Broadband Observations of the Compton-Thick Nucleus of NGC 3393

Koss, Michael; Romero-Cañizales, C.; Baronchelli, L.; Teng, Stacy H.; Baloković, Mislav; Puccetti, S.; Bauer, F. E.; Arévalo, P.; Assef, Roberto J.; Ballantyne, D. R.; Brandt, W. N.; Brightman, Murray; Comastri, A.; Gandhi, P.; Harrison, Fiona A.; Luo, B.; Schawinski, Kevin; Stern, Daniel; Treister, Ezequiel

doi:10.1088/0004-637x/807/2/149

Cited by 73 publications

(115 citation statements)

References 72 publications

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“…Even if not intrinsically weak, the line detection is severely hampered by the low S/N. Throughsimulations, Koss et al (2015) found that the strong Fe Kα line (EW=1.11 keV) in a Compton-thick AGN NGC3933 (z=0.0125) can be detected at an S/N=3 by the 4Ms CDF-S only if z 0.2 < . This explains why the detection of neutral Fe Kα lines is inefficient in identifying Compton-thick AGNs in our high-z sample (Section 3.4.3).…”

Section: Distribution Of N H Excluding Compton-thick Sourcesmentioning

confidence: 99%

X-Ray Spectral Analyses of AGNs from the 7Ms Chandra Deep Field-South Survey: The Distribution, Variability, and Evolutions of AGN Obscuration

Liu

Tozzi²,

Wang

et al. 2017

ApJS

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We present a detailed spectral analysis of the brightest active galactic nuclei (AGNs) identified in the 7Ms Chandra Deep Field-South (CDF-S) survey over a time span of 16 years. Using a model of an intrinsically absorbed power-law plus reflection, with possible soft excess and narrow Fe Kα line, we perform a systematic X-ray spectral analysis, both on the total 7Ms exposure and in four different periods with lengths of 2–21 months. With this approach, we not only present the power-law slopes, column densities , observed fluxes, and absorption-corrected 2–10 keV luminosities L X for our sample of AGNs, but also identify significant spectral variabilities among them on timescales of years. We find that the variabilities can be ascribed to two different types of mechanisms, either flux-driven or flux-independent. We also find that the correlation between the narrow Fe line EW and can be well explained by the continuum suppression with increasing . Accounting for the sample incompleteness and bias, we measure the intrinsic distribution of for the CDF-S AGN population and present reselected subsamples that are complete with respect to . The -complete subsamples enable us to decouple the dependences of on L X and on redshift. Combining our data with those from C-COSMOS, we confirm the anticorrelation between the average and L X of AGN, and find a significant increase of the AGN-obscured fraction with redshift at any luminosity. The obscured fraction can be described as .

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Section: Distribution Of N H Excluding Compton-thick Sourcesmentioning

confidence: 99%

X-Ray Spectral Analyses of AGNs from the 7Ms Chandra Deep Field-South Survey: The Distribution, Variability, and Evolutions of AGN Obscuration

Liu

Tozzi²,

Wang

et al. 2017

ApJS

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“…Using simulations, Koss et al (2015) found that robust characterization of typical nearby CTAGN, such as NGC 3393, is only possible at relatively low redshifts of z 0.2 if one relies upon detection of the Fe Kα emission line and broad-band continuum for spectral modelling.…”

Section: Implications For Identifying Ctagn At a Low X-ray Signal To mentioning

confidence: 99%

The weak Fe fluorescence line and long-term X-ray evolution of the Compton-thick active galactic nucleus in NGC 7674

Gandhi

Annuar

Lansbury

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We present NuSTAR X-ray observations of the active galactic nucleus (AGN) in NGC 7674. The source shows a flat X-ray spectrum, suggesting that it is obscured by Compton-thick gas columns. Based upon long-term flux dimming, previous work suggested the alternate possibility that the source is a recently switched-off AGN with the observed X-rays being the lagged echo from the torus. Our high-quality data show the source to be reflection-dominated in hard X-rays, but with a relatively weak neutral Fe Kα emission line (equivalent width [EW] of ≈ 0.4 keV) and a strong Fe XXVI ionised line (EW ≈ 0.2 keV). We construct an updated longterm X-ray light curve of NGC 7674 and find that the observed 2-10 keV flux has remained constant for the past ≈ 20 years, following a high flux state probed by Ginga. Light travel time arguments constrain the minimum radius of the reflector to be ∼ 3.2 pc under the switchedoff AGN scenario, ≈ 30 times larger than the expected dust sublimation radius, rendering this possibility unlikely. A patchy Compton-thick AGN (CTAGN) solution is plausible, requiring a minimum line-of-sight column density (N H ) of 3 × 10 24 cm −2 at present, and yields an intrinsic 2-10 keV luminosity of (3-5) × 10 43 erg s −1 . Realistic uncertainties span the range of ≈ (1-13) × 10 43 erg s −1 . The source has one of the weakest fluorescence lines amongst bona fide CTAGN, and is potentially a local analogue of bolometrically luminous systems showing complex neutral and ionised Fe emission. It exemplifies the difficulty of identification and proper characterisation of distant CTAGN based on the strength of the neutral Fe Kα line.

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“…Dominance of the R component in the hard X-ray band is not favored either, as the EW of Fe Kα is relatively low. Instead, IRAS 09104+4109 resembles heavily obscured AGNs in the nearby universe, in which both T and R components contribute to the X-ray spectrum in the NuSTAR band (e.g., Puccetti et al 2014;Koss et al 2015;M. Baloković et al 2016, in preparation).…”

Section: The X-ray Datamentioning

confidence: 99%

The Geometry of the Infrared and X-Ray Obscurer in a Dusty Hyperluminous Quasar

Farrah

Baloković

Stern

et al. 2016

ApJ

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We study the geometry of the active galactic nucleus (AGN) obscurer in IRAS 09104+4109, an IR-luminous, radio-intermediate FR-I source at z = 0.442, using infrared data from Spitzer and Herschel, X-ray data from NuSTAR, Swift, Suzaku, and Chandra, and an optical spectrum from Palomar. The infrared data imply a total restframe 1-1000 μm luminosity of 5.5×10 46 erg s −1 and require both an AGN torus and a starburst model. The AGN torus has an anisotropy-corrected IR luminosity of 4.9×10 46 erg s −1 and a viewing angle and half-opening angle both of approximately 36°from pole-on. The starburst has a star formation rate of (110±34) M e yr −1 and an age of <50 Myr. These results are consistent with two epochs of luminous activity in IRAS 09104+4109: one approximately 150 Myr ago, and one ongoing. The X-ray data suggest a photon index of Γ ; 1.8 and a line-ofsight column density of N H ; 5×10 23 cm −2 . This argues against a reflection-dominated hard X-ray spectrum, which would have implied a much higher N H and luminosity. The X-ray and infrared data are consistent with a bolometric AGN luminosity of L bol ∼(0.5-2.5)×10 47 erg s −1. The X-ray and infrared data are further consistent with coaligned AGN obscurers in which the line of sight "skims" the torus. This is also consistent with the optical spectra, which show both coronal iron lines and broad lines in polarized but not direct light. Combining constraints from the X-ray, optical, and infrared data suggestthat the AGN obscurer is within a vertical height of 20 pc, and a radius of 125 pc, of the nucleus.

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Broadband Observations of the Compton-Thick Nucleus of NGC 3393

Cited by 73 publications

References 72 publications

X-Ray Spectral Analyses of AGNs from the 7Ms Chandra Deep Field-South Survey: The Distribution, Variability, and Evolutions of AGN Obscuration

X-Ray Spectral Analyses of AGNs from the 7Ms Chandra Deep Field-South Survey: The Distribution, Variability, and Evolutions of AGN Obscuration

The weak Fe fluorescence line and long-term X-ray evolution of the Compton-thick active galactic nucleus in NGC 7674

The Geometry of the Infrared and X-Ray Obscurer in a Dusty Hyperluminous Quasar

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