1. Lens parameters for Gaia18cbf – a long gravitational microlensing event in the Galactic planeK. Kruszyńska, Ł. Wyrzykowski, K. A. Rybicki, M. Maskoliūnas, E. Bachelet, N. Rattenbury, P. Mróz, P. Zieliński, K. Howil, Z. Kaczmarek, S. T. Hodgkin, N. Ihanec, I. Gezer, M. Gromadzki, P. Mikołajczyk, A. Stankevičiūtė, V. Čepas, E. Pakštienė, K. Šiškauskaitė, J. Zdanavičius, V. Bozza, M. Dominik, R. Figuera Jaimes, A. Fukui, M. Hundertmark, N. Narita, R. Street, Y. Tsapras, Mateusz Bronikowski, M. Jabłońska, A. Jabłonowska, O. Ziółkowska, 2022, original scientific article Abstract: Context. The timescale of a microlensing event scales as a square root of a lens mass. Therefore, long-lasting events are important candidates for massive lenses, including black holes.
Aims. Here, we present the analysis of the Gaia18cbf microlensing event reported by the Gaia Science Alerts system. It exhibited a long timescale and features that are common for the annual microlensing parallax effect. We deduce the parameters of the lens based on the derived best fitting model.
Methods. We used photometric data collected by the Gaia satellite as well as the follow-up data gathered by the ground-based observatories. We investigated the range of microlensing models and used them to derive the most probable mass and distance to the lens using a Galactic model as a prior. Using a known mass-brightness relation, we determined how likely it is that the lens is a main-sequence (MS) star.
Results. This event is one of the longest ever detected, with the Einstein timescale of tE = 491.41−84.94+128.31 days for the best solution and tE = 453.74−105.74+178.69 days for the second best. Assuming Galaxy priors, this translates to the most probable lens masses of ML = 2.65−1.48+5.09 M⊙ and ML = 1.71−1.06+3.78 M⊙, respectively. The limits on the blended light suggest that this event was most likely not caused by a MS star, but rather by a dark remnant of stellar evolution.
Keywords: gravitational lensing: micro, Galaxy: stellar content, stars: black holes, stars: neutron, Astrophysics - Solar and Stellar Astrophysics
Published in RUNG: 13.11.2023; Views: 643; Downloads: 4
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2. Importance of pedestrianization for urban regeneration. Assessing new bridge solutions for the Golden Horn : Pedestrianization in Golden HornPinar Özge Gezer, 2020, master's thesis Abstract: The Golden Horn (in Turkish Halic means Gulf or Altın Boynuz "Golden Horn") is a historic inlet of the Bosphorus dividing the city of İstanbul and forming the natural harbor that has sheltered Ottoman and other ships for thousands of years. It is a scimitar-shaped estuary that joins the Bosphorus just at the point where that strait enters the Sea of Marmara, thus forming a peninsula the tip of which is "Old İstanbul".
This thesis work focuses on design proposal for the pedestrian bridge for Golden Horn Dis-trict, which links the royal and later historical peninsula to the rest of the city. The main challenge of the thesis is creation of continuous pedestrian network to guarantee uninter-rupted pedestrian connectivity as well as systematic activation of social and environmental urban regeneration.
Keywords: bridge, pedestrianization, walkability, Golden Horn, historical penninsula, connection, transportation, cultural park, green areas, attraction points, İstanbul, Leonardo Da Vinci
Published in RUNG: 28.02.2020; Views: 3303; Downloads: 111
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