Unabsorbed Seyfert 2 galaxies
نویسندگان
چکیده
منابع مشابه
Unabsorbed Seyfert 2 galaxies : the case of “ naked ” AGN ⋆
Hawkins (2004) reported on a class of “naked” AGN characterized by strong amplitude optical brightness variability and the complete absence of broad emission lines in the optical spectrum. The variability suggests that the nucleus is seen directly, however the absence of broad lines contradicts the simple formulation of Unified Models for AGN. We present the results of quasi-simultaneous spectr...
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We present an analysis of six 12 μm selected Seyfert 2 galaxies that have been reported to be unabsorbed in the X-ray. By comparing the luminosities of these galaxies in the mid-IR (12 μm), optical ([O III]) and hard X-ray (2-10 keV), we show that they are all under-luminous in the 2-10 keV X-ray band. Four of the objects exhibit X-ray spectra indicative of a hard excess, consistent with a heav...
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An enigmatic group of objects, unabsorbed Seyfert 2s may have intrinsically weak broad line regions, obscuration in the line of sight to the BLR but not to the X-ray corona, or so much obscuration that the X-ray continuum is completely suppressed and the observed spectrum is actually scattered into the line of sight from nearby material. NGC 3660 has been shown to have weak broad optical/near i...
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We present a compilation of radio, infrared, optical and hard X-ray (2-10kev) data for a sample of 90 Seyfert 2 galaxies(Sy2s) with spectropolarimetric observations (41 Sy2s with detection of polarized broad lines (PBL) and 49 without PBL). Compared to Sy2s without PBL, Sy2s with PBL tend to be earlier-type spirals, and show warmer mid-infrared color and significant excess of emissions (includi...
متن کاملSeyfert Galaxies and BeppoSAX
In this review, rather than present and discuss in detail the first results obtained by BeppoSAX (see Boella et al. 1997 for an overall description of the mission) on Seyfert galaxies (these results are presented in detail elsewhere in this volume, see in particular the contributions by Perola, Comastri and Salvati), I will discuss current ideas on the X–ray emission of both type 1 and 2 object...
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ژورنال
عنوان ژورنال: Astronomy & Astrophysics
سال: 2002
ISSN: 0004-6361,1432-0746
DOI: 10.1051/0004-6361:20021161