Browsing by Author "Kino, M."

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  • Discovery of off-axis jet structure of TeV blazar Mrk 501 with mm-VLBI
    (2016-02-01) Koyama, S.; Kino, M.; Giroletti, M.; Doi, A.; Giovannini, G.; Orienti, M.; Hada, K.; Ros, E.; Niinuma, K.; Nagai, H.; Savolainen, T.; Krichbaum, T. P.; Pérez-Torres, M.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Context. High-resolution millimeter wave very-long-baseline interferometry (mm-VLBI) is an ideal tool for probing the structure at the base of extragalactic jets in detail. The TeV blazar Mrk 501 is one of the best targets among BL Lac objects for studying the nature of off-axis jet structures because it shows different jet position angles at different scales. Aims. The aim of this study is to investigate the properties of the off-axis jet structure through high-resolution mm-VLBI images at the jet base and physical parameters such as kinematics, flux densities, and spectral indices. Methods. We performed Very Long Baseline Array (VLBA) observations over six epochs from 2012 February to 2013 February at 43 GHz. Quasi-simultaneous Global Millimeter VLBI Array (GMVA) observations at 86 GHz were performed in May 2012. Results. We discover a new jet component at the northeast direction from the core in all the images at 43 and 86 GHz. The new component shows the off-axis location from the persistent jet extending to the southeast. The 43 GHz images reveal that the scattering of the positions of the NE component is within ∼0.2 mas. The 86 GHz data reveals a jet component located 0.75 mas southeast of the radio core. We also discuss the spectral indices between 43 and 86 GHz, where the northeast component has steeper spectral index and the southeast component has comparable or flatter index than the radio core does.
  • Ordered magnetic fields around the 3C 84 central black hole
    (2024-02-01) Paraschos, G. F.; Kim, J. Y.; Wielgus, M.; Röder, J.; Krichbaum, T. P.; Ros, E.; Agudo, I.; Myserlis, I.; Moscibrodzka, M.; Traianou, E.; Zensus, J. A.; Blackburn, L.; Chan, C. K.; Issaoun, S.; Janssen, M.; Johnson, M. D.; Fish, V. L.; Akiyama, K.; Alberdi, A.; Alef, W.; Algaba, J. C.; Anantua, R.; Asada, K.; Azulay, R.; Bach, U.; Baczko, A. K.; Ball, D.; Baloković, M.; Barrett, J.; Bauböck, M.; Benson, B. A.; Bintley, D.; Blundell, R.; Bouman, K. L.; Bower, G. C.; Boyce, H.; Bremer, M.; Brinkerink, C. D.; Brissenden, R.; Britzen, S.; Broderick, A. E.; Broguiere, D.; Bronzwaer, T.; Bustamante, S.; Byun, D. Y.; Carlstrom, J. E.; Ceccobello, C.; Chael, A.; Chang, D. O.; Chatterjee, K.; Chatterjee, S.; Chen, M. T.; Chen, Y.; Cheng, X.; Cho, I.; Christian, P.; Conroy, N. S.; Conway, J. E.; Cordes, J. M.; Crawford, T. M.; Crew, G. B.; Cruz-Osorio, A.; Cui, Y.; Dahale, R.; Davelaar, J.; De Laurentis, M.; Deane, R.; Dempsey, J.; Desvignes, G.; Dexter, J.; Dhruv, V.; Doeleman, S. S.; Dougal, S.; Dzib, S. A.; Eatough, R. P.; Emami, R.; Falcke, H.; Farah, J.; Fomalont, E.; Ford, H. A.; Foschi, M.; Fraga-Encinas, R.; Freeman, W. T.; Friberg, P.; Fromm, C. M.; Fuentes, A.; Galison, P.; Gammie, C. F.; García, R.; Gentaz, O.; Georgiev, B.; Goddi, C.; Gold, R.; Gómez-Ruiz, A. I.; Gómez, J. L.; Gu, M.; Gurwell, M.; Hada, K.; Haggard, D.; Haworth, K.; Hecht, M. H.; Hesper, R.; Heumann, D.; Ho, L. C.; Ho, P.; Honma, M.; Huang, C. L.; Huang, L.; Hughes, D. H.; Ikeda, S.; Impellizzeri, C. M.V.; Inoue, M.; James, D. J.; Jannuzi, B. T.; Jeter, B.; Jaing, W.; Jiménez-Rosales, A.; Jorstad, S.; Joshi, A. V.; Jung, T.; Karami, M.; Karuppusamy, R.; Kawashima, T.; Keating, G. K.; Kettenis, M.; Kim, D. J.; Kim, J.; Kino, M.; Koay, J. Y.; Kocherlakota, P.; Kofuji, Y.; Koch, P. M.; Koyama, S.; Kramer, C.; Kramer, J. A.; Kramer, M.; Kuo, C. Y.; La Bella, N.; Lauer, T. R.; Lee, D.; Lee, S. S.; Leung, P. K.; Levis, A.; Li, Z.; Lico, R.; Lindahl, G.; Lindqvist, M.; Lisakov, M.; Liu, J.; Liu, K.; Liuzzo, E.; Lo, W. P.; Lobanov, A. P.; Loinard, L.; Lonsdale, C. J.; Lowitz, A. E.; Lu, R. S.; MacDonald, N. R.; Mao, J.; Marchili, N.; Markoff, S.; Marrone, D. P.; Marscher, A. P.; Martí-Vidal, I.; Matsushita, S.; Matthews, L. D.; Medeiros, L.; Menten, K. M.; Michalik, D.; Mizuno, I.; Mizuno, Y.; Moran, J. M.; Moriyama, K.; Mulaudzi, W.; Müller, C.; Müller, H.; Mus, A.; Musoke, G.; Nadolski, A.; Nagai, H.; Nagar, N. M.; Nakamura, M.; Narayanan, G.; Natarajan, I.; Nathanail, A.; Navarro Fuentes, S.; Neilsen, J.; Neri, R.; Ni, C.; Noutsos, A.; Nowak, M. A.; Oh, J.; Okino, H.; Olivares, H.; Ortiz-León, G. N.; Oyama, T.; ÖZel, F.; Palumbo, D. C.M.; Park, J.; Parsons, H.; Patel, N.; Pen, U. L.; Piétu, V.; Plambeck, R.; Popstefanija, A.; Porth, O.; Pötzl, F. M.; Prather, B.; Preciado-López, J. A.; Psaltis, D.; Pu, H. Y.; Ramakrishnan, V.; Rao, R.; Rawlings, M. G.; Raymond, A. W.; Rezzolla, L.; Ricarte, A.; Ripperda, B.; Roelofs, F.; Rogers, A.; Romero-Cañizales, C.; Roshanineshat, A.; Rottmann, H.; Roy, A. L.; Ruiz, I.; Ruszczyk, C.; Rygl, K. L.J.; Sánchez, S.; Sánchez-Argüelles, D.; Sánchez-Portal, M.; Sasada, M.; Satapathy, K.; Savolainen, T.; Schloerb, F. P.; Schonfeld, J.; Schuster, K.; Shao, L.; Shen, Z.; Small, D.; Sohn, B. W.; Soohoo, J.; Sosapanta Salas, L. D.; Souccar, K.; Sun, H.; Tazaki, F.; Tetarenko, A. J.; Tiede, P.; Tilanus, R. P.J.; Titus, M.; Torne, P.; Toscano, T.; Trent, T.; Trippe, S.; Turk, M.; Van Bemmel, I.; Van Langevelde, H. J.; Van Rossum, D. R.; Vos, J.; Wagner, J.; Ward-Thompson, D.; Wardle, J.; Washington, J. E.; Weintroub, J.; Wharton, R.; Wiik, K.; Witzel, G.; Wondrak, M. F.; Wong, G. N.; Wu, Q.; Yadlapalli, N.; Yamaguchi, P.; Yfantis, A.; Yoon, D.; Young, A.; Young, K.; Younsi, Z.; Yu, W.; Yuan, F.; Yuan, Y. F.; Zhang, S.; Zhao, G. Y.; Zhao, S. S.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Context. 3C 84 is a nearby radio source with a complex total intensity structure, showing linear polarisation and spectral patterns. A detailed investigation of the central engine region necessitates the use of very-long-baseline interferometry (VLBI) above the hitherto available maximum frequency of 86 GHz. Aims. Using ultrahigh resolution VLBI observations at the currently highest available frequency of 228 GHz, we aim to perform a direct detection of compact structures and understand the physical conditions in the compact region of 3C 84. Methods. We used Event Horizon Telescope (EHT) 228 GHz observations and, given the limited (u, v)-coverage, applied geometric model fitting to the data. Furthermore, we employed quasi-simultaneously observed, ancillary multi-frequency VLBI data for the source in order to carry out a comprehensive analysis of the core structure. Results. We report the detection of a highly ordered, strong magnetic field around the central, supermassive black hole of 3C 84. The brightness temperature analysis suggests that the system is in equipartition. We also determined a turnover frequency of νm = (113 ± 4) GHz, a corresponding synchrotron self-absorbed magnetic field of BSSA = (2.9 ± 1.6) G, and an equipartition magnetic field of Beq = (5.2 ± 0.6) G. Three components are resolved with the highest fractional polarisation detected for this object (mnet = (17.0 ± 3.9)%). The positions of the components are compatible with those seen in low-frequency VLBI observations since 2017-2018. We report a steeply negative slope of the spectrum at 228 GHz. We used these findings to test existing models of jet formation, propagation, and Faraday rotation in 3C 84. Conclusions. The findings of our investigation into different flow geometries and black hole spins support an advection-dominated accretion flow in a magnetically arrested state around a rapidly rotating supermassive black hole as a model of the jet-launching system in the core of 3C 84. However, systematic uncertainties due to the limited (u, v)-coverage, however, cannot be ignored. Our upcoming work using new EHT data, which offer full imaging capabilities, will shed more light on the compact region of 3C 84.
  • Radio-to-gamma-ray monitoring of the narrow-line Seyfert 1 galaxy PMN J0948 + 0022 from 2008 to 2011
    (2012) Foschini, L.; Angelakis, E.; Fuhrmann, L.; Ghisellini, G.; Hovatta, T.; Lahteenmaki, A.; Lister, M.L.; Braito, V.; Gallo, L.; Hamilton, T.S.; Kino, M.; Komossa, S.; Pushkarev, A.B.; Thompson, D.J.; Tibolla, O.; Tramacere, A.; Carramiñana, A.; Carrasco, L.; Falcone, A.; Giroletti, M.; Grupe, D.; Kovalev, Y.Y.; Krichbaum, T.P.; Max-Moerbeck, W.; Nestoras, I.; Pearson, T.J.; Porras, A.; Readhead, A.C.S.; Recillas, E.; Richards, J.L.; Riquelme, D.; Sievers, A.; Tammi, J.; Tornikoski, M.; Ungerechts, H.; Zensus, J.A.; Celotti, A.; Bonnoli, G.; Doi, A.; Maraschi, L.; Tagliaferri, G.; Tavecchio, F.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
  • A wide and collimated radio jet in 3C84 on the scale of a few hundred gravitational radii
    (2018-06-01) Giovannini, G.; Savolainen, T.; Orienti, M.; Nakamura, M.; Nagai, H.; Kino, M.; Giroletti, M.; Hada, K.; Bruni, G.; Kovalev, Y. Y.; Anderson, J. M.; D'Ammando, F.; Hodgson, J.; Honma, M.; Krichbaum, T. P.; Lee, S. S.; Lico, R.; Lisakov, M. M.; Lobanov, A. P.; Petrov, L.; Sohn, B. W.; Sokolovsky, K. V.; Voitsik, P. A.; Zensus, J. A.; Tingay, S.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Understanding the formation of relativistic jets in active galactic nuclei remains an elusive problem 1 .This is partly because observational tests of jet formation models suffer from the limited angular resolution of ground-based very-long-baseline interferometry that has thus far been able to probe the structure of the jet acceleration and collimation region in only two sources 2,3 . Here, we report observations of 3C84 (NGC 1275)-the central galaxy of the Perseus cluster-made with an interferometric array including the orbiting radio telescope of the RadioAstron 4 mission. The data transversely resolve the edge-brightened jet in 3C84 only 30 μas from the core, which is ten times closer to the central engine than was possible in previous ground-based observations 5 and allows us to measure the jet collimation profile from ~102 to ~104 gravitational radii (r g) from the black hole. The previously found 5, almost cylindrical jet profile on scales larger than a few thousand r g is seen to continue at least down to a few hundred r g from the black hole, and we find a broad jet with a transverse radius of â‰250 r g at only 350 r g from the core. This implies that either the bright outer jet layer goes through a very rapid lateral expansion on scales â‰102 r g or it is launched from the accretion disk.