Ara es mostren els items 13-25 de 25

    • Primordial black holes capture by stars and induced collapse to low-mass stellar black holes 

      Oncins Marco, Gerard; Miralda Escudé, Jordi; Gutiérrez Cabello, Jordi; Gil Pons, Pilar (Oxford University Press, 2022-10-04)
      Article
      Accés obert
      Primordial black holes in the asteroid-mass window, which might constitute all the dark matter, can be captured by stars when they traverse them at low enough velocity. After being placed on a bound orbit during star ...
    • Rings and spirals in barred galaxies III. Further comparisons and links to observations 

      Masdemont Soler, Josep; Bosma, A.; Romero Gómez, Mercè; Athanassoula, Evangelie (2010)
      Article
      Accés restringit per política de l'editorial
      In a series of papers, we propose a theory to explain the formation and properties of rings and spirals in barred galaxies. The building blocks of these structures are orbits guided by the manifolds emanating from the ...
    • Short-timescale X-ray spectral variability in the Seyfert 1 galaxy NGC 3783 

      Costanzo, Danilo; Dadina, M.; Vignali, Cristian; Marco, Barbara de; Cappi, Massimo; Petrucci, P.O.; Bianchi, Stefano; Kriss, G.A.; Kaastra, J.S.; Mehdipour, M.; Matzeu, G.A. (EDP Sciences, 2022-03-01)
      Article
      Accés obert
      Aims. We report on the X-ray time-resolved spectral analysis of XMM-Newton observations of NGC 3783. Our main goal is to detect transient features in the Fe K line complex in order to study the dynamics of the innermost ...
    • Supermassive black hole winds in X-rays: SUBWAYS: I. Ultra-fast outflows in quasars beyond the local Universe 

      Matzeu, G.A.; Brusa, Marcella; Lanzuisi, Giorgio; Dadina, M.; Bianchi, Stefano; Kriss, G.A.; Mehdipour, M.; Nardini, Emanuele; Chartas, George; Middei, Riccardo; Piconcelli, Enrico; Marco, Barbara de (EDP Sciences, 2023-02-01)
      Article
      Accés obert
      We present a new X-ray spectroscopic study of 22 luminous (2 × 1045 ¿ Lbol/erg s-1 ¿ 2 × 1046) active galactic nuclei (AGNs) at intermediate redshifts (0.1 ¿ z ¿ 0.4), as part of the SUpermassive Black hole Winds in the ...
    • Supermassive black hole winds in X-rays: SUBWAYS: II. HST UV spectroscopy of winds at intermediate redshifts 

      Mehdipour, M.; Kriss, G.A.; Brusa, Marcella; Matzeu, G.A.; Gaspari, Massimo; Kraemer, Steve; Mathur, Smita; Behar, Ehud; Bianchi, Stefano; Cappi, Massimo; Chartas, George; Marco, Barbara de (EDP Sciences, 2023-02-01)
      Article
      Accés obert
      We present a UV spectroscopic study of ionized outflows in 21 active galactic nuclei (AGN), observed with the Hubble Space Telescope (HST). The targets of the Supermassive Black Hole Winds in X-rays (SUBWAYS) sample were ...
    • 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 ...