in the kinematic data reasonably well. To investigate how well such a small perturbation in the halo potential represents the observed asymmetries in the rotation curve and in the velocity field of WLM, we measure the value of the perturbation parameter Ɛper from the kinematic data on the rotation curve of both sides in the outer part. We obtain the value of the perturbation parameter denoting the perturbed halo potential of about 0.2.

Information

Type
Poster Paper
Copyright
© The Author(s), 2025. Published by Cambridge University Press on behalf of International Astronomical Union

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