Characterization of the variability of Young Stellar sources in Star-forming regions across the Galaxy

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dc.contributor.advisorSupervisor: Borissova, Jura
dc.contributor.advisorInternal reviewer: Bayo, Amelia
dc.contributor.advisorExternal reviewer: Lucas, Phil
dc.contributor.advisorExternal reviewer: Minniti, Dante
dc.contributor.authorMedina Peña, Nicolás
dc.coverage.spatialValparaíso
dc.date.accessioned2025-03-28T14:16:26Z
dc.date.available2025-03-28T14:16:26Z
dc.date.issued2022
dc.description.abstractThis thesis presents observational and statistical study of the irregular variable stars in four star-forming regions of our galaxy, namely: IC 2944/2948 (SFR1); G305 (SFR2); NGC 6357/NGC 6334 (SFR3), and the Lagoon nebula complex (SFR4). Based on the VISTA Variables in the Vía Láctea (VVV) ESO large survey we aim to unveil and characterize the Young Stellar Object (YSOs) population by analyzing the Ks-band variability. An automated process was developed to generate and analyze more than 24 million unevenly sampled time series over five years between 2010 and 2015, projected on ∼20 deg2 area. We analyzed and tested several variability indices (features) and concluded that the total amplitude ∆Ks and the η index can be used as principal variability indicators for this type of variability. Our simulations also show that to select reliable variable star candidates with low content of contaminant sources, such as saturated objects or bogus the thresholds of the amplitudes ∆Ks > 0.6 mag and η values < 0.95 (except for a variable source inside the SFR1 with η = 3.2) is necessary. Our final catalog contains 1096 high-amplitude irregular variable stars distributed along the bulge and the south-plane of the galaxy. The 524 of them present photometric measurements in J- and H-bands allowing us to construct the color-color diagram and quantify their status. More than 58% show intrinsic reddening, thus their variability can be connected to the early stages of the YSOs (stages I-II). The spatial location of classified variables correlates with star-formation features in both visible and infrared bands. Overdensities of the sample are distributed over HII regions, IRDCs, and their surroundings. We identified more than 3000 periodic stars inside the VVV time series as a byproduct.
dc.facultadFacultad de Ciencias
dc.identifier.urihttps://repositoriobibliotecas.uv.cl/handle/uvscl/15609
dc.language.isoen
dc.publisherUniversidad de Valparaíso
dc.rights.urihttp://creativecommons.org/licenses/by-nc-sa/3.0/cl/
dc.titleCharacterization of the variability of Young Stellar sources in Star-forming regions across the Galaxy
dc.typeTDOC
uv.catalogadorPJR CIEN
uv.colectionTesis
uv.departamentoFacultad de Ciencias. Instituto de Física y Astronomía
uv.notageneralDoctorado en Astrofísica. Universidad de Valparaíso. 2022.

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