uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
A study of possible chemical inhomogeneities of dwarf irregular galaxies and the influence on the Z-L relationship
Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics, The Uppsala Astronomical Observatory.
1999 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

A study on the chemical abundances of dwarf irregular galaxies (dI's) is presented in this work. This type of galaxies have typically low metallicity. First of all, a definition of dI is proposed, in order to obtain a homogeneous group of targets.

Due to the small size of the dI galaxies and the absence of strong dynamical processes a homogeneous chemical composition is normally assumed. The main argument is that the gas in the interstellar medium of the galaxies are probably not too much affected by internal dynamics and could therefore be well mixed. This hypothesis has been investigated. Optical spectra for various star-forming regions (HII regions) in five dI's have been obtained and analysed. For all the HII regions, the chemical abundances of the whole region have been determined. Spectra of four of these HII regions are of very high quality which allow an additional study of possible variations of the chemical abundances within the regions. It could be concluded that the existence of variations in the chemical abundances, especially at large scales, may depend on thephysical properties of the galaxy and its environment.

Another important aspect to study is the behaviour of the dI galaxies in the metallicity-luminosity plane. A deep study of previous relationships for this kind of objects were performed as well as the possible sources of dispersion from this relationship. With the results on the chemical abundances of eight galaxies and the latest distance determinations a new, weak, relationship between the metallicity and the luminosity was derived. The influence of the environment and other physical properties of the galaxies have also been studied.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis , 1999. , 26 p.
Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1104-232X ; 461
Keyword [en]
Astronomy, dwarf irregular galaxies, chemical abundances, metallicity-luminosity relationship, individual galaxies: NGC 6822, IC 4662, IC 10, ESO 245-G05, NGC 1569, IC 5152, DDO 53 and DDO 190
Keyword [sv]
National Category
Astronomy, Astrophysics and Cosmology
Research subject
URN: urn:nbn:se:uu:diva-342ISBN: 91-554-4492-XOAI: oai:DiVA.org:uu-342DiVA: diva2:162735
Public defence
1999-06-05, Lecture hall at the Uppsala Astronomical Observatory, Uppsala University, Uppsala, 10:30
Available from: 1999-05-15 Created: 1999-05-15Bibliographically approved

Open Access in DiVA

No full text
Buy this publication >>

By organisation
The Uppsala Astronomical Observatory
Astronomy, Astrophysics and Cosmology

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 39 hits
ReferencesLink to record
Permanent link

Direct link