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dc.contributor.authorAlloin, Danielle Mariept_BR
dc.contributor.authorSantos-Lleo, M.pt_BR
dc.contributor.authorPeterson, Bradley M.pt_BR
dc.contributor.authorWamsteker, W.pt_BR
dc.contributor.authorAltieri, B.pt_BR
dc.contributor.authorBrinkmann, W.pt_BR
dc.contributor.authorCrenshaw, Daniel Michaelpt_BR
dc.contributor.authorGeorge, I.M.pt_BR
dc.contributor.authorClavel, J.pt_BR
dc.contributor.authorGlass, I.S.pt_BR
dc.contributor.authorJohnson, W.N.pt_BR
dc.contributor.authorKriss, Gerard A.pt_BR
dc.contributor.authorMalkan, M.A.pt_BR
dc.contributor.authorPolidan, R.S.pt_BR
dc.contributor.authorReichert, G.A.pt_BR
dc.contributor.authorRodriguez-Pascual, P.M.pt_BR
dc.contributor.authorRomanishin, W.pt_BR
dc.contributor.authorStarr, C.H.pt_BR
dc.contributor.authorStirpe, Giovanna M.pt_BR
dc.contributor.authorTaylor, M.pt_BR
dc.contributor.authorTurner, T.J.pt_BR
dc.contributor.authorVega, H.J. dept_BR
dc.contributor.authorWinge, Claudiapt_BR
dc.contributor.authorWood, D.O.S.pt_BR
dc.date.accessioned2014-07-18T02:04:39Zpt_BR
dc.date.issued1995pt_BR
dc.identifier.issn0004-6361pt_BR
dc.identifier.urihttp://hdl.handle.net/10183/98097pt_BR
dc.description.abstractWith the aim of better understanding the physical processes that produce the continuous emission in active galactic nuclei (AGNs), a snapshot of the overall continuous energy distribution of NGC 3783, from γ-ray to radio wavelengths, has been obtained within the framework of the World Astronomy Days. The data collected in this campaign are from GRO, ROSAT, Voyager 2, IUE, HST, ESO, CTIO, SAAO and the VLA. Great care has been taken in disentangling the genuine AGN continuous emission from other contributions: depending on the waveband, the latter might be (i) unrelated contaminating sources in cases where the instrument field of view is large, (ii) components within which the AGN is embedded, such as the stellar bulge population which accounts for a significant fraction of the optical continuum, and free-bound and FeII blends which contribute to the ultraviolet flux. After correction for these other contributions, the continuous emission of the isolated AGN appears to be rather ftat (i.e., approximately equal energy per unit logarithmic frequency) from soft γ-ray to infrared wavelengths. At high energies (0.1 MeV to 0.1 keV), the AGN continuum can be fitted by a power law Fv ∝ v-α with a spectral index α ≈ 1. At longer wavelengths, two excesses above this power law ("bumps") appear: in the ultraviolet, the classical big blue bump, which can be interpreted as thermal emission from the accretion disc surrounding a massive black hoJe, and in the infrared a second bump which can be ascribed to thermal emission from dust in the vicinity of the AGN, heated by ultraviolet radiation from the central source. By fitting accretion-disc models to the observed AGN spectral energy distribution, we find values for the accretion disc innermost temperature, accretion rate, and black hole mass, with some differences that depend on whether or not we extrapolate the high-energy power law up to infrared wavelengths. A fit to the IR bump above the extended a = 1 power law suggests the presence of a dust component covering the region from a distance r ≈ 80 light days (hot grains at a temperature T ≈ 1500 K) to r ≈ 60 light years (cool grains at T ≈ 200 K). The total mass of dust is around 60 Mʘ.en
dc.format.mimetypeapplication/pdf
dc.language.isoengpt_BR
dc.relation.ispartofAstronomy and Astrophysics. Berlin. Vol. 293, no. 2 (Jan. 1995), p. 293-308pt_BR
dc.rightsOpen Accessen
dc.subjectAstrofisica extragalaticapt_BR
dc.subjectGalaxies: Seyferten
dc.subjectGaláxia NGC 3783pt_BR
dc.subjectGalaxies: individual: NGC 3783en
dc.subjectGalaxies: nucleien
dc.subjectNucleo galaticopt_BR
dc.subjectGalaxias seyfertpt_BR
dc.subjectRadiation mechanisms: non-thermalen
dc.subjectRadiation mechanisms: thermalen
dc.subjectBuracos negrospt_BR
dc.subjectBlack hole physicsen
dc.titleA snapshot of the continuous emission of the active galactic nucleus in ngc 3783 from gamma-ray to radio wavelengthspt_BR
dc.typeArtigo de periódicopt_BR
dc.identifier.nrb000263014pt_BR
dc.type.originEstrangeiropt_BR


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