Multiwavelength tests of the dusty torus model for Seyfert galaxies

Mulchaey, John S.; Koratkar, Anuradha; Ward, M. J.; Wilson, A. S.; Whittle, M.; Antonucci, Robert; Kinney, A. L.; Hurt, Todd

doi:10.1086/174933

Cited by 215 publications

(310 citation statements)

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“…This line is emitted by the narrow-line region, which extends outside the obscuring material thought to surround the broad-line region of type 2 AGN (Antonucci 1993;Urry & Padovani 1995). Observational support for this assumption comes from the similarity of IR/[O iii] ratios in type 1 and type 2 AGNs found by Mulchaey (1994). Moreover, the [O iii]5007 line has the advantage of being strong and easily detected in most AGNs, and Simpson (1998) and Kauffmann et al (2003) have shown that it is a good tracer of AGN activity and is not severely contaminated by star formation.…”

Section: [O Iii]5007 Luminosity As a Tracer Of The Bolometric Luminositymentioning

confidence: 91%

Space Density of Optically Selected Type 2 Quasars

Reyes¹,

Zakamska²,

Strauss³

et al. 2008

The Astronomical Journal

274

167

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Type 2 quasars are luminous active galactic nuclei whose central regions are obscured by large amounts of gas and dust. In this paper, we present a catalog of type 2 quasars from the Sloan Digital Sky Survey, selected based on their optical emission lines. The catalog contains 887 objects with redshifts z < 0.83; this is 6 times larger than the previous version and is by far the largest sample of type 2 quasars in the literature. We derive the [O iii]5007 luminosity function (LF) for 10 8.3 L < L [O iii] < 10 10 L (corresponding to intrinsic luminosities up to M[2500 Å] −28 mag or bolometric luminosities up to 4 × 10 47 erg s −1 ). This LF provides robust lower limits to the actual space density of obscured quasars due to our selection criteria, the details of the spectroscopic target selection, and other effects. We derive the equivalent LF for the complete sample of type 1 (unobscured) quasars and determine the ratio of type 2 to type 1 quasar number densities. Our data constrain this ratio to be at least ∼ 1.5:1 for 10 8.3 L < L [O iii] < 10 9.5 L at z < 0.3, and at least ∼ 1.2:1 for L [O iii] ∼ 10 10 L at 0.3 < z < 0.83. Type 2 quasars are at least as abundant as type 1 quasars in the relatively nearby universe (z 0.8) for the highest luminosities.

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Section: [O Iii]5007 Luminosity As a Tracer Of The Bolometric Luminositymentioning

confidence: 91%

Space Density of Optically Selected Type 2 Quasars

Reyes¹,

Zakamska²,

Strauss³

et al. 2008

The Astronomical Journal

274

167

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“…A complete sample would be designed to select AGN by an isotropic property, such as the hard Xray emission, which is commonly used as an isotropic indicator of AGN luminosity (see e.g. Mulchaey et al 1994;Meléndez et al 2008a;Rigby, Diamond-Stanic, & Aniano 2009;Diamond-Stanic, Rieke, & Rigby 2009). …”

Section: Sample Selectionmentioning

confidence: 99%

The nuclear and extended mid-infrared emission of Seyfert galaxies

García-Bernete¹,

Almeida²,

Acosta–Pulido³

et al. 2016

Mon. Not. R. Astron. Soc.

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We present subarcsecond resolution mid-infrared (MIR) images obtained with 8-10 m-class ground-based telescopes of a complete volume-limited (D L <40 Mpc) sample of 24 Seyfert galaxies selected from the Swift/BAT nine month catalog. We use those MIR images to study the nuclear and circumnuclear emission of the galaxies. Using different methods to classify the MIR morphologies on scales of ∼400 pc, we find that the majority of the galaxies (75-83%) are extended or possibly extended and 17-25% are point-like. This extended emission is compact and it has low surface brightness compared with the nuclear emission, and it represents, on average, ∼30% of the total MIR emission of the galaxies in the sample. We find that the galaxies whose circumnuclear MIR emission is dominated by star formation show more extended emission (650±700 pc) than AGN-dominated systems (300±100 pc). In general, the galaxies with point-like MIR morphologies are face-on or moderately inclined (b/a∼0.4-1.0), and we do not find significant differences between the morphologies of Sy1 and Sy2. We used the nuclear and circumnuclear fluxes to investigate their correlation with different AGN and SF activity indicators. We find that the nuclear MIR emission (the inner ∼70 pc) is strongly correlated with the X-ray emission (the harder the X-rays the better the correlation) and with the [O IV] λ25.89 µm emission line, indicating that it is AGN-dominated. We find the same results, although with more scatter, for the circumnuclear emission, which indicates that the AGN dominates the MIR emission in the inner ∼400 pc of the galaxies, with some contribution from star formation.

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“…For this purpose, we note that the electron energy density in the lobes has been constrained in Paper I to be J m Ϫ3 , where D is the There is a good correlation between kinetic luminosities and narrow-line luminosities of AGNs over 5 orders of magnitude (Rawlings & Saunders 1991;Ceolotti & Fabian 1993). The luminosity of [O iii], the strongest narrow emission line, in turn correlates well with the X-ray continuum luminosity over 5 orders of magnitude (Grossan 1992;Mulchaey et al 1994). From these two correlations, we infer that the nucleus of NGC 1316 used to have a 2-10 keV luminosity of W or 34 4 # 10 larger.…”

Section: Kinetic Power Of the Lobe Sustainmentmentioning

confidence: 99%

“…5 # 10 correlation in type I Seyfert galaxies (Grossan 1992;Mulchaey et al 1994). The amounts of molecular and neutral hydrogen in NGC 1316 are estimated to be 8.95 M , using the SCO line and less than 8.87 M , using the 21 cm line, respectively.…”

Section: Other Propertiesmentioning

confidence: 99%

The Declined Activity in the Nucleus of NGC 1316

Iyomoto

Makishima

Tashiro

et al. 1998

The Astrophysical Journal

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NGC 1316 (Fornax A) is a radio galaxy with prototypical double lobes, where the magnetic field intensity is accurately measured via the inverse Compton technique. The radio-emitting electrons in the lobes are inferred to have a synchrotron lifetime of ∼0.1 Gyr. Considering the lobe energetics, we estimate the past nuclear X-ray luminosity of NGC 1316 to be at least ∼ W ( ergs s Ϫ1 ). Thus, the nucleus was rather active at 34 41 4 # 10 4 # 10 least 0.1 Gyr ago. In contrast, we confirmed with ASCA and ROSAT that the nucleus of NGC 1316 is very faint in X-rays at present, with the 2-10 keV luminosity of any active galactic nucleus-like hard component being less than W ( ergs s Ϫ1 ), even assuming a nuclear obscuration up to ∼10 28 m Ϫ2 (10 24 cm Ϫ2 ).33 40 2 # 10 2 # 10 This is at least an order of magnitude lower than the estimated past activity, indicating that the nucleus is presently very inactive. From these two results, we conclude that the nucleus of NGC 1316 has become dormant during the last 0.1 Gyr. This suggests the possible abundance of "dormant" quasars in nearby galaxies.

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Multiwavelength tests of the dusty torus model for Seyfert galaxies

Cited by 215 publications

References 0 publications

Space Density of Optically Selected Type 2 Quasars

Space Density of Optically Selected Type 2 Quasars

The nuclear and extended mid-infrared emission of Seyfert galaxies

The Declined Activity in the Nucleus of NGC 1316

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