Navegação Ciências Exatas e da Terra por Assunto "X-rays: galaxies"

Resultados 1-13 de 13

    • Anisotropic emission stellar population and x-ray sources in the seyfert 2 galaxy eso 138 - g01 

      Schmitt, Henrique Roberto; Storchi-Bergmann, Thaisa (1995) [Artigo de periódico]
      We present narrow-band CCD images of the high-excitation Seyfert 2 galaxy ES0138-G01, centred on the emission tines [O III] λ5007, Hα+[N II] λλ6548, 6584 and adjacent continua. The continuum-subtracted [O III] image presents ...

    • CHEERS results from NGC 3393 : III. Chandra x-ray spectroscopy of the narrow line region 

      Maksym, W. Peter; Fabbiano, Giuseppina; Elvis, Martin; Karovska, Margarita; Paggi, Alessandro; Raymond, John Charles; Wang, Junfeng; Storchi-Bergmann, Thaisa; Risaliti, Guido (2019) [Artigo de periódico]
      We present spatially resolved Chandra narrow-band imaging and imaging spectroscopy of NGC 3393. This galaxy hosts a Compton-thick Seyfert 2 active galactic nucleus (AGN) with sub-kpc bipolar outflows that are strongly ...

    • CHEERS results from NGC 3393 : II. Investigating the extended narrow-line region using deep Chandra observations and Hubble Space Telescope narrow-line imaging 

      Maksym, W. Peter; Fabbiano, Giuseppina; Elvis, Martin; Karovska, Margarita; Paggi, Alessandro; Raymond, John Charles; Wang, Junfeng; Storchi-Bergmann, Thaisa (2017) [Artigo de periódico]
      The CHandra Extended Emission Line Region Survey (CHEERS) is an X-ray study of nearby active galactic nuclei (AGNs) designed to take full advantage of Chandraʼs unique angular resolution by spatially resolving feedback ...

    • Destruction and multiple ionization of PAHs by X-rays in circumnuclear regions of AGNs 

      Monfredini, Thiago; Quitián-Lara, Heidy M.; Fantuzzi, Felipe; Wolff, Wania; Mendoza, Edgar; Lago, Alexsandre F.; Sales, Dinalva Aires de; Pastoriza, Miriani Griselda; Roberty, Heloísa Maria Boechat (2019) [Artigo de periódico]
      The infrared signatures of polycyclic aromatic hydrocarbons (PAHs) are observed in a variety of astrophysical objects, including the circumnuclear medium of active galactic nuclei (AGNs). These are sources of highly energetic ...

    • Extended gas in Seyfert 2 galaxies : implications for the nuclear source 

      Fraquelli, Henrique Aita; Storchi-Bergmann, Thaisa; Levenson, Nancy A. (2003) [Artigo de periódico]
      We use long-slit spectroscopic optical data to derive the properties of the extended emitting gas and the nuclear luminosity of a sample of 18 Seyfert 2 galaxies. From the emissionline luminosities and ratios we derive the ...

    • Insights on the dusty torus and neutral torus from optical and X-ray obscuration in a complete volume limited hard X-ray AGN sample 

      Davies, Richard I.; Burtscher, Leonard; Rosario, David; Storchi-Bergmann, Thaisa; Contursi, Alessandra; Genzel, Reinhard; Gracia-Carpio, Javier; Hicks, Erin K. S.; Janssen, Annemieke; Koss, Michael; Lin, Ming-Yi; Lutz, Dieter; Maciejewski, Witold B.; Muller-Sanchez, Francisco; Orban de Xivry, Gilles; Ricci, Claudio; Riffel, Rogério; Riffel, Rogemar André; Schartmann, Marc; Müller, Allan Schnorr; Sternberg, Amiel; Sturm, Eckhard; Tacconi, Linda J.; Veilleux, Sylvain (2015) [Artigo de periódico]
      We describe a complete volume limited sample of nearby active galaxies selected by their 14–195 keV luminosity, and outline its rationale for studying the mechanisms regulating gas inflow and outflow. We also describe a ...

    • Models for jet power in elliptical galaxies : a case for rapidly spinning black holes 

      Nemmen, Rodrigo S.; Bower, Richard G.; Babul, Arif; Storchi-Bergmann, Thaisa (2007) [Artigo de periódico]
      The power of jets from black holes is expected to depend on both the spin of the black hole and the structure of the accretion disc in the region of the last stable orbit.We investigate these dependencies using two different ...

    • On the black hole mass of the γ-ray emitting narrow-line Seyfert 1 galaxy 1H 0323+342 

      Landt, Hermine; Ward, Martin John; Baloković, Mislav; Kynoch, Daniel; Storchi-Bergmann, Thaisa; Boisson, Catherine; Done, Chris; Schimoia, Jáderson da Silva; Stern, Daniel (2017) [Artigo de periódico]
      Narrow-line Seyfert 1 galaxies have been identified by the Fermi Gamma-Ray Space Telescope as a rare class of γ -ray emitting active galactic nuclei. The lowest redshift candidate among them is the source 1H 0323+342. Here ...

    • The Eddington ratio-dependent ‘changing look’ events in NGC 2992 

      Pereira, Muryel Guolo; Dutra, Daniel Ruschel; Grupe, Dirk; Peterson, Bradley M.; Storchi-Bergmann, Thaisa; Schimoia, Jáderson da Silva; Nemmen, Rodrigo S.; Robinson, Andrew (2021) [Artigo de periódico]
      We present an analysis of historical multiwavelength emission of the `Changing Look’ (CL) Active Galactic Nucleu (AGN) in NGC 2992, covering epochs ranging from 1978 to 2021, as well as new X-ray and optical spectra. The ...

    • The globular cluster system of NGC 5846 revisited : colours, sizes and x-ray counterparts 

      Chies-Santos, Ana Leonor; Pastoriza, Miriani Griselda; Santiago, Basilio Xavier; Forbes, Duncan A. (2006) [Artigo de periódico]
      Context. NGC5846 is a giant elliptical galaxy with a previously well studied globular cluster system (GCS), known to have a bimodal colour distribution with a remarkably high red fraction. Aims. Here we revisit the central ...

    • The narrow-line region of narrow-line Seyfert 1 galaxies 

      Rodriguez-Ardila, Alberto; Binette, Luc; Pastoriza, Miriani Griselda; Donzelli, Carlos J. (2000) [Artigo de periódico]
      This work studies the optical emission-line properties and physical conditions of the narrow-line region (NLR) of seven narrow-line Seyfert 1 galaxies (NLS1's) for which high signal-to-noise ratio spectroscopic observations ...

    • The obscuring starburst of NGC 6221 and implications for the hard x-ray background 

      Levenson, Nancy A.; Fernandes Junior, Roberto Cid; Weaver, Kim A.; Heckman, Timothy M.; Storchi-Bergmann, Thaisa (2001) [Artigo de periódico]
      We present NGC 6221 as a case study of "X-ray-loud composite galaxies", which appear similar to starbursts at optical wavelengths and resemble traditional active galactic nuclei in X-rays. The net optical spectrum of NGC ...

    • Visible and near-infrared spectroscopy of Seyfert 1 and narrow-line Seyfert 1 galaxies 

      Rodriguez-Ardila, Alberto; Pastoriza, Miriani Griselda; Donzelli, Carlos J. (2000) [Artigo de periódico]
      This paper studies the continuum and emission-line properties of a sample composed of 16 normal Seyfert 1 and seven narrow-line Seyfert 1 (NLS1) galaxies using optical and near-IR CCD spectroscopy. The continuum emission ...