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17 results on '"Lee, C.-U"'

1. A giant planet beyond the snow line in microlensing event OGLE-2011-BLG-0251

Author

Kains, N., Street, R.A., Choi, J.-Y., Han, C., Udalski, A., Almeida, L.A., Jablonski, F., Tristram, P.J., Jørgensen, Uffe Gråe, Szymański, M.K., Kubiak, M., Pietrzyński, G., Soszyński, I., Poleski, R., Kozłowski, S., Pietrukowicz, P., Ulaczyk, K., Wyrzykowski, Ł., Skowron, J., Tsapras, Y., Alsubai, K.A., Bozza, V., Browne, P., Burgdorf, M. J., Calchi Novati, S., Dodds, P., Dominik, M., Dreizler, S., Fang, X.-S., Grundahl, F., Gu, C.-H., Hardis, S., Harpsøe, Kennet Bomann West, Hessman, F. V., Hinse, T. C., Hornstrup, Allan, Hundertmark, M., Jessen-Hansen, Jens, Kerins, E., Liebig, C., Lund, M., Lundkvist, M., Mancini, L., Mathiasen, M., Penny, M. T., Rahvar, S., Ricci, D., Sahu, K.C., Scarpetta, G., Skottfelt, J., Snodgrass, C., Southworth, J., Surdej, J., Tregloan-Reed, J., Wambsganss, J., Wertz, O., Bajek, D., Bramich, D.M., Horne, K., Ipatov, S., Steele, I.A., Abe, F., Bennett, D.P., Bond, I.A., Botzler, C.S., Chote, P., Freeman, M., Fukui, A., Furusawa, K., Itow, Y., Ling, C.H., Masuda, K., Matsubara, Y, Miyake, N., Muraki, Y., Ohnishi, K., Rattenbury, N., Saito, T., Sullivan, D.J., Sumi, T., Suzuki, D., Suzuki, K., Sweatman, W.L., Takino, S., Wada, K., Yock, P.C.M., Allen, W., Batista, V., Chung, S.-J., Christie, G., Depoy, D.L., Drummond, J., Gaudi, B.S., Gould, A., Henderson, C., Jung, Y.K., Koo, J.-R., Lee, C.-U., McCormick, J., McGregor, D., Muñoz, J.A., Natusch, T., Ngan, H., Park, H., Pogge, R.W., Shin, I.-G., Yee, J., Albrow, M.D., Bachelet, E., Beaulieu, J.-P., Brillant, S., Caldwell, J.A.R., Cassan, A., Cole, A., Corrales, E., Coutures, Ch., Dieters, S., Dominis Prester, D., Donatowicz, J., Fouqué, P., Greenhill, J., Kane, S.R., Kubas, D., Marquette, J.-B., Martin, R., Meintjes, P., Menzies, J., Pollard, K.R., Williams, A., Wouters, D., Zub, M., Science & Technology Facilities Council, and University of St Andrews. School of Physics and Astronomy

Subjects
planets and satellites: detection, 010504 meteorology & atmospheric sciences, Satellites, bulge [Galaxy], FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Discovery, Gravitational microlensing, 01 natural sciences, Galaxy: bulge, Einstein radius, Lens, gravitational lensing: weak, Settore FIS/05 - Astronomia e Astrofisica, Planet, Snow, 0103 physical sciences, gravitational lensing, weak, planets and satellites, detection, planetary systems, Galaxy, bulge, Binary, QB Astronomy, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, QB, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Giant planet, Systems, Search, Astronomy and Astrophysics, Radius, Frequency, Planetary system, Mass ratio, Mass, Light curve, Stars, Algorithm, detection [Planets and satellites], Planetary systems, Space and Planetary Science, Dwarf, Astrophysics::Earth and Planetary Astrophysics, weak [Gravitational lensing], Astrophysics - Earth and Planetary Astrophysics
Abstract

We present the analysis of the gravitational microlensing event OGLE-2011-BLG-0251. This anomalous event was observed by several survey and follow-up collaborations conducting microlensing observations towards the Galactic Bulge. Based on detailed modelling of the observed light curve, we find that the lens is composed of two masses with a mass ratio q=1.9 x 10^-3. Thanks to our detection of higher-order effects on the light curve due to the Earth's orbital motion and the finite size of source, we are able to measure the mass and distance to the lens unambiguously. We find that the lens is made up of a planet of mass 0.53 +- 0.21,M_Jup orbiting an M dwarf host star with a mass of 0.26 +- 0.11 M_Sun. The planetary system is located at a distance of 2.57 +- 0.61 kpc towards the Galactic Centre. The projected separation of the planet from its host star is d=1.408 +- 0.019, in units of the Einstein radius, which corresponds to 2.72 +- 0.75 AU in physical units. We also identified a competitive model with similar planet and host star masses, but with a smaller orbital radius of 1.50 +- 0.50 AU. The planet is therefore located beyond the snow line of its host star, which we estimate to be around 1-1.5 AU., 12 pages, 7 figures, 3 tables; A&A in press

Published
2013
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2. Photometric multi-site campaign on the open cluster NGC 884

Author

Saesen, S., primary, Carrier, F., additional, Pigulski, A., additional, Aerts, C., additional, Handler, G., additional, Narwid, A., additional, Fu, J. N., additional, Zhang, C., additional, Jiang, X. J., additional, Vanautgaerden, J., additional, Kopacki, G., additional, Stęślicki, M., additional, Acke, B., additional, Poretti, E., additional, Uytterhoeven, K., additional, Gielen, C., additional, Østensen, R., additional, De Meester, W., additional, Reed, M. D., additional, Kołaczkowski, Z., additional, Michalska, G., additional, Schmidt, E., additional, Yakut, K., additional, Leitner, A., additional, Kalomeni, B., additional, Cherix, M., additional, Spano, M., additional, Prins, S., additional, Van Helshoecht, V., additional, Zima, W., additional, Huygen, R., additional, Vandenbussche, B., additional, Lenz, P., additional, Ladjal, D., additional, Puga Antolín, E., additional, Verhoelst, T., additional, De Ridder, J., additional, Niarchos, P., additional, Liakos, A., additional, Lorenz, D., additional, Dehaes, S., additional, Reyniers, M., additional, Davignon, G., additional, Kim, S.-L., additional, Kim, D. H., additional, Lee, Y.-J., additional, Lee, C.-U., additional, Kwon, J.-H., additional, Broeders, E., additional, Van Winckel, H., additional, Vanhollebeke, E., additional, Waelkens, C., additional, Raskin, G., additional, Blom, Y., additional, Eggen, J. R., additional, Degroote, P., additional, Beck, P., additional, Puschnig, J., additional, Schmitzberger, L., additional, Gelven, G. A., additional, Steininger, B., additional, Blommaert, J., additional, Drummond, R., additional, Briquet, M., additional, and Debosscher, J., additional

Published
2010
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4. WEBT multiwavelength monitoring and XMM-Newton observations of 
BL Lacertaein 2007–2008*

Author

Raiteri, C. M., Villata, M., Capetti, A., Aller, M. F., Bach, U., Calcidese, P., Gurwell, M. A., Larionov, V. M., Ohlert, J., Nilsson, K., Strigachev, A., Agudo, I., Aller, H. D., Bachev, R., Benítez, E., Berdyugin, A., Böttcher, M., Buemi, C. S., Buttiglione, S., Carosati, D., Charlot, P., Chen, W. P., Dultzin, D., Forné, E., Fuhrmann, L., Gómez, J. L., Gupta, A. C., Heidt, J., Hiriart, D., Hsiao, W.-S., Jelínek, M., Jorstad, S. G., Kimeridze, G. N., Konstantinova, T. S., Kopatskaya, E. N., Kostov, A., Kurtanidze, O. M., Lähteenmäki, A., Lanteri, L., Larionova, L. V., Leto, P., Latev, G., Le Campion, J.-F., Lee, C.-U., Ligustri, R., Lindfors, E., Marscher, A. P., Mihov, B., Nikolashvili, M. G., Nikolov, Y., Ovcharov, E., Principe, D., Pursimo, T., Ragozzine, B., Robb, R. M., Ros, J. A., Sadun, A. C., Sagar, R., Semkov, E., Sigua, L. A., Smart, R. L., Sorcia, M., Takalo, L. O., Tornikoski, M., Trigilio, C., Uckert, K., Umana, G., Valcheva, A., Volvach, A., Raiteri, C. M., Villata, M., Capetti, A., Aller, M. F., Bach, U., Calcidese, P., Gurwell, M. A., Larionov, V. M., Ohlert, J., Nilsson, K., Strigachev, A., Agudo, I., Aller, H. D., Bachev, R., Benítez, E., Berdyugin, A., Böttcher, M., Buemi, C. S., Buttiglione, S., Carosati, D., Charlot, P., Chen, W. P., Dultzin, D., Forné, E., Fuhrmann, L., Gómez, J. L., Gupta, A. C., Heidt, J., Hiriart, D., Hsiao, W.-S., Jelínek, M., Jorstad, S. G., Kimeridze, G. N., Konstantinova, T. S., Kopatskaya, E. N., Kostov, A., Kurtanidze, O. M., Lähteenmäki, A., Lanteri, L., Larionova, L. V., Leto, P., Latev, G., Le Campion, J.-F., Lee, C.-U., Ligustri, R., Lindfors, E., Marscher, A. P., Mihov, B., Nikolashvili, M. G., Nikolov, Y., Ovcharov, E., Principe, D., Pursimo, T., Ragozzine, B., Robb, R. M., Ros, J. A., Sadun, A. C., Sagar, R., Semkov, E., Sigua, L. A., Smart, R. L., Sorcia, M., Takalo, L. O., Tornikoski, M., Trigilio, C., Uckert, K., Umana, G., Valcheva, A., and Volvach, A.

Abstract

Context. BL Lacertaeis the prototype of the blazar subclass named after it. Yet, it has occasionally shown a peculiar behaviour that has questioned a simple interpretation of its broad-band emission in terms of synchrotron plus synchrotron self-Compton (SSC) radiation.

Published
2009
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5. A new activity phase of the blazar 3C 454.3*

Author

Raiteri, C. M., Villata, M., Larionov, V. M., Gurwell, M. A., Chen, W. P., Kurtanidze, O. M., Aller, M. F., Böttcher, M., Calcidese, P., Hroch, F., Lähteenmäki, A., Lee, C.-U., Nilsson, K., Ohlert, J., Papadakis, I. E., Agudo, I., Aller, H. D., Angelakis, E., Arkharov, A. A., Bach, U., Bachev, R., Berdyugin, A., Buemi, C. S., Carosati, D., Charlot, P., Chatzopoulos, E., Forné, E., Frasca, A., Fuhrmann, L., Gómez, J. L., Gupta, A. C., Hagen-Thorn, V. A., Hsiao, W.-S., Jordan, B., Jorstad, S. G., Konstantinova, T. S., Kopatskaya, E. N., Krichbaum, T. P., Lanteri, L., Larionova, L. V., Latev, G., Le Campion, J.-F., Leto, P., Lin, H.-C., Marchili, N., Marilli, E., Marscher, A. P., McBreen, B., Mihov, B., Nesci, R., Nicastro, F., Nikolashvili, M. G., Novak, R., Ovcharov, E., Pian, E., Principe, D., Pursimo, T., Ragozzine, B., Ros, J. A., Sadun, A. C., Sagar, R., Semkov, E., Smart, R. L., Smith, N., Strigachev, A., Takalo, L. O., Tavani, M., Tornikoski, M., Trigilio, C., Uckert, K., Umana, G., Valcheva, A., Vercellone, S., Volvach, A., Wiesemeyer, H., Raiteri, C. M., Villata, M., Larionov, V. M., Gurwell, M. A., Chen, W. P., Kurtanidze, O. M., Aller, M. F., Böttcher, M., Calcidese, P., Hroch, F., Lähteenmäki, A., Lee, C.-U., Nilsson, K., Ohlert, J., Papadakis, I. E., Agudo, I., Aller, H. D., Angelakis, E., Arkharov, A. A., Bach, U., Bachev, R., Berdyugin, A., Buemi, C. S., Carosati, D., Charlot, P., Chatzopoulos, E., Forné, E., Frasca, A., Fuhrmann, L., Gómez, J. L., Gupta, A. C., Hagen-Thorn, V. A., Hsiao, W.-S., Jordan, B., Jorstad, S. G., Konstantinova, T. S., Kopatskaya, E. N., Krichbaum, T. P., Lanteri, L., Larionova, L. V., Latev, G., Le Campion, J.-F., Leto, P., Lin, H.-C., Marchili, N., Marilli, E., Marscher, A. P., McBreen, B., Mihov, B., Nesci, R., Nicastro, F., Nikolashvili, M. G., Novak, R., Ovcharov, E., Pian, E., Principe, D., Pursimo, T., Ragozzine, B., Ros, J. A., Sadun, A. C., Sagar, R., Semkov, E., Smart, R. L., Smith, N., Strigachev, A., Takalo, L. O., Tavani, M., Tornikoski, M., Trigilio, C., Uckert, K., Umana, G., Valcheva, A., Vercellone, S., Volvach, A., and Wiesemeyer, H.

Abstract

Aims. The Whole Earth Blazar Telescope (WEBT) consortium has been monitoring the blazar 3C 454.3from the radio to the optical bands since 2004 to study its emission variability properties.

Published
2008
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6. Results of WEBT, VLBA and RXTE monitoring of 3C 279during 2006–2007*

Author

Larionov, V. M., Jorstad, S. G., Marscher, A. P., Raiteri, C. M., Villata, M., Agudo, I., Aller, M. F., Arkharov, A. A., Asfandiyarov, I. M., Bach, U., Bachev, R., Berdyugin, A., Böttcher, M., Buemi, C. S., Calcidese, P., Carosati, D., Charlot, P., Chen, W.-P., Di Paola, A., Dolci, M., Dogru, S., Doroshenko, V. T., Efimov, Yu. S., Erdem, A., Frasca, A., Fuhrmann, L., Giommi, P., Glowienka, L., Gupta, A. C., Gurwell, M. A., Hagen-Thorn, V. A., Hsiao, W.-S., Ibrahimov, M. A., Jordan, B., Kamada, M., Konstantinova, T. S., Kopatskaya, E. N., Kovalev, Y. Y., Kovalev, Y. A., Kurtanidze, O. M., Lähteenmäki, A., Lanteri, L., Larionova, L. V., Leto, P., Le Campion, P., Lee, C.-U., Lindfors, E., Marilli, E., McHardy, I., Mingaliev, M. G., Nazarov, S. V., Nieppola, E., Nilsson, K., Ohlert, J., Pasanen, M., Porter, D., Pursimo, T., Ros, J. A., Sadakane, K., Sadun, A. C., Sergeev, S. G., Smith, N., Strigachev, A., Sumitomo, N., Takalo, L. O., Tanaka, K., Trigilio, C., Umana, G., Ungerechts, H., Volvach, A., Yuan, W., Larionov, V. M., Jorstad, S. G., Marscher, A. P., Raiteri, C. M., Villata, M., Agudo, I., Aller, M. F., Arkharov, A. A., Asfandiyarov, I. M., Bach, U., Bachev, R., Berdyugin, A., Böttcher, M., Buemi, C. S., Calcidese, P., Carosati, D., Charlot, P., Chen, W.-P., Di Paola, A., Dolci, M., Dogru, S., Doroshenko, V. T., Efimov, Yu. S., Erdem, A., Frasca, A., Fuhrmann, L., Giommi, P., Glowienka, L., Gupta, A. C., Gurwell, M. A., Hagen-Thorn, V. A., Hsiao, W.-S., Ibrahimov, M. A., Jordan, B., Kamada, M., Konstantinova, T. S., Kopatskaya, E. N., Kovalev, Y. Y., Kovalev, Y. A., Kurtanidze, O. M., Lähteenmäki, A., Lanteri, L., Larionova, L. V., Leto, P., Le Campion, P., Lee, C.-U., Lindfors, E., Marilli, E., McHardy, I., Mingaliev, M. G., Nazarov, S. V., Nieppola, E., Nilsson, K., Ohlert, J., Pasanen, M., Porter, D., Pursimo, T., Ros, J. A., Sadakane, K., Sadun, A. C., Sergeev, S. G., Smith, N., Strigachev, A., Sumitomo, N., Takalo, L. O., Tanaka, K., Trigilio, C., Umana, G., Ungerechts, H., Volvach, A., and Yuan, W.

Abstract

Context. The quasar 3C 279is among the most extreme blazars in terms of luminosity and variability of flux at all wavebands. Its variations in flux and polarization are quite complex and therefore require intensive monitoring observations at multiple wavebands to characterise and interpret the observed changes.

Published
2008
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7. RACE-OC project: rotation and variability in the open cluster NGC 2099(M 37)

Author

Messina, S., Distefano, E., Parihar, P., Kang, Y. B., Kim, S.-L., Rey, S.-C., Lee, C.-U., Messina, S., Distefano, E., Parihar, P., Kang, Y. B., Kim, S.-L., Rey, S.-C., and Lee, C.-U.

Abstract

Context. Rotation and solar-type magnetic activity are closely related to each other in main-sequence stars of G or later spectral types. The presence and level of magnetic activity depend on star's rotation, and rotation itself is strongly influenced by strength and topology of the magnetic fields. Open clusters represent especially useful targets to investigate the connection between rotation and activity.

Published
2008
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8. Radio-to-UV monitoring of AO 0235+164by the WEBT and Swift during the 2006–2007 outburst

Author

Raiteri, C. M., Villata, M., Larionov, V. M., Aller, M. F., Bach, U., Gurwell, M., Kurtanidze, O. M., Lähteenmäki, A., Nilsson, K., Volvach, A., Aller, H. D., Arkharov, A. A., Bachev, R., Berdyugin, A., Böttcher, M., Buemi, C. S., Calcidese, P., Cozzi, E., Di Paola, A., Dolci, M., Fan, J. H., Forné, E., Foschini, L., Gupta, A. C., Hagen-Thorn, V. A., Hooks, L., Hovatta, T., Joshi, M., Kadler, M., Kimeridze, G. N., Konstantinova, T. S., Kostov, A., Krichbaum, T. P., Lanteri, L., Larionova, L. V., Lee, C.-U., Leto, P., Lindfors, E., Montagni, F., Nesci, R., Nieppola, E., Nikolashvili, M. G., Ohlert, J., Oksanen, A., Ovcharov, E., Pääkkönen, P., Pasanen, M., Pursimo, T., Ros, J. A., Semkov, E., Sigua, L. A., Smart, R. L., Strigachev, A., Takalo, L. O., Torii, K., Torniainen, I., Tornikoski, M., Trigilio, C., Tsunemi, H., Umana, G., Valcheva, A., Raiteri, C. M., Villata, M., Larionov, V. M., Aller, M. F., Bach, U., Gurwell, M., Kurtanidze, O. M., Lähteenmäki, A., Nilsson, K., Volvach, A., Aller, H. D., Arkharov, A. A., Bachev, R., Berdyugin, A., Böttcher, M., Buemi, C. S., Calcidese, P., Cozzi, E., Di Paola, A., Dolci, M., Fan, J. H., Forné, E., Foschini, L., Gupta, A. C., Hagen-Thorn, V. A., Hooks, L., Hovatta, T., Joshi, M., Kadler, M., Kimeridze, G. N., Konstantinova, T. S., Kostov, A., Krichbaum, T. P., Lanteri, L., Larionova, L. V., Lee, C.-U., Leto, P., Lindfors, E., Montagni, F., Nesci, R., Nieppola, E., Nikolashvili, M. G., Ohlert, J., Oksanen, A., Ovcharov, E., Pääkkönen, P., Pasanen, M., Pursimo, T., Ros, J. A., Semkov, E., Sigua, L. A., Smart, R. L., Strigachev, A., Takalo, L. O., Torii, K., Torniainen, I., Tornikoski, M., Trigilio, C., Tsunemi, H., Umana, G., and Valcheva, A.

Abstract

Context.The blazar AO 0235+164was claimed to show a quasi-periodic behaviour in the radio and optical bands in the past, with the main outbursts repeating every 5–6 years. However, the predicted 2004 outburst did not occur, and further analysis suggested a longer time scale, according to which the next event would have occurred in the 2006–2007 observing season. Moreover, an extra emission component contributing to the UV and soft X-ray flux was detected, whose nature is not yet clear. An optical outburst was observed in late 2006–early 2007, which triggered a Whole Earth Blazar Telescope (WEBT) campaign as well as target of opportunity (ToO) observations by the Swift satellite.

Published
2008
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9. WEBT and XMM-Newton observations of 3C 454.3during the post-outburst phase*

Author

Raiteri, C. M., Villata, M., Larionov, V. M., Pursimo, T., Ibrahimov, M. A., Nilsson, K., Aller, M. F., Kurtanidze, O. M., Foschini, L., Ohlert, J., Papadakis, I. E., Sumitomo, N., Volvach, A., Aller, H. D., Arkharov, A. A., Bach, U., Berdyugin, A., Böttcher, M., Buemi, C. S., Calcidese, P., Charlot, P., Delgado Sánchez, A. J., Di Paola, A., Djupvik, A. A., Dolci, M., Efimova, N. V., Fan, J. H., Forné, E., Gomez, C. A., Gupta, A. C., Hagen-Thorn, V. A., Hooks, L., Hovatta, T., Ishii, Y., Kamada, M., Konstantinova, T., Kopatskaya, E., Kovalev, Yu. A., Kovalev, Y. Y., Lähteenmäki, A., Lanteri, L., Le Campion, J.-F., Lee, C.-U., Leto, P., Lin, H.-C., Lindfors, E., Mingaliev, M. G., Mizoguchi, S., Nicastro, F., Nikolashvili, M. G., Nishiyama, S., Östman, L., Ovcharov, E., Pääkkönen, P., Pasanen, M., Pian, E., Rector, T., Ros, J. A., Sadakane, K., Selj, J. H., Semkov, E., Sharapov, D., Somero, A., Stanev, I., Strigachev, A., Takalo, L., Tanaka, K., Tavani, M., Torniainen, I., Tornikoski, M., Trigilio, C., Umana, G., Vercellone, S., Valcheva, A., Volvach, L., Yamanaka, M., Raiteri, C. M., Villata, M., Larionov, V. M., Pursimo, T., Ibrahimov, M. A., Nilsson, K., Aller, M. F., Kurtanidze, O. M., Foschini, L., Ohlert, J., Papadakis, I. E., Sumitomo, N., Volvach, A., Aller, H. D., Arkharov, A. A., Bach, U., Berdyugin, A., Böttcher, M., Buemi, C. S., Calcidese, P., Charlot, P., Delgado Sánchez, A. J., Di Paola, A., Djupvik, A. A., Dolci, M., Efimova, N. V., Fan, J. H., Forné, E., Gomez, C. A., Gupta, A. C., Hagen-Thorn, V. A., Hooks, L., Hovatta, T., Ishii, Y., Kamada, M., Konstantinova, T., Kopatskaya, E., Kovalev, Yu. A., Kovalev, Y. Y., Lähteenmäki, A., Lanteri, L., Le Campion, J.-F., Lee, C.-U., Leto, P., Lin, H.-C., Lindfors, E., Mingaliev, M. G., Mizoguchi, S., Nicastro, F., Nikolashvili, M. G., Nishiyama, S., Östman, L., Ovcharov, E., Pääkkönen, P., Pasanen, M., Pian, E., Rector, T., Ros, J. A., Sadakane, K., Selj, J. H., Semkov, E., Sharapov, D., Somero, A., Stanev, I., Strigachev, A., Takalo, L., Tanaka, K., Tavani, M., Torniainen, I., Tornikoski, M., Trigilio, C., Umana, G., Vercellone, S., Valcheva, A., Volvach, L., and Yamanaka, M.

Abstract

Context.The quasar-type blazar 3C 454.3was observed to undergo an unprecedented optical outburst in spring 2005, affecting the source brightness from the near-IR to the X-ray frequencies. This was first followed by a millimetric and then by a radio outburst, which peaked in February 2006.

Published
2007
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10. The radio delay of the exceptional 3C 454.3outburst*

Author

Villata, M., Raiteri, C. M., Aller, M. F., Bach, U., Ibrahimov, M. A., Kovalev, Y. Y., Kurtanidze, O. M., Larionov, V. M., Lee, C.-U., Leto, P., Lähteenmäki, A., Nilsson, K., Pursimo, T., Ros, J. A., Sumitomo, N., Volvach, A., Aller, H. D., Arai, A., Buemi, C. S., Coloma, J. M., Doroshenko, V. T., Efimov, Yu. S., Fuhrmann, L., Hagen-Thorn, V. A., Kamada, M., Katsuura, M., Konstantinova, T., Kopatskaya, E., Kotaka, D., Kovalev, Yu. A., Kurosaki, M., Lanteri, L., Larionova, L., Mingaliev, M. G., Mizoguchi, S., Nakamura, K., Nikolashvili, M. G., Nishiyama, S., Sadakane, K., Sergeev, S. G., Sigua, L. A., Sillanpää, A., Smart, R. L., Takalo, L. O., Tanaka, K., Tornikoski, M., Trigilio, C., Umana, G., Villata, M., Raiteri, C. M., Aller, M. F., Bach, U., Ibrahimov, M. A., Kovalev, Y. Y., Kurtanidze, O. M., Larionov, V. M., Lee, C.-U., Leto, P., Lähteenmäki, A., Nilsson, K., Pursimo, T., Ros, J. A., Sumitomo, N., Volvach, A., Aller, H. D., Arai, A., Buemi, C. S., Coloma, J. M., Doroshenko, V. T., Efimov, Yu. S., Fuhrmann, L., Hagen-Thorn, V. A., Kamada, M., Katsuura, M., Konstantinova, T., Kopatskaya, E., Kotaka, D., Kovalev, Yu. A., Kurosaki, M., Lanteri, L., Larionova, L., Mingaliev, M. G., Mizoguchi, S., Nakamura, K., Nikolashvili, M. G., Nishiyama, S., Sadakane, K., Sergeev, S. G., Sigua, L. A., Sillanpää, A., Smart, R. L., Takalo, L. O., Tanaka, K., Tornikoski, M., Trigilio, C., and Umana, G.

Abstract

Context.In spring 2005 the blazar 3C 454.3was observed in an unprecedented bright state from the near-IR to the hard X-ray frequencies. A mm outburst peaked in June–July 2005, and it was followed by a flux increase at high radio frequencies.

Published
2007
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11. Multifrequency variability of the blazar AO 0235+164

Author

Raiteri, C. M., Villata, M., Kadler, M., Ibrahimov, M. A., Kurtanidze, O. M., Larionov, V. M., Tornikoski, M., Boltwood, P., Lee, C.-U., Aller, M. F., Romero, G. E., Aller, H. D., Araudo, A. T., Arkharov, A. A., Bach, U., Barnaby, D., Berdyugin, A., Buemi, C. S., Carini, M. T., Carosati, D., Cellone, S. A., Cool, R., Dolci, M., Efimova, N. V., Fuhrmann, L., Hagen-Thorn, V. A., Holcomb, M., Ilyin, I., Impellizzeri, V., Ivanidze, R. Z., Kapanadze, B. Z., Kerp, J., Konstantinova, T. S., Kovalev, Y. Y., Kovalev, Yu. A., Kraus, A., Krichbaum, T. P., Lähteenmäki, A., Lanteri, L., Leto, P., Lindfors, E., Mattox, J. R., Napoleone, N., Nikolashvili, M. G., Nilsson, K., Ohlert, J., Papadakis, I. E., Pasanen, M., Poteet, C., Pursimo, T., Ros, E., Sigua, L. A., Smith, S., Takalo, L. O., Trigilio, C., Tröller, M., Umana, G., Ungerechts, H., Walters, R., Witzel, A., Xilouris, E., Raiteri, C. M., Villata, M., Kadler, M., Ibrahimov, M. A., Kurtanidze, O. M., Larionov, V. M., Tornikoski, M., Boltwood, P., Lee, C.-U., Aller, M. F., Romero, G. E., Aller, H. D., Araudo, A. T., Arkharov, A. A., Bach, U., Barnaby, D., Berdyugin, A., Buemi, C. S., Carini, M. T., Carosati, D., Cellone, S. A., Cool, R., Dolci, M., Efimova, N. V., Fuhrmann, L., Hagen-Thorn, V. A., Holcomb, M., Ilyin, I., Impellizzeri, V., Ivanidze, R. Z., Kapanadze, B. Z., Kerp, J., Konstantinova, T. S., Kovalev, Y. Y., Kovalev, Yu. A., Kraus, A., Krichbaum, T. P., Lähteenmäki, A., Lanteri, L., Leto, P., Lindfors, E., Mattox, J. R., Napoleone, N., Nikolashvili, M. G., Nilsson, K., Ohlert, J., Papadakis, I. E., Pasanen, M., Poteet, C., Pursimo, T., Ros, E., Sigua, L. A., Smith, S., Takalo, L. O., Trigilio, C., Tröller, M., Umana, G., Ungerechts, H., Walters, R., Witzel, A., and Xilouris, E.

Abstract

Aims.A huge multiwavelength campaign targeting the blazar AO 0235+164was organized by the Whole Earth Blazar Telescope (WEBT) in 2003–2005 to study the variability properties of the source.

Published
2006
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12. The unprecedented optical outburst of the quasar 3C 454.3

Author

Villata, M., Raiteri, C. M., Balonek, T. J., Aller, M. F., Jorstad, S. G., Kurtanidze, O. M., Nicastro, F., Nilsson, K., Aller, H. D., Arai, A., Arkharov, A., Bach, U., Benítez, E., Berdyugin, A., Buemi, C. S., Böttcher, M., Carosati, D., Casas, R., Caulet, A., Chen, W. P., Chiang, P.-S., Chou, Y., Ciprini, S., Coloma, J. M., Di Rico, G., Díaz, C., Efimova, N. V., Forsyth, C., Frasca, A., Fuhrmann, L., Gadway, B., Gupta, S., Hagen-Thorn, V. A., Harvey, J., Heidt, J., Hernandez-Toledo, H., Hroch, F., Hu, C.-P., Hudec, R., Ibrahimov, M. A., Imada, A., Kamata, M., Kato, T., Katsuura, M., Konstantinova, T., Kopatskaya, E., Kotaka, D., Kovalev, Y. Y., Kovalev, Yu. A., Krichbaum, T. P., Kubota, K., Kurosaki, M., Lanteri, L., Larionov, V. M., Larionova, L., Laurikainen, E., Lee, C.-U., Leto, P., Lähteenmäki, A., López-Cruz, O., Marilli, E., Marscher, A. P., McHardy, I. M., Mondal, S., Mullan, B., Napoleone, N., Nikolashvili, M. G., Ohlert, J. M., Postnikov, S., Pursimo, T., Ragni, M., Ros, J. A., Sadakane, K., Sadun, A. C., Savolainen, T., Sergeeva, E. A., Sigua, L. A., Sillanpää, A., Sixtova, L., Sumitomo, N., Takalo, L. O., Teräsranta, H., Tornikoski, M., Trigilio, C., Umana, G., Volvach, A., Voss, B., Wortel, S., Villata, M., Raiteri, C. M., Balonek, T. J., Aller, M. F., Jorstad, S. G., Kurtanidze, O. M., Nicastro, F., Nilsson, K., Aller, H. D., Arai, A., Arkharov, A., Bach, U., Benítez, E., Berdyugin, A., Buemi, C. S., Böttcher, M., Carosati, D., Casas, R., Caulet, A., Chen, W. P., Chiang, P.-S., Chou, Y., Ciprini, S., Coloma, J. M., Di Rico, G., Díaz, C., Efimova, N. V., Forsyth, C., Frasca, A., Fuhrmann, L., Gadway, B., Gupta, S., Hagen-Thorn, V. A., Harvey, J., Heidt, J., Hernandez-Toledo, H., Hroch, F., Hu, C.-P., Hudec, R., Ibrahimov, M. A., Imada, A., Kamata, M., Kato, T., Katsuura, M., Konstantinova, T., Kopatskaya, E., Kotaka, D., Kovalev, Y. Y., Kovalev, Yu. A., Krichbaum, T. P., Kubota, K., Kurosaki, M., Lanteri, L., Larionov, V. M., Larionova, L., Laurikainen, E., Lee, C.-U., Leto, P., Lähteenmäki, A., López-Cruz, O., Marilli, E., Marscher, A. P., McHardy, I. M., Mondal, S., Mullan, B., Napoleone, N., Nikolashvili, M. G., Ohlert, J. M., Postnikov, S., Pursimo, T., Ragni, M., Ros, J. A., Sadakane, K., Sadun, A. C., Savolainen, T., Sergeeva, E. A., Sigua, L. A., Sillanpää, A., Sixtova, L., Sumitomo, N., Takalo, L. O., Teräsranta, H., Tornikoski, M., Trigilio, C., Umana, G., Volvach, A., Voss, B., and Wortel, S.

Abstract

Context.The radio quasar 3C 454.3underwent an exceptional optical outburst lasting more than 1 year and culminating in spring 2005. The maximum brightness detected was $R=12.0$, which represents the most luminous quasar state thus far observed ($M_B \sim -31.4$).

Published
2006
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13. Multi-colour optical monitoring of eight red blazars

Author

Gu, M. F., Lee, C.-U., Pak, S., Yim, H. S., Fletcher, A. B., Gu, M. F., Lee, C.-U., Pak, S., Yim, H. S., and Fletcher, A. B.

Abstract

Context.We present the observational results of multi-colour optical monitoring of eight red blazars from 2003 September to 2004 February.Aims.The aim of our monitoring is to investigate the spectral variability as well as the flux variations at short and long time scales.Methods.The observations were carried out using the 1.0 m robotic telescope of Mt. Lemmon Optical Astronomy Observatory, in Arizona, USA, the 0.6 m telescope of Sobaeksan Optical Astronomy Observatory and the 1.8 m telescope of Bohyunsan Optical Astronomy Observatory, in the Republic of Korea.Results.During the observations, all sources show strong flux variations with amplitudes of larger than 0.5 mag. Variations with amplitudes of over 1 mag are found in four sources. Intraday variations with amplitudes larger than 0.15 mag, and a rapid brightness increase with a rate of ~0.2 mag per day in four days, are detected in S5 0716+71. We investigate the relationship between the colour index and source brightness for each source. We find that two out of three FSRQs tend to be redder when they are brighter, and, conversely, all BL Lac objects tend to be bluer. In particular, we find a significant anti-correlation between the $V-I$colour index and Rmagnitude for 3C 454.3. This implies that the spectrum became steeper when the source was brighter, which is opposite to the common trend for blazars. In contrast, significant positive correlations are found in 3C 66A, S5 0716+71, and BL Lac. However, there are only very weak correlations for PKS 0735+17 and OJ 287.Conclusions.We propose that the different relative contributions of the thermal versus non-thermal radiation to the optical emission may be responsible for the different trends of the colour index with brightness in FSRQs and BL Lac objects.

Published
2006
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14. Multiband photometric re-classification of ROTSE-I δScuti type stars*

Author

Jin, H., Kim, S.-L., Kwon, S.-G., Youn, J.-H., Lee, C.-U., Lee, D.-J., Kim, K.-S., Jin, H., Kim, S.-L., Kwon, S.-G., Youn, J.-H., Lee, C.-U., Lee, D.-J., and Kim, K.-S.

Abstract

We present multi-passband CCD photometry of 20 ROTSE-I δScuti type pulsating stars and 1 RR Lyrae star to re-classify their variable types using the comparison of amplitudes between Vand Ipassbands. For the re-classification, we used a criterion that pulsating stars have larger amplitude differences between passbands than eclipsing binaries because brightness changes of pulsating stars are mainly due to the temperature variations. As a result, only six stars were re-confirmed as δScuti variables and thirteen stars turned out to be W UMa type eclipsing binaries. The other two stars were identified as one cataclysmic variable and one non-variable, respectively. Our results suggest that a number of ROTSE-I δScuti type stars, which do not show typical pulsating light curves of high amplitude δScuti stars, are W UMa type eclipsing binaries.

Published
2003
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15. The high activity of 3C?454.3 in autumn 2007

Author

Raiteri, C., Villata, M., Chen, W., Hsiao, W.-S., Kurtanidze, O., Nilsson, K., Larionov, V., Gurwell, M., Agudo, I., Aller, H., Aller, M., Angelakis, E., Arkharov, A., Bach, U., B?ttcher, M., Buemi, C., Calcidese, P., Charlot, P., D'Ammando, F., Donnarumma, I., Forn?, E., Frasca, A., Fuhrmann, L., G?mez, J., Hagen-Thorn, V., Jorstad, S., Kimeridze, G., Krichbaum, T., L?hteenm?ki, A., Lanteri, L., Latev, G., Le Campion, J.-F., Lee, C.-U., Leto, P., Lin, H.-C., Marchili, N., Marilli, E., Marscher, A., Nesci, R., Nieppola, E., Nikolashvili, M., Ohlert, J., Ovcharov, E., Principe, D., Pursimo, T., Ragozzine, B., Sadun, A., Sigua, L., Smart, R., Strigachev, A., Takalo, L., Tavani, M., Thum, C., Tornikoski, M., Trigilio, C., Uckert, K., Umana, G., Valcheva, A., Vercellone, S., Volvach, A., and Wiesemeyer, H.

Abstract

Context. The quasar-type blazar 3C 454.3 underwent a phase of high activity in summer and autumn?2007 that was intensively monitored in the radio-to-optical bands by the Whole Earth Blazar Telescope (WEBT). The ?-ray satellite Astro-rivelatore Gamma a Immagini LEggero (AGILE) detected this source first in late July, and then in November?December 2007.Aims. We present the multifrequency data collected by the WEBT and collaborators during the second AGILE observing period, complemented by contemporaneous data from the UltraViolet and Optical Telescope (UVOT) onboard the Swift satellite. The aim is to trace in detail the behaviour of the synchrotron emission from the blazar jet, and to investigate the contribution from the thermal emission component.Methods. Optical data from about twenty telescopes have been homogeneously calibrated and carefully assembled to construct an R-band light curve containing about 1340?data points over 42?days. This extremely well-sampled optical light curve allows us to follow the dramatic flux variability of the source in detail. In addition, we show radio-to-UV spectral energy distributions (SEDs) at different epochs, which represent different brightness levels.Results. In the considered period, the source varied by 2.6?mag over two weeks in the R?band. Many episodes of fast (i.e.?intranight) variability were observed, most notably on December?12, when a flux increase of about 1.1?mag in 1.5?h was detected, followed by a steep decrease of about 1.2?mag in 1?h. The contribution by the thermal component is difficult to assess, due to the uncertainties in the Galactic, and possibly also intrinsic, extinction in the UV?band. However, polynomial fitting of radio-to-UV?SEDs reveals an increasing spectral bending towards fainter states, suggesting a UV?excess likely due to the thermal emission from the accretion disc.Conclusions. Once the AGILE data are completely analysed, the low-frequency observations presented in this letter will offer a powerful tool to investigate optical-? flux correlations, i.e.?the relationship between the synchrotron and inverse-Compton emission components.

Published
2008

16. RACE-OC project: rotation and variability in the open cluster NGC 2099 (M?37)

Author

Messina, S., Distefano, E., Parihar, P., Kang, Y., Kim, S.-L., Rey, S.-C., and Lee, C.-U.

Abstract

Context. Rotation and solar-type magnetic activity are closely related to each other in main-sequence stars of G or later spectral types. The presence and level of magnetic activity depend on star's rotation, and rotation itself is strongly influenced by strength and topology of the magnetic fields. Open clusters represent especially useful targets to investigate the connection between rotation and activity.Aims. The open cluster NGC 2099 has been studied as a part of the RACE-OC project (Rotation and ACtivity Evolution in Open Clusters), which is aimed at exploring the evolution of rotation and magnetic activity in the late-type members of open clusters of different ages.Methods. We collected time series CCD photometric observations of this cluster in January?2004, and we determined the presence of periodicities in the flux variation related to the stellar rotation by Fourier analysis. We investigate the relations between activity manifestations, such as the light curve amplitude, and global stellar parameters.Results. We have discovered 135 periodic variables, 122 of which are candidate cluster members. Determination of rotation periods of G- and K-type stars has allowed us to better explore the evolution of angular momentum at an age of about 500?Myr. In our analysis, we have also identified 3?new detached eclipsing binary candidates among cluster members.Conclusions. A comparison with the older Hyades cluster (~625?Myr) shows that the newly-determined distribution of rotation periods is consistent with the scenario of rotational braking of main-sequence spotted stars as they age. However, a comparison with the younger M?34 cluster (~200?Myr) shows that the G8-K5?members of these clusters have the same rotation period distribution. That is, G8-K5?members in NGC?2099 seem to have experienced no significant braking in the age range from ~200 to ~500?Myr. Finally, NGC?2099 members have a smaller level of photospheric magnetic activity, as measured by light curve amplitude, than in younger stars of the same mass and rotation, suggesting that the activity level also depends on some other age-dependent parameters.

Published
2008

17. OGLE 2008–BLG–290: an accurate measurement of the limb darkening of a galactic bulge K Giant spatially resolved by microlensing

Author

Fouqué, P., Heyrovský, D., Dong, S., Gould, A., Udalski, A., Albrow, M. D., Batista, V., Beaulieu, J.-P., Bennett, D. P., Bond, I. A., Bramich, D. M., Calchi Novati, S., Cassan, A., Coutures, C., Dieters, S., Dominik, M., Dominis Prester, D., Greenhill, J., Horne, K., Jørgensen, U. G., Kozłowski, S., Kubas, D., Lee, C.-H., Marquette, J.-B., Mathiasen, M., Menzies, J., Monard, L. A. G., Nishiyama, S., Papadakis, I., Street, R., Sumi, T., Williams, A., Yee, J. C., Brillant, S., Caldwell, J. A. R., Cole, A., Cook, K. H., Donatowicz, J., Kains, N., Kane, S. R., Martin, R., Pollard, K. R., Sahu, K. C., Tsapras, Y., Wambsganss, J., DePoy, D. L., Gaudi, B. S., Han, C., Lee, C.-U., Park, B.-G., Kubiak, M., Szymański, M. K., Pietrzyński, G., Soszyński, I., Szewczyk, O., Ulaczyk, K., Abe, F., Fukui, A., Furusawa, K., Gilmore, A. C., Hearnshaw, J. B., Itow, Y., Kamiya, K., Kilmartin, P. M., Korpela, A. V., Lin, W., Ling, C. H., Masuda, K., Matsubara, Y., Miyake, N., Muraki, Y., Nagaya, M., Ohnishi, K., Okumura, T., Perrott, Y., Rattenbury, N. J., Saito, To., Sako, T., Sato, S., Skuljan, L., Sullivan, D., Sweatman, W., Tristram, P. J., Allan, A., Bode, M. F., Burgdorf, M. J., Clay, N., Fraser, S. N., Hawkins, E., Kerins, E., Lister, T. A., Mottram, C. J., Saunders, E. S., Snodgrass, C., Steele, I. A., Anguita, T., Bozza, V., Harpsøe, K., Hinse, T. C., Hundertmark, M., Kjærgaard, P., Liebig, C., Mancini, L., Masi, G., Rahvar, S., Ricci, D., Scarpetta, G., Southworth, J., Surdej, J., Thöne, C. C., Riffeser, A., and Seitz, S.

Abstract

Context. Not only is gravitational microlensing a successful tool for discovering distant exoplanets, but it also enables characterization of the lens and source stars involved in the lensing event.Aims. In high-magnification events, the lens caustic may cross over the source disk, which allows determination of the angular size of the source and measurement of its limb darkening.Methods. When such extended-source effects appear close to maximum magnification, the resulting light curve differs from the characteristic Paczyński point-source curve. The exact shape of the light curve close to the peak depends on the limb darkening of the source. Dense photometric coverage permits measurement of the respective limb-darkening coefficients.Results. In the case of the microlensing event OGLE 2008-BLG-290, the K giant source star reached a peak magnification at about 100. Thirteen different telescopes have covered this event in eight different photometric bands. Subsequent light-curve analysis yielded measurements of linear limb-darkening coefficients of the source in six photometric bands. The best-measured coefficients lead to an estimate of the source effective temperature of about 4700$^{+100}_{-200}$K. However, the photometric estimate from colour-magnitude diagrams favours a cooler temperature of 4200 ±100 K.Conclusions. Because the limb-darkening measurements, at least in the CTIO/SMARTS2 $V_\mathrm{s}$- and $I_\mathrm{s}$-bands, are among the most accurate obtained, the above disagreement needs to be understood. A solution is proposed, which may apply to previous events where such a discrepancy also appeared.

Published
2010

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