Zobrazeno 1 - 10
of 489
pro vyhledávání: '"WIITA, PAUL J."'
Autor:
Tripathi, Ashutosh, Gupta, Alok C., Smith, Krista Lynne, Wiita, Paul J., Aller, Margo F., Volvach, Alexandr E., Lähteenmäki, Anne, Aller, Hugh D., Tornikoski, Merja, Volvach, Larisa N.
Publikováno v:
The Astrophysical Journal, Volume 977, Number 2, 166 (2024)
We examine lengthy radio light curves of the flat spectrum radio galaxy 3C 454.3 for possible quasi-periodic oscillations (QPOs). The data used in this work were collected at five radio frequencies, 4.8, 8.0, 14.5, 22.0, and 37.0 GHz between 1979--20
Externí odkaz:
http://arxiv.org/abs/2412.10771
Autor:
Dogra, Karan, Gupta, Alok C., Raiteri, C. M., Villata, M., Wiita, Paul J., Kurtanidze, S. O., Jorstad, S. G., Bachev, R., Damljanovic, G., Lorey, C., Savchenko, S. S., Vince, O., Abdelkareem, M., Aceituno, F. J., Acosta-Pulido, J. A., Agudo, I., Andreuzzi, G., Ata, S. A., Baida, G. V., Barbieri, L., Blinov, D. A., Bonnoli, G., Borman, G. A., Carnerero, M. I., Carosati, D., Casanova, V., Chen, W. P., Cui, Lang, Elhosseiny, E. G., Elsaesser, D., Escudero, J., Feige, M., Gazeas, K., Gennadievna, L. E., Grishina, T. S., Gu, Minfeng, Hagen-Thorn, V. A., Hemrich, F., Hsiao, H. Y., Ismail, M., Ivanidze, R. Z., Jovanovic, M. D., Kamel, T. M., Kimeridze, G. N., Kopatskaya, E. N., Kuberek, D., Kurtanidze, O. M., Kurtenkov, A., Larionov, V. M., Larionova, L. V., Liao, M., Lin, H. C., Mannheim, K., Marchini, A., Marinelli, C., Marscher, A. P., Morcuende, D., Morozova, D. A., Nazarov, S. V., Nikolashvili, M. G., Reinhart, D., Santos, J. O., Scherbantin, A., Semkov, E., Shishkina, E. V., Sigua, L. A., Singh, A. K., Sota, A., Steineke, R., Stojanovic, M., Strigachev, A., Takey, A., Tawfeek, Amira A., Troitskiy, I. S., Troitskaya, Y. V., Tsai, An-Li, Vasilyev, A. A., Vrontaki, K., Zhang, Zhongli, Zhovtan, A. V., Zottmann, N., Zuo, Wenwen
Publikováno v:
ApJS(2025) 276:1
Due to its peculiar and highly variable nature, the blazar 3C 454.3 has been extensively monitored by the WEBT team. Here, we present for the first time these long-term optical flux and color variability results using data acquired in B, V, R, and I
Externí odkaz:
http://arxiv.org/abs/2412.10766
Autor:
Zhou, Dongtao, Zhang, Zhongli, Gupta, Alok C., Kushwaha, Pankaj, Wiita, Paul J., Gu, Minfeng, Xu, Haiguang
Publikováno v:
2024MNRAS.532.3285Z
We present analyses of Suzaku XIS light curves and spectra of the BL Lac object OJ 287 with observations positioned primarily around proposed recurrent optical outbursts. The first two observations were performed in 2007 April 10 - 13 (epoch 1) and 2
Externí odkaz:
http://arxiv.org/abs/2408.02371
Autor:
Valtonen, Mauri J., Zola, Staszek, Gupta, Alok C., Kishore, Shubham, Gopakumar, Achamveedu, Jorstad, Svetlana G., Wiita, Paul J., Gu, Minfeng, Nilsson, Kari, Marscher, Alan P., Zhang, Zhongli, Hudec, Rene, Matsumoto, Katsura, Drozdz, Marek, Ogloza, Waldemar, Berdyugin, Andrei V., Reichart, Daniel E., Mugrauer, Markus, Dey, Lankeswar, Pursimo, Tapio, Lehto, Harry J., Ciprini, Stefano, Nakaoka, T., Uemura, M., Imazawa, Ryo, Zejmo, Michal, Kouprianov, Vladimir V., Davidson, Jr., James W., Sadun, Alberto, Strobl, Jan, Weaver, Z. R., Jelinek, Martin
We report the study of a huge optical intraday flare on November 12, 2021, at 2 am UT, in the blazar OJ287. 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 multifreq
Externí odkaz:
http://arxiv.org/abs/2405.08627
The extreme TeV blazar 1ES 0229+200 is a high-frequency-peaked BL Lacertae object. It has not shown intraday variability in extensive optical and X-ray observations. Nor has it shown any significant variability on any measurable timescale in the 1-10
Externí odkaz:
http://arxiv.org/abs/2404.13638
Blazars are characterized by largely aperiodic variability on timescales ranging from minutes to decades across the electromagnetic spectrum. The TESS (Transiting Exoplanet Survey Satellite) mission provides continuous sampling of blazar variability
Externí odkaz:
http://arxiv.org/abs/2403.14744
In a previous paper, we reported evidence for quasi-periodicities in the \textsl{TESS} light curves of BL Lacerate and two other blazars found serendipitously in the SDSS AGN catalog. In this work, we find tentative evidence for quasi-periodic featur
Externí odkaz:
http://arxiv.org/abs/2402.04352
We report the time series analysis of TESS light curves of three blazars, BL Lacertae, 1RXS J111741.0+254858, and 1RXS J004519.6+212735, obtained using a customized approach for extracting AGN light curves. We find tentative evidence for quasi-period
Externí odkaz:
http://arxiv.org/abs/2312.14144
Autor:
Tripathi, Tushar, Gupta, Alok C., Takey, Ali, Bachev, Rumen, Vince, Oliver, Strigachev, Anton, Kushwaha, Pankaj, Elhosseiny, E. G., Wiita, Paul J., Damljanovic, G., Dhiman, Vinit, Fouad, A., Gaur, Haritma, Gu, Minfeng, Hamed, G. E., Kishore, Shubham, Kurtenkov, A., Rastogi, Shantanu, Semkov, E., Zead, I., Zhang, Zhongli
We present an extensive recent multi-band optical photometric observations of the blazar S5 0716+714 carried out over 53 nights with two telescopes in India, two in Bulgaria, one in Serbia, and one in Egypt during 2019 November -- 2022 December. We c
Externí odkaz:
http://arxiv.org/abs/2311.10358
Autor:
A, Krishna Mohana, Gupta, Alok C., Marscher, Alan P., Sotnikova, Yulia V., Jorstad, S. G., Wiita, Paul J., Cui, Lang, Aller, Margo F., Aller, Hugh D., Kovalev, Yu. A., Kovalev, Y. Y., Liu, Xiang, Mufakharov, T. V., Popkov, A. V., Mingaliev, M. G., Erkenov, A. K., Nizhelsky, N. A., Tsybulev, P. G., Zhao, Wei, Weaver, Z. R., Morozova, D. A.
Publikováno v:
MNRAS 527 (2024) 6970
We present the results of our study of cross-correlations between long-term multi-band observations of the radio variability of the blazar 3C 279. More than a decade (2008-2022) of radio data were collected at seven different frequencies ranging from
Externí odkaz:
http://arxiv.org/abs/2311.02395