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2. Population study of Galactic supernova remnants at very high γ-ray energies with H.E.S.S

Author

Christo Venter, H. Iwasaki, Gilles Maurin, Q. Piel, J. F. Glicenstein, J. Becker Tjus, A. Zech, M. Büchele, Julien Lefaucheur, Nachiketa Chakraborty, R. Liu, C. Mariaud, L. O'c. Drury, A.M. Taylor, C. Perennes, T. Garrigoux, Riaan Steenkamp, Ruben Lopez-Coto, Pierre Brun, M. Lemoine-Goumard, A. Wörnlein, P.-O. Petrucci, H. Ndiyavala, G. Lamanna, S. J. Fegan, A. Djannati-Ataï, N. W. Pekeur, P. Wagner, Alison Mitchell, Dieter Horns, Jean-Pierre Ernenwein, Zorawar Wadiasingh, B. Condon, I. Shilon, M. Seglar-Arroyo, Jan Conrad, Marco Padovani, Clemens Hoischen, A. A. Zdziarski, Frank M. Rieger, Johannes Veh, D. Gottschall, D. A. Sanchez, J. Hawkes, Anne Lemiere, Gavin Rowell, M. Bryan, R. C. G. Chaves, E. O. Angüner, Reinhard Schlickeiser, D. Zaborov, D. Jankowsky, Monica Barnard, A. S. Seyffert, Axel Donath, R. de los Reyes, A. W. Chen, M. Tluczykont, D. Fernandez, V. Poireau, Cameron B Rulten, C. Romoli, K. Morå, F. Gaté, Felix Spanier, I. Jung-Richardt, Manuel Meyer, H. Abdalla, Christian Stegmann, I. Oya, Stefan Wagner, Yasunobu Uchiyama, D. Wouters, M. A. Kastendieck, G. Vasileiadis, Nu. Komin, Jim Hinton, Y. A. Gallant, Fabian Schüssler, Matteo Cerruti, Stefan Ohm, Markus Holler, Felix Jankowsky, J. Decock, M. Mayer, S. Pita, Dmitry Khangulyan, Dorit Glawion, E. Moulin, Tomasz Bulik, S. Nakashima, J. Zorn, Robert Wagner, Thomas Lohse, L. Mohrmann, Felix Aharonian, L. Dirson, C. Farnier, Ramin Marx, E. Leser, M. Panter, U. Katz, Stefano Gabici, J. Dyks, C. van Rensburg, Werner Hofmann, G. Emery, Samar Safi-Harb, Thomas Vuillaume, B. Khélifi, S. Saito, Justine Devin, M. Lorentz, S. Bonnefoy, Constantin Steppa, M. Füßling, S. Eschbach, Jacek Niemiec, G. Hermann, Regis Terrier, Stefan Klepser, A. Balzer, Heinrich J. Völk, M. Mohamed, Olaf Reimer, P. P. Krüger, F. Voisin, D. Klochkov, Alexandre Marcowith, D.A. Prokhorov, M. Renaud, F. Zefi, D. Kerszberg, Rachel Simoni, Helen Poon, M. Jingo, R. D. Parsons, D. J. van der Walt, L. Oakes, J. Bolmont, I. Sushch, A. Ivascenko, R. Blackwell, S. Colafrancesco, Michael Backes, H. Prokoph, Masanori Arakawa, Gianluca Giavitto, V. Marandon, K. Dutson, Thomas Murach, Joachim Hahn, J. Lau, M. Settimo, Andreas Quirrenbach, Sami Caroff, Włodek Kluźniak, M. Capasso, S. Krakau, V. Sahakian, P. Bordas, Michael Zacharias, F. Niederwanger, J. P. Lees, H. Odaka, Tim Holch, S. Raab, A. Abramowski, G. Heinzelmann, N. Maxted, Krzysztof Katarzynski, A. Jacholkowska, Naomi Tsuji, Tanya Edwards, K. Kosack, Konrad Bernlöhr, Jacco Vink, Catherine Boisson, L. Tibaldo, D. Berge, Christoph Deil, Sabrina Casanova, Gerard Fontaine, G. Pelletier, B. Peyaud, Ullrich Schwanke, G. Pühlhofer, Johan Bregeon, J.-P. Tavernet, Kleopas Shiningayamwe, R. J. White, A. Reimer, A. Viana, Domenico Tiziani, D. Malyshev, Łukasz Stawarz, S. Bernhard, B. van Soelen, Michal Ostrowski, B. Rudak, J.-P. Lenain, F. Ait Benkhali, P. T. O'Brien, M. V. Fernandes, Manami Sasaki, S. Schwemmer, Andrea Santangelo, Gilles Henri, C. van Eldik, Stefan Funk, Alicja Wierzcholska, Marek Jamrozy, Helene Sol, B. Giebels, R. J. Tuffs, L. Jouvin, Iryna Lypova, Yvonne Becherini, K. Egberts, J. Chevalier, R. Rauth, Thomas Tavernier, N. Shafi, Natalia Żywucka, M. de Naurois, Ruizhi Yang, Tadayuki Takahashi, A. Schulz, Isak Delberth Davids, A. Fiasson, Roberta Zanin, P. Willmann, C. Trichard, P. J. Meintjes, A. Ziegler, H. Laffon, M. Arrieta, P. deWilt, J. King, Marion Spir-Jacob, Maria Haupt, Michelle Tsirou, L. Rinchiuso, Rafal Moderski, A. Carosi, Francois Brun, P. Vincent, M.-H. Grondin, Markus Böttcher, M. Katsuragawa, Pierre-Henri Aubert, M. Kraus, Michael Punch, Laboratoire Univers et Théories ( LUTH ), Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire d'Annecy de Physique des Particules ( LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules ), Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Université Savoie Mont Blanc ( USMB [Université de Savoie] [Université de Chambéry] ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire de Physique Nucléaire et de Hautes Énergies ( LPNHE ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire Univers et Particules de Montpellier ( LUPM ), Centre National de la Recherche Scientifique ( CNRS ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Université Montpellier 2 - Sciences et Techniques ( UM2 ) -Université de Montpellier ( UM ), 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 ), Institut de Recherches sur les lois Fondamentales de l'Univers ( IRFU ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay, Laboratoire Leprince-Ringuet ( LLR ), Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -École polytechnique ( X ) -Centre National de la Recherche Scientifique ( CNRS ), AstroParticule et Cosmologie ( APC - UMR 7164 ), Centre National de la Recherche Scientifique ( CNRS ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Observatoire de Paris-Université Paris Diderot - Paris 7 ( UPD7 ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ), Centre de Physique des Particules de Marseille ( CPPM ), Centre National de la Recherche Scientifique ( CNRS ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Aix Marseille Université ( AMU ), Institut de Planétologie et d'Astrophysique de Grenoble ( IPAG ), Observatoire des Sciences de l'Univers de Grenoble ( OSUG ), Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ) -Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ) -Centre National de la Recherche Scientifique ( CNRS ), HESS, Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE (UMR_7585)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Particules de Montpellier (LUPM), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), 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), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), 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 National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université de Montpellier (UM)-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), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Aix Marseille Université (AMU), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2), Faculty of Science, High Energy Astrophys. & Astropart. Phys (API, FNWI), and API Other Research (FNWI)

Subjects
electron, Milky Way, [ PHYS.ASTR ] Physics [physics]/Astrophysics [astro-ph], Astrophysics::High Energy Astrophysical Phenomena, Hochenergie-Astrophysik Theorie - Abteilung Hofmann, Infrarot-Astrophysik - Abteilung Hofmann, Cosmic ray, magnetic field, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Compact star, 7. Clean energy, 01 natural sciences, Luminosity, HESS, 0103 physical sciences, supernova, ddc:530, luminosity, flux: upper limit, cosmic radiation: acceleration, 010303 astronomy & astrophysics, HESS - Abteilung Hofmann, Astrophysics::Galaxy Astrophysics, ISM: supernova remnants, Astroparticle physics, Physics, radio wave, density, energy: high, cosmic radiation: spectrum, 010308 nuclear & particles physics, supernova remnants [ISM], Molecular cloud, shell model, Institut für Physik und Astronomie, Astronomy and Astrophysics, gamma rays: general, Galactic plane, Supernova, gamma ray: VHE, Space and Planetary Science, cosmic radiation: galaxy, ddc:520, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], general [gamma rays]
Abstract

著者人数: H.E.S.S. Collaboration 253名 (所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): 桂川, 美穂; 中島, 真也; 小高, 裕和; 高橋, 忠幸), Number of authors: H.E.S.S. Collaboration 253 (Affiliation. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS): Katsuragawa, Miho; Nakashima, Shinya; Odaka, Hirokazu; Takahashi, Tadayuki), Accepted: 2018-02-08, 資料番号: SA1170368000

Published
2018

3. The ultraluminous X-ray source NGC 1313 X-2

Author

Fabien Grisé, Stuart D. Ryder, Ian Smith, Christian Motch, Markus Böttcher, Manfred W. Pakull, and Roberto Soria

Subjects
Physics, Ultraluminous X-ray source, Astrophysics::High Energy Astrophysical Phenomena, media_common.quotation_subject, Astrophysics (astro-ph), FOS: Physical sciences, Photometric system, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Wavelength, Amplitude, Accretion disc, Space and Planetary Science, Sky, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics, media_common
Abstract

NGC 1313 X-2 is one of the brightest ultraluminous X-ray sources in the sky, at both X-ray and optical wavelengths; therefore, quite a few studies of available ESO VLT and HST data have appeared in the literature. Here, we present our analysis of VLT/FORS1 and HST/ACS photometric data, confirming the identification of the B ~ 23 mag blue optical counterpart. We show that the system is part of a poor cluster with an age of 20 Myr, leading to an upper mass limit of some 12 M_sun for the mass donor. We attribute the different results with respect to earlier studies to the use of isochrones in the F435W and F555W HST/ACS photometric system that appear to be incompatible with the corresponding Johnson B and V isochrones. The counterpart exhibits significant photometric variability of about 0.2 mag amplitude, both between the two HST observations and during the one month of monitoring with the VLT. This includes variability within one night and suggests that the light is dominated by the accretion disk in the system and not by the mass donor., Comment: 13 pages, 11 figures. Accepted for publication in Astronomy & Astrophysics

Published
2008

4. Redshift limits of BL Lacertae objects from optical spectroscopy

Author

Markus Böttcher, J. C. Shields, S. Basu, and Justin D. Finke

Subjects
Physics, Astrophysics (astro-ph), Continuum (design consultancy), Cosmic distance ladder, FOS: Physical sciences, Astronomy and Astrophysics, Context (language use), Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Galaxy, Redshift, law.invention, Telescope, Space and Planetary Science, law, Spectroscopy, Equivalent width
Abstract

Context: BL Lacertae objects have been the targets for numerous recent multiwavelength campaigns, continuum spectral variability studies, and theoretical spectral and variability modeling. A meaningful interpretation of the results of such studies requires a reliable knowledge of the objects' redshifts; however, the redshifts for many are still unknown or uncertain. Aims: Therefore, we hope to determine or constrain the redshifts of six BL Lac objects with unknown or poorly known redshifts. Methods: Observations were made of these objects with the MDM 2.4 m Hiltner telescope. Although no spectral features were detected, and thus no redshifts could be measured, lower redshift limits were assigned to the objects based on the expected equivalent widths of absorption features in their host galaxies. Redshifts were also estimated for some objects by assuming the host galaxies are standard candles and using host galaxy apparent magnitudes taken from the literature. Results: The commonly used redshift of $z=0.102$ for 1219+285 is almost certainly wrong, while the redshifts of the other objects studied remain undetermined., Comment: 4 pages, 2 figures. Accepted by A&A Research Notes

Published
2007

5. A swirling jet in the quasar 1308+326

Author

Marita Krause, M. F. Aller, Emma Kun, A. Witzel, Markus Böttcher, Silke Britzen, Christian Fendt, László Á. Gergely, Hugh D. Aller, Lydia Moser, Andreas Eckart, Shan-Jie Qian, J. Schmidt, Marios Karouzos, and Wolfgang Steffen

Subjects
01.03. Fizikai tudományok, Physics, Active galactic nucleus, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Rotation around a fixed axis, Astronomy, Astronomy and Astrophysics, Quasar, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Magnetic flux, Binary black hole, Space and Planetary Science, 0103 physical sciences, Very-long-baseline interferometry, Tidal force, 010303 astronomy & astrophysics, Very Long Baseline Array
Abstract

Context. Despite numerous and detailed studies of the jets of active galactic nuclei (AGN) on pc-scales, many questions are still debated. The physical nature of the jet components is one of the most prominent unsolved problems, as is the launching mechanism of jets in AGN. The quasar 1308+326 (z = 0.997) allows us to study the overall properties of its jet in detail and to derive a more physical understanding of the nature and origin of jets in general. The long-term data provided by the Monitoring Of Jets in Active galactic nuclei with Very Long Baseline Array (VLBA) experiments (MOJAVE) survey permit us to trace out the structural changes in 1308+326 that we present here. The long-lived jet features in this source can be followed for about two decades.Aims. We investigate the very long baseline interferomety (VLBI) morphology and kinematics of the jet of 1308+326 to understand the physical nature of this jet and jets in general, the role of magnetic fields, and the causal connection between jet features and the launching process.Methods. Fifty VLBA observations performed at 15 GHz from the MOJAVE survey were re-modeled with Gaussian components and re-analyzed (the time covered: 20 Jan. 1995–25 Jan. 2014). The analysis was supplemented by multi-wavelength radio-data (UMRAO, at 4.8, 8.0, and 14.5 GHz) in polarization and total intensity. We fit the apparent motion of the jet features with the help of a model of a precessing nozzle.Results. The jet features seem to be emitted with varying viewing angles and launched into an ejection cone. Tracing the component paths yields evidence for rotational motion. Radio flux-density variability can be explained as a consequence of enhanced Doppler boosting corresponding to the motion of the jet relative to the line of sight. Based on the presented kinematics and other indicators, such as electric-vector polarization position-angle (EVPA) rotation, we conclude that the jet of 1308+326 has a helical structure, meaning that the components are moving along helical trajectories and the trajectories themselves are also experiencing a precessing motion. A model of a precessing nozzle was applied to the data and a subset of the observed jet feature paths can be modeled successfully within this model. The data till 2012 are consistent with a swing period of 16.9 yr. We discuss several scenarios to explain the observed motion phenomena, including a binary black hole model. It seems unlikely that the accretion disk around the primary black hole, which is disturbed by the tidal forces of the secondary black hole, is able to launch a persistent axisymmetric jet.Conclusions. We conclude that we are observing a rotating helix. In particular, the observed EVPA swings can be explained by a shock moving through a straight jet that is pervaded by a helical magnetic field. We compare our results for 1308+326 with other astrophysical scenarios where similar, wound-up filamentary structures are found. They are all related to accretion-driven processes. A helically moving or wound up object is often explained by filamentary features moving along magnetic field lines of magnetic flux tubes. It seems that a “component” comprises plasma tracing the magnetic field, which guides the motion of the radiating radio-band plasma. Further investigations and modeling are in preparation.

Published
2017

6. Gravitational light-bending preventsγγabsorption in gravitational lenses

Author

Hannes Thiersen and Markus Böttcher

Subjects
Gravitation, Physics, 010308 nuclear & particles physics, Space and Planetary Science, 0103 physical sciences, Astronomy and Astrophysics, Astrophysics, Bending, Atomic physics, Absorption (electromagnetic radiation), 010303 astronomy & astrophysics, 01 natural sciences
Published
2016

7. Probing cluster environments of blazars throughγγabsorption

Author

Markus Böttcher, I. Sushch, 24922986 - Sushch, Iurii, and 24420530 - Böttcher, Markus

Subjects
Physics, general [BL Lacertae objects], Astrophysics::High Energy Astrophysical Phenomena, media_common.quotation_subject, Compton scattering, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, non-thermal [radiation mechanisms], Universe, Galaxy, Redshift, Stars, individual: 1ES1440+122 [BL Lacertae objects], Extragalactic background light, Space and Planetary Science, Intracluster medium, clusters: general [galaxies], Blazar, Astrophysics::Galaxy Astrophysics, media_common
Abstract

Most blazars are known to be hosted in giant elliptic galaxies, but their cluster environments have not been thoroughly investigated. Cluster environments may contain radiation fields of low-energy photons created by nearby galaxies and/or stars in the intracluster medium that produce diffuse intracluster light. These radiation fields may absorb very high energy γ rays (VHE; E & 100 GeV) and trigger pair cascades with further production of subsequent generations of γ rays with lower energies via inverse Compton scattering on surrounding radiation fields leaving a characteristic imprint in the observed spectral shape. The change of the spectral shape of the blazar reflects the properties of its ambient medium. We show, however, that neither intracluster light nor the radiation field of an individual nearby galaxy can cause substantial γγ absorption. Substantial γγ absorption is possible only in the case of multiple, &5, luminous nearby galaxies. This situation is not found in the local Universe, but may be possible at larger redshifts (z & 2). Since VHE γ rays from such distances are expected to be strongly absorbed by the extragalactic background light, we consider possible signatures of γ-ray induced pair cascades by calculating the expected GeV flux which appears to be below the Fermi-LAT sensitivity even for ∼10 nearby galaxies.

Published
2014

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