A fast and long-lived outflow from the supermassive black hole in NGC 5548

Kaastra, J. S.; Kriss, G. A.; Cappi, M.; Mehdipour, M.; Petrucci, P.-O.; Steenbrugge, K. C.; Arav, Nahum; Behar, E.; Bianchi, S.; Boissay, R.; Branduardi‐Raymont, G.; Chamberlain, Carter; Costantini, E.; Ely, Justin; Ebrero, J.; Gesu, Laura Di; Harrison, Fiona A.; Kaspi, S.; Malzac, J.; Marco, Barbara De; Matt, Giorgio; Nandra, K.; Paltani, S.; Person, R.; Peterson, B. M.; Pinto, C.; Ponti, G.; Núñez, F. Pozo; Rosa, A. De; Seta, Hiromi; Ursini, F.; Vries, C. P. de; Walton, D. J.; Whewell, M.

doi:10.1126/science.1253787

Cited by 194 publications

(278 citation statements)

References 36 publications

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“…From their data we calculate a G ratio of 8.8 +6.2 −6.1 and 4.6 +2.8 −1.4 and an R ratio of 3.3 +1.5 −1.4 and 2.8 +1.5 −0.6 for the HETG and LETG data, respectively. Given the large errors, these results are consistent with the XMM-Newton results of Kaastra et al (2014). Therefore, we will use here the latter data given the higher quality, although the observations are not contemporaneous with our optical spectroscopy.…”

Section: Plasma Diagnostics and The Similarity Between Ngc 5548 And Nsupporting

confidence: 76%

“…Neither of the studies mentioned in Section 2.2 detects all three O VII lines and, therefore, no density and/or ionisation parameter can be determined from this triplet for the period 2002-2007. However, the entire O VII triplet is detected by Kaastra et al (2014) when the source was in an obscured state similar to what is generally observed for NGC 4151. Kaastra et al (2014) assumed that the narrow emission lines are not absorbed by the warm absorber (similar to the study of Detmers et al 2009) and from their data we determine a G ratio of 4.40±0.57 and an R ratio of 3.49±0.35 (filled triangle in Fig.…”

Section: Plasma Diagnostics and The Similarity Between Ngc 5548 And Nmentioning

confidence: 66%

“…The trend for this much weaker X-ray emission line is similar to that observed for the O VII f line; a decrease in flux during the observing period by a factor of ∼ > 3. Finally, it is worth noting that the flux of both the O VII f line and the unabsorbed X-ray continuum recovered by the summer of 2013 to a level only slightly below that observed in 2002 (Kaastra et al 2014). …”

Section: The X-ray Coronal Linesmentioning

confidence: 99%

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Strong variability of the coronal line region in NGC 5548

Landt¹,

Ward²,

Steenbrugge³

et al. 2015

Mon. Not. R. Astron. Soc.

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We present the second extensive study of the coronal line variability in an active galaxy. Our data set for the well-studied Seyfert galaxy NGC 5548 consists of five epochs of quasi-simultaneous optical and near-infrared spectroscopy spanning a period of about five years and three epochs of X-ray spectroscopy overlapping in time with it. Whereas the broad emission lines and hot dust emission varied only moderately, the coronal lines varied strongly. However, the observed high variability is mainly due to a flux decrease. Using the optical [Fe VII] and X-ray O VII emission lines we estimate that the coronal line gas has a relatively low density of n e ∼ 10 3 cm −3 and a relatively high ionisation parameter of log U ∼ 1. The resultant distance of the coronal line gas from the ionising source of about eight light years places this region well beyond the hot inner face of the dusty torus. These results imply that the coronal line region is an independent entity. We find again support for the X-ray heated wind scenario of Pier & Voit; the increased ionising radiation that heats the dusty torus also increases the cooling efficiency of the coronal line gas, most likely due to a stronger adiabatic expansion. The much stronger coronal line variability of NGC 5548 relative to that of NGC 4151 can also be explained within this picture. NGC 5548 has much stronger coronal lines relative to the low ionisation lines than NGC 4151 indicating a stronger wind, in which case a stronger adiabatic expansion of the gas and so fading of the line emission is expected.

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Section: Plasma Diagnostics and The Similarity Between Ngc 5548 And Nsupporting

confidence: 76%

Section: Plasma Diagnostics and The Similarity Between Ngc 5548 And Nmentioning

confidence: 66%

Section: The X-ray Coronal Linesmentioning

confidence: 99%

See 1 more Smart Citation

Strong variability of the coronal line region in NGC 5548

Landt¹,

Ward²,

Steenbrugge³

et al. 2015

Mon. Not. R. Astron. Soc.

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show abstract

“…2, and which is much larger than individual measurement uncertainties (plotted for the other sources). We further note that NGC 5548 is in a historically low X-ray and UV flux state for the past few years (Kaastra et al 2014). If the 95 GHz emission is coming from similar inner regions as the X-ray and UV, it is not surprising that the 95 GHz flux now is much lower than expected.…”

Section: Beam Sizes and Variabilitymentioning

confidence: 92%

Discovery of millimetre-wave excess emission in radio-quiet active galactic nuclei

Behar

Baldi

Laor

et al. 2015

Monthly Notices of the Royal Astronomical Society

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The physical origin of radio emission in Radio Quiet Active Galactic Nuclei (RQ AGN) remains unclear, whether it is a downscaled version of the relativistic jets typical of Radio Loud (RL) AGN, or whether it originates from the accretion disk. The correlation between 5 GHz and X-ray luminosities of RQ AGN, which follows L R = 10 −5 L X observed also in stellar coronae, suggests an association of both X-ray and radio sources with the accretion disk corona. Observing RQ AGN at higher (mm-wave) frequencies, where synchrotron self absorption is diminished, and smaller regions can be probed, is key to exploring this association. Eight RQ AGN, selected based on their high X-ray brightness and variability, were observed at 95 GHz with the CARMA and ATCA telescopes. All targets were detected at the 1 − 10 mJy level. Emission excess at 95 GHz of up to ×7 is found with respect to archival low-frequency steep spectra, suggesting a compact, optically-thick core superimposed on the more extended structures that dominate at low frequencies. Though unresolved, the 95 GHz fluxes imply optically thick source sizes of 10 −4 − 10 −3 pc, or ∼ 10 − 1000 gravitational radii. The present sources lie tightly along an L R (95 GHz) = 10 −4 L X (2-10 keV) correlation, analogous to that of stellar coronae and RQ AGN at 5 GHz, while RL AGN are shown to have higher L R /L X ratios. The present observations argue that simultaneous mm-wave and X-ray monitoring of RQ AGN features a promising method for understanding accretion disk coronal emission.

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“…We then fitted the full energy range of available X-ray data from XMM EPIC. The bluest bins chosen also do not cover the absorption features observed by Kaastra et al (2014), which may be expected in AGN with high N H columns (see Table 4). We do not tie the N H,int and intrinsic E(B − V) values together.…”

Section: Broadband Sed Fittingmentioning

confidence: 99%

Reaching the peak of the quasar spectral energy distribution – I. Observations and models

Collinson

Ward

Done

et al. 2015

Monthly Notices of the Royal Astronomical Society

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We perform a spectral analysis of a sample of 11 medium redshift (1.5 z 2.2) quasars. Our sample all have optical spectra from the SDSS, infrared spectra from GNIRS and TSPEC, and X-ray spectra from XMM-Newton. We first analyse the Balmer broad emission line profiles which are shifted into the IR spectra to constrain black hole masses. Then we fit an energy-conserving, three component accretion model of the broadband spectral energy distribution (SED) to our multiwavelength data. Five out of the 11 quasars show evidence of an SED peak, allowing us to constrain their bolometric luminosity from these models and estimate their mass accretion rates. Based on our limited sample, we suggest that estimating bolometric luminosities from L 5100 Å and L 2−10 keV may be unreliable, as has been also noted for a low-redshift, X-ray selected AGN sample.

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A fast and long-lived outflow from the supermassive black hole in NGC 5548

Cited by 194 publications

References 36 publications

Strong variability of the coronal line region in NGC 5548

Strong variability of the coronal line region in NGC 5548

Discovery of millimetre-wave excess emission in radio-quiet active galactic nuclei

Reaching the peak of the quasar spectral energy distribution – I. Observations and models

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