Exploració per tema "Galaxies"

Ara es mostren els items 18-25 de 25

    • Tails and bridges in the parabolic restricted three-body problem 

      Barrabés Vera, Esther; Cors Iglesias, Josep Maria; García Taberner, Laura; Ollé Torner, Mercè (2017-01-01)
      Article
      Accés obert
      After a close encounter of two galaxies, bridges and tails can be seen between or around them. A bridge would be a spiral arm between a galaxy and its companion, whereas a tail would correspond to a long and curving set ...

    • The lively accretion disc in NGC 2992-II. The 2019/2021 X-ray monitoring campaigns 

      Middei, Riccardo; Marinucci, Andrea; Braito, V.; Marco, Barbara de; Luminari, Alfredo; Matt, Giorgio; Nardini, Emanuele; Perri, Matteo; Reeves, J. N.; Vagnetti, Fausto (Oxford University Press, 2022-08-01)
      Article
      Accés obert
      We report on the short- and long-term X-ray properties of the bright nearby Seyfert 2 galaxy NGC 2992, which was extensively observed with Swift, XMM–Newton, and NuSTAR. Swift targeted the source more than 100 times between ...

    • The lively accretion disk in NGC 2992. III. Tentative evidence of rapid ultrafast outflow variability 

      Luminari, Alfredo; Marinucci, Andrea; Bianchi, Stefano; Marco, Barbara de; Feruglio, Chiara; Matt, Giorgio; Middei, Riccardo; Nardini, Emanuele; Piconcelli, Enrico; Puccetti, Simonetta; Tombesi, Francesco (Institute of Physics (IOP), 2023-06-01)
      Article
      Accés obert
      We report on the 2019 XMM-Newton+NuSTAR monitoring campaign of the Seyfert galaxy NGC 2992, observed at one of its highest flux levels in the X-rays. The time-averaged spectra of the two XMM-Newton orbits show ultrafast ...

    • The XMM-Newton/2dF survey - II. The nature of X-ray-faint optically bright X-ray sources 

      Georgakakis, Antonis; Georgantopoulos, Ioannis; Vallbé Mumbrú, Marc; Kolokotronis, Vaggelis; Basilakos, Spyros; Plionis, Manolis; Stewart, Gordon C.; Shanks, Tom; Boyle, Brian J. (Oxford University Press, 2004-03-21)
      Article
      Accés obert
      In this paper we investigate the properties of low X-ray-to-optical flux ratio sources detected in a wide area (2.5deg^2) shallow (f(0.5-8keV)~10e-14cgs) XMM-Newton survey. We find a total of 26 sources (5% of the total ...

    • Tracking the spectral properties of ESO 511-G030 across different epochs 

      Middei, Riccardo; Petrucci, P.O.; Bianchi, Stefano; Ursini, Francesco; Matzeu, G.A.; Vagnetti, Fausto; Tortosa, Alessia; Marinucci, Andrea; Matt, Giorgio; Piconcelli, Enrico; De Rosa, Alessandra; Marco, Barbara de; Reeves, James; Perri, Matteo; Guainazzi, Matteo; Cappi, Massimo; Done, Chris (EDP Sciences, 2023-04-01)
      Article
      Accés obert
      The Type 1 active galactic nucleus (AGN) ESO 511-G030, a formerly bright and soft excess dominated source, was observed in 2019 in the context of a multi-wavelength monitoring campaign. In the new exposures, the source was ...

    • Transient obscuration event captured in NGC 3227: II. Warm absorbers and obscuration events in archival XMM-Newton and NuSTAR observations 

      Mehdipour, M.; Kriss, G.A.; Kaastra, J.S.; Marco, Barbara de (EDP Sciences, 2022-01-01)
      Article
      Accés obert
      The relationship between warm absorber (WA) outflows of active galactic nuclei and nuclear obscuration activities caused by optically thick clouds (obscurers) crossing the line of sight is still unclear. NGC 3227 is a ...

    • Transient obscuration event captured in NGC 3227: IV. Origin of the obscuring cloud variability 

      Grafton Waters, Sam; Mao, Junjie; Mehdipour, M.; Branduardi Raymont, Graziella; Page, Mat; Kaastra, J.S.; Pinto, Ciro; Kriss, G.A.; Walton, D. J.; Petrucci, P.O.; Ponti, Gabriele; Marco, Barbara de; Bianchi, Stefano; Behar, Ehud; Ebrero, Jacob (EDP Sciences, 2023-05-01)
      Article
      Accés obert
      Context. Obscuration events in type I active galactic nuclei (AGN) have been detected more frequently in recent years. The strong flux decrease in the soft X-ray band between observations has been caused by clouds with ...

    • Un planeta con dos soles. ¿Tatooine o Kepler-16b? 

      Moreno Lupiáñez, Manuel (2011-10-25)
      Report de recerca
      Accés obert
      La existencia de un mundo con atardeceres dobles, similar al que se mostró en la película "Star Wars" hace más de 30 años, ya es un hecho científico. La misión Kepler, de la Nasa, ha logrado la primera detección directa ...