Red giant stars as standard candles
department or school: Science, Faculty of
department or school: Physics and Astronomy, Department of
data provider: DSpace
degree campus: UBCV
creator: Parada Torres, Javiera Fernanda
issued: 2022-07-29T18:42:04Z
issued: 2022
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: This thesis introduces two new extragalactic distance determination methods; the first uses the median magnitude of carbon-rich asymptotic giant branch stars (CS), while the second uses the combined luminosity function of the red-giant branch (RGB) and oxygen-rich asymptotic giant branch stars (AGB). The sample of CS and RGB+AGB stars are selected from near-infrared JHKs-bands colour-magnitude diagrams (CMD), as in these filters RGs are bright and easy to identify. Both methods use the Magellanic Clouds (MC) as the fundamental calibrators and are tested in four Magellanic type galaxies: NGC 6822, IC 1613, WLM and NGC 3109, these target galaxies are all members of the Local Group. For the CS method, the CS J-band luminosity function is fitted using a Lorentzian distribution modified to allow the distribution to be asymmetric. The parameters of the best-fit distribution are then used to determine if the CS luminosity function of a given galaxy resembles that of the Large or Small MC (LMC or SMC). Based on this resemblance, either the LMC or SMC is used as the calibrator and the distance to the given galaxy is estimated using the median J-magnitude of the CS samples. The second method uses an un-binned maximum likelihood estimator to find the distance modulus that minimizes the difference between the luminosity function of the RGB+AGB stars in a target galaxy and the model distribution given by the luminosity function of the RGB+AGB stars in the MC. The model luminosity function can be given by the LMC and SMC individually or as a linear combination (LC) of both. The LC includes a "shape'' parameter that quantifies how "LMC-'' or "SMC-like'' a target galaxy is. Except for the NGC 3109 Ks luminosity function, the LC "shape'' results agree with the CS "LMC/SMC-like'' classification. Estimations of the distances through the tip of the RGB method are also included to test the performance and compare the results when the three different methods are applied to the same data …
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/82226
note: Red giant stars as standard candlesbyJaviera Fernanda Parada TorresBSc., Universidad de Concepcion, 2012MSc., University of British Columbia, 2016a thesis submitted in partial fulfillmentof the requirements for the degree ofDoctor of Philosophyinthe faculty of graduate and postdoctoral studies(Astronomy)The University of British Columbia(Vancouver)July 2022© Javiera Fernanda Parada Torres, 2022The following individuals certify that they have read, and recommend to the Facultyof Graduate and Postdoctoral Studies for acceptance, the thesis entitled:Red giant stars as standard candlessubmitted by Javiera Fernanda Parada Torres in partial fulfillment of the re-quirements for the degree of Doctor of Philosophy in Astronomy.Examining Committee:Harvey Richer, Professor, Physics & Astronomy, University of British ColumbiaSupervisorJeremy Heyl, Professor, Physics & Astronomy, University of British ColumbiaCo-supervisorPaul Hickson, Professor, Physics & Astronomy, University of British ColumbiaUniversity ExaminerGrenfell Patey, Professor, Chemistry University of British ColumbiaUniversity ExaminerWendy Freedman, Professor, Astronomy & Astrophysics, University of ChicagoExternal ExaminerAdditional Supervisory Committee Members:Ingrid Stairs, Professor, Physics & Astronomy, University of British ColumbiaSupervisory Committee MemberChris Waltham, Professor, Physics & Astronomy, University of British ColumbiaSupervisory Committee MemberiiAbstractThis thesis introduces two new extragalactic distance determination methods; thefirst uses the median magnitude of carbon-rich asymptotic giant branch stars (CS),while the second uses the combined luminosity function of the red-giant branch(RGB) and oxygen-rich asymptotic giant branch stars (AGB). The sample of CS andRGB+AGB stars are selected from near-infrared 𝐽𝐻𝐾𝑠-bands colour-magnitudediagrams (CMD), as in these filters RGs are bright and easy to identify. Bothmethods use the Magellanic Clouds (MC) as the fundamental calibrators and a…
has type: Thesis/Dissertation
date issued: 2022-11
is shown at: 10.14288/1.0416480
language: eng
degree discipline: Astronomy
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: Richer, Harvey Brian, 1944-
contributor: Heyl, Jeremy
type: Text
identifier URI: http://hdl.handle.net/2429/82226