Complex X‐Ray Absorption and the Fe Kα Profile in NGC 3516

Turner, T. J.; Kraemer, Steve; George, I. M.; Reeves, J. N.; Bottorff, M. C.

doi:10.1086/425961

Cited by 72 publications

(132 citation statements)

References 56 publications

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“…It is clear that the other layers of lower ξ gas may exist along the same sight-line but at larger radial distances from the central source: the highest-ξ zone could not exist outside the other gas layers as shielding would prevent it achieving log ξ > ∼ 4. Similar models have been discussed for sources such as e.g., NGC 3516 (Turner et al 2005) and NGC 4151 ) and thus it seems that spectral variations driven by a time-variable disk wind may be applicable across the Seyfert population.…”

Section: Discussionsupporting

confidence: 58%

The variable X-ray spectrum of Markarian 766

Turner

Miller

Reeves

et al. 2007

A&A

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Context. The variable X-ray spectra of AGN systematically show steep power-law high states and hard-spectrum low states. The hard, low state has previously been found to be a component with only weak variability. The origin of this component and the relative importance of effects such as absorption and relativistic blurring are currently not clear. Aims. In a follow-up of previous principal components analysis we aim to determine the relative importance of scattering and absorption effects on the time-varying X-ray spectrum of the narrow-line Seyfert 1 galaxy Mrk 766. Methods. Time-resolved spectroscopy, slicing XMM and Suzaku data down to 25 ks elements is used to investigate whether absorption or scattering components dominate the spectral variations in Mrk 766. Results. Time-resolved spectroscopy confirms that spectral variability in Mrk 766 can be explained by either of two interpretations of principal components analysis. Detailed investigation confirm rapid changes in the relative strengths of scattered and direct emission or rapid changes in absorber covering fraction provide good explanations of most of the spectral variability. However, a strong correlation between the 6.97 keV absorption line and primary continuum together with rapid opacity changes show that variations in a complex and multi-layered absorber, most likely a disk wind, are the dominant source of spectral variability in Mrk 766.

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Section: Discussionsupporting

confidence: 58%

The variable X-ray spectrum of Markarian 766

Turner

Miller

Reeves

et al. 2007

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“…The highest velocity zone, at v r ∼ −0.02c, in which H-and He-like Fe lines form, is too highly ionized to produce detectable UV lines and, in fact, no UV absorption is detected at this velocity. And, as we have found in previous studies (e.g., Turner et al 2005), no lines are detected from the high-ionization, high-column, partial-covering zone. For the remaining zones, we list the model parameters, with U given for the equivalent ξ , and possible associated UV components, in Table 6.…”

Section: Connection With the X-ray Absorberssupporting

confidence: 84%

“…Coupled with their relatively high values of U, one consequence of the low column densities is that none of the three strongest components are sufficiently optically thick to the ionization radiation to justify including the effects of screening by intervening absorbers, e.g., as is the case in NGC 3516 (Kraemer et al 2002;Turner et al 2005) and NGC 4151 (Kraemer et al 2001(Kraemer et al , 2006. Also, while, as noted in Section 3, the continuum and BLR emission is reddened, consistent with an intervening column of N H = 1.0 × 10 21 cm −2 of dusty gas, none of the models for the UV absorber components have a sufficient column den- sity to account for the reddening.…”

Section: Model Resultsmentioning

confidence: 99%

Observations of Outflowing Ultraviolet Absorbers in NGC 4051 With the Cosmic Origins Spectrograph

Kraemer¹,

Crenshaw²,

Dunn³

et al. 2012

ApJ

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We present new Hubble Space Telescope (HST)/Cosmic Origins Spectrograph (COS) observations of the narrowline Seyfert 1 galaxy NGC 4051. These data were obtained as part of a coordinated observing program including X-ray observations with the Chandra/High Energy Transmission Grating (HETG) spectrometer and Suzaku. We detected nine kinematic components of UV absorption, which were previously identified using the HST/Space Telescope Imaging Spectrograph (STIS). None of the absorption components showed evidence for changes in column density or profile within the ∼10 yr between the STIS and COS observations, which we interpret as evidence of (1) saturation, for the stronger components, or (2) very low densities, i.e., n H < 1 cm −3 , for the weaker components. After applying a + 200 km s −1 offset to the HETG spectrum, we found that the radial velocities of the UV absorbers lay within the O vii profile. Based on photoionization models, we suggest that, while UV components 2, 5, and 7 produce significant O vii absorption, the bulk of the X-ray absorption detected in the HETG analysis occurs in more highly ionized gas. Moreover, the mass-loss rate is dominated by high-ionization gas which lacks a significant UV footprint.

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“…NGC 3516: the detection of narrow highly ionized absorption features in the Chandra HETG and XMM-Newton EPIC pn spectra of this source have already been published by Turner et al (2005) and Turner et al (2008). In particular, the authors reported the presence of H/He-line resonant absorption lines from Mg, Si, S and Fe.…”

Section: Appendix B: Notes On Single Sourcesmentioning

confidence: 82%

Evidence for ultra-fast outflows in radio-quiet AGNs

Tombesi

Cappi²,

Reeves

et al. 2010

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Context. Blue-shifted Fe K absorption lines have been detected in recent years between 7 and 10 keV in the X-ray spectra of several radio-quiet AGNs. The derived blue-shifted velocities of the lines can often reach mildly relativistic values, up to 0.2-0.4c. These findings are important because they suggest the presence of a previously unknown massive and highly ionized absorbing material outflowing from their nuclei, possibly connected with accretion disk winds/outflows. Aims. The scope of the present work is to statistically quantify the parameters and incidence of the blue-shifted Fe K absorption lines through a uniform analysis on a large sample of radio-quiet AGNs. This allows us to assess their global detection significance and to overcome any possible publication bias. Methods. We performed a blind search for narrow absorption features at energies greater than 6.4 keV in a sample of 42 radio-quiet AGNs observed with XMM-Newton. A simple uniform model composed by an absorbed power-law plus Gaussian emission and absorption lines provided a good fit for all the data sets. We derived the absorption lines parameters and calculated their detailed detection significance making use of the classical F-test and extensive Monte Carlo simulations. Results. We detect 36 narrow absorption lines on a total of 101 XMM-Newton EPIC pn observations. The number of absorption lines at rest-frame energies higher than 7 keV is 22. Their global probability to be generated by random fluctuations is very low, less than 3 × 10 −8 , and their detection have been independently confirmed by a spectral analysis of the MOS data, with associated random probability <10 −7 . We identify the lines as Fe XXV and Fe XXVI K-shell resonant absorption. They are systematically blue-shifted, with a velocity distribution ranging from zero up to ∼0.3c, with a peak and mean value at ∼0.1c. We detect variability of the lines on both EWs and blue-shifted velocities among different XMM-Newton observations even on time-scales as short as a few days, possibly suggesting somewhat compact absorbers. Moreover, we find no significant correlation between the cosmological red-shifts of the sources and the lines blue-shifted velocities, ruling out any systematic contamination by local absorption. If we define ultra-fast outflows (UFOs) those highly ionized absorbers with outflow velocities higher than 10 4 km s −1 , then the majority of the lines are consistent with being associated to UFOs and the fraction of objects with detected UFOs in the whole sample is at least ∼35%. This fraction is similar for type 1 and type 2 sources. The global covering fraction of the absorbers is consequently estimated to be in the range C ∼ 0.4−0.6, thereby implying large opening angles. Conclusions. From our systematic X-ray spectral analysis on a large sample of radio-quiet AGNs we have been able to clearly assess the global veracity of the blue-shifted Fe K absorption lines at E > 7 keV and to overcome their publication bias. These lines indicate that UFOs are a rather ...

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Complex X‐Ray Absorption and the Fe Kα Profile in NGC 3516

Cited by 72 publications

References 56 publications

The variable X-ray spectrum of Markarian 766

The variable X-ray spectrum of Markarian 766

Observations of Outflowing Ultraviolet Absorbers in NGC 4051 With the Cosmic Origins Spectrograph

Evidence for ultra-fast outflows in radio-quiet AGNs

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