Navegação Ciências Exatas e da Terra por Assunto "Acreção"

Resultados 1-15 de 15

    • AGN STORM 2 : IV. Swift x-ray and ultraviolet/optical monitoring of Mrk 817 

      Cackett, Edward M.; Storchi-Bergmann, Thaisa; Zaidouni, Fatima (2023) [Artigo de periódico]
      The AGN STORM 2 campaign is a large, multiwavelength reverberation mapping project designed to trace out the structure of Mrk 817 from the inner accretion disk to the broad emission line region and out to the dusty torus. ...

    • An embedded active nucleus in the OH megamaser galaxy IRAS16399-0937 

      Sales, Dinalva Aires de; Robinson, Andrew; Axon, David J.; Gallimore, Jack F.; Kharb, Preeti; Curran, R. L.; O'Dea, Christopher Peter; Baum, Stefi Alison; Elitzur, Moshe; Mittal, Rupal (2015) [Artigo de periódico]
      We present a multiwavelength study of the OH megamaser galaxy IRAS16399−0937, based on new Hubble Space Telescope (HST)/Advanced Camera for Surveys F814W and Hα+[N ii] images and archive data from HST, Two Micron All Sky ...

    • DB white dwarfs in the Sloan Digital Sky Survey data release 10 and 12 

      Koester, Detlev; Kepler, Souza Oliveira (2015) [Artigo de periódico]
      Aims. White dwarfs with helium-dominated atmospheres (spectral types DO, DB) comprise approximately 20% of all white dwarfs. There are fewer studies than of their hydrogen-rich counterparts (DA) and thus several questions ...

    • Discovery of a new AM CVn system with the Kepler satellite 

      Fontaine, Gilles; Brassard, P.; Green, Elisabeth M.; Charpinet, Stéphane; Dufour, Patrick; Hubeny, Ivan; Steeghs, Danny; Aerts, Conny; Randall, S. K.; Bergeron, Pierre; Guvenen, B.; O'Malley, C. J.; Van Grootel, Valérie; Ostensen, Roy; Bloemen, Steven; Silvotti, Roberto; Howell, Steve; Baran, Andrzej; Kepler, Souza Oliveira; Marsh, Tom; Montgomery, Michael Houston; Oreiro, Raquel; Provencal, Judith L.; Telting, John; Winget, Donald Earl; Zima, Wolfgang; Christensen-Dalsgaard, Jorgen; Kjeldsen, Hans (2011) [Artigo de periódico]
      We report the discovery of a new AM CVn system on the basis of broadband photometry obtained with the Kepler satellite supplemented by ground-based optical spectroscopy. Initially retained on Kepler target lists as a ...

    • Evolution of the accretion disc around the supermassive black hole of NGC 7213 

      Schimoia, Jáderson da Silva; Storchi-Bergmann, Thaisa; Winge, Claudia; Nemmen, Rodrigo S.; Eracleous, Michael (2017) [Artigo de periódico]
      We present observations of the double-peaked broad Hα profile emitted by the active nucleus of NGC7213 using the Gemini South Telescope in 13 epochs between 2011 September 27 and 2013 July 23. This is the first time that ...

    • Gas streaming motions towards the nucleus of M81 

      Müller, Allan Schnorr; Storchi-Bergmann, Thaisa; Riffel, Rogemar André; Ferrari, Fabricio; Steiner, João Evangelista; Axon, David J.; Robinson, Andrew (2011) [Artigo de periódico]
      We present two-dimensional stellar and gaseous kinematics of the inner 120×250 pc2 of the LINER/Seyfert 1 galaxy M81, from optical spectra obtained with the Gemini Multi-Object Spectrograph (GMOS) integral field spectrograph ...

    • MaNGA 8313-1901 : gas accretion observed in a blue compact dwarf galaxy 

      Ju, Mengting; Yin, Jun; Liu, Rongrong; Hao, Lei; Shao, Zhengyi; Feng, Shuai; Riffel, Rogério; Liu, Chenxu; Stark, David V.; Shen, Shiyin; Telles, Jose Eduardo; Fernández-Trincado, José Gregorio; Wang, Junfeng; Xu, Haiguang; Bizyaev, D.; Rong, Yu (2022) [Artigo de periódico]
      Gas accretion is an important process in the evolution of galaxies, but it has limited direct observational evidences. In this paper, we report the detection of a possible ongoing gas accretion event in a blue compact dwarf ...

    • Radiatively inefficient accretion flow in the nucleus of NGC 1097 

      Nemmen, Rodrigo S.; Storchi-Bergmann, Thaisa; Yuan, Feng; Eracleous, Michael; Terashima, Yuichi; Wilson, Andrew S. (2006) [Artigo de periódico]
      We present a model for the accretion flow around the supermassive black hole in the LINER nucleus of NGC 1097 that fits the optical to X-ray spectral energy distribution (SED). The X-ray segment of the SED is based on ...

    • Short timescale monitoring of the X-ray, UV, and broad double-pead emission line of the nucleus of 1097 

      Schimoia, Jáderson da Silva; Storchi-Bergmann, Thaisa; Grupe, Dirk; Eracleous, Michael; Peterson, Bradley M.; Baldwin, Jack A.; Nemmen, Rodrigo S.; Winge, Claudia (2015) [Artigo de periódico]
      Recent studies have suggested that the short-timescale (<~ 7 days) variability of the broad (∼10,000 km s-ˡ) doublepeaked Hα profile of the LINER nucleus of NGC 1097 could be driven by a variable X-ray emission from a ...

    • Short timescale variations of the Hα double-peaked profile of the nucleus of NGC 1097 

      Schimoia, Jáderson da Silva; Storchi-Bergmann, Thaisa; Nemmen, Rodrigo S.; Winge, Claudia; Eracleous, Michael (2012) [Artigo de periódico]
      The broad (FWHM ∼ 10,000 km s-ˡ) double-peaked Hα profile from the LINER/Seyfert 1 nucleus of NGC 1097 was discovered in 1991 and monitored for the following 11 years. The profile showed variations attributed to the rotation ...

    • A strong correlation between circumnuclear dust and black hole accretion in early-type galaxies 

      Lopes, Ramiro Duarte Simões; Storchi-Bergmann, Thaisa; Saraiva, Maria de Fátima Oliveira; Martini, Paul (2007) [Artigo de periódico]
      We present a detailed investigation of the incidence of circumnuclear dust structure in a large, well-matched sample of early-type galaxies with and without active galactic nuclei (AGNs). All 34 early-type AGN hosts in our ...

    • The complex gas kinematics in the nucleus of the Seyfert 2 galaxy NGC 1386 : rotation, outflows, and inflows 

      Lena, Davide; Robinson, Andrew; Storchi-Bergmann, Thaisa; Müller, Allan Schnorr; Seelig, T.; Riffel, Rogemar André; Nagar, Neil M.; Couto, Guilherme dos Santos; Shadler, l (2015) [Artigo de periódico]
      We present optical integral field spectroscopy of the circum-nuclear gas of the Seyfert 2 galaxy NGC 1386. The data cover the central 7″ × 9″ (530 × 680 pc) at a spatial resolution of 0″. 9 (68 pc), and the spectral range ...

    • The origin of dust in early-type galaxies and implications for accretion onto supermassive black holes 

      Martini, Paul; Dicken, Daniel; Storchi-Bergmann, Thaisa (2013) [Artigo de periódico]
      We have conducted an archival Spitzer study of 38 early-type galaxies in order to determine the origin of the dust in approximately half of this population. Our sample galaxies generally have good wavelength coverage from ...

    • The solar twin planet search : V. close-in, low-mass planet candidates and evidence of planet accretion in the solar twin HIP 68468 

      Meléndez, Jorge; Bedell, Megan; Bean, Jacob L.; Ramírez, Iván; Asplund, Martin; Dreizler, Stefan; Yan, Hong Liang; Shi, Jianrong; Lind, Karin; Ferraz-Mello, Sylvio; Galarza, Jhon Joel Yana; Santos, Leonardo Augusto Gonçalves dos; Spina, Lorenzo; Maia, Marcelo Tucci; Alves-Brito, Alan; Monroe, TalaWanda Rose; Casagrande, Luca (2017) [Artigo de periódico]
      Context. More than two thousand exoplanets have been discovered to date. Of these, only a small fraction have been detected around solar twins, which are key stars because we can obtain accurate elemental abundances ...

    • Whole Earth Telescope observations of V471 Tauri : the nature of the white dwarf variations 

      Clemens, J. Christopher; Nather, R. Edward; Winget, Donald Earl; Robinson, E.L.; Wood, Matthew A.; Claver, C.F.; Provencal, Judith L.; Kleinman, Scot James; Bradley, Paul A.; Frueh, M.L.; Grauer, Albert D.; Hine, B.P.; Fontaine, Gilles; Achilleos, Nicholas; Wickramasinghe, D.T.; Marar, T.M. Krishnan; Seetha, S.; Ashoka, B.N.; O'Donoghue, Darragh; Warner, B.; Kurtz, Donald W.; Martinez, Peter; Vauclair, Gérard; Chevreton, Michel; Barstow, Martin A.; Kanaan Neto, Antonio Nemer; Kepler, Souza Oliveira; Augusteijn, T.; Paradijs, J. van; Hansen, Carl J. (1992) [Artigo de periódico]
      We have conducted time-series photometric observations of the binary star V471 Tauri using the Whole Earth Telescope observing network. Our purpose was to determine the mechanism responsible for causing the 555 and 277 s ...