Search

Your search keyword '"Acosta-Pulido JA"' showing total 8 results
Start Over Author "Acosta-Pulido JA"
8 results on '"Acosta-Pulido JA"'

2. Infrared properties of blazars: putting the GASP-WEBT sources into context

Author

C. M. Raiteri, M. I. Carnerero, J. A. Acosta-Pulido, P. A. González-Morales, A. Bueno Bueno, D. Gorshanov, N. V. Efimova, M. J. Arévalo, Valeri M. Larionov, A. Manilla-Robles, A. Pastor Yabar, Sergio Velasco, Arkady A. Arkharov, I. Puerto Giménez, A. B. Grinon-Marin, A. Di Paola, M. Villata, Filippo D'Ammando, C. Lázaro, Raiteri CM, Villata M, Carnerero MI, Acosta-Pulido JA, Larionov VM, DAmmando F, Arevalo MJ, Arkharov AA, Bueno AB, Di Paola A, Efimova NV, Gonzalez-Morales PA, Gorshanov DL, Grinon-Marin AB, Lazaro C, Manilla-Robles A, Yabar AP, Gimenez IP, and Velasco S

Subjects
media_common.quotation_subject, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Context (language use), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, law.invention, Telescope, galaxies: active, BL Lacertae objects: general, quasars: general, law, Blazar, Astrophysics::Galaxy Astrophysics, media_common, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Astronomy, Astronomy and Astrophysics, Quasar, Light curve, Astrophysics - Astrophysics of Galaxies, Galaxy, Redshift, Space and Planetary Science, Sky, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract

The infrared properties of blazars can be studied from the statistical point of view with the help of sky surveys, like that provided by the Wide-field Infrared Survey Explorer (WISE) and the Two Micron All Sky Survey (2MASS). However, these sources are known for their strong and unpredictable variability, which can be monitored for a handful of objects only. In this paper we consider the 28 blazars (14 BL Lac objects and 14 flat-spectrum radio quasars, FSRQs) that are regularly monitored by the GLAST-AGILE Support Program (GASP) of the Whole Earth Blazar Telescope (WEBT) since 2007. They show a variety of infrared colours, redshifts, and infrared-optical spectral energy distributions (SEDs), and thus represent an interesting mini-sample of bright blazars that can be investigated in more detail. We present near-IR light curves and colours obtained by the GASP from 2007 to 2013, and discuss the infrared-optical SEDs. These are analysed with the aim of understanding the interplay among different emission components. BL Lac SEDs are accounted for by synchrotron emission plus an important contribution from the host galaxy in the closest objects, and dust signatures in 3C 66A and Mkn 421. FSRQ SEDs require synchrotron emission with the addition of a quasar-like contribution, which includes radiation from a generally bright accretion disc, broad line region, and a relatively weak dust torus., 20 pages, 13 figures, 4 tables, in press for MNRAS

Published
2014

3. MAGIC gamma-ray and multi-frequency observations of flat spectrum radio quasar PKS 1510-089 in early 2012

Author

Aleksic, J., Ansoldi, S., Antonelli, L. A., Antoranz, P., Babic, A., Bangale, P., Bednarek, W., Bernardini, E., Biland, A., Blanch, O., Bonnefoy, S., Contreras, J. L., Paneque, D., Paoletti, R., Cortina, J., Paredes, J. M., Covino, S., Paredes-Fortuny, X., Da, Vela P., Partini, S., Dazzi, F., Persic, M., De, Angelis A., Prada, F., De, Caneva G., PradaMoroni, P. G., De, Lotto B., Prandini, E., Delgado, Mendez C., Preziuso, S., Doert, M., Bonnoli, G., Dominguez, A., Puljak, I., Reinthal, R., Dominis, Prester D., Rhode, W., Dorner, D., Ribo, M., Doro, M., Rico, J., Einecke, S., Eisenacher, D., Elsaesser, D., Farina, E., Ferenc, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., Garcia, Lopez R. J., Rodriguez, Garcia J., Garczarczyk, M., Garrido, Terrats D., Gaug, M., Godinovic, N., Gonzalez, Munoz A., Gozzini, S. R., Hadasch, D., Herrera, J., Herrero, A., Rugamer, S., Hildebrand, D., Hose, J., Hrupec, D., Idec, W., Kadenius, V., Kellermann, H., Kodani, K., Konno, Y., Krause, J., Kubo, H., Saggion, A., Kushida, J., La, Barbera A., Lelas, D., Lewandowska, N., Lindfors, E., Lombardi, S., Lopez, M., Lopez-Coto, R., Lopez-Oramas, A., Lorenz, E., Saito, T., Lozano, I., Makariev, M., Mallot, K., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martinez, M., Saito, K., Mazin, D., Menzel, U., Meucci, M., Miranda, J. M., Mirzoyan, R., Moralejo, A., Munar-Adrover, P., Nakajima, D., Niedzwiecki, A., Nilsson, K., Borracci, F., Nishijima, K., Noda, K., Nowak, N., Orito, R., Overkemping, A., Paiano, S., Palatiello, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shore, S. N., Sillanpaa, A., Sitarek, J., Snidaric, I., Sobczynska, D., Bretz, T., Spanier, F., Stamatescu, V., Stamerra, A., Steinbring, T., Storz, J., Strzys, M., Sun, S., Suric, T., Takalo, L., Takami, H., Carmona, E., Tavecchio, F., Temnikov, P., Terzic, T., Tescaro, D., Teshima, M., Thaele, J., Tibolla, O., Torres, D. F., Toyama, T., Treves, A., Carosi, A., Uellenbeck, M., Vogler, P., Wagner, R. M., Zandanel, F., Zanin, R., Lucarelli, F., Pittori, C., Vercellone, S., Verrecchia, F., Buson, S., Carreto, Fidalgo D., D'Ammando, F., Stawarz, Lukasz, Colin, P., Colombo, E., Hayashida, Masaaki, Barres, de Almeida U., Barrio, J. A., Becerra, Gonzalez J., Department of Radio Science and Engineering, Aalto-yliopisto, Aalto University, Aleksic J, Ansoldi S, Antonelli LA, Antoranz P, Babic A, Bangale P, de Almeida UB, Barrio JA, Gonzalez JB, Bednarek W, Bernardini E, Biland A, Blanch O, Bonnefoy S, Bonnoli G, Borracci F, Bratz T, Carmona E, Carosi A, Fidalgo DC, Colin P, Colombo E, Contreras JL, Cortina I, Covino S, Da Vela P, Dazzi F, De Angelis A, De Caneva G, De Lotto B, Mendez CD, Doert M, Dominguez A, Presters DD, Dorner D, Doro M, Einecke S, Eisenacher D, Elsaesser D, Farina E, Ferenc D, Fonseca MV, Font L, Frantzen K, Fruck C, Lopez RJG, Garczarczyk M, Terrats DG, Gaug M, Godinovic N, Munoz AG, Gozzini SR, Hadasch D, Hayashida M, Herrera J, Herrero A, Hildebrand D, Hose J, Hrupec D, Idec W, Kadenius V, Kellermann H, Kodani K, Konno Y, Krause J, Kubo H, Kushida J, La Barbera A, Lelas D, Lewandowska N, Lindfors E, Lombardi S, Lopez M, Lopez-Coto R, Lopez-Oramas A, Lorenz E, Lozano I, Makariev M, Mallotw K, Maneva G, Mankuzhiyil N, Mannheim K, Maraschi L, Marcote B, Mariotti M, Martinez M, Mazin D, Menzel U, Meucci M, Miranda JM, Mirzoyan R, Moralejo A, Munar-Adrover P, Nakajima D, Niedzwiecki A, Nilsson K, Nishijima K, Noda K, Nowak N, Orito R, Overkemping A, Paiano S, Palatiello M, Paneque D, Paoletti R, Paredes JM, Paredes-Fortuny X, Partini S, Persic M, Prada F, Moroni PGP, Prandini E, Preziuso S, Puljak I, Reinthal R, Rhode W, Ribo M, Rico J, Garcia JR, Rugamer S, Saggion A, Saito T, Saito K, Satalecka K, Scalzotto V, Scapin V, Schultz C, Schweizer T, Shore SN, Sillanpaa A, Sitarek J, Snidaric I, Sobczynska D, Spanier F, Stamatescu V, Stamerra A, Steinbring T, Storz J, Strzys M, Sun S, Suric T, Takalo L, Takami H, Tavecchio F, Temnikov P, Terzic T, Tescaro D, Teshima M, Thaele J, Tibolla O, Torres DF, Toyama T, Treves A, Uellenbeck M, Vogler P, Wagner RM, Zandanel F, Zanin R, Lucarelli F, Pittori C, Vercellone S, Verrecchia F, Buson S, DAmmando F, Stawarz L, Giroletti M, Orienti M, Mundell C, Steele I, Zarpudin B, Raiteri CM, Villata M, Sandrinelli A, Lahteenmaki A, Tammi J, Tornikoski M, Hovatta T, Readhead ACS, Max-Moerbeck W, Richards JL, Jorstad S, Marscher A, Gurwell MA, Larionov VM, Blinov DA, Konstantinova TS, Kopatskaya EN, Larionova LV, Earionova EG, Morozova DA, Troitky IS, Mokrushina AA, Pavlova YV, Chen WP, Lin HC, Panwar N, Agudo I, Casadio C, Gomez JL, Molina SN, Kurtanidze OM, Nikolashvili MG, Kurtanidze SO, Chigladze RA, Acosta-Pulido JA, Carnerero MI, Manilla-Robles A, Ovcharov E, Bozhilov V, Metodieva I, Aller MF, Aller HD, Fuhrman L, Angelakis E, Nestoras I, Krichbaue TP, Zensue JA, Ungerechts H, and Sievers A

Subjects
ACTIVE GALACTIC NUCLEI, LARGE-AREA TELESCOPE, HIGH-ENERGY EMISSION, BASE-LINE ARRAY, BLAZAR 3C 279, MULTIWAVELENGTH OBSERVATIONS, X-RAY, POLARIMETRIC OBSERVATIONS, BACKGROUND-RADIATION, HIGH-FREQUENCIES, galaxies [Gamma rays], galaxies: active, galaxies: jets, gamma rays: galaxies, quasars: individual: PKS1510-089, Astrophysics, 01 natural sciences, QD, MAGIC (telescope), 010303 astronomy & astrophysics, QC, QB, High Energy Astrophysical Phenomena (astro-ph.HE), astro-ph.HE, Physics, Galaxies: active, Gamma rays: galaxies, Spectral energy distribution, Electrónica, Física nuclear, Electricidad, Astrophysics - High Energy Astrophysical Phenomena, Galaxies: jets, Quasars: individual: PKS 1510-089, Astronomy and Astrophysics, Space and Planetary Science, active [Galaxies], Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, galaxies: active / galaxies: jets / gamma rays: galaxies / quasars: individual: PKS 1510-089, Radio spectrum, 0103 physical sciences, individual: PKS 1510-089 [Quasars], Blazar, Very Long Baseline Array, 010308 nuclear & particles physics, Compton scattering, Quasar, ddc:520, jets [Galaxies], Fermi Gamma-ray Space Telescope
Abstract

著者人数: 219名, Accepted: 2014-05-30, 資料番号: SA1140143000

Published
2014
Full Text
View/download PDF

4. The awakening of BL Lacertae: observations by Fermi, Swift, and the GASP-WEBT

Author

V. T. Doroshenko, A. Berdyugin, M. I. Carnerero, Filippo D'Ammando, Stoyanka Peneva, Evgeni Semkov, D. O. Mirzaqulov, D. Carosati, A. C. Sadun, Elina Lindfors, M. J. Arévalo, J. Phipps, Dmitry A. Blinov, Rumen Bachev, Evgeni Ovcharov, S. G. Sergeev, Givi N. Kimeridze, K. A. Stoyanov, Svetlana G. Jorstad, Valeri M. Larionov, Neelam Panwar, Y. Metodieva, Y. Jadhav, R. Ligustri, Meenakshi Kohli, V. Kadenius, Alan P. Marscher, Antoniya Valcheva, N. Smith, I. M. McHardy, Sh. A. Ehgamberdiev, Sunay Ibryamov, Elena G. Larionova, Paul S. Smith, A. Sillanpää, R. Reinthal, C. M. Raiteri, A. Strigachev, Tatiana S. Konstantinova, Iván Agudo, M. G. Nikolashvili, V. Bozhilov, N. G. Pulatova, S. V. Nazarov, Carolina Casadio, Helmut Wiesemeyer, David Hiriart, G. A. Borman, Ivan S. Troitsky, R. D. Schwartz, Ekaterina Koptelova, Markus Böttcher, M. Villata, Kari Nilsson, E. N. Kopatskaya, Wen Ping Chen, B. McBreen, J. A. Ros, L. V. Larionova, Lorand A. Sigua, J. A. Acosta-Pulido, Ann E. Wehrle, Mark Gurwell, S. A. Klimanov, Manasvita Joshi, M. Pasanen, Erika Benítez, D. N. Okhmat, L. O. Takalo, N. V. Efimova, Brian W. Taylor, Omar M. Kurtanidze, Clemens Thum, Sol N. Molina, D. A. Morozova, Pedro A. Gonzalez-Morales, Yu. S. Efimov, José L. Gómez, Raiteri CM, Villata M, DAmmando F, Larionov VM, Gurwell MA, Mirzaqulov DO, Smith PS, Acosta-Pulido JA, Agudo I, Arevalo MJ, Bachev R, Benitez E, Berdyugin A, Blinov DA, Borman GA, Bottcher M, Bozhilov V, Carnerero MI, Carosati D, Casadio C, Chen WP, Doroshenko VT, Efimova YS, Efimova NV, Ehgamberdiev SA, Gomez JL, Gonzalez-Morales PA, Hiriart D, Ibryamov S, Jadhav Y, Jorstad SG, Joshi M, Kadenius V, Klimanov SA, Kohli M, Konstantinova TS, Kopatskaya EN, Koptelova E, Kimeridze G, Kurtanidze OM, Larionova EG, Larionova LV, Ligustri R, Lindfors E, Marscher AP, McBreen B, McHardy IM, Metodieva Y, Molina SN, Morozova DA, Nazarov SV, Nikolashvili MG, Nilsson K, Okhmat DN, Ovcharov E, Panwar N, Pasanen M, Peneva S, Phipps J, Pulatova NG, Reinthal R, Ros JA, Sadun AC, Schwartz RD, Semkov E, Sergeev SG, Sigua LA, Sillanpaa A, Smith N, Stoyanov K, Strigachev A, Takalo LO, Taylor B, Thum C, Troitsky IS, Valcheva A, Wehrle AE, and Wiesemeyer H

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Cosmology and Nongalactic Astrophysics (astro-ph.CO), ta115, Astrophysics::High Energy Astrophysical Phenomena, Astronomy, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Polarization (waves), law.invention, Telescope, Wavelength, Space and Planetary Science, Observatory, law, Degree of polarization, galaxies: active, BL Lacertae objects: general, BL Lacertae objects: individual: BL Lacertae, galaxies: jets, Blazar, Astrophysics - High Energy Astrophysical Phenomena, BL Lac object, Fermi Gamma-ray Space Telescope, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Since the launch of the Fermi satellite, BL Lacertae has been moderately active at gamma-rays and optical frequencies until May 2011, when the source started a series of strong flares. The exceptional optical sampling achieved by the GLAST-AGILE Support Program (GASP) of the Whole Earth Blazar Telescope (WEBT) in collaboration with the Steward Observatory allows us to perform a detailed comparison with the daily gamma-ray observations by Fermi. Discrete correlation analysis between the optical and gamma-ray emission reveals correlation with a time lag of 0 +- 1 d, which suggests cospatiality of the corresponding jet emitting regions. A better definition of the time lag is hindered by the daily gaps in the sampling of the extremely fast flux variations. In general, optical flares present more structure and develop on longer time scales than corresponding gamma-ray flares. Observations at X-rays and at millimetre wavelengths reveal a common trend, which suggests that the region producing the mm and X-ray radiation is located downstream from the optical and gamma-ray-emitting zone in the jet. The mean optical degree of polarisation slightly decreases over the considered period and in general it is higher when the flux is lower. The optical electric vector polarisation angle (EVPA) shows a preferred orientation of about 15 deg, nearly aligned with the radio core EVPA and mean jet direction. Oscillations around it increase during the 2011-2012 outburst. We investigate the effects of a geometrical interpretation of the long-term flux variability on the polarisation. A helical magnetic field model predicts an evolution of the mean polarisation that is in reasonable agreement with the observations. These can be fully explained by introducing slight variations in the compression factor in a transverse shock waves model., 17 pages, 17 figures, 1 table, accepted for publication in MNRAS

Published
2013

5. Variability of the blazar 4C 38.41 (B3 1633+382) from GHz frequencies to GeV energies

Author

Neelam Panwar, M. J. Arévalo, Clemens Thum, Antoniya Valcheva, Mark Gurwell, Elena G. Larionova, R. D. Schwartz, S. N. Molina, Evgeni Ovcharov, M. Pasanen, J. Leon-Tavares, J. A. Ros, A. Di Paola, L. V. Larionova, Svetlana G. Jorstad, H. C. Lin, K. Blumenthal, A. Sillanpää, Tatiana S. Konstantinova, D. O. Mirzaqulov, D. A. Morozova, R. Reinthal, Jochen Heidt, Carolina Casadio, Anne Lähteenmäki, Ekaterina Koptelova, Sh. A. Ehgamberdiev, David Hiriart, Merja Tornikoski, J. A. Acosta-Pulido, D. Carosati, Mauro Dolci, G. M. Richter, Ann E. Wehrle, A. I. Gonzále, I. Agudo, T. M. Carleton, José L. Gómez, I. M. McHardy, Alan P. Marscher, I. S. Troitsky, I. Puerto-Gimenez, M. G. Nikolashvili, E. N. Kopatskaya, Paolo Leto, Corrado Trigilio, G. Umana, N. Smith, T. Sakamoto, Kari Nilsson, Omar M. Kurtanidze, Wen Ping Chen, Sofia O. Kurtanidze, Raúl Mújica, A. Bueno, Filippo D'Ammando, C. M. Raiteri, L. O. Takalo, Valeri M. Larionov, Brian W. Taylor, M. I. Carnerero, Sh. Holikov, A. A. Arkharov, N. V. Efimova, Joni Tammi, Manasvita Joshi, Paul S. Smith, M. Villata, Andrei Berdyugin, Erika Benítez, U. Bach, Dmitry A. Blinov, Hugh D. Aller, V. A. Hagen-Thorn, M. F. Aller, Elina Lindfors, Carla Buemi, Anne Lähteenmäki Group, Aalto-yliopisto, Aalto University, Raiteri CM, Villata M, Smith PS, Larionov VM, Acosta-Pulido JA, Aller MF, DAmmando F, Gurwell MA, Jorstad SG, Joshi M, Kurtanidze OM, Lahteenmaki A, Mirzaqulov DO, Agudo I, Aller HD, Arevalo MJ, Arkharov AA, Bach U, Benitez E, Berdyugin A, Blinov DA, Blumenthal K, Buemi CS, Bueno A, Carleton TM, Carnerero MI, Carosati D, Casadio C, Chen WP, Di Paola A, Dolci M, Efimova NV, Ehgamberdiev SA, Gomez JL, Gonzalez AI, Hagen-Thorn VA, Heidt J, Hiriart D, Holikov S, Konstantinova TS, Kopatskaya EN, Koptelova E, Kurtanidze SO, Larionova EG, Larionova LV, Leon-Tavares J, Leto P, Lin HC, Lindfors E, Marscher AP, McHardy IM, Molina SN, Morozova DA, Mujica R, Nikolashvili MG, Nilsson K, Ovcharov EP, Panwar N, Pasanen M, Puerto-Gimenez I, Reinthal R, Richter GM, Ros JA, Sakamoto T, Schwartz RD, Sillanpaa A, Smith N, Takalo LO, Tammi J, Taylor B, Thum C, Tornikoski M, Trigilio C, Troitsky IS, Umana G, Valcheva AT, and Wehrle AE

Subjects
Brightness, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Astrophysics::High Energy Astrophysical Phenomena, education, jets [galaxies], Flux, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, individual: 4C 38.41 [quasars], 0103 physical sciences, Blazar, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Jet (fluid), Line-of-sight, general [quasars], 010308 nuclear & particles physics, Astronomy and Astrophysics, Viewing angle, Light curve, galaxies: active – quasars: general – quasars: individual: 4C 38.41 – galaxies: jets, 13. Climate action, Space and Planetary Science, active [galaxies], Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics, Fermi Gamma-ray Space Telescope
Abstract

The quasar-type blazar 4C 38.41 (B3 1633+382) experienced a large outburst in 2011, which was detected throughout the entire electromagnetic spectrum. We present the results of low-energy multifrequency monitoring by the GASP project of the WEBT consortium and collaborators, as well as those of spectropolarimetric/spectrophotometric monitoring at the Steward Observatory. We also analyse high-energy observations of the Swift and Fermi satellites. In the optical-UV band, several results indicate that there is a contribution from a QSO-like emission component, in addition to both variable and polarised jet emission. The unpolarised emission component is likely thermal radiation from the accretion disc that dilutes the jet polarisation. We estimate its brightness to be R(QSO) ~ 17.85 - 18 and derive the intrinsic jet polarisation degree. We find no clear correlation between the optical and radio light curves, while the correlation between the optical and \gamma-ray flux apparently fades in time, likely because of an increasing optical to \gamma-ray flux ratio. As suggested for other blazars, the long-term variability of 4C 38.41 can be interpreted in terms of an inhomogeneous bent jet, where different emitting regions can change their alignment with respect to the line of sight, leading to variations in the Doppler factor \delta. Under the hypothesis that in the period 2008-2011 all the \gamma-ray and optical variability on a one-week timescale were due to changes in \delta, this would range between ~ 7 and ~ 21. If the variability were caused by changes in the viewing angle \theta\ only, then \theta\ would go from ~ 2.6 degr to ~ 5 degr. Variations in the viewing angle would also account for the dependence of the polarisation degree on the source brightness in the framework of a shock-in-jet model., Comment: 19 pages, 23 figures, in press for Astronomy and Astrophysics

Published
2012

6. Multiwavelength behaviour of the blazar OJ 248 from radio to gamma-rays

Author

M. I. Carnerero, Sofia O. Kurtanidze, J. A. Acosta-Pulido, E. N. Kopatskaya, Paolo Leto, C. S. Lin, A. B. Grinon-Marin, Sol N. Molina, D. A. Morozova, H. C. Lin, R. Bachev, Neelam Panwar, A. I. Manilla-Robles, M. Orienti, Valeri M. Larionov, Marcello Giroletti, J. L. Gomez, P. A. González-Morales, Antoniya Valcheva, Carolina Casadio, Anne Lähteenmäki, Helmut Wiesemeyer, Uwe Bach, Goran Damljanović, Corrado Trigilio, Y. T. Metodieva, D. O. Mirzaqulov, Sunay Ibryamov, Elena G. Larionova, A. Bueno Bueno, T. S. Grishina, H. Y. Hsiao, V. Ramakrishnan, G. Umana, D. Carosati, Wen Ping Chen, Arkady A. Arkharov, V. Bozhilov, Ivan Agudo, Mark Gurwell, A. Pastor Yabar, I. M. McHardy, David Hiriart, Carla Buemi, Manasvita Joshi, A. Strigachev, Alan P. Marscher, S. G. Jorstad, A. Di Paola, Lorand A. Sigua, L. V. Larionova, M. J. Arévalo, N. V. Efimova, D. Blinov, Erika Benítez, C. M. Raiteri, Brian W. Taylor, Omar M. Kurtanidze, I. Puerto Giménez, Evgeni Ovcharov, Yu. V. Troitskaya, M. G. Nikolashvili, Sergio Velasco, Ann E. Wehrle, A. A. Mokrushina, Paul S. Smith, M. Villata, Ivan S. Troitsky, Sh. A. Ehgamberdiev, Merja Tornikoski, M. Rossini, G. M. Richter, Filippo D'Ammando, C. Lázaro, O. Vince, Carnerero MI, Raiteri CM, Villata M, Acosta-Pulido JA, DAmmando F, Smith PS, Larionov VM, Agudo I, Arevalo MJ, Arkharov AA, Bach U, Bachev R, Benitez E, Blinov DA, Bozhilov V, Buemi CS, Bueno AB, Carosati D, Casadio C, Chen WP, Damljanovic G, Di Paola A, Efimova NV, Ehgamberdiev SA, Giroletti M, Gomez JL, Gonzalez-Morales PA, Grinon-Marin AB, Grishina TS, Gurwell MA, Hiriart D, Hsiao HY, Ibryamov S, Jorstad SG, Joshi M, Kopatskaya EN, Kurtanidze OM, Kurtanidze SO, Lahteenmaki A, Larionova EG, Larionova LV, Lazaro C, Leto P, Lin CS, Lin HC, Manilla-Robles AI, Marscher AP, McHardy IM, Metodieva Y, Mirzaqulov DO, Mokrushina AA, Molina SN, Morozova DA, Nikolashvili MG, Orienti M, Ovcharov E, Panwar N, Yabar AP, Gimenez IP, Ramakrishnan V, Richter GM, Rossini M, Sigua LA, Strigachev A, Taylor B, Tornikoski M, Trigilio C, Troitskaya YV, Troitsky IS, Umana G, Valcheva A, Velasco S, Vince O, Wehrle AE, Wiesemeyer H, Anne Lähteenmäki Group, Department of Radio Science and Engineering, Aalto-yliopisto, and Aalto University

Subjects
active [Galaxies], Radio galaxy, Astrophysics::High Energy Astrophysical Phenomena, ta221, galaxies: active, ta1171, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, law.invention, Telescope, Observatory, law, quasars: general, Emission spectrum, Blazar, ta216, Physics, individual: OJ 248 [Quasars], ta115, ta213, ta114, Linear polarization, quasars: individual: OJ 248, Astronomy, Astronomy and Astrophysics, general [Quasars], galaxies: active, galaxies: jets, quasars: general, quasars: individual: OJ 248, galaxies: jets, Light curve, Astrophysics - Astrophysics of Galaxies, Space and Planetary Science, jets [Galaxies], Astrophysics - High Energy Astrophysical Phenomena, Fermi Gamma-ray Space Telescope
Abstract

We present an analysis of the multiwavelength behaviour of the blazar OJ 248 at z = 0.939 in the period 2006-2013. We use low-energy data (optical, near-infrared, and radio) obtained by 21 observatories participating in the GLAST-AGILE Support Program (GASP) of the Whole Earth Blazar Telescope (WEBT), as well as data from the Swift (optical-UV and X-rays) and Fermi (gamma-rays) satellites, to study flux and spectral variability and correlations among emissions in different bands. We take into account the effect of absorption by the Damped Lyman Alpha intervening system at z = 0.525. Two major outbursts were observed in 2006-2007 and in 2012-2013 at optical and near-IR wavelengths, while in the high-frequency radio light curves prominent radio outbursts are visible peaking at the end of 2010 and beginning of 2013, revealing a complex radio-optical correlation. Cross-correlation analysis suggests a delay of the optical variations after the gamma-ray ones of about a month, which is a peculiar behaviour in blazars. We also analyse optical polarimetric and spectroscopic data. The average polarization percentage P is less than 3 per cent, but it reaches about 19 per cent during the early stage of the 2012-2013 outburst. A vague correlation of P with brightness is observed. There is no preferred electric vector polarisation angle and during the outburst the linear polarization vector shows wide rotations in both directions, suggesting a complex behaviour or structure of the jet and possible turbulence. The analysis of 140 optical spectra acquired at the Steward Observatory reveals a strong Mg II broad emission line with an essentially stable flux of 6.2 e-15 erg cm-2 s-1 and a full width at half-maximum of 2053 km s-1., Comment: 16 pages, 20 figures, 2 tables, in press for MNRAS

Published
2015

7. Rapid quasi-periodic oscillations in the relativistic jet of BL Lacertae.

Author

Jorstad SG, Marscher AP, Raiteri CM, Villata M, Weaver ZR, Zhang H, Dong L, Gómez JL, Perel MV, Savchenko SS, Larionov VM, Carosati D, Chen WP, Kurtanidze OM, Marchini A, Matsumoto K, Mortari F, Aceti P, Acosta-Pulido JA, Andreeva T, Apolonio G, Arena C, Arkharov A, Bachev R, Banfi M, Bonnoli G, Borman GA, Bozhilov V, Carnerero MI, Damljanovic G, Ehgamberdiev SA, Elsässer D, Frasca A, Gabellini D, Grishina TS, Gupta AC, Hagen-Thorn VA, Hallum MK, Hart M, Hasuda K, Hemrich F, Hsiao HY, Ibryamov S, Irsmambetova TR, Ivanov DV, Joner MD, Kimeridze GN, Klimanov SA, Knött J, Kopatskaya EN, Kurtanidze SO, Kurtenkov A, Kuutma T, Larionova EG, Leonini S, Lin HC, Lorey C, Mannheim K, Marino G, Minev M, Mirzaqulov DO, Morozova DA, Nikiforova AA, Nikolashvili MG, Ovcharov E, Papini R, Pursimo T, Rahimov I, Reinhart D, Sakamoto T, Salvaggio F, Semkov E, Shakhovskoy DN, Sigua LA, Steineke R, Stojanovic M, Strigachev A, Troitskaya YV, Troitskiy IS, Tsai A, Valcheva A, Vasilyev AA, Vince O, Waller L, Zaharieva E, and Chatterjee R

Abstract

Blazars are active galactic nuclei (AGN) with relativistic jets whose non-thermal radiation is extremely variable on various timescales 1-3 . This variability seems mostly random, although some quasi-periodic oscillations (QPOs), implying systematic processes, have been reported in blazars and other AGN. QPOs with timescales of days or hours are especially rare 4 in AGN and their nature is highly debated, explained by emitting plasma moving helically inside the jet 5 , plasma instabilities 6,7 or orbital motion in an accretion disc 7,8 . Here we report results of intense optical and γ-ray flux monitoring of BL Lacertae (BL Lac) during a dramatic outburst in 2020 (ref.  9 ). BL Lac, the prototype of a subclass of blazars 10 , is powered by a 1.7 × 10 8  M Sun (ref.  11 ) black hole in an elliptical galaxy (distance = 313 megaparsecs (ref.  12 )). Our observations show QPOs of optical flux and linear polarization, and γ-ray flux, with cycles as short as approximately 13 h during the highest state of the outburst. The QPO properties match the expectations of current-driven kink instabilities 6 near a recollimation shock about 5 parsecs (pc) from the black hole in the wake of an apparent superluminal feature moving down the jet. Such a kink is apparent in a microwave Very Long Baseline Array (VLBA) image., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

Published
2022
Full Text
View/download PDF

8. Blazar spectral variability as explained by a twisted inhomogeneous jet.

Author

Raiteri CM, Villata M, Acosta-Pulido JA, Agudo I, Arkharov AA, Bachev R, Baida GV, Benítez E, Borman GA, Boschin W, Bozhilov V, Butuzova MS, Calcidese P, Carnerero MI, Carosati D, Casadio C, Castro-Segura N, Chen WP, Damljanovic G, D'Ammando F, Di Paola A, Echevarría J, Efimova NV, Ehgamberdiev SA, Espinosa C, Fuentes A, Giunta A, Gómez JL, Grishina TS, Gurwell MA, Hiriart D, Jermak H, Jordan B, Jorstad SG, Joshi M, Kopatskaya EN, Kuratov K, Kurtanidze OM, Kurtanidze SO, Lähteenmäki A, Larionov VM, Larionova EG, Larionova LV, Lázaro C, Lin CS, Malmrose MP, Marscher AP, Matsumoto K, McBreen B, Michel R, Mihov B, Minev M, Mirzaqulov DO, Mokrushina AA, Molina SN, Moody JW, Morozova DA, Nazarov SV, Nikolashvili MG, Ohlert JM, Okhmat DN, Ovcharov E, Pinna F, Polakis TA, Protasio C, Pursimo T, Redondo-Lorenzo FJ, Rizzi N, Rodriguez-Coira G, Sadakane K, Sadun AC, Samal MR, Savchenko SS, Semkov E, Skiff BA, Slavcheva-Mihova L, Smith PS, Steele IA, Strigachev A, Tammi J, Thum C, Tornikoski M, Troitskaya YV, Troitsky IS, Vasilyev AA, and Vince O

Abstract

Blazars are active galactic nuclei, which are powerful sources of radiation whose central engine is located in the core of the host galaxy. Blazar emission is dominated by non-thermal radiation from a jet that moves relativistically towards us, and therefore undergoes Doppler beaming. This beaming causes flux enhancement and contraction of the variability timescales, so that most blazars appear as luminous sources characterized by noticeable and fast changes in brightness at all frequencies. The mechanism that produces this unpredictable variability is under debate, but proposed mechanisms include injection, acceleration and cooling of particles, with possible intervention of shock waves or turbulence. Changes in the viewing angle of the observed emitting knots or jet regions have also been suggested as an explanation of flaring events and can also explain specific properties of blazar emission, such as intra-day variability, quasi-periodicity and the delay of radio flux variations relative to optical changes. Such a geometric interpretation, however, is not universally accepted because alternative explanations based on changes in physical conditions-such as the size and speed of the emitting zone, the magnetic field, the number of emitting particles and their energy distribution-can explain snapshots of the spectral behaviour of blazars in many cases. Here we report the results of optical-to-radio-wavelength monitoring of the blazar CTA 102 and show that the observed long-term trends of the flux and spectral variability are best explained by an inhomogeneous, curved jet that undergoes changes in orientation over time. We propose that magnetohydrodynamic instabilities or rotation of the twisted jet cause different jet regions to change their orientation and hence their relative Doppler factors. In particular, the extreme optical outburst of 2016-2017 (brightness increase of six magnitudes) occurred when the corresponding emitting region had a small viewing angle. The agreement between observations and theoretical predictions can be seen as further validation of the relativistic beaming theory.

Published
2017
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results