The nature of kinematic structures in the Galactic disc

Iryna Kushniruk

Research output: ThesisDoctoral Thesis (compilation)

116 Downloads (Pure)


The velocity distribution of stars in the Galactic disc is complex and consists of a vast number of kinematic structures, that is, stars that share similar velocity components. The reasons why some stars move together may be different and are related to dynamical processes connected to the Galaxy, both internal as well as external ones, such as resonances with the Galactic bar or the Galactic spiral arm structure, dissolution of open clusters, or merger events with other galaxies. Therefore, studies of kinematic structures of the Galactic disc may provide information about the formation and evolution history of the Milky Way.

In this thesis we focus on detecting and chemo-dynamical characterisation of kinematic structures of the Galactic disc using the most recent and up-to-date astrometric, spectroscopic, and photometric surveys. In Paper I we studied kinematic structures in the solar neighbourhood with the wavelet transform method. In Paper II and Paper III we studied origin of the Arcturus stream and HR 1614 moving group respectively by studying chemo-dynamical properties of the structures.

The result of Paper I is the detection of old and well-known kinematic groups together with three new velocity structures. The results of Paper II and Paper III show that both the Arcturus and the HR 1614 structures are composed of thin and thick disc stars and are not dissolved open clusters or accreted stellar populations. We conclude that the origin of kinematic structures is complex and might be a combination of several dynamical processes such as resonances and phase mixing.
Original languageEnglish
  • Bensby, Thomas, Supervisor
  • Feltzing, Sofia, Assistant supervisor
ISBN (Print)978-91-7895-482-7
ISBN (electronic) 978-91-7895-483-4
Publication statusPublished - 2020

Bibliographical note

Defence details

Date: 2020-11-06

Time: 09:00

Place: Lundmarksalen, Institutionen för Astronomi och Teoretisk Fysik, Sölvegatan 27. Join via zoom: Webinar ID: 684 6522 1013
Passcode: 279843

External reviewer(s)

Name: Schiavon, Ricardo

Title: Reader in Astrophysics

Affiliation: The Astrophysics Research Institute, at Liverpool John Moores University


Subject classification (UKÄ)

  • Natural Sciences
  • Astronomy, Astrophysics and Cosmology


  • Galaxy : evolution
  • Galaxy: structure
  • Galaxy : kinematics and dynamics


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