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1. Extreme photometric and polarimetric variability of blazar S4 0954+65 at its maximum optical and γ-ray brightness levels.

Author

Raiteri, C M, Villata, M, Carnerero, M I, Savchenko, S S, Kurtanidze, S O, Vlasyuk, V V, Marchini, A, Matsumoto, K, Lorey, C, Joner, M D, Gazeas, K, Carosati, D, Mirzaqulov, D O, Acosta Pulido, J A, Agudo, I, Bachev, R, Benítez, E, Borman, G A, Calcidese, P, and Chen, W P

Subjects
BL Lacertae objects, POLARIMETRY, MAGNETIC reconnection, BREWSTER'S angle, ACTIVE galaxies, RADARSAT satellites
Abstract

In 2022 the BL Lac object S4 0954+65 underwent a major variability phase, reaching its historical maximum brightness in the optical and γ-ray bands. We present optical photometric and polarimetric data acquired by the Whole Earth Blazar Telescope (WEBT) Collaboration from 2022 April 6 to July 6. Many episodes of unprecedented fast variability were detected, implying an upper limit to the size of the emitting region as low as |$10^{-4}$| parsec. The WEBT data show rapid variability in both the degree and angle of polarization. We analyse different models to explain the polarization behaviour in the framework of a twisting jet model, which assumes that the long-term trend of the flux is produced by variations in the emitting region viewing angle. All the models can reproduce the average trend of the polarization degree, and can account for its general anticorrelation with the flux, but the dispersion of the data requires the presence of intrinsic mechanisms, such as turbulence, shocks, or magnetic reconnection. The WEBT optical data are compared to γ-ray data from the Fermi satellite. These are analysed with both fixed and adaptive binning procedures. We show that the strong correlation between optical and γ-ray data without measurable delay assumes different slopes in faint and high brightness states, and this is compatible with a scenario where in faint states we mainly see the imprint of the geometrical effects, while in bright states the synchrotron self-Compton process dominates. [ABSTRACT FROM AUTHOR]

Published
2023
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2. Multiwavelength Observations of the Blazar VER J0521+211 during an Elevated TeV Gamma-Ray State

Author

Abe, H., Abe, S., Acciari, V. A., Agudo, I., Aniello, T., Ansoldi, S., Antonelli, L. A., Arbet Engels, A., Arcaro, C., Artero, M., Asano, K., Baack, D., Babić, A., Baquero, A., Barres de Almeida, U., Barrio, J. A., Batković, I., Baxter, J., Becerra González, J., Bednarek, W., Bernardini, E., Bernardos, M., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Bošnjak, Ž., Burelli, I., Busetto, G., Carosi, R., Carretero-Castrillo, M., Castro-Tirado, A. J., Ceribella, G., Chai, Y., Chilingarian, A., Cikota, S., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D'Amico, G., D'Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Del Popolo, A., Delfino, M., Delgado, J., Delgado Mendez, C., Depaoli, D., Di Pierro, F., Di Venere, L., Do Souto Espiñeira, E., Dominis Prester, D., Donini, A., Dorner, D., Doro, M., Elsaesser, D., Emery, G., Escudero, J., Fallah Ramazani, V., Fariña, L., Fattorini, A., Foffano, L., Font, L., Fruck, C., Fukami, S., Fukazawa, Y., García López, R. J., Garczarczyk, M., Gasparyan, S., Gaug, M., Giesbrecht Paiva, J. G., Giglietto, N., Giordano, F., Gliwny, P., Godinović, N., Grau, R., Green, D., Green, J. G., Hadasch, D., Hahn, A., Hassan, T., Heckmann, L., Herrera, J., Hrupec, D., Hütten, M., Imazawa, R., Inada, T., Iotov, R., Ishio, K., Jiménez Martínez, I., Jormanainen, J., Kerszberg, D., Kobayashi, Y., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Linhoff, L., Lombardi, S., Longo, F., López-Coto, R., López-Moya, M., López-Oramas, A., Loporchio, S., Lorini, A., Lyard, E., Machado de Oliveira Fraga, B., Majumdar, P., Makariev, M., Maneva, G., Mang, N., Manganaro, M., Mangano, S., Mannheim, K., Mariotti, M., Martínez, M., Mas-Aguilar, A., Mazin, D., Menchiari, S., Mender, S., Mićanović, S., Miceli, D., Miener, T., Miranda, J. M., Mirzoyan, R., Molina, E., Mondal, H. A., Moralejo, A., Morcuende, D., Moreno, V., Nakamori, T., Nanci, C., Nava, L., Neustroev, V., Nievas Rosillo, M., Nigro, C., Nilsson, K., Nishijima, K., Njoh Ekoume, T., Noda, K., Nozaki, S., Ohtani, Y., Oka, T., Okumura, A., Otero-Santos, J., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Pavletić, L., Persic, M., Pihet, M., Pirola, G., Podobnik, F., Prada Moroni, P. G., Prandini, E., Principe, G., Priyadarshi, C., Rhode, W., Ribó, M., Rico, J., Righi, C., Rugliancich, A., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Saturni, F. G., Schleicher, B., Schmidt, K., Schmuckermaier, F., Schubert, J. L., Schweizer, T., Sitarek, J., Sliusar, V., Sobczynska, D., Spolon, A., Stamerra, A., Strišković, J., Strom, D., Strzys, M., Suda, Y., Surić, T., Tajima, H., Takahashi, M., Takeishi, R., Tavecchio, F., Temnikov, P., Terauchi, K., Terzić, T., Teshima, M., Tosti, L., Truzzi, S., Tutone, A., Ubach, S., van Scherpenberg, J., Vazquez Acosta, M., Ventura, S., Verguilov, V., Viale, I., Vigorito, C. F., Vitale, V., Vovk, I., Walter, R., Will, M., Wunderlich, C., Yamamoto, T., Zarić, D., Other, Groups, Cerruti, collaborations: M., Acosta-Pulido, J. A., Apolonio, G., Bachev, R., Baloković, M., Benítez, E., Björklund, I., Bozhilov, V., Brown, L. F., Bugg, A., Carbonell, W., Carnerero, M. I., Carosati, D., Casadio, C., Chamani, W., Chen, W. P., Chigladze, R. A., Damljanovic, G., Epps, K., Erkenov, A., Feige, M., Finke, J., Fuentes, A., Gazeas, K., Giroletti, M., Grishina, T. S., Gupta, A. C., Gurwell, M. A., Heidemann, E., Hiriart, D., Hou, W. J., Hovatta, T., Ibryamov, S., Joner, M. D., Jorstad, S. G., Kania, J., Kiehlmann, S., Kimeridze, G. N., Kopatskaya, E. N., Kopp, M., Korte, M., Kotas, B., Koyama, S., Kramer, J. A., Kunkel, L., Kurtanidze, S. O., Kurtanidze, O. M., Lähteenmäki, A., López, J. M., Larionov, V. M., Larionova, E. G., Larionova, L. V., Leto, C., Lorey, C., Mújica, R., Madejski, G. M., Marchili, N., Marscher, A. P., Minev, M., Modaressi, A., Morozova, D. A., Mufakharov, T., Myserlis, I., Nikiforova, A. A., Nikolashvili, M. G., Ovcharov, E., Perri, M., Raiteri, C. M., Readhead, A. C. S., Reimer, A., Reinhart, D., Righini, S., Rosenlehner, K., Sadun, A. C., Savchenko, S. S., Scherbantin, A., Schneider, L., Schoch, K., Seifert, D., Semkov, E., Sigua, L. A., Singh, C., Sola, P., Sotnikova, Y., Spencer, M., Steineke, R., Stojanovic, M., Strigachev, A., Tornikoski, M., Traianou, E., Tramacere, A., Troitskaya, Yu. V., Troitskiy, I. S., Trump, J. B., Tsai, A., Valcheva, A., Vasilyev, A. A., Verrecchia, F., Villata, M., Vince, O., Vrontaki, K., Weaver, Z. R., Zaharieva, E., Zottmann, N., Ministerio de Ciencia e Innovación (España), European Commission, Federal Ministry of Education and Research (Germany), Istituto Nazionale di Fisica Nucleare, Istituto Nazionale di Astrofisica, Swiss National Science Foundation, Department of Atomic Energy (India), Ministry of Education, Culture, Sports, Science and Technology (Japan), Ministry of Education and Science (Bulgaria), and Academy of Finland

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), BL Lacertae objects: individual (VER J0521+211 = RGB J0521.8+2112) – galaxies: active – galaxies: jets – gamma rays: galaxies – radiation mechanisms: non-thermal, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Active galactic nuclei, High energy astrophysics, Blazars, BL Lacertae objects, Relativistic jets, Gamma-rays, Non-thermal radiation sources, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), ddc:520, Física nuclear, Astrophysics - High Energy Astrophysical Phenomena
Abstract

Full list of authors: Adams, C. B.; Batista, P.; Benbow, W.; Brill, A.; Brose, R.; Buckley, J. H.; Capasso, M.; Christiansen, J. L.; Errando, M.; Feng, Q.; Finley, J. P.; Foote, G. M.; Fortson, L.; Furniss, A.; Gallagher, G.; Gent, A.; Giuri, C.; Hanlon, W. F.; Hanna, D.; Hassan, T.; Hervet, O.; Holder, J.; Hona, B.; Hughes, G.; Humensky, T. B.; Jin, W.; Kaaret, P.; Kertzman, M.; Kieda, D.; Kleiner, T. K.; Krennrich, F.; Kumar, S.; Lang, M. J.; Lundy, M.; Maier, G.; Millis, J.; Moriarty, P.; Mukherjee, R.; Nievas-Rosillo, M.; Ong, R. A.; Otte, A. N.; Patel, S.; Patel, S. R.; Pfrang, K.; Pohl, M.; Prado, R. R.; Pueschel, E.; Quinn, J.; Ragan, K.; Reynolds, P. T.; Ribeiro, D.; Roache, E.; Ryan, J. L.; Sadeh, I; Santander, M.; Sembroski, G. H.; Shang, R.; Stevenson, B.; Tucci, J., V; Vassiliev, V. V.; Wakely, S. P.; Weinstein, A.; Wells, R. M.; Williams, D. A.; Williamson, T. J.; Acciari, V. A.; Aniello, T.; Ansoldi, S.; Antonelli, L. A.; Engels, A. Arbet; Arcaro, C.; Artero, M.; Asano, K.; Baack, D.; Babic, A.; Baquero, A.; de Almeida, U. Barres; Barrio, J. A.; Batkovic, I; Becerra Gonzalez, J.; Bednarek, W.; Bernardini, E.; Bernardos, M.; Berti, A.; Besenrieder, J.; Bhattacharyya, W.; Bigongiari, C.; Biland, A.; Blanch, O.; Bokenkamp, H.; Bonnoli, G.; Bosnjak, Z.; Burelli, I; Busetto, G.; Carosi, R.; Ceribella, G.; Cerruti, M.; Chai, Y.; Chilingarian, A.; Cikota, S.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; D'Amico, G.; D'Elia, V; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Lotto, B.; Del Popolo, A.; Delfino, M.; Delgado, J.; Delgado Mendez, C.; Depaoli, D.; Di Pierro, F.; Di Venere, L.; Do Souto Espineira, E.; Prester, D. Dominis; Donini, A.; Dorner, D.; Doro, M.; Elsaesser, D.; Ramazani, V. Fallah; Farina, L.; Fattorini, A.; Font, L.; Fruck, C.; Fukami, S.; Fukazawa, Y.; Garcia Lopez, R. J.; Garczarczyk, M.; Gasparyan, S.; Gaug, M.; Giglietto, N.; Giordano, F.; Gliwny, P.; Godinovic, N.; Green, J. G.; Green, D.; Hadasch, D.; Hahn, A.; Hassan, T.; Heckmann, L.; Herrera, J.; Hrupec, D.; Hutten, M.; Inada, T.; Iotov, R.; Ishio, K.; Iwamura, Y.; Jimenez Martinez, I; Jormanainen, J.; Jouvin, L.; Kerszberg, D.; Kobayashi, Y.; Kubo, H.; Kushida, J.; Lamastra, A.; Lelas, D.; Leone, F.; Lindfors, E.; Linhoff, L.; Lombardi, S.; Longo, F.; Lopez-Coto, R.; Lopez-Moya, M.; Lopez-Oramas, A.; Loporchio, S.; Lorini, A.; de Oliveira Fraga, B. Machado; Maggio, C.; Majumdar, P.; Makariev, M.; Maneva, G.; Manganaro, M.; Mannheim, K.; Mariotti, M.; Martinez, M.; Aguilar, A. Mas; Mazin, D.; Menchiari, S.; Mender, S.; Micanovic, S.; Miceli, D.; Miener, T.; Miranda, J. M.; Mirzoyan, R.; Molina, E.; Mondal, H. A.; Moralejo, A.; Morcuende, D.; Moreno, V; Nakamori, T.; Nanci, C.; Nava, L.; Neustroev, V; Nievas Rosillo, M.; Nigro, C.; Nilsson, K.; Nishijima, K.; Noda, K.; Nozaki, S.; Ohtani, Y.; Oka, T.; Otero-Santos, J.; Paiano, S.; Palatiello, M.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Pavletic, L.; Penil, P.; Persic, M.; Pihet, M.; Moroni, P. G. Prada; Prandini, E.; Priyadarshi, C.; Puljak, I; Rhode, W.; Ribo, M.; Rico, J.; Righi, C.; Rugliancich, A.; Sahakyan, N.; Saito, T.; Sakurai, S.; Satalecka, K.; Saturni, F. G.; Schleicher, B.; Schmidt, K.; Schmuckermaier, F.; Schubert, J. L.; Schweizer, T.; Sitarek, J.; Snidaric, I; Sobczynska, D.; Spolon, A.; Stamerra, A.; Striskovic, J.; Strom, D.; Strzys, M.; Suda, Y.; Suric, T.; Takahashi, M.; Takeishi, R.; Tavecchio, F.; Temnikov, P.; Terzic, T.; Teshima, M.; Tosti, L.; Truzzi, S.; Tutone, A.; Ubach, S.; van Scherpenberg, J.; Vanzo, G.; Vazquez Acosta, M.; Ventura, S.; Verguilov, V.; Viale, I; Vigorito, C. F.; Vitale, V.; Vovk, I; Will, M.; Wunderlich, C.; Yamamoto, T.; Zaric, D.; VERITAS Collaboration; MAGIC Collaboration.--This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited., We report on a long-lasting, elevated gamma-ray flux state from VER J0521+211 observed by VERITAS, MAGIC, and Fermi-LAT in 2013 and 2014. The peak integral flux above 200 GeV measured with the nightly binned light curve is (8.8 ± 0.4) × 10−7 photons m−2 s−1, or ∼37% of the Crab Nebula flux. Multiwavelength observations from X-ray, UV, and optical instruments are also presented. A moderate correlation between the X-ray and TeV gamma-ray fluxes was observed, and the X-ray spectrum appeared harder when the flux was higher. Using the gamma-ray spectrum and four models of the extragalactic background light (EBL), a conservative 95% confidence upper limit on the redshift of the source was found to be z ≤ 0.31. Unlike the gamma-ray and X-ray bands, the optical flux did not increase significantly during the studied period compared to the archival low-state flux. The spectral variability from optical to X-ray bands suggests that the synchrotron peak of the spectral energy distribution (SED) may become broader during flaring states, which can be adequately described with a one-zone synchrotron self-Compton model varying the high-energy end of the underlying particle spectrum. The synchrotron peak frequency of the SED and the radio morphology of the jet from the MOJAVE program are consistent with the source being an intermediate-frequency-peaked BL Lac object. © 2022. The Author(s). Published by the American Astronomical Society., This research is supported by grants from the U.S. Department of Energy Office of Science, the U.S. National Science Foundation, and the Smithsonian Institution in the U.S.; by NSERC in Canada; and by the Helmholtz Association in Germany. This research used resources provided by the Open Science Grid, which is supported by the National Science Foundation and the U.S. Department of Energy's Office of Science, and resources of the National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy Office of Science User Facility operated under contract No. DE-AC02-05CH11231. We acknowledge the excellent work of the technical support staff at the Fred Lawrence Whipple Observatory and at the collaborating institutions in the construction and operation of the instrument. The MAGIC Collaboration would like to thank the Instituto de Astrofísica de Canarias for the excellent working conditions at the Observatorio del Roque de los Muchachos in La Palma. The financial support of the German BMBF, MPG, and HGF; the Italian INFN and INAF; the Swiss National Fund SNF; the ERDF under the Spanish Ministerio de Ciencia e Innovación (MICINN) (PID2019-104114RB-C31, PID2019-104114RB-C32, PID2019-104114RB-C33, PID2019-105510GB-C31,PID2019-107847RB-C41, PID2019-107847RB-C42, PID2019-107847RB-C44, PID2019-107988GB-C22); the Indian Department of Atomic Energy; the Japanese ICRR, the University of Tokyo, JSPS, and MEXT; the Bulgarian Ministry of Education and Science, National RI Roadmap Project DO1-400/18.12.2020; and the Academy of Finland grant No. 320045 is gratefully acknowledged. This work was also supported by the Spanish Centro de Excelencia "Severo Ochoa" (SEV-2016-0588, SEV-2017-0709, CEX2019-000920-S), the Unidad de Excelencia "María de Maeztu" (CEX2019-000918-M, MDM-2015-0509-18-2), and the CERCA program of the Generalitat de Catalunya; by the Croatian Science Foundation (HrZZ) Project IP-2016-06-9782 and the University of Rijeka Project uniri-prirod-18-48; by the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3; by the Polish National Research Centre grant UMO-2016/22/M/ST9/00382; and by the Brazilian MCTIC, CNPq, and FAPERJ. Q.F. was supported by NSF grant PHY-1806554 at Barnard College.

Published
2022
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3. two-zone model as origin of hard TeV spectrum in extreme BL lacs.

Author

Aguilar-Ruiz, E, Fraija, N, Galván-Gámez, A, and Benítez, E

Subjects
SPECTRAL energy distribution, SYNCHROTRON radiation, BL Lacertae objects, RADIO jets (Astrophysics), PARTICLE acceleration
Abstract

The emission of the so-called extreme BL Lacs poses challenges to the particle acceleration models. The hardness of their spectrum, ≲ 2, in the high-energy band demands unusual parameters using the standard one-zone synchrotron self-Compton (SSC) model with a deficient magnetized plasma. Some authors use either two-zone or hadronic/lepto-hadronic models to relax these atypical values. In this work, we present a lepto-hadronic two-zone model to explain the multi-wavelength observations of the six best-known extreme BL Lacs. The very-high-energy gamma-ray observations are described by the photo-hadronic processes in a blob close to the AGN core and by SSC and external inverse Compton-processes in an outer blob. The photo-hadronic interactions occur when accelerated protons in the inner blob interact with annihilation line photons from a sub-relativistic pair plasma. The X-ray observations are described by synchrotron radiation from the outer blob. The parameter values found from the description of the spectral energy distribution for each object with our phenomenological model are similar to each other, and lie in the typical range reported in BL Lacs. [ABSTRACT FROM AUTHOR]

Published
2022
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4. The complex variability of blazars: time-scales and periodicity analysis in S4 0954+65.

Author

Raiteri, C M, Villata, M, Larionov, V M, Jorstad, S G, Marscher, A P, Weaver, Z R, Acosta-Pulido, J A, Agudo, I, Andreeva, T, Arkharov, A, Bachev, R, Benítez, E, Berton, M, Björklund, I, Borman, G A, Bozhilov, V, Carnerero, M I, Carosati, D, Casadio, C, and Chen, W P

Subjects
BL Lacertae objects, ACTIVE galactic nuclei, BREWSTER'S angle, LIGHT curves, ACTIVE galaxies
Abstract

Among active galactic nuclei, blazars show extreme variability properties. We here investigate the case of the BL Lac object S4 0954+65 with data acquired in 2019–2020 by the Transiting Exoplanet Survey Satellite (TESS) and by the Whole Earth Blazar Telescope (WEBT) Collaboration. The 2-min cadence optical light curves provided by TESS during three observing sectors of nearly 1 month each allow us to study the fast variability in great detail. We identify several characteristic short-term time-scales, ranging from a few hours to a few days. However, these are not persistent, as they differ in the various TESS sectors. The long-term photometric and polarimetric optical and radio monitoring undertaken by the WEBT brings significant additional information, revealing that (i) in the optical, long-term flux changes are almost achromatic, while the short-term ones are strongly chromatic; (ii) the radio flux variations at 37 GHz follow those in the optical with a delay of about 3 weeks; (iii) the range of variation of the polarization degree and angle is much larger in the optical than in the radio band, but the mean polarization angles are similar; (iv) the optical long-term variability is characterized by a quasi-periodicity of about 1 month. We explain the source behaviour in terms of a rotating inhomogeneous helical jet, whose pitch angle can change in time. [ABSTRACT FROM AUTHOR]

Published
2021
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5. The dual nature of blazar fast variability: Space and ground observations of S5 0716+714.

Author

Raiteri, C M, Villata, M, Carosati, D, Benítez, E, Kurtanidze, S O, Gupta, A C, Mirzaqulov, D O, D'Ammando, F, Larionov, V M, Pursimo, T, Acosta-Pulido, J A, Baida, G V, Balmaverde, B, Bonnoli, G, Borman, G A, Carnerero, M I, Chen, W-P, Dhiman, V, Di Maggio, A, and Ehgamberdiev, S A

Subjects
BL Lacertae objects, TIME series analysis, SPACE telescopes, CUBIC curves
Abstract

Blazar S5 0716+714 is well-known for its short-term variability, down to intraday time-scales. We here present the 2-min cadence optical light curve obtained by the TESS space telescope in 2019 December–2020 January and analyse the object fast variability with unprecedented sampling. Supporting observations by the Whole Earth Blazar Telescope Collaboration in B, V, R , and I bands allow us to investigate the spectral variability during the TESS pointing. The spectral analysis is further extended in frequency to the UV and X-ray bands with data from the Neil Gehrels Swift Observatory. We develop a new method to unveil the shortest optical variability time-scales. This is based on progressive de-trending of the TESS light curve by means of cubic spline interpolations through the binned fluxes, with decreasing time bins. The de-trended light curves are then analysed with classical tools for time-series analysis (periodogram, autocorrelation, and structure functions). The results show that below 3 d there are significant characteristic variability time-scales of about 1.7, 0.5, and 0.2 d. Variability on time-scales |$\lesssim 0.2$|  d is strongly chromatic and must be ascribed to intrinsic energetic processes involving emitting regions, likely jet substructures, with dimension less than about 10−3 pc. In contrast, flux changes on time-scales |$\gtrsim 0.5$|  d are quasi-achromatic and are probably due to Doppler factor changes of geometric origin. [ABSTRACT FROM AUTHOR]

Published
2021
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6. Multi-wavelength Observations of the Flaring Gamma-ray Blazar 3C 66A in 2008 October

Author

Abdo, A. A., Ackermann, M., Ajello, M., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Bechtol, K., Bellazzini, R., Berenji, B., Blandford, R. D., Bonamente, Emanuele, Borgland, A. W., Bouvier, A., Bregeon, J., Brez, A., Brigida, M., Bruel, P., Buehler, R., Buson, S., Caliandro, G. A., Cameron, R. A., Caraveo, P. A., Carrigan, S., Casandjian, J. M., Cavazzuti, E., Cecchi, Claudia, Çelik, Ö., Charles, E., Chekhtman, A., Cheung, C. C., Chiang, J., Ciprini, S., Claus, R., Cohen Tanugi, J., Conrad, J., Costamante, L., Cutini, S., Davis, D. S., Dermer, C. D., Palma, F. d., Digel, S. W., Couto, E. d., Drell, P. S., Dubois, R., Dumora, D., Favuzzi, C., Fegan, S. J., Fortin, P., Frailis, M., Fuhrmann, L., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Gehrels, N., Germani, S., Giglietto, N., Giommi, P., Giordano, F., Giroletti, M., Glanzman, T., Godfrey, G., Grenier, I. A., Grove, J. E., Guillemot, L., Guiriec, S., Hadasch, D., Hayashida, M., Hays, E., Horan, D., Hughes, R. E., Itoh, R., Jóhannesson, G., Johnson, A. S., Johnson, T. J., Johnson, W. N., Kamae, T., Katagiri, H., Kataoka, J., Knödlseder, J., Kuss, M., Lande, J., Latronico, L., Lee, S., Longo, F., Loparco, F., Lott, B., Lovellette, M. N., Lubrano, P., Makeev, A., Mazziotta, M. N., Mcenery, J. E., Mehault, J., Michelson, P. F., Mizuno, T., Moiseev, A. A., Monte, C., Monzani, M. E., Morselli, A., Moskalenko, I. V., Murgia, S., Nakamori, T., Naumann Godo, M., Nestoras, I., Nolan, P. L., Norris, J. P., Nuss, E., Ohsugi, T., Okumura, A., Omodei, N., Orlando, E., Ormes, J. F., Ozaki, M., Paneque, D., Panetta, J. H., Parent, D., Pelassa, V., Pepe, M., Pesce Rollins, M., Piron, F., Porter, T. A., Rainò, S., Rando, R., Razzano, M., Reimer, A., Reimer, O., Reyes, L. C., Ripken, J., Ritz, S., Romani, R. W., Roth, M., Sadrozinski, H. F., Sanchez, D., Sander, A., Scargle, J. D., Sgrò, C., Shaw, M. S., Smith, P. D., Spandre, G., Spinelli, P., Strickman, M. S., Suson, D. J., Takahashi, H., Tanaka, T., Thayer, J. B., Thayer, J. G., Thompson, D. J., Tibaldo, L., Torres, D. F., Tosti, Gino, Tramacere, A., Usher, T. L., Vandenbroucke, J., Vasileiou, V., Vilchez, N., Vitale, V., Waite, A. P., Wang, P., Winer, B. L., Wood, K. S., Yang, Z., Ylinen, T., Ziegler, M., Acciari, V. A., Aliu, E., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Böttcher, M., Boltuch, D., Bradbury, S. M., Buckley, J. H., Bugaev, V., Byrum, K., Cannon, A., Cesarini, A., Christiansen, J. L., Ciupik, L., Cui, W., I. d., La, Dickherber, R., Errando, M., Falcone, A., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Gillanders, G. H., Godambe, S., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Holder, J., Hui, C. M., Humensky, T. B., Imran, A., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Konopelko, A., Krawczynski, H., Krennrich, F., Lang, M. J., Lebohec, S., Maier, G., Mcarthur, S., Mccann, A., Mccutcheon, M., Moriarty, P., Mukherjee, R., Ong, R. A., Otte, A. N., Pandel, D., Perkins, J. S., Pichel, A., Pohl, M., Quinn, J., Ragan, K., Reynolds, P. T., Roache, E., Rose, H. J., Schroedter, M., Sembroski, G. H., Senturk, G. D., Smith, A. W., Steele, D., Swordy, S. P., Tešić, G., Theiling, M., Thibadeau, S., Varlotta, A., Vassiliev, V. V., Vincent, S., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Williams, D. A., Wissel, S., Wood, M., Villata, M., Raiteri, C. M., Gurwell, M. A., Larionov, V. M., Kurtanidze, O. M., Aller, M. F., Lähteenmäki, A., Chen, W. P., Berduygin, A., Agudo, I., Aller, H. D., Arkharov, A. A., Bach, U., Bachev, R., Beltrame, P., Benítez, E., Buemi, C. S., Dashti, J., Calcidese, P., Capezzali, D., Carosati, D., Rio, D. D., Paola, A. D., Diltz, C., Dolci, M., Dultzin, D., Forné, E., Gómez, J. L., Hagen Thorn, V. A., Halkola, A., Heidt, J., Hiriart, D., Hovatta, T., Hsiao, H., Jorstad, S. G., Kimeridze, G. N., Konstantinova, T. S., Kopatskaya, E. N., Koptelova, E., Leto, P., Ligustri, R., Lindfors, E., Lopez, J. M., Marscher, A. P., Mommert, M., Mujica, R., Nikolashvili, M. G., Nilsson, K., Palma, N., Pasanen, M., Roca Sogorb, M., Ros, J. A., Roustazadeh, P., Sadun, A. C., Saino, J., Sigua, L. A., Sillanää, A., Sorcia, M., Takalo, L. O., Tornikoski, M., Trigilio, C., Turchetti, R., Umana, G., Belloni, T., Blake, C. H., Bloom, J. S., Angelakis, E., Fumagalli, M., Hauser, M., Prochaska, J. X., Riquelme, D., Sievers, A., Starr, D. L., Tagliaferri, G., Ungerechts, H., Wagner, S., Zensus, J. A., Collaboration, F. L., Collaboration, V., Consortium, G., Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de Physique Théorique et Astroparticules (LPTA), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Fermi-LAT, Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Abdo, A. A., Ackermann, M., Ajello, M., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Bechtol, K., Bellazzini, R., Berenji, B., Blandford, R. D., Bonamente, E., Borgland, A. W., Bouvier, A., Bregeon, J., Brez, A., Brigida, M., Bruel, P., Buehler, R., Buson, S., Caliandro, G. A., Cameron, R. A., Caraveo, P. A., Carrigan, S., Casandjian, J. M., Cavazzuti, E., Cecchi, C., Çelik, Ö., Charles, E., Chekhtman, A., Cheung, C. C., Chiang, J., Ciprini, S., Claus, R., Cohen Tanugi, J., Conrad, J., Costamante, L., Cutini, S., Davis, D. S., Dermer, C. D., de Palma, F., Digel, S. W., do Couto, e. Silva E., Drell, P. S., Dubois, R., Dumora, D., Favuzzi, C., Fegan, S. J., Fortin, P., Frailis, M., Fuhrmann, L., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Gehrels, N., Germani, S., Giglietto, N., Giommi, P., Giordano, F., Giroletti, M., Glanzman, T., Godfrey, G., Grenier, I. A., Grove, J. E., Guillemot, L., Guiriec, S., Hadasch, D., Hayashida, M., Hays, E., Horan, D., Hughes, R. E., Itoh, R., Jóhannesson, G., Johnson, A. S., Johnson, T. J., Johnson, W. N., Kamae, T., Katagiri, H., Kataoka, J., Knödlseder, J., Kuss, M., Lande, J., Latronico, L., Lee, S. H., Longo, Francesco, Loparco, F., Lott, B., Lovellette, M. N., Lubrano, P., Makeev, A., Mazziotta, M. N., Mcenery, J. E., Mehault, J., Michelson, P. F., Mizuno, T., Moiseev, A. A., Monte, C., Monzani, M. E., Morselli, A., Moskalenko, I. V., Murgia, S., Nakamori, T., Naumann Godo, M., Nestoras, I., Nolan, P. L., Norris, J. P., Nuss, E., Ohsugi, T., Okumura, A., Omodei, N., Orlando, E., Ormes, J. F., Ozaki, M., Paneque, D., Panetta, J. H., Parent, D., Pelassa, V., Pepe, M., Pesce Rollins, M., Piron, F., Porter, T. A., Rainò, S., Rando, R., Razzano, M., Reimer, A., Reimer, O., Reyes, L. C., Ripken, J., Ritz, S., Romani, R. W., Roth, M., Sadrozinski, H. F. W., Sanchez, D., Sander, A., Scargle, J. D., Sgrò, C., Shaw, M. S., Smith, P. D., Spandre, G., Spinelli, P., Strickman, M. S., Suson, D. J., Takahashi, H., Tanaka, T., Thayer, J. B., Thayer, J. G., Thompson, D. J., Tibaldo, L., Torres, D. F., Tosti, G., Tramacere, A., Usher, T. L., Vandenbroucke, J., Vasileiou, V., Vilchez, N., Vitale, V., Waite, A. P., Wang, P., Winer, B. L., Wood, K. S., Yang, Z., Ylinen, T., Ziegler, M., Acciari, V. A., Aliu, E., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Böttcher, M., Boltuch, D., Bradbury, S. M., Buckley, J. H., Bugaev, V., Byrum, K., Cannon, A., Cesarini, A., Christiansen, J. L., Ciupik, L., Cui, W., de la Calle Perez, I., Dickherber, R., Errando, M., Falcone, A., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Gillanders, G. H., Godambe, S., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Holder, J., Hui, C. M., Humensky, T. B., Imran, A., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Konopelko, A., Krawczynski, H., Krennrich, F., Lang, M. J., Lebohec, S., Maier, G., Mcarthur, S., Mccann, A., Mccutcheon, M., Moriarty, P., Mukherjee, R., Ong, R. A., Otte, A. N., Pandel, D., Perkins, J. S., Pichel, A., Pohl, M., Quinn, J., Ragan, K., Reynolds, P. T., Roache, E., Rose, H. J., Schroedter, M., Sembroski, G. H., Senturk G., Demet, Smith, A. W., Steele, D., Swordy, S. P., Tešić, G., Theiling, M., Thibadeau, S., Varlotta, A., Vassiliev, V. V., Vincent, S., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Williams, D. A., Wissel, S., Wood, M., Villata, M., Raiteri, C. M., Gurwell, M. A., Larionov, V. M., Kurtanidze, O. M., Aller, M. F., Lähteenmäki, A., Chen, W. P., Berduygin, A., Agudo, I., Aller, H. D., Arkharov, A. A., Bach, U., Bachev, R., Beltrame, P., Benítez, E., Buemi, C. S., Dashti, J., Calcidese, P., Capezzali, D., Carosati, D., Da Rio, D., Di Paola, A., Diltz, C., Dolci, M., Dultzin, D., Forné, E., Gómez, J. L., Hagen Thorn, V. A., Halkola, A., Heidt, J., Hiriart, D., Hovatta, T., Hsiao, H. Y., Jorstad, S. G., Kimeridze, G. N., Konstantinova, T. S., Kopatskaya, E. N., Koptelova, E., Leto, P., Ligustri, R., Lindfors, E., Lopez, J. M., Marscher, A. P., Mommert, M., Mujica, R., Nikolashvili, M. G., Nilsson, K., Palma, N., Pasanen, M., Roca Sogorb, M., Ros, J. A., Roustazadeh, P., Sadun, A. C., Saino, J., Sigua, L. A., Sillanää, A., Sorcia, M., Takalo, L. O., Tornikoski, M., Trigilio, C., Turchetti, R., Umana, G., Belloni, T., Blake, C. H., Bloom, J. S., Angelakis, E., Fumagalli, M., Hauser, M., Prochaska, J. X., Riquelme, D., Sievers, A., Starr, D. L., Tagliaferri, G., Ungerechts, H., Wagner, S., Zensus, J. A., Abdo, A, Ackermann, M, Ajello, M, Baldini, L, Ballet, J, Barbiellini, G, Bastieri, D, Bechtol, K, Bellazzini, R, Berenji, B, Blandford, R, Bonamente, E, Borgland, A, Bouvier, A, Bregeon, J, Brez, A, Brigida, M, Bruel, P, Buehler, R, Buson, S, Caliandro, G, Cameron, R, Caraveo, P, Carrigan, S, Casandjian, J, Cavazzuti, E, Cecchi, C, Celik, O, Charles, E, Chekhtman, A, Cheung, C, Chiang, J, Ciprini, S, Claus, R, Cohen-Tanugi, J, Conrad, J, Costamante, L, Cutini, S, Davis, D, Dermer, C, De Palma, F, Digel, S, Do Couto E Silva, E, Drell, P, Dubois, R, Dumora, D, Favuzzi, C, Fegan, S, Fortin, P, Frailis, M, Fuhrmann, L, Fukazawa, Y, Funk, S, Fusco, P, Gargano, F, Gasparrini, D, Gehrels, N, Germani, S, Giglietto, N, Giommi, P, Giordano, F, Giroletti, M, Glanzman, T, Godfrey, G, Grenier, I, Grove, J, Guillemot, L, Guiriec, S, Hadasch, D, Hayashida, M, Hays, E, Horan, D, Hughes, R, Itoh, R, Johannesson, G, Johnson, A, Johnson, T, Johnson, W, Kamae, T, Katagiri, H, Kataoka, J, Knodlseder, J, Kuss, M, Lande, J, Latronico, L, Lee, S, Longo, F, Loparco, F, Lott, B, Lovellette, M, Lubrano, P, Makeev, A, Mazziotta, M, Mcenery, J, Mehault, J, Michelson, P, Mizuno, T, Moiseev, A, Monte, C, Monzani, M, Morselli, A, Moskalenko, I, Murgia, S, Nakamori, T, Naumann-Godo, M, Nestoras, I, Nolan, P, Norris, J, Nuss, E, Ohsugi, T, Okumura, A, Omodei, N, Orlando, E, Ormes, J, Ozaki, M, Paneque, D, Panetta, J, Parent, D, Pelassa, V, Pepe, M, Pesce-Rollins, M, Piron, F, Porter, T, Raino, S, Rando, R, Razzano, M, Reimer, A, Reimer, O, Reyes, L, Ripken, J, Ritz, S, Romani, R, Roth, M, Sadrozinski, H, Sanchez, D, Sander, A, Scargle, J, Sgro, C, Shaw, M, Smith, P, Spandre, G, Spinelli, P, Strickman, M, Suson, D, Takahashi, H, Tanaka, T, Thayer, J, Thompson, D, Tibaldo, L, Torres, D, Tosti, G, Tramacere, A, Usher, T, Vandenbroucke, J, Vasileiou, V, Vilchez, N, Vitale, V, Waite, A, Wang, P, Winer, B, Wood, K, Yang, Z, Ylinen, T, Ziegler, M, Acciari, V, Aliu, E, Arlen, T, Aune, T, Beilicke, M, Benbow, W, Bottcher, M, Boltuch, D, Bradbury, S, Buckley, J, Bugaev, V, Byrum, K, Cannon, A, Cesarini, A, Christiansen, J, Ciupik, L, Cui, W, De La Calle Perez, I, Dickherber, R, Errando, M, Falcone, A, Finley, J, Finnegan, G, Fortson, L, Furniss, A, Galante, N, Gall, D, Gillanders, G, Godambe, S, Grube, J, Guenette, R, Gyuk, G, Hanna, D, Holder, J, Hui, C, Humensky, T, Imran, A, Kaaret, P, Karlsson, N, Kertzman, M, Kieda, D, Konopelko, A, Krawczynski, H, Krennrich, F, Lang, M, Lebohec, S, Maier, G, Mcarthur, S, Mccann, A, Mccutcheon, M, Moriarty, P, Mukherjee, R, Ong, R, Otte, A, Pandel, D, Perkins, J, Pichel, A, Pohl, M, Quinn, J, Ragan, K, Reynolds, P, Roache, E, Rose, H, Schroedter, M, Sembroski, G, Senturk, G, Smith, A, Steele, D, Swordy, S, Tesic, G, Theiling, M, Thibadeau, S, Varlotta, A, Vassiliev, V, Vincent, S, Wakely, S, Ward, J, Weekes, T, Weinstein, A, Weisgarber, T, Williams, D, Wissel, S, Wood, M, Villata, M, Raiteri, C, Gurwell, M, Larionov, V, Kurtanidze, O, Aller, M, Lahteenmaki, A, Chen, W, Berduygin, A, Agudo, I, Aller, H, Arkharov, A, Bach, U, Bachev, R, Beltrame, P, Benitez, E, Buemi, C, Dashti, J, Calcidese, P, Capezzali, D, Carosati, D, Da Rio, D, Di Paola, A, Diltz, C, Dolci, M, Dultzin, D, Forne, E, Gomez, J, Hagen-Thorn, V, Halkola, A, Heidt, J, Hiriart, D, Hovatta, T, Hsiao, H, Jorstad, S, Kimeridze, G, Konstantinova, T, Kopatskaya, E, Koptelova, E, Leto, P, Ligustri, R, Lindfors, E, Lopez, J, Marscher, A, Mommert, M, Mujica, R, Nikolashvili, M, Nilsson, K, Palma, N, Pasanen, M, Roca-Sogorb, M, Ros, J, Roustazadeh, P, Sadun, A, Saino, J, Sigua, L, Sillanaa, A, Sorcia, M, Takalo, L, Tornikoski, M, Trigilio, C, Turchetti, R, Umana, G, Belloni, T, Blake, C, Bloom, J, Angelakis, E, Fumagalli, M, Hauser, M, Prochaska, J, Riquelme, D, Sievers, A, Starr, D, Tagliaferri, G, Ungerechts, H, Wagner, S, Zensus, J, Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
individual: 3C 66A [BL Lacertae objects], Ciencias Físicas, spectral energy-distribution, Astrophysics, BL Lacertae objects: individual (3C 66A), bright blazars, 01 natural sciences, law.invention, purl.org/becyt/ford/1 [https], bl lacertae objects, Astronomi, astrofysik och kosmologi, law, Astronomy, Astrophysics and Cosmology, 010303 astronomy & astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), radio-sources, [SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], epoch vlbi survey, 95.45.+i, 96.60.qe,95.55.Ka, Gamma ray, veritas observations, large-area telescope, Wavelength, Gamma rays: galaxie, active [galaxies], galaxies [gamma rays], Spectral energy distribution, BL Lacertae objects: individual: 3C 66A, Astrophysics - High Energy Astrophysical Phenomena, CIENCIAS NATURALES Y EXACTAS, BL Lac object, individual (3C 66A) [BL Lacertae objects], [PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], Astrophysics::High Energy Astrophysical Phenomena, galaxies: active, FOS: Physical sciences, Telescope, 0103 physical sciences, gamma rays: galaxies, Blazar, tev blazars, 010308 nuclear & particles physics, Scattering, background-radiation, Astronomy and Astrophysics, purl.org/becyt/ford/1.3 [https], Astronomía, Space and Planetary Science, active galactic nuclei, ddc:520, Fermi Gamma-ray Space Telescope
Abstract

著者人数：328名, Accepted: 2010-10-29, 資料番号: SA1002650000

Published
2011

7. Polarization angle swings in blazars: The case of 3C 279.

Author

Kiehlmann, S., Savolainen, T., Jorstad, S. G., Sokolovsky, K. V., Schinzel, F. K., Marscher, A. P., Larionov, V. M., Agudo, I., Akitaya, H., Benítez, E., Berdyugin, A., Blinov, D. A., Bochkarev, N. G., Borman, G. A., Burenkov, A. N., Casadio, C., Doroshenko, V. T., Efimova, N. V., Fukazawa, Y., and Gömez, J. L.

Subjects
POLARIZATION (Nuclear physics), BL Lacertae objects, ACTIVE galaxies, ELECTROMAGNETIC waves, ASTROPHYSICAL radiation, MAGNETIC fields, QUASARS
Abstract

Context. Over the past few years, on several occasions, large, continuous rotations of the electric vector position angle (EVPA) of linearly polarized optical emission from blazars have been reported. These events are often coincident with high energy γ-ray flares and they have attracted considerable attention, since they could allow us to probe the magnetic field structure in the γ-ray emitting region of the jet. The flat-spectrum radio quasar 3C 279 is one of the most prominent examples showing this behaviour. Aims. Our goal is to study the observed EVPA rotations and to distinguish between a stochastic and a deterministic origin of the polarization variability. Methods. We have combined multiple data sets of R-band photometry and optical polarimetry measurements of 3C 279, yielding exceptionally well-sampled flux density and polarization curves that cover a period of 2008-2012. Several large EVPA rotations are identified in the data. We introduce a quantitative measure for the EVPA curve smoothness, which is then used to test a set of simple random walk polarization variability models against the data. Results. 3C 279 shows different polarization variation characteristics during an optical low-flux state and a flaring state. The polarization variation during the flaring state, especially the smooth ~360° rotation of the EVPA in mid-2011, is not consistent with the tested stochastic processes. Conclusions. We conclude that, during the two different optical flux states, two different processes govern polarization variation, which is possibly a stochastic process during the low-brightness state and a deterministic process during the flaring activity. [ABSTRACT FROM AUTHOR]

Published
2016
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8. The WEBT campaign on the BL Lac object PG 1553+113 in 2013. An analysis of the enigmatic synchrotron emission.

Author

Raiteri, C. M., Stamerra, A., Villata, M., Larionov, V. M., Acosta-Pulido, J. A., Arévalo, M. J., Arkharov, A. A., Bachev, R., Benítez, E., Bozhilov, V. V., Borman, G. A., Buemi, C. S., Calcidese, P., Carnerero, M. I., Carosati, D., Chigladze, R. A., Damljanovic, G., Di Paola, A., Doroshenko, V. T., and Efimova, N. V.

Subjects
BL Lacertae objects, SYNCHROTRON radiation, RADIO telescopes, ASTRONOMICAL observations, SPECTRAL energy distribution
Abstract

A multifrequency campaign on the BL Lac object PG 1553+113 was organized by the Whole Earth Blazar Telescope (WEBT) in 2013 April-August, involving 19 optical, two near-IR, and three radio telescopes. The aim was to study the source behaviour at low energies during and around the high-energy observations by the Major Atmospheric Gamma-ray Imaging Cherenkov telescopes in April-July. We also analyse the UV and X-ray data acquired by the Swift and XMM-Newton satellites in the same period. The WEBT and satellite observations allow us to detail the synchrotron emission bump in the source spectral energy distribution (SED). In the optical, we found a general bluer-when-brighter trend. The X-ray spectrum remained stable during 2013, but a comparison with previous observations suggests that it becomes harder when the X-ray flux increases. The long XMM-Newton exposure reveals a curved X-ray spectrum. In the SED, the XMM-Newton data show a hard near-UV spectrum, while Swift data display a softer shape that is confirmed by previous Hubble Space Telescope/Cosmic Origins Spectrograph and International Ultraviolet Explorer observations. Polynomial fits to the optical-X-ray SED show that the synchrotron peak likely lies in the 4-30 eV energy range, with a general shift towards higher frequencies for increasing X-ray brightness. However, the UV and X-ray spectra do not connect smoothly. Possible interpretations include: (i) orientation effects, (ii) additional absorption, (iii) multiple emission components, and (iv) a peculiar energy distribution of relativistic electrons. We discuss the first possibility in terms of an inhomogeneous helical jet model. [ABSTRACT FROM AUTHOR]

Published
2015
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9. A hydrodynamical model for the Fermi-LAT γ-ray light curve of blazar PKS 1510-089.

Author

Cabrera, J. I., Coronado, Y., Benítez, E., Mendoza, S., Hiriart, D., and Sorcia, M.

Subjects
RADIO jets (Astrophysics), BL Lacertae objects, LIGHT curves, LUMINOSITY distance, VELOCITY
Abstract

A physical description of the formation and propagation of working surfaces inside the relativistic jet of the blazar PKS 1510-089 are used to model its γ-ray variability light curve using Fermi-LAT data from 2008 to 2012. The physical model is based on conservation laws of mass and momentum at the working surface as explained by Mendoza et al. (2009). The hydrodynamical description of a working surface is parametrized by the initial velocity and mass injection rate at the base of the jet. We show that periodic variations on the injected velocity profiles are able to account for the observed luminosity, fixing model parameters such as mass ejection rates of the central engine injected at the base of the jet, oscillation frequencies of the flow and maximum Lorentz factors of the bulk flow during a particular burst. [ABSTRACT FROM AUTHOR]

Published
2013
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10. MULTIWAVELENGTH OBSERVATIONS OF THE GAMMA-RAY BLAZAR PKS 0528+134 IN QUIESCENCE.

Author

PALMA, N. I., BÖTTCHER, M., DE LA CALLE, I., AGUDO, I., ALLER, M., ALLER, H., BACH, U., BENÍTEZ, E., BUEMI, C. S., ESCANDE, L., GÓMEZ, J. L., GURWELL, M. A., HEIDT, J., HIRIART, D., JORSTAD, S. G., JOSHI, M., LÄHTEENMÄKI, A., LARIONOV, V. M., LETO, P., and LI, Y.

Subjects
GAMMA rays, BL Lacertae objects, MAGNETIC flux, ASTROPHYSICAL spectropolarimetry, WAVELENGTHS
Abstract

We present multiwavelength observations of the ultraluminous blazar-type radio loud quasar PKS 0528+134 in quiescence during the period 2009 July-December. Four Target-of-Opportunity observations with the XMM-Newton satellite in the 0.2-10 keV range were supplemented with optical observations at the MDM Observatory, radio and optical data from the GLAST-AGILE Support Program of the Whole Earth Blazar Telescope and the Very Long Baseline Array, additional X-ray data from the Rossi X-ray Timing Explorer (2-10 keV) and from Suzaku (0.5-10 keV) as well as y-ray data from the Fermi Large Area Telescope in the 100 MeV-200 0eV range. In addition, publicly available data from the SMARTS blazar monitoring program and the University of Arizona/Steward Observatory Fermi Support program were included in our analysis. We found no evidence of significant flux or spectral variability in y-rays and most radio bands. However, significant flux variability on a timescale of several hours was found in the optical regime, accompanied by a weak trend of spectral softening with increasing flux. We suggest that this might be the signature of a contribution of unbeamed emission, possibly from the accretion disk, at the blue end of the optical spectrum. The optical flux is weakly polarized with rapid variations of the degree and direction of polarization, while the polarization of the 43 GHz radio core remains steady, perpendicular to the jet direction. Optical spectropolarimetry of the object in the quiescent state suggests a trend of increasing degree of polarization with increasing wavelength, providing additional evidence for an unpolarized emission component, possibly thermal emission from the accretion disk, contributing toward the blue end of the optical spectrum. Over an extended period of several months, PKS 0528+ 134 shows moderate (amplitude ≲50%) flux variability in the X-rays and most radio frequencies on ~1-2 week timescales. We constructed four spectral energy distributions (SEDs) corresponding to the times of the XMM-Newton observations. We find that even in the quiescent state, the bolometric luminosity of PKS 0528+ 134 is dominated by its y-ray emission. A leptonic single-zone jet model produced acceptable fits to the SEDs with contributions to the high-energy emission from both synchrotron self- Compton radiation and Comptonization of direct accretion disk emission. Fit parameters close to equipartition between the energy densities of the magnetic field and the relativistic electron population were obtained. The moderate variability on long timescales, compared to expected radiative cooling timescales, implies the existence of ongoing particle acceleration, while the observed optical polarization variability seems to point toward a turbulent acceleration process. Turbulent particle acceleration at stationary features along the jet therefore appears to be a viable possibility for the quiescent state of PKS 0528+134. [ABSTRACT FROM AUTHOR]

Published
2011
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11. Long-term optical photopolarimetric monitoring of Blazars at San Pedro martir

Author

Benítez, E., Heidt, J., Hiriart, D., Iván Agudo, Cabrera, J. I., Dultzin, D., Gonzalez, M. M., Lopez, J. M., Mujica, R., Nilsson, K., Sacahui, R., and Sorcia, M.

Subjects
active [Galaxies], general, general [BL Lacertae objects], Física, Astronomía y Matemáticas, BL Lacertae objects, active, Galaxies
Abstract

Variability of optical polarized light has result to be a powerful tool for studying Blazars, since it enable us to determine the strength and orientation of magnetic field associated with the relativistic jet. Also, polarized light is a valuable way of testing the location of the -ray emission, although the physical mechanisms responsible of its production remain unclear. Most importantly, since multi-wavelength campaigns typically concentrate on sources during highly active states, the characteristic polarimetric properties of Blazars in the pre-and post outbursts states are less known. Thus, we have started a dedicated monitoring program of Blazars from the GASP sample at San Pedro Mártir, in order to study their polarimetric variability properties. In this work we want to show the current status of the program presenting some preliminary results on the optical-polarimetric and -ray variability observed with Fermi-LAT on the blazar PKS 1510-089.

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