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Wyświetlanie 1-10 z 12
Tytuł:
Promise of persistent multi-messenger astronomy with the Blazar OJ 287
Autorzy:
Gomez, Jose L.
Valtonen, Mauri J.
Dey, Lankeswar
Hudec, Rene
Zoła, Stanisław
Jermak, Helen
Berdyugin, Andrei V.
Komossa, S.
Gopakumar, Achamveedu
Pursimo, Tapio
Opis:
Successful observations of the seven predicted bremsstrahlung flares from the unique bright blazar OJ 287 firmly point to the presence of a nanohertz gravitational wave (GW) emitting supermassive black hole (SMBH) binary central engine. We present arguments for the continued monitoring of the source in several electromagnetic windows to firmly establish various details of the SMBH binary central engine description for OJ 287. In this article, we explore what more can be known about this system, particularly with regard to accretion and outflows from its two accretion disks. We mainly concentrate on the expected impact of the secondary black hole on the disk of the primary on 3 December 2021 and the resulting electromagnetic signals in the following years. We also predict the times of exceptional fades, and outline their usefulness in the study of the host galaxy. A spectral survey has been carried out, and spectral lines from the secondary were searched for but were not found. The jet of the secondary has been studied and proposals to discover it in future VLBI observations are mentioned. In conclusion, the binary black hole model explains a large number of observations of different kinds in OJ 287. Carefully timed future observations will be able to provide further details of its central engine. Such multi-wavelength and multidisciplinary efforts will be required to pursue multi-messenger nanohertz GW astronomy with OJ 287 in the coming decades.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
Observational implications of OJ 287’s predicted 2022 disk impact in the black hole binary model
Autorzy:
Kouprianov, Vladimir V.
Uemura, Makoto
Tornikoski, Merja
Matsumoto, Katsura
Štrobl, Jan
Dey, Lankeswar
Reichart, Daniel E.
Mugrauer, Markus
Pursimo, Tapio
Knudstrup, Emil
Nilsson, Kari
Gomez, Jose L.
Berdyugin, Andrei V.
Sadun, Alberto
Sillanpää, Aimo
Drozdz, Marek
Jelínek, Martin
Zejmo, Michal
Valtonen, Mauri J.
Gupta, Alok C.
Hudec, Rene
Lähteenmäki, Anne
Zoła, Stanisław
Lehto, Harry J.
Gopakumar, Achamveedu
Imazawa, Ryo
Ciprini, Stefano
Opis:
We present a summary of the results of the OJ 287 observational campaign, which was carried out during the 2021/2022 observational season. This season is special in the binary model because the major axis of the precessing binary happens to lie almost exactly in the plane of the accretion disc of the primary. This leads to pairs of almost identical impacts between the secondary black hole and the accretion disk in 2005 and 2022. In 2005, a special flare called "blue flash" was observed 35 days after the disk impact, which should have also been verifiable in 2022. We did observe a similar flash and were able to obtain more details of its properties. We describe this in the framework of expanding cloud models. In addition, we were able to identify the flare arising exactly at the time of the disc crossing from its photo-polarimetric and gamma-ray properties. This is an important identification, as it directly confirms the orbit model. Moreover, we saw a huge flare that lasted only one day. We may understand this as the lighting up of the jet of the secondary black hole when its Roche lobe is suddenly flooded by the gas from the primary disk. Therefore, this may be the first time we directly observed the secondary black hole in the OJ 287 binary system.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
Refining the OJ 287 2022 impact flare arrival epoch
Autorzy:
Berdyugin, Andrei V.
Nilsson, Kari
Jelínek, Martin
Matsumoto, Katsura
Tornikoski, Merja
Mugrauer, Markus
Uemura, Makoto
Gopakumar, A.
Štrobl, Jan
Ciprini, Stefano
Drozdz, Marek
Zejmo, Michal
Reichart, Daniel E.
Kouprianov, Vladimir V.
Sillanpää, Aimo
Hudec, Rene
Lehto, Harry J.
Pursimo, Tapio
Valtonen, Mauri J.
Gomez, Jose L.
Zoła, Stanisław
Sadun, Alberto
Dey, Lankeswar
Lähteenmäki, Anne
Gupta, Alok C.
Imazawa, Ryo
Knudstrup, Emil
Opis:
The bright blazar OJ 287 routinely parades high brightness bremsstrahlung flares, which are explained as being a result of a secondary supermassive black hole (SMBH) impacting the accretion disc of a more massive primary SMBH in a binary system. The accretion disc is not rigid but rather bends in a calculable way due to the tidal influence of the secondary. Next, we refer to this phenomenon as a variable disc level. We begin by showing that these flares occur at times predicted by a simple analytical formula, based on general relativity inspired modified Kepler equation, which explains impact flares since 1888. The 2022 impact flare, namely flare number 26, is rather peculiar as it breaks the typical pattern of two impact flares per 12-yr cycle. This is the third bremsstrahlung flare of the current cycle that follows the already observed 2015 and 2019 impact flares from OJ 287. It turns out that the arrival epoch of flare number 26 is sensitive to the level of primary SMBH’s accretion disc relative to its mean level in our model. We incorporate these tidally induced changes in the level of the accretion disc to infer that the thermal flare should have occurred during 2022 July–August, when it was not possible to observe it from the Earth. Thereafter, we explore possible observational evidence for certain pre-flare activity by employing spectral and polarimetric data from our campaigns in 2004/05 and 2021/22. We point out theoretical and observational implications of two observed mini-flares during 2022 January–February.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
Forty years after the first dark resonance experiment : an overview of the COSMA project results
Autorzy:
Sudyka, Julia
Deans, C.
Petrov, N.
Marmugi, L.
Khanbekyan, Alek.
Rassi, D.
Tonoyan, A.
Cecchi, R.
Cartaleva, S.
Pustelny, Szymon
Mitra, S.
Marinelli, C.
Wickenbrock, A.
Wilson Gordon, A.
Papoyan, A.
Alipieva, E.
Todorov, P.
Sarkisyan, D.
Nikolov, N.
Zhivun, E.
Moi, L.
Budker, D.
Wojciechowski, Adam
Gateva, S.
Stiaccini, L.
Taslakov, M.
Drampyan, R.
Hussain, S.
Entin, V.
Krasteva, A.
Slavov, D.
Taskova, E. T.
Andreeva, C.
Mirzoyan, R.
Shmavonyan, S.
Sargsyan, A.
Margalit, L.
Biancalana, V.
Ghosh, P. N.
Mariotti, E.
Renzoni, F.
Khanbekyan, Alen
Chapovsky, P.
Dancheva, Y.
Nasyrov, K. A.
Patton, B.
Azizbekyan, H.
Gozzini, S.
Dey, S.
Gawlik, Wojciech
Tsvetkov, S.
Ozun, O.
Stabrawa, Artur
Bevilacqua, G.
Ray, B.
Wydawca:
Society of Photo-Optical Instrumentation Engineers
Opis:
COSMA: Coherent Optics Sensors for Medical Application is an European Marie Curie Project running from 2012 to March 2016, with the participation of 10 teams from Armenia, Bulgaria, India, Israel, Italy, Poland, Russia, UK, USA. The main objective was to focus theoretical and experimental research on biomagnetism phenomena, with the specific aim to develop all-optical sensors dedicated to their detection and suitable for applications in clinical diagnostics. The paper presents some of the most recent results obtained during the exchange visits of the involved scientists, after an introduction about the phenomenon which is the pillar of this kind of research and of many other new fields in laser spectroscopy, atomic physics, and quantum optics: the dark resonance.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Inne
Tytuł:
On the need of an ultramassive black hole in OJ 287
Autorzy:
Lähteenmäki, Anne
Valtonen, Mauri J
Pursimo, Tapio
Gomez, Jose L.
Drozdz, Marek
Nilsson, Kari
Sadun, Alberto
Gopakumar, A.
Imazawa, Ryo
Ciprini, Stefano
Berdyugin, Andrei V.
Matsumoto, Katsura
Sillanpää, Aimo
Gupta, Alok C.
Uemura, Makoto
Zoła, Stanisław
Jelínek, Martin
Davidson, James W.
Zejmo, Michal
Lehto, Harry J.
Knudstrup, Emil
Mugrauer, Markus
Hudec, Rene
Štrobl, Jan
Tornikoski, Merja
Reichart, Daniel E.
Dey, Lankeswar
Kouprianov, Vladimir V.
Opis:
The highly variable blazar OJ 287 is commonly discussed as an example of a binary black hole system. The 130 yr long optical light curve is well explained by a model where the central body is a massive black hole of 18.35 $\times$ 10$^{9}$ solar mass that supports a thin accretion disc. The secondary black hole of 0.15 $\times$ 10$^{9}$ solar mass impacts the disc twice during its 12 yr orbit, and causes observable flares. Recently, it has been argued that an accretion disc with a typical Active Galactic Nuclei (AGN) accretion rate and above mentioned central body mass should be at least six magnitudes brighter than OJ 287’s host galaxy and would therefore be observationally excluded. Based on the observations of OJ 287’s radio jet, detailed in Marscher and Jorstad (2011), and up-to-date accretion disc models of Azadi et al. (2022), we show that the V-band magnitude of the accretion disc is unlikely to exceed the host galaxy brightness by more than one magnitude, and could well be fainter than the host. This is because accretion power is necessary to launch the jet as well as to create electromagnetic radiation, distributed across many wavelengths, and not concentrated especially on the optical V-band. Further, we note that the claimed V-band concentration of accretion power leads to serious problems while interpreting observations of other AGN. Therefore, we infer that the mass of the primary black hole and its accretion rate do not need to be smaller than what is determined in the standard model for OJ 287.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
State of the art and prospects for halide perovskite nanocrystals
Autorzy:
Bladt, Eva
Mora-Seró, Iván
Hofkens, Johan
Dutta, Anirban
Yan, Fei
Pradhan, Narayan
Li, Xiaoming
Scheblykin, Ivan G.
Roeffaers, Maarten B. J.
Rogach, Andrey L.
Hoye, Robert L. Z.
Wang, Yue
Gerhard, Marina
Korgel, Brian A.
Kumar, Sudhir
Zhang, Jin Z.
Samanta, Anunay
Galian, Raquel E.
Kovalenko, Maksym V.
Quan, Li Na
Debroye, Elke
Steele, Julian A.
Bakr, Osman M.
Yang, Peidong
Scheel, Manuel A.
Dey, Amrita
Manna, Liberato
Zhang, Yangning
Tisdale, William A.
Zhang, Qiao
Stolarczyk, Jacek
Cao, Muhan
Vincon, Ilka
Bao, Qiaoliang
Polavarapu, Lakshminarayana
Stranks, Samuel D.
Bodnarchuk, Maryna I.
Biju, Vasudevanpillai
Han, Chuang
Gao, Mengyu
Nag, Angshuman
Sun, Handong
Bals, Sara
Müller-Buschbaum, Peter
Yan, Yong
Shih, Chih-Jen
Demir, Hilmi Volkan
Zhong, Haizheng
Wu, Xian-gang
Mohammed, Omar F.
Son, Dong Hee
Gamelin, Daniel R.
Ha, Seung Kyun
Zeng, Haibo
De, Apurba
Kamat, Prashant V.
Wang, Ziyu
Yin, Jun
Luther, Joseph M.
Ye, Junzhi
Xu, Ke
Pérez-Prieto, Julia
Debnath, Tushar
Chouhan, Lata
Li, Yanxiu
Shamsi, Javad
Krahne, Roman
Feldmann, Jochen
Kshirsagar, Anuraj S.
Li, Liang
Opis:
Metal-halide perovskites have rapidly emerged as one of the most promising materials of the 21st century, with many exciting properties and great potential for a broad range of applications, from photovoltaics to optoelectronics and photocatalysis. The ease with which metal-halide perovskites can be synthesized in the form of brightly luminescent colloidal nanocrystals, as well as their tunable and intriguing optical and electronic properties, has attracted researchers from different disciplines of science and technology. In the last few years, there has been a significant progress in the shape-controlled synthesis of perovskite nanocrystals and understanding of their properties and applications. In this comprehensive review, researchers having expertise in different fields (chemistry, physics, and device engineering) of metal-halide perovskite nanocrystals have joined together to provide a state of the art overview and future prospects of metal-halide perovskite nanocrystal research.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Wyświetlanie 1-10 z 12

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