The period luminosity relation of Cepheids in the light of Gaia

Abstract. Cepheids are bright variable stars that pulsate radially and have a strong relation between the luminosity and the period of the pulsation. The relation is known as the Period-Luminosity (PL) relation making them useful for extragalactic distance estimations. The goal of this Thesis is to determine the PL/PW relations of Cepheids using the Gaia data, that contains observations of 9575 individual Cepheids. The PL/PW relations are calibrated using the Magellanic Clouds, and the results are consistent with the literature values. The calibrated relations are then used to the Milky Way Cepheids, and distances obtained by the relations are well consistent with the Gaia parallax distances, up to 3000 parsecs