Browsing by Author "Orienti, M."

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  • AGILE detection of extreme gamma-ray activity from the blazar PKS 1510-089 during March 2009. Multifrequency analysis
    (2011) "D'Ammando", F.; Raiteri, C.M.; Villata, M.; Romano, P.; Pucella, G.; Krimm, H.A.; Covino, S.; Orienti, M.; Giovannini, G.; Vercellone, S.; Pian, E.; Donnarumma, I.; Vittorini, V.; Tavani, M.; Argan, A.; Barbiellini, G.; Boffelli, F.; Bulgarelli, A.; Caraveo, P.; Cattaneo, P.W.; Chen, A.W.; Cocco, V.; Costa, E.; Del Monte, E.; de Paris, G.; Di Cocco, G.; Evangelista, Y.; Feroci, M.; Ferrari, A.; Fiorini, M.; Froysland, T.; Frutti, M.; Fuschino, F.; Galli, M.; Gianotti, F.; Giuliani, A.; Labanti, C.; Lapshov, I.; Lazzarotto, F.; Lipari, P.; Longo, F.; Marisaldi, M.; Mereghetti, S.; Morselli, A.; Pacciani, L.; Pellizzoni, A.; Perotti, F.; Piano, G.; Picozza, P.; Pilia, M.; Porrovecchio, Geiland; Prest, M.; Rapisarda, M.; Rappoldi, A.; Rubini, A.; Sabatini, S.; Soffitta, P.; Striani, E.; Trifoglio, M.; Trois, A.; Vallazza, E.; Zambra, A.; Zanello, D.; Agudo, I.; Aller, H.D.; Aller, M.F.; Arkharov, A.A.; Bach, U.; Benitez, E.; Berdyugin, A.; Blinov, D.A.; Buemi, C.S.; Chen, W.P.; di Paola, A.; Dolci, M.; Forné, E.; Fuhrmann, L.; Gómez, J.L.; Gurwell, M.A.; Jordan, B.; Jorstad, S.G.; Heidt, J.; Hiriart, D.; Hovatta, T.; Hsiao, H.Y.; Kimeridze, G.; Konstantinova, T.S.; Kopatskaya, E.N.; Koptelova, E.; Kurtanidze, O.M.; Kurtanidze, S.O.; Larionov, V.M.; Lähteenmäki, A.; Leto, P.; Lindfors, E.; Marscher, A.P.; McBreen, B.; McHardy, I.M.; Morozova, D.A.; Nilsson, K.; Pasanen, M.; Roca-Sogorb, M.; Sillanpää, A.; Takalo, L.O.; Tornikoski, M.; Trigilio, C.; Troitsky, I.S.; Umana, G.; Antonelli, Lucio A.; Colafrancesco, S.; Pittori, C.; Santolamazza, P.; Verrecchia, F.; Giommi, P.; Salotti, L.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
  • AGILE, Fermi, Swift, and GASP/WEBT multi-wavelength observations of the high-redshift blazar 4C +71.07 in outburst
    (2019-01-11) Vercellone, S.; Romano, P.; Piano, G.; Vittorini, V.; Donnarumma, I.; Munar-Adrover, P.; Raiteri, C. M.; Villata, M.; Verrecchia, F.; Lucarelli, F.; Pittori, C.; Bulgarelli, A.; Fioretti, V.; Tavani, M.; Acosta-Pulido, J. A.; Agudo, I.; Arkharov, A. A.; Bach, U.; Bachev, R.; Borman, G. A.; Butuzova, M. S.; Carnerero, M. I.; Casadio, C.; Damljanovic, G.; D'Ammando, F.; Di Paola, A.; Doroshenko, V. T.; Efimova, N. V.; Ehgamberdiev, S. A.; Giroletti, M.; Gómez, J. L.; Grishina, T. S.; Järvelä, E.; Klimanov, S. A.; Kopatskaya, E. N.; Kurtanidze, O. M.; Lähteenmäki, A.; Larionov, V. M.; Larionova, L. V.; Mihov, B.; Mirzaqulov, D. O.; Molina, S. N.; Morozova, D. A.; Nazarov, S. V.; Orienti, M.; Righini, S.; Savchenko, S. S.; Semkov, E.; Slavcheva-Mihova, L.; Strigachev, A.; Tornikoski, M.; Troitskaya, Y. V.; Vince, O.; Cattaneo, P. W.; Colafrancesco, S.; Longo, F.; Morselli, A.; Paoletti, F.; Parmiggiani, N.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Context. The flat-spectrum radio quasar 4C +71.07 is a high-redshift (z = 2.172), gamma-loud blazar whose optical emission is dominated by thermal radiation from the accretion disc. Aims. 4C +71.07 has been detected in outburst twice by the AGILE gamma-ray satellite during the period from the end of October to mid-November 2015, when it reached a gamma-ray flux of the order of F(E > 100 MeV) = (1.2 +/- 0.3) x 10(-6) photons cm (2) s(-1) and F(E > 100 MeV) = (3.1 +/- 0.6) x 10(-6) photons cm(-2) s(-1), respectively, allowing us to investigate the properties of the jet and the emission region. Methods. We investigated its spectral energy distribution by means of almost-simultaneous observations covering the cm, mm, near-infrared, optical, ultraviolet, X-ray, and gamma-ray energy bands obtained by the GASP-WEBT Consortium and the Swift, AGILE, and Fermi satellites. Results. The spectral energy distribution of the second gamma-ray flare (whose energy coverage is more dense) can be modelled by means of a one-zone leptonic model, yielding a total jet power of about 4 x 10(47) erg s(-1). Conclusions. During the most prominent gamma-ray flaring period our model is consistent with a dissipation region within the broad-line region. Moreover, this class of high-redshift, flat-spectrum radio quasars with high-mass black holes might be good targets for future gamma-ray satellites such as e-ASTROGAM.
  • The awakening of the γ-ray narrow-line Seyfert 1 galaxy PKS 1502+036
    (2016-12) D'Ammando, F.; Orienti, M.; Finke, J.; Hovatta, T.; Giroletti, M.; Max-Moerbeck, W.; Pearson, T. J.; Readhead, A. C. S.; Reeves, R. A.; Richards, J. L.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    After a long low-activity period, a γ-ray flare from the narrow-line Seyfert 1 PKS 1502+036 (z = 0.4089) was detected by the Large Area Telescope (LAT) on board Fermi in 2015. On 2015 December 20, the source reached a daily peak flux, in the 0.1-300 GeV band, of (93 ± 19) × 10-8 ph cm-2 s-1, attaining a flux of (237 ± 71) × 10-8 ph cm-2 s-1 on 3-h time-scales, which corresponds to an isotropic luminosity of (7.3 ± 2.1) × 1047 erg s-1. The γ-ray flare was not accompanied by significant spectral changes. We report on multiwavelength radio-to-γ-ray observations of PKS 1502+036 during 2008 August-2016 March by Fermi-LAT, Swift, XMM-Newton, Catalina Real-Time Transient Survey and the Owens Valley Radio Observatory (OVRO). An increase in activity was observed on 2015 December 22 by Swift in optical, UV and X-rays. The OVRO 15 GHz light curve reached the highest flux density observed from this source on 2016 January 12, indicating a delay of about three weeks between the γ-ray and 15 GHz emission peaks. This suggests that the γ-ray-emitting region is located beyond the broad-line region. We compared the spectral energy distribution (SED) of an average activity state with that of the flaring state. The two SED, with the high-energy bump modelled as an external Compton component with seed photons from a dust torus, could be fitted by changing the electron distribution parameters as well as the magnetic field. The fit of the disc emission during the average state constrains the black hole mass to values lower than 108 M⊙. The SED, high-energy emission mechanisms and γ-ray properties of the source resemble those of a flat spectrum radio quasar.
  • Discovery of off-axis jet structure of TeV blazar Mrk 501 with mm-VLBI
    (2016-02-01) Koyama, S.; Kino, M.; Giroletti, M.; Doi, A.; Giovannini, G.; Orienti, M.; Hada, K.; Ros, E.; Niinuma, K.; Nagai, H.; Savolainen, T.; Krichbaum, T. P.; Pérez-Torres, M.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Context. High-resolution millimeter wave very-long-baseline interferometry (mm-VLBI) is an ideal tool for probing the structure at the base of extragalactic jets in detail. The TeV blazar Mrk 501 is one of the best targets among BL Lac objects for studying the nature of off-axis jet structures because it shows different jet position angles at different scales. Aims. The aim of this study is to investigate the properties of the off-axis jet structure through high-resolution mm-VLBI images at the jet base and physical parameters such as kinematics, flux densities, and spectral indices. Methods. We performed Very Long Baseline Array (VLBA) observations over six epochs from 2012 February to 2013 February at 43 GHz. Quasi-simultaneous Global Millimeter VLBI Array (GMVA) observations at 86 GHz were performed in May 2012. Results. We discover a new jet component at the northeast direction from the core in all the images at 43 and 86 GHz. The new component shows the off-axis location from the persistent jet extending to the southeast. The 43 GHz images reveal that the scattering of the positions of the NE component is within ∼0.2 mas. The 86 GHz data reveals a jet component located 0.75 mas southeast of the radio core. We also discuss the spectral indices between 43 and 86 GHz, where the northeast component has steeper spectral index and the southeast component has comparable or flatter index than the radio core does.
  • The most powerful flaring activity from the NLSy1 PMN J0948+0022
    (2015) "D'Ammando", F.; Orienti, M.; Finke, J.; Raiteri, C.M.; Hovatta, T.; Larsson, J.; Max-Moerbeck, W.; Perkins, J.; Readhead, A.C.S.; Richards, J.L.; Beilicke, M.; Benbow, W.; Berger, K.; Bird, R.; Bugaev, V.; Cardenzana, J.V.; Cerruti, M.; Chen, X.; Ciupik, L.; Dickinson, H.J.; Eisch, J.D.; Errando, M.; Falcone, A.; Finley, J.P.; Fleischhack, H.; Fortin, P.; Fortson, L.; Furniss, A.; Gerard, L.; Gillanders, G.H.; Griffiths, S.T.; Grube, J.; Gyuk, G.; Håkansson, N.; Holder, J.; Humensky, T.B.; Kar, P.; Kertzman, M.; Khassen, Y.; Kieda, D.; Krennrich, F.; Kumar, S.; Lang, M.J.; Maier, G.; McCann, A.; Meagher, K.; Moriarty, P.; Mukherjee, R.; Nieto, D.; de Bhróithe, "A.O'Faoláin"; Ong, R.A.; Otte, A.N.; Pohl, M.; Popkow, A.; Prokoph, H.; Pueschel, E.; Quinn, J.; Ragan, K.; Reynolds, P.T.; Richards, G.T.; Roache, E.; Rousselle, J.; Santander, M.; Sembroski, G.H.; Smith, A.W.; Staszak, D.; Telezhinsky, I.; Tucci, J.V.; Tyler, J.; Varlotta, A.; Vassiliev, V.V.; Wakely, S.P.; Weinstein, A.; Welsing, R.; Williams, D.A.; Zitzer, B.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
  • Multiwavelength behaviour of the blazar OJ 248 from radio to gamma-rays
    (2015) Carnerero, M.I.; Raiteri, C.M.; Villata, M.; Acosta-Pulido, J.A.; "D'Ammando", F.; Smith, P.S.; Larionov, V.M.; Agudo, I.; Arévalo, M.J.; Arkharov, A.A.; Bach, U.; Bachev, R.; Benítez, E.; Blinov, D.A.; Bozhilov, V.; Buemi, C.S.; Bueno Bueno, A.; Carosati, D.; Casadio, C.; Chen, W.P.; Damljanovic, G.; Paola, A.Di; Efimova, N.V.; Ehgamberdiev, Sh.A.; Giroletti, M.; Gómez, J.L.; Gonzá lez-Morales, P.A.; Grinon-Marin, A.B.; Grishina, T.S.; Gurwell, M.A.; Hiriart, D.; Hsiao, H.Y.; Ibryamov, S.; Jorstad, S.G.; Joshi, M.; Kopatskaya, E.N.; Kurtanidze, O.M.; Kurtanidze, S.O.; Lähteenmäki, A.; Larionova, E.G.; Larionova, L.V.; Lázaro, C.; Leto, P.; Lin, C.S.; Lin, H.C.; Manilla-Robles, A.I.; Marscher, A.P.; McHardy, I.M.; Metodieva, Y.; Mirzaqulov, D.O.; Mokrushina, A.A.; Molina, S.N.; Morozova, D.A.; Nikolashvili, M.G.; Orienti, M.; Ovcharov, E.; Panwar, N.; Pastor Yabar, A.; Puerto Giménez, I.; Ramakrishnan, V.; Richter, G.M.; Rossini, M.; Sigua, L.A.; Strigachev, A.; Taylor, B.; Tornikoski, M.; Trigilio, C.; Troitskaya, Yu.V.; Troitsky, I.S.; Umana, G.; Valcheva, A.; Velasco, S.; Vince, O.; Wehrle, A.E.; Wiesemeyer, H.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
  • Radio follow-up of the γ-ray flaring gravitational lens JVAS B0218+357
    (2016-04-01) Spingola, C.; Dallacasa, D.; Orienti, M.; Giroletti, M.; McKean, J. P.; Cheung, C. C.; Hovatta, T.; Ciprini, S.; D'Ammando, F.; Falco, E.; Larsson, S.; Max-Moerbeck, W.; Ojha, R.; Readhead, A. C S; Richards, J. L.; Scargle, J.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    We present results on multifrequency Very Long Baseline Array (VLBA) monitoring observations of the double-image gravitationally lensed blazar JVAS B0218+357. Multi-epoch observations started less than one month after the γ -ray flare detected in 2012 by the Large Area Telescope on board Fermi, and spanned a 2-month interval. The radio light curves did not reveal any significant flux density variability, suggesting that no clear correlation between the high-energy and low-energy emission is present. This behaviour was confirmed also by the long-term Owens Valley Radio Observatory monitoring data at 15 GHz. The milliarcsecondscale resolution provided by the VLBA observations allowed us to resolve the two images of the lensed blazar, which have a core-jet structure. No significant morphological variation is found by the analysis of the multi-epoch data, suggesting that the region responsible for the γ -ray variability is located in the core of the active galactic nuclei, which is opaque up to the highest observing frequency of 22 GHz.
  • Radio-gamma-ray connection and spectral evolution in 4C +49.22 (S4 1150+49): the Fermi, Swift and Planck view
    (2014) Cutini, S.; Ciprini, S.; Orienti, M.; Tramacere, A.; "D'Ammando", F.; Verrecchia, F.; Polenta, G.; Carrasco, L.; "D'Elia", V.; Giommi, P.; González-Nuevo, J.; Grandi, P.; Harrison, D.; Hays, E.; Larsson, S.; Lähteenmäki, A.; León-Tavares, J.; López-Caniego, M.; Natoli, P.; Ojha, R.; Partridge, B.; Porras, A.; Reyes, L.; Recillas, E.; Torresi, E.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
  • RadioAstron discovery of a mini-cocoon around the restarted parsec-scale jet in 3C 84
    (2023-08-01) Savolainen, T.; Giovannini, G.; Kovalev, Y. Y.; Perucho, M.; Anderson, J. M.; Bruni, G.; Edwards, P. G.; Fuentes, A.; Giroletti, M.; Gomez, J. L.; Hada, K.; Lee, S. S.; Lisakov, M. M.; Lobanov, A. P.; Lopez-Miralles, J.; Orienti, M.; Petrov, L.; Plavin, A. V.; Sohn, B. W.; Sokolovsky, K. V.; Voitsik, P. A.; Zensus, J. A.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    We present RadioAstron space-based very long baseline interferometry (VLBI) observations of the nearby radio galaxy 3C 84 (NGC 1275) at the centre of the Perseus cluster. The observations were carried out during a perigee passage of the Spektr-R spacecraft on September 21a-22, 2013 and involved a global array of 24 ground radio telescopes observing at 5 GHz and 22 GHz, together with the Space Radio Telescope (SRT). Furthermore, the Very Long Baseline Array (VLBA) and the phased Very Large Array (VLA) observed the source quasi-simultaneously at 15 GHz and 43 GHz. Fringes between the ground array and the SRT were detected on baseline lengths up to 8.1 times the Eartha-s diameter, providing unprecedented resolution for 3C 84 at these wavelengths. We note that the corresponding fringe spacing is 125 μas at 5 GHz and 27 μas at 22 GHz. Our space-VLBI images reveal a previously unseen sub-structure inside the compact âà1 pc long jet that was ejected about ten years earlier. In the 5 GHz image, we detected, for the first time, low-intensity emission from a cocoon-like structure around the restarted jet. Our results suggest that the increased power of the young jet is inflating a bubble of hot plasma as it carves its way through the ambient medium of the central region of the galaxy. Here, we estimate the minimum energy stored in the mini-cocoon, along with its pressure, volume, expansion speed, and the ratio of heavy particles to relativistic electrons, as well as the density of the ambient medium. About half of the energy delivered by the jet is dumped into the mini-cocoon and the quasi-spherical shape of the bubble suggests that this energy may be transferred to a significantly larger volume of the interstellar medium than what would be accomplished by the well-collimated jet on its own. The pressure of the hot mini-cocoon also provides a natural explanation for the almost cylindrical jet profile seen in the 22 GHz RadioAstron image.
  • VHE gamma-ray detection of FSRQ QSO B1420+326 and modeling of its enhanced broadband state in 2020
    (2021-03-29) Acciari, V. A.; Ansoldi, S.; Antonelli, L. A.; Arbet Engels, A.; Artero, M.; Asano, K.; Baack, D.; Babić, A.; Baquero, A.; Barres De Almeida, U.; Barrio, J. A.; Becerra González, J.; Bednarek, W.; Bellizzi, L.; Bernardini, E.; Bernardos, M.; Berti, A.; Besenrieder, J.; Bhattacharyya, W.; Bigongiari, C.; Biland, A.; Blanch, O.; Bonnoli, G.; Bošnjak, A.; Busetto, G.; Carosi, R.; Ceribella, G.; Cerruti, M.; Chai, Y.; Chilingarian, A.; Cikota, S.; Colak, S. M.; 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.; 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.; Fallah Ramazani, V.; Fattorini, A.; Ferrara, G.; Foffano, L.; Fonseca, M. V.; Font, L.; Fruck, C.; Fukami, S.; Garciá López, R. J.; Garczarczyk, M.; Gasparyan, S.; Gaug, M.; Giglietto, N.; Giordano, F.; Gliwny, P.; Godinović, N.; Green, J. G.; Green, D.; Hadasch, D.; Hahn, A.; Heckmann, L.; Herrera, J.; Hoang, J.; Hrupec, D.; Hütten, M.; Inada, T.; Inoue, S.; Ishio, K.; Iwamura, Y.; Jormanainen, J.; Jouvin, L.; Kajiwara, Y.; Karjalainen, M.; Kerszberg, D.; Kobayashi, Y.; Kubo, H.; Kushida, J.; Lamastra, A.; Lelas, D.; Leone, F.; Lindfors, E.; Lombardi, S.; Longo, F.; López-Coto, R.; López-Moya, M.; López-Oramas, A.; Loporchio, S.; Machado De Oliveira Fraga, B.; Maggio, C.; Majumdar, P.; Makariev, M.; Mallamaci, M.; Maneva, G.; Manganaro, M.; Mannheim, K.; Maraschi, L.; Mariotti, M.; Martínez, M.; Mazin, D.; Mender, S.; Micánović, S.; Miceli, D.; Miener, T.; Minev, M.; Miranda, J. M.; Mirzoyan, R.; Molina, E.; Moralejo, A.; Morcuende, D.; Moreno, V.; Moretti, E.; Neustroev, V.; Nigro, C.; Nilsson, K.; Ninci, D.; Nishijima, K.; Noda, K.; Nozaki, S.; Ohtani, Y.; Oka, T.; Otero-Santos, J.; Paiano, S.; Palatiello, M.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Pavletić, L.; Peñil, P.; Perennes, C.; Persic, M.; Prada Moroni, P. G.; Prandini, E.; Priyadarshi, C.; Puljak, I.; Rhode, W.; Ribó, M.; Rico, J.; Righi, C.; Rugliancich, A.; Saha, L.; Sahakyan, N.; Saito, T.; Sakurai, S.; Satalecka, K.; Saturni, F. G.; Schleicher, B.; Schmidt, K.; Schweizer, T.; Sitarek, J.; Šnidarić, I.; Sobczynska, D.; Spolon, A.; Stamerra, A.; Strom, D.; Strzys, M.; Suda, Y.; Surić, T.; Takahashi, M.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Teshima, M.; Torres-Albà, N.; Tosti, L.; Truzzi, S.; Tutone, A.; Van Scherpenberg, J.; Vanzo, G.; Vazquez Acosta, M.; Ventura, S.; Verguilov, V.; Vigorito, C. F.; Vitale, V.; Vovk, I.; Will, M.; Zarić, D.; Angioni, R.; D'Ammando, F.; Ciprini, S.; Cheung, C. C.; Orienti, M.; Pacciani, L.; Prajapati, P.; Kumar, P.; Ganesh, S.; Kurtenkov, A.; Marchini, A.; Carrasco, L.; Escobedo, G.; Porras, A.; Recillas, E.; Lähteenmäki, A.; Tornikoski, M.; Berton, M.; Tammi, J.; Vera, R. J.C.; Jorstad, S. G.; Marscher, A. P.; Weaver, Z. R.; Hart, M.; Hallum, M. K.; Larionov, V. M.; Borman, G. A.; Grishina, T. S.; Kopatskaya, E. N.; Larionova, E. G.; Nikiforova, A. A.; Morozova, D. A.; Savchenko, S. S.; Troitskaya, Yu V.; Troitsky, I. S.; Vasilyev, A. A.; Hodges, M.; Hovatta, T.; Kiehlmann, S.; Max-Moerbeck, W.; Readhead, A. C.S.; Reeves, R.; Pearson, T. J.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Context. QSO B1420+326 is a blazar classified as a flat-spectrum radio quasar (FSRQ). At the beginning of the year 2020, it was found to be in an enhanced flux state and an extensive multiwavelength campaign allowed us to trace the evolution of the flare. Aims. We search for very high-energy (VHE) gamma-ray emission from QSO B1420+326 during this flaring state. We aim to characterize and model the broadband emission of the source over different phases of the flare. Methods. The source was observed with a number of instruments in radio, near-infrared, optical (including polarimetry and spectroscopy), ultraviolet, X-ray, and gamma-ray bands. We use dedicated optical spectroscopy results to estimate the accretion disk and the dust torus luminosity. We performed spectral energy distribution modeling in the framework of combined synchrotron-self-Compton and external Compton scenario in which the electron energy distribution is partially determined from acceleration and cooling processes. Results. During the enhanced state, the flux of both SED components of QSO B1420+326 drastically increased and the peaks were shifted to higher energies. Follow-up observations with the MAGIC telescopes led to the detection of VHE gamma-ray emission from this source, making it one of only a handful of FSRQs known in this energy range. Modeling allows us to constrain the evolution of the magnetic field and electron energy distribution in the emission region. The gamma-ray flare was accompanied by a rotation of the optical polarization vector during a low -polarization state. Also, a new superluminal radio knot contemporaneously appeared in the radio image of the jet. The optical spectroscopy shows a prominent FeII bump with flux evolving together with the continuum emission and a MgII line with varying equivalent width.
  • A wide and collimated radio jet in 3C84 on the scale of a few hundred gravitational radii
    (2018-06-01) Giovannini, G.; Savolainen, T.; Orienti, M.; Nakamura, M.; Nagai, H.; Kino, M.; Giroletti, M.; Hada, K.; Bruni, G.; Kovalev, Y. Y.; Anderson, J. M.; D'Ammando, F.; Hodgson, J.; Honma, M.; Krichbaum, T. P.; Lee, S. S.; Lico, R.; Lisakov, M. M.; Lobanov, A. P.; Petrov, L.; Sohn, B. W.; Sokolovsky, K. V.; Voitsik, P. A.; Zensus, J. A.; Tingay, S.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Understanding the formation of relativistic jets in active galactic nuclei remains an elusive problem 1 .This is partly because observational tests of jet formation models suffer from the limited angular resolution of ground-based very-long-baseline interferometry that has thus far been able to probe the structure of the jet acceleration and collimation region in only two sources 2,3 . Here, we report observations of 3C84 (NGC 1275)-the central galaxy of the Perseus cluster-made with an interferometric array including the orbiting radio telescope of the RadioAstron 4 mission. The data transversely resolve the edge-brightened jet in 3C84 only 30 μas from the core, which is ten times closer to the central engine than was possible in previous ground-based observations 5 and allows us to measure the jet collimation profile from ~102 to ~104 gravitational radii (r g) from the black hole. The previously found 5, almost cylindrical jet profile on scales larger than a few thousand r g is seen to continue at least down to a few hundred r g from the black hole, and we find a broad jet with a transverse radius of â‰250 r g at only 350 r g from the core. This implies that either the bright outer jet layer goes through a very rapid lateral expansion on scales â‰102 r g or it is launched from the accretion disk.
  • XIPE: The X-ray imaging polarimetry explorer
    (2016) Soffitta, P.; Bellazzini, R.; Bozzo, E.; Burwitz, V.; Castro-Tirado, A. J.; Costa, E.; Courvoisier, T.; Feng, H.; Gburek, S.; Goosmann, R.; Karas, V.; Matt, G.; Muleri, F.; Nandra, K.; Pearce, M.; Poutanen, J.; Reglero, V.; Sabau Maria, D.; Santangelo, A.; Tagliaferri, G.; Tenzer, C.; Vink, J.; Weisskopf, M. C.; Zane, S.; Agudo, I.; Antonelli, A.; Attina, P.; Baldini, L.; Bykov, A.; Carpentiero, R.; Cavazzuti, E.; Churazov, E.; Del Monte, E.; De Martino, D.; Donnarumma, I.; Doroshenko, V.; Evangelista, Y.; Ferreira, I.; Gallo, E.; Grosso, N.; Kaaret, P.; Kuulkers, E.; Laranaga, J.; Latronico, L.; Lumb, D. H.; Macian, J.; Malzac, J.; Marin, F.; Massaro, E.; Minuti, M.; Mundell, C.; Ness, J. U.; Oosterbroek, T.; Paltani, S.; Pareschi, G.; Perna, R.; Petrucci, P. O.; Pinazo, H. B.; Pinchera, M.; Rodriguez, J. P.; Roncadelli, M.; Santovincenzo, A.; Sazonov, S.; Sgro, C.; Spiga, D.; Svoboda, J.; Theobald, C.; Theodorou, T.; Turolla, R.; Wilhelmi De Ona, E.; Winter, B.; Akbar, A. M.; Allan, H.; Aloisio, R.; Altamirano, D.; Amati, L.; Amato, E.; Angelakis, E.; Arezu, J.; Atteia, J. L.; Axelsson, M.; Bachetti, M.; Ballo, L.; Balman, S.; Bandiera, R.; Barcons, X.; Basso, S.; Baykal, A.; Becker, W.; Behar, E.; Beheshtipour, B.; Belmont, R.; Berger, E.; Bernardini, F.; Bianchi, S.; Bisnovatyi-Kogan, G.; Blasi, P.; Blay, P.; Bodaghee, A.; Boer, M.; Boettcher, M.; Bogdanov, S.; Bombaci, I.; Bonino, R.; Braga, J.; Brandt, W.; Brez, A.; Bucciantini, N.; Burderi, L.; Caiazzo, I.; Campana, R.; Campana, S.; Capitanio, F.; Cappi, M.; Cardillo, M.; Casella, P.; Catmabacak, O.; Cenko, B.; Cerda-Duran, P.; Cerruti, C.; Chaty, S.; Chauvin, M.; Chen, Y.; Chenevez, J.; Chernyakova, M.; Cheung Teddy, C. C.; Christodoulou, D.; Connell, P.; Corbet, R.; Coti Zelati, F.; Covino, S.; Cui, W.; Cusumano, G.; D'Ai, A.; D'Ammando, F.; Dadina, M.; Dai, Z.; De Rosa, A.; De Ruvo, L.; Degenaar, N.; Del Santo, M.; Del Zanna, L.; Dewangan, G.; Di Cosimo, S.; Di Lalla, N.; Di Persio, G.; Di Salvo, T.; Dias, T.; Done, C.; Dovciak, M.; Doyle, G.; Ducci, L.; Elsner, R.; Enoto, T.; Escada, J.; Esposito, P.; Eyles, C.; Fabiani, S.; Falanga, M.; Falocco, S.; Fan, Y.; Fender, R.; Feroci, M.; Ferrigno, C.; Forman, W.; Foschini, L.; Fragile, C.; Fuerst, F.; Fujita, Y.; Gasent-Blesa, J. L.; Gelfand, J.; Gendre, B.; Ghirlanda, G.; Ghisellini, G.; Giroletti, M.; Goetz, D.; Gogus, E.; Gomez, J. L.; Gonzalez, D.; Gonzalez-Riestra, R.; Gotthelf, E.; Gou, L.; Grandi, P.; Grinberg, V.; Grise, F.; Guidorzi, C.; Gurlebeck, N.; Guver, T.; Haggard, D.; Hardcastle, M.; Hartmann, D.; Haswell, C.; Heger, A.; Hernanz, M.; Heyl, J.; Ho, L.; Hoormann, J.; Horak, J.; Huovelin, J.; Huppenkothen, D.; Iaria, R.; Inam Sitki, C.; Ingram, A.; Israel, G.; Izzo, L.; Burgess, M.; Jackson, M.; Ji, L.; Jiang, J.; Johannsen, T.; Jones, C.; Jorstad, S.; Kajava, J. J E; Kalamkar, M.; Kalemci, E.; Kallman, T.; Kamble, A.; Kislat, F.; Kiss, M.; Klochkov, D.; Koerding, E.; Kolehmainen, M.; Koljonen, K.; Komossa, S.; Kong, A.; Korpela, S.; Kowalinski, M.; Krawczynski, H.; Kreykenbohm, I.; Kuss, M.; Lai, D.; Lan, M.; Larsson, J.; Laycock, S.; Lazzati, D.; Leahy, D.; Li, H.; Li, J.; Li, L. X.; Li, T.; Li, Z.; Linares, M.; Lister, M.; Liu, H.; Lodato, G.; Lohfink, A.; Longo, F.; Luna, G.; Lutovinov, A.; Mahmoodifar, S.; Maia, J.; Mainieri, V.; Maitra, C.; Maitra, D.; Majczyna, A.; Maldera, S.; Malyshev, D.; Manfreda, A.; Manousakis, A.; Manuel, R.; Margutti, R.; Marinucci, A.; Markoff, S.; Marscher, A.; Marshall, H.; Massaro, F.; McLaughlin, M.; Medina-Tanco, G.; Mehdipour, M.; Middleton, M.; Mignani, R.; Mimica, P.; Mineo, T.; Mingo, B.; Miniutti, G.; Mirac, S. M.; Morlino, G.; Motlagh, A. V.; Motta, S. E.; Mushtukov, A.; Nagataki, S.; Nardini, F.; Nattila, J.; Navarro, G. J.; Negri, B.; Negro, M.; Nenonen, S.; Neustroev, V.; Nicastro, F.; Norton, A.; Nucita, A.; O'Brien, P.; O'Dell, S.; Odaka, H.; Olmi, B.; Omodei, N.; Orienti, M.; Orlandini, M.; Osborne, J.; Pacciani, L.; Paliya, V. S.; Papadakis, I.; Papitto, A.; Paragi, Z.; Pascal, P.; Paul, B.; Pavan, L.; Pellizzoni, A.; Perinati, E.; Pesce-Rollins, M.; Piconcelli, E.; Pili, A. G.; Pilia, M.; Pohl, Martin; Ponti, G.; Porquet, D.; Possenti, A.; Postnov, K.; Prandoni, I.; Produit, N.; Puehlhofer, G.; Ramsey, B.; Razzano, M.; Rea, N.; Reig, P.; Reinsch, K.; Reiprich, T.; Reynolds, M.; Risaliti, G.; Roberts, T.; Rodriguez, J.; Rossi, M. E.; Rosswog, S.; Rozanska, A.; Rubini, A.; Rudak, B.; Russell, D.; Ryde, F.; Sabatini, S.; Sala, G.; Salvati, M.; Sasaki, M.; Savolainen, T.; Saxton, R.; Scaringi, S.; Schawinski, K.; Schulz, N. S.; Schwope, A.; Severgnini, P.; Sharon, M.; Shaw, A.; Shearer, A.; Shesheng, X.; Shih, I. C.; Silva, K.; Silva, R.; Silver, E.; Smale, A.; Spada, F.; Spandre, G.; Stamerra, A.; Stappers, B.; Starrfield, S.; Stawarz, L.; Stergioulas, N.; Stevens, A.; Stiele, H.; Suleimanov, V.; Sunyaev, R.; Slowikowska, A.; Tamborra, F.; Tavecchio, F.; Taverna, R.; Tiengo, A.; Tolos, L.; Tombesi, F.; Tomsick, J.; Tong, H.; Torok, G.; Torres, D. F.; Tortosa, A.; Tramacere, A.; Trimble, V.; Trinchieri, G.; Tsygankov, S.; Tuerler, M.; Turriziani, S.; Ursini, F.; Uttley, P.; Varniere, P.; Vincent, F.; Vurgun, E.; Wang, C.; Wang, Z.; Watts, A.; Wheeler, J. C.; Wiersema, K.; Wijnands, R.; Wilms, J.; Wolter, A.; Wood, K.; Wu, K.; Wu, X.; Xiangyu, W.; Xie, F.; Xu, R.; Yan, S. P.; Yang, J.; Yu, W.; Yuan, F.; Zajczyk, A.; Zanetti, D.; Zanin, R.; Zanni, C.; Zappacosta, L.; Zdziarski, A. A.; Zech, A.; Zhang, H.; Zhang, S.; Zhang, W.; Zoghbi, A.
     A4 Artikkeli konferenssijulkaisussa
    XIPE, the X-ray Imaging Polarimetry Explorer, is a mission dedicated to X-ray Astronomy. At the time of writing XIPE is in a competitive phase A as fourth medium size mission of ESA (M4). It promises to reopen the polarimetry window in high energy Astrophysics after more than 4 decades thanks to a detector that efficiently exploits the photoelectric effect and to X-ray optics with large effective area. XIPE uniqueness is time-spectrally-spatially-resolved X-ray polarimetry as a breakthrough in high energy astrophysics and fundamental physics. Indeed the payload consists of three Gas Pixel Detectors at the focus of three X-ray optics with a total effective area larger than one XMM mirror but with a low weight. The payload is compatible with the fairing of the Vega launcher. XIPE is designed as an observatory for X-ray astronomers with 75 % of the time dedicated to a Guest Observer competitive program and it is organized as a consortium across Europe with main contributions from Italy, Germany, Spain, United Kingdom, Poland, Sweden.