Gravitational Microlensing in the Milky Way with the Hubble Space Telescope and OGLE-III

Gravitational lensing is a powerful tool for astronomers to study the Universe. It occurs on both cosmological and local (Galactic) scales. This thesis focuses on observational studies of Galactic microlensing, which, as I will show, have significant impact on studies of the Galactic structure and the mass function of lenses in the MilkyWay. The first chapter provides a basic treatment of gravitational lensing and of the data analysis procedures used throughout this thesis. The next chapter is devoted to the investigation of blending issues. The ground-based microlensed stars (blends) are resolved into separate components using the Hubble Space Telescope (HST). With Difference Image Analysis, seven microlensed stars are recognised. Blending fractions are calculated from the HST images and compared with the fractions derived from light curve fitting. Chapters 3 and 4 present my studies of HST two-epoch images of 37 Galactic bulge fields; this work has been published in Monthly Notices of the Royal Astronomical Society and the Astrophysical Journal. The superb resolution of the HST allows the measurement of stellar positions with milli-arcsecond accuracy. Using the two-epoch images, I build a catalogue of stellar proper motions for ∼26,000 stars. For each field I calculate dispersions from the relative proper motions. Small gradients in these proper motion dispersions and in the anisotropy are clearly detected. For the first time, a covariance in the longitudinal and latitudinal motions is discovered. These results will provide strong constraints on theoretical Galactic models. In the fourth chapter I present the first ever direct detection of a lens toward the Galactic bulge. Using the HST, the luminous lens and source responsible for the microlensing event MACHO-95-BLG-37 were resolved. Having the colours of the stars, relative proper motion and parameters from the light curve fitting, I derive the distances to both the source and lens, as well as the lens mass. This method can in principle be extended to many other microlensing events in the future, and provides a promising way to constrain lens masses. The final chapter presents an independent attempt to reduce the huge amount of OGLE–III data. To test the methodology, I focus on one OGLE–III field, in order to calculate the detection efficiency and derive the optical depth. I develop a pipeline for constructing template images, performing photometry and building a light curve database. The simulator for the OGLE–III images and the microlensing events’ search engine are described. Reduction of the OGLE–III data combined with the Monte Carlo simulations leads to a robust determination of the detection efficiency and the optical depth τ=(2.91 ± 0.77)*10^-6 in the chosen field. The pipeline, together with the image simulator and calibration routines, will be used in the near future to construct the first observational map of the optical depth of the Galactic bulge

Możliwości rozwiązania problemów logistyki miejskiej w obszarze infrastruktury drogowej na przykładzie Konstantynowa Łódzkiego

Konstantynów Łódzki is part of the Łódź Metropolitan Area, with almost 18 thousand residents. Its location causes it to be a popular place of settlement for people working in Łódź. The city is connected by a tram line with Łódź and several roads connecting them with the center of the agglomeration and transferring traffic in the north-south direction. Currently, the road infrastructure is the most important element that gives residents the possibility of moving around. This situation causes a number of transportrelated problems. The aim of the article is to propose a solution to the problems faced by the road transport logistics in Konstantynów Łódzki. Based on data from road traffic studies and analyses of the existing trans-port infrastructure, a forecast relating to traffic until 2040 was made. This forecast and a number of other factors allowed outlining the necessary changes in the transport infrastructure, which give an opportunity to solve the existing and growing problems in the area of Konstantynów Łódzki’s urban logistics.Konstantynów Łódzki jest częścią Łódzkiego Obszaru Metropolitalnego i ma prawie 18 tys. mieszkańców. Jego położenie powoduje, że jest popularnym miejscem osiedlania się osób pracujących w Łodzi. Miasto połączone jest z Łodzią linią tramwajową oraz kilkoma drogami łączącymi je z centrum aglomeracji oraz przenoszącymi ruch w relacji północ–południe. Obecnie infrastruktura drogowa jest najważniejszym elementem dającym możliwość przemieszczania się mieszkańców. Taka sytuacja powoduje szereg problemów transportowych. Celem artykułu jest zaproponowanie rozwiązania problemów logistyki transportu drogowego Konstantynowa Łódzkiego. Na podstawie danych z badań ruchu drogowego oraz analizy istniejącej infrastruktury transportowej dokonano prognozy ruchu drogowego do 2040 r. Prognoza ta oraz szereg innych czynników pozwoliły na nakreślenie niezbędnych zmian w infrastrukturze transportowej, które dają szansę na rozwiązanie istniejących i narastających problemów w obszarze logistyki miejskiej Konstantynowa Łódzkiego

Hold your breath beetle : mites!

Respiratory gas exchange in insects occurs via a branching tracheal system. The entrances to the air-filled tracheae are the spiracles, which are gate-like structures in the exoskeleton. The open or closed state of spiracles defines the three possible gas exchange patterns of insects. In resting insects, spiracles may open and close over time in a repeatable fashion that results in a discontinuous gas exchange (DGE) pattern characterized by periods of zero organism-to-environment gas exchange. Several adaptive hypotheses have been proposed to explain why insects engage in DGE, but none have attracted overwhelming support. We provide support for a previously untested hypothesis that posits that DGE minimizes the risk of infestation of the tracheal system by mites and other agents. Here, we analyze the respiratory patterns of 15 species of ground beetle (Carabidae), of which more than 40% of individuals harbored external mites. Compared with mite-free individuals, infested one’s engaged significantly more often in DGE. Mite-free individuals predominantly employed a cyclic or continuous gas exchange pattern, which did not include complete spiracle closure. Complete spiracle closure may prevent parasites from invading, clogging, or transferring pathogens to the tracheal system or from foraging on tissue not protected by thick chitinous layers