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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:
The unique blazar OJ 287 and its massive binary black hole central engine
Autorzy:
Susobhanan, Abhimanyu
Piirola, Vilppu
Pihajoki, Pauli
Ciprini, Stefano
Komossa, Stefanie
Gopakumar, Achamveedu
Pursimo, Tapio
Valtonen, Mauri
Hudec, Rene
Jermak, Helen
Kidger, Mark
Dey, Lankeswar
Zoła, Stanisław
Nilsson, Kari
Berdyugin, Andrei
Opis:
The bright blazar OJ 287 is the best-known candidate for hosting a nanohertz gravitational wave (GW) emitting supermassive binary black hole (SMBBH) in the present observable universe. The binary black hole (BBH) central engine model, proposed by Lehto and Valtonen in 1996, was influenced by the two distinct periodicities inferred from the optical light curve of OJ 287. The current improved model employs an accurate general relativistic description to track the trajectory of the secondary black hole (BH) which is crucial to predict the inherent impact flares of OJ 287. The successful observations of three predicted impact flares open up the possibility of using this BBH system to test general relativity in a hitherto unexplored strong field regime. Additionally, we briefly describe an ongoing effort to interpret observations of OJ 287 in a Bayesian framework.
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:
Identifying the secondary jet in the RadioAstron image of OJ 287
Autorzy:
Berdyugin, Andrei V.
Nilsson, Kari
Jelínek, Martin
Matsumoto, Katsura
Mugrauer, Markus
Uemura, Makoto
Zhang, Zhongli
Ogloza, Waldemar
Kishore, Shubham
Štrobl, Jan
Ciprini, Stefano
Drozdz, Marek
Zejmo, Michal
Reichart, Daniel E.
Kouprianov, Vladimir V.
Hudec, Rene
Pursimo, Tapio
Susobhanan, Abhimanyu
Valtonen, Mauri J.
Sadun, Alberto
Dey, Lankeswar
Gu, Minfeng
Gupta, Alok C.
Wiita, Paul J.
Davidson, James W.
Imazawa, Ryo
Gopakumar, Achamveedu
Nakaoka, Tatsuya
Zoła, Stanisław
Opis:
The 136 yr long optical light curve of OJ 287 is explained by a binary black hole model where the secondary is in a 12 yr orbit around the primary. Impacts of the secondary on the accretion disk of the primary generate a series of optical flares that follow a quasi-Keplerian relativistic mathematical model. The orientation of the binary in space is determined from the behavior of the primary jet. Here, we ask how the jet of the secondary black hole projects onto the sky plane. Assuming that the jet is initially perpendicular to the disk, and that it is ballistic, we follow its evolution after the Lorentz transformation to the observer’s frame. Since the orbital speed of the secondary is of the order of one-tenth of the speed of light, the result is a change in the jet direction by more than a radian during an orbital cycle. We match the theoretical jet line with the recent 12 μas resolution RadioAstron map of OJ 287 and determine the only free parameter of the problem, the apparent speed of the jet relative to speed of light. It turns out that the Doppler factor of the jet, δ ∼ 5, is much lower than in the primary jet. Besides following a unique shape of the jet path, the secondary jet is also distinguished by a different spectral shape than in the primary jet. The present result on the spectral shape agrees with the huge optical flare of 2021 November 12, also arising from the secondary jet.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
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:
Evidence of jet activity from the secondary black hole in the OJ 287 binary system
Autorzy:
Berdyugin, Andrei V.
Nilsson, Kari
Valtonen, Mauri J.
Jorstad, Svetlana G.
Jelínek, Martin
Matsumoto, Katsura
Mugrauer, Markus
Zhang, Zhongli
Marscher, Alan P.
Kishore, Shubham
Ogloza, Waldemar
Štrobl, Jan
Ciprini, Stefano
Drozdz, Marek
Zejmo, Michal
Uemura, M.
Reichart, Daniel E.
Kouprianov, Vladimir V.
Nakaoka, T.
Hudec, Rene
Lehto, Harry J.
Pursimo, Tapio
Sadun, Alberto
Minfeng, Gu
Weaver, Z. R.
Dey, Lankeswar
Gupta, Alok C.
Wiita, Paul J.
Davidson, James W.
Imazawa, Ryo
Gopakumar, Achamveedu
Zoła, Stanisław
Opis:
We report the study of a huge optical intraday flare on 2021 November 12 at 2 a.m. UT in the blazar OJ 287. In the binary black hole model, it is associated with an impact of the secondary black hole on the accretion disk of the primary. Our multifrequency observing campaign was set up to search for such a signature of the impact based on a prediction made 8 yr earlier. The first I-band results of the flare have already been reported by Kishore et al. (2024). Here we combine these data with our monitoring in the R-band. There is a big change in the R–I spectral index by 1.0 ± 0.1 between the normal background and the flare, suggesting a new component of radiation. The polarization variation during the rise of the flare suggests the same. The limits on the source size place it most reasonably in the jet of the secondary BH. We then ask why we have not seen this phenomenon before. We show that OJ 287 was never before observed with sufficient sensitivity on the night when the flare should have happened according to the binary model. We also study the probability that this flare is just an oversized example of intraday variability using the Krakow data set of intense monitoring between 2015 and 2023. We find that the occurrence of a flare of this size and rapidity is unlikely. In machine-readable Tables 1 and 2, we give the full orbit-linked historical light curve of OJ 287 as well as the dense monitoring sample of Krakow.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Wyświetlanie 1-10 z 12

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