Study of three distinct populations of stellar clusters in the spiral galaxy M81
Star clusters are considered the fundamental building blocks of the Universe and they provide a unique laboratory for studying the ongoing and past star formation in their host galaxies.In this thesis we report a complete sample of stellar clusters in M81 along with the analysis of their properties....
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2017 |
| País: | México |
| Institución: | Instituto Nacional de Astrofísica, Óptica y Electrónica |
| Repositorio: | Repositorio Institucional del INAOE |
| Idioma: | inglés |
| OAI Identifier: | oai:inaoe.repositorioinstitucional.mx:1009/793 |
| Acceso en línea: | http://inaoe.repositorioinstitucional.mx/jspui/handle/1009/793 |
| Access Level: | acceso abierto |
| Palabra clave: | info:eu-repo/classification/Galaxias individuales (M81)/Galaxies individual (M81) info:eu-repo/classification/Cúmulos de estrellas/Star clusters info:eu-repo/classification/Galaxias espirales/Spiral galaxies info:eu-repo/classification/cti/1 info:eu-repo/classification/cti/21 info:eu-repo/classification/cti/2105 info:eu-repo/classification/cti/220209 |
| Sumario: | Star clusters are considered the fundamental building blocks of the Universe and they provide a unique laboratory for studying the ongoing and past star formation in their host galaxies.In this thesis we report a complete sample of stellar clusters in M81 along with the analysis of their properties. This work was done using high-resolution observations carried out with Hubble Space Telescope/Advanced Camera for Surveys (HST/ACS) images in the filters F435W, F606W and F814W. These images cover the entire optical extent of the galaxy. The sample contains 435 compact star clusters (FWHM < 10 pixels; 9 pc) which include 263 blue clusters and 172 globular clusters. Additionally, we report the detection of 30 low surface brightness and fuzzy stellar clusters, named “faint fuzzy”, for the first time in M81. From the analysis of the blue compact star clusters we found that they are distributed along the spiral arms on M81 and its luminosity function follows a power-law distribution with an index of 2.0, which is the typical value found for young massive compact star clusters in other galaxies. On the other hand, the globular star clusters have photometric masses between 105 and 2x107Mʘ and they are distributed uniformly across the face of M81. We analyze the surface brightness profiles of 128 globular clusters in the B and I bands and fit them with a King model (King, 1962). From these analyses we obtained their structural parameters core radius (rc), half-light radius (rh), concentration parameter (c) and central surface brightness (µ0). The distributions of these parameters in the two bands can be represented by log-normals function with median values rc = [0:6; 0:7] pc, rh = [3:8; 4:2] pc , c = [76; 73] and μ0 = [17:7; 15:5] mag/arcsec2 in the B and I bands, respectively. In general, there is a good correlation between the structural parameter values in both bands. We found that 6 stellar clusters are in their post core-collapse phase and 3 clusters have blue cores, including the brightest cluster in M81, named M81-GC1. Through the comparison of the structural parameters of the globular cluster population in M81 with those in the MilkyWay we found that they have almost the same total number of globular clusters, as well as similar luminosity distribution. |
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