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Wyszukujesz frazę "Popowicz, Adam" wg kryterium: Autor


Tytuł:
Optimization of exposure time division for multi-object photometry
Autorzy:
Kurek, Aleksander
Popowicz, Adam
Opis:
Optical observations of wide fields of view entail the problem of selecting the best exposure time. As many objects are usually observed simultaneously, the quality of photometry of the brightest ones is always better than that of the dimmer ones, even though all of them are frequently equally interesting for astronomers. Thus, measuring all objects with the highest possible precision is desirable. In this paper, we present a new optimization algorithm, dedicated for the division of exposure time into sub-exposures, which enables photometry with a more balanced noise budget. The proposed technique increases the photometric precision of dimmer objects at the expense of the measurement fidelity of the brightest ones. We have tested the method on real observations using two telescope setups, demonstrating its usefulness and good consistency with theoretical expectations. The main application of our approach is a wide range of sky surveys, including ones performed by space telescopes. The method can be used to plan virtually any photometric observation of objects that show a wide range of magnitudes.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
Beyond the current noise limit in imaging through turbulent medium
Autorzy:
Kurek, Aleksander
Pollo, Agnieszka
Popowicz, Adam
Smolka, Bogdan
Opis:
Shift-and-add is an approach employed to mitigate the phenomenon of resolution degradation in images acquired through a turbulent medium. Using this technique, a large number of consecutive short exposures is registered below the coherence time of the atmosphere or other blurring medium. The acquired images are shifted to the position of the brightest speckle and stacked together to obtain high resolution and high signal-to-noise frame. In this Letter, we present a highly efficient method for determination of frame shifts, even if in a single frame the object cannot be distinguished from the background noise. The technique utilizes our custom genetic algorithm, which iteratively evolves a set of image shifts. We used the maximal energy of stacked images as an objective function for shifts estimation and validate the efficiency of the method on simulated and real images of simple and complex sources. Obtained results confirmed that our proposed method allows for the recovery of spatial distribution of objects even only 2% brighter than their background. The presented approach extends significantly current limits of image reconstruction with the use of shift-and-add method. The applications of our algorithm include both the optical and the infrared imaging. Our method may be also employed as a digital image stabilizer in extremely low light level conditions in professional and consumer applications.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
Is the symbiotic recurrent nova T CrB late? Recent photometric evolution and comparison with past pre-outburst behaviour
Autorzy:
Dubois, Franky
Szyszka, Krzysztof
Kvernadze, Teimuraz
Merc, Jaroslav
Maskoliūnas, Marius
Galdies, Charles
Pylypenko, Uliana
Golonka, Jan
Zdanavičius, Justas
Moździerski, Dawid
Drozdz, Marek
Vanaverbeke, Siegfried
Burgaz, Umut
Brincat, Stephen M
Kotysz, Krzysztof
Olszewska, Justyna M.
Dennefeld, Michel
Zieliński, Paweł
Marzec, Mateusz
Szklarz, Mateusz
Japelj, Jure
Zoła, Stanisław
Gazeas, Kosmas
Damljanović, Goran
Čepas, Vytautas
Gil, Bartosz
Reguitti, Andrea
Pakštienė, Erika
Bronikowski, Mateusz
Awiphan, Supachai
Gurgul, Agnieszka
Wyrzykowski, Łukasz
Mikołajczyk, Przemysław J.
Carrasco, Josep Manel
Qvam, Jan Kåre Trandem
Hambsch, Franz-Josef
Stojanović, Milan
Popowicz, Adam
Badura, Magdalena
Pucek, Alicja
Kowalska, Aleksandra
Joachimczyk, Barbara
Bąkowska, Karolina
Mihelcic, Matej
Hofbauer, Piotr
Ogłoza, Waldemar
Beck, Paul G.
Liakos, Alexios
Kurowski, Sebastian
Opis:
T CrB is a symbiotic recurrent nova that last erupted in 1946. Given its recurrence time-scale of approximately 80 yr, the next outburst is eagerly anticipated by the astronomical community. In this work, we analyse the optical light curves of T CrB, comparing recent photometric evolution with historical data to evaluate potential predictive indicators of nova eruptions. Although the ‘superactive’ phases preceding both the 1946 and anticipated eruptions are strikingly similar, the subsequent photometric behaviour differs. We find that the decline in brightness observed in 2023, interpreted by some as a ‘pre-eruption dip’, deviates from the deep minimum recorded prior to the 1946 event and does not reliably predict the eruption timing. Recent photometric and spectroscopic observations indicate that the system is returning to a high-accretion state. Given this, an eruption may be imminent, even without distinct precursors. While the next eruption of T CrB will be a major scientific event, its expected peak brightness of V $\sim$ 2 mag highlights the importance of setting realistic public expectations for what will be a visually modest, yet astrophysically very significant, celestial event.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
What is the link between internal communication, organizational culture and environmental strategy? The context of company size and employee perception
Autorzy:
Piwowar-Sulej, Katarzyna
Popowicz, Ewa
Sulich, Adam
Tematy:
Business strategy
Environmental sustainability
Green communication
Organizational culture
Pokaż więcej
Wydawca:
Akademia Leona Koźmińskiego w Warszawie
Powiązania:
https://bibliotekanauki.pl/articles/43853907.pdf  Link otwiera się w nowym oknie
Opis:
Purpose – The article explores the linkages between the type of environmental strategy (ES), the use of internal communication (IC), and the greening of organizational culture (OC). Moreover, the article empirically examines whether company size matters in the use of environmental IC practices in the green context. Additionally, the article considers differences between people employed at different organizational hierarchy levels. The basis for such a comparison is their opinions about the effectiveness of communication practices. Design/methodology/approach – Empirical research employed a survey method done on 199 organizations in 2020. Statistical analyses used the chi-squared test, Kendall’s Tau-b correlation coefficient, and the Mann–Whitney U test. Findings – The research showed that companies with a proactive green strategy more often use different communication practices related to ES and have a greener culture. The study proved that larger companies more often use the analyzed communication practices. However, we found no significant difference in opinion between middle managers and line employees about the effectiveness of these practices. Practical implications – The main contribution to business practice is the exploratory model based on the empirical study, which allows organizations to successfully implement the ES. Originality/value – Studies rarely combine the three organizational elements: IC, OC, and ES. This article provides new empirical evidence on relationships between features of OC, green strategy types, and communication practices.
Dostawca treści:
Biblioteka Nauki
Artykuł

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