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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)


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Menezes, R. B. [1] ; Steiner, J. E. [1] ; Ricci, T. V. [1]
Total Authors: 3
[1] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, BR-05508090 Sao Paulo - Brazil
Total Affiliations: 1
Document type: Journal article
Source: Astrophysical Journal Letters; v. 765, n. 2 MAR 10 2013.
Web of Science Citations: 4

We present an analysis of a data cube of the central region of M104, the Sombrero galaxy, obtained with the GMOS-IFU of the Gemini-South telescope, and report the discovery of collimation and scattering of the active galactic nucleus (AGN) emission in the circumnuclear region of this galaxy. Analysis with PCA Tomography and spectral synthesis revealed the existence of collimation and scattering of the AGN featureless continuum and also of a broad component of the H alpha emission line. The collimation and scattering of this broad H alpha component was also revealed by fitting the {[}NII] lambda lambda 6548, 6583 and H alpha emission lines as a sum of Gaussian functions. The spectral synthesis, together with a V-I image obtained with the Hubble Space Telescope, showed the existence of circumnuclear dust, which may cause the light scattering. We also identify a dusty feature that may be interpreted as a torus/disk structure. The existence of two opposite regions with featureless continuum (P.A. = -18 degrees +/- 13 degrees and P.A. = 162 degrees +/- 13 degrees) along a direction perpendicular to the torus/disk (P.A. = 72 degrees +/- 14 degrees) suggests that this structure is approximately edge-on and collimates the AGN emission. The edge-on torus/disk also hides the broad-line region. The proposed scenario is compatible with the unified model and explains why only a weak broad component of the H alpha emission line is visible and also why many previous studies detected no broad H alpha. The technique used here proved to be an efficient method not only for detecting scattered light, but also for testing the unified model in low-luminosity AGNs. (AU)

FAPESP's process: 12/02268-8 - Galactic nuclei in the local universe: supermassive black holes and stellar archeology of galaxies of high and low masses
Grantee:Roberto Bertoldo Menezes
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 08/06988-0 - Characterization and environment of low luminosity active nuclei
Grantee:Tiago Vecchi Ricci
Support type: Scholarships in Brazil - Doctorate