The distribution of mass with spiral galaxies. Unique solutions from gas and stellar kinematics
PhD ceremony: Mr. T.P.K. Martinsson, 16.15 uur, Aula Academiegebouw, Broerstraat 5, Groningen
Dissertation: The distribution of mass with spiral galaxies. Unique solutions from gas and stellar kinematics
Promotor(s): prof. M.A.W. Verheijen
Faculty: Mathematics and Natural Sciences
This thesis investigates the amount and distribution of dynamically distinct components such as stars, gas, and dark matter, in thirty spiral galaxies similar to our own Milky Way, with direct implications for our general understanding of the formation and evolution of galaxies. With optical and radio spectroscopy, I have measured the total dynamical mass of each galaxy based on the rotation speed of the disk. The total mass of a galaxy's disk component follows from the measured random motions of the stars while the masses of the atomic and molecular gas disks follow directly from their emission in the infrared and radio regions of the electromagnetic spectrum. The mass and distribution of the dark matter is then calculated by considering the difference between the total dynamical mass and the mass of the visible components. Contrary to what is commonly assumed, I have found that dark matter is an important and often dominant mass component even in the most luminous, central regions of spiral galaxies. On average, the visible components of spiral galaxies contribute approximately 30 percent to the total mass within a radius comparable to that of the orbit of the Sun in our Milky Way galaxy; the remaining 70 percent of the mass is dark. This implies that the luminous mass of disk galaxies is approximately three times lower than commonly assumed.
Last modified: | 13 March 2020 01.09 a.m. |
More news
-
01 April 2025
NSC’s electoral reform plan may have unwanted consequences
The new voting system, proposed by minister Uitermark, could jeopardize the fundamental principle of proportional representation, says Davide Grossi, Professor of Collective Decision Making and Computation at the University of Groningen
-
01 April 2025
‘AiNed’ National Growth Fund grant for speeding adoption of AI at SMEs
Professor Ming Cao receives an ‘AiNed’ Growth Fund grant of EUR 2.4 million for research that will contribute to faster adoption of AI at SMEs in the technical industry in the Netherlands.
-
01 April 2025
'Diversity leads to better science'
In addition to her biological research on ageing, Hannah Dugdale also studies disparities relating to diversity in science. Thanks to the latter, she is one of the two 2024 laureates of the Athena Award, an NWO prize for successful and inspiring...