4U 1344-60: a bright intermediate Seyfert galaxy at<i>z</i>= 0.012 with a relativistic Fe K$\mathsf{\alpha}$ emission line

Piconcelli, E.; Sánchez‐Portal, M.; Guainazzi, M.; Martocchia, A.; Motch, C.; Schröder, A. C.; Bianchi, S.; Jiménez‐Bailón, E.; Matt, Giorgio

doi:10.1051/0004-6361:20064956

Cited by 16 publications

(36 citation statements)

References 60 publications

(78 reference statements)

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“…Although its X-ray spectrum is heavily absorbed by the Galactic interstellar matter (N H ≈ 1 × 10 22 cm −2 ) it has clearly revealed an emission excess in the broadened red wing of the iron line in a previous XMM-Newton observation (Piconcelli et al 2006). 4U 1344-60 was discovered for the first time by the X-ray satellite Uhuru.…”

Section: Introductionmentioning

confidence: 70%

“…4U 1344-60 also exhibited a complex absorption in the X-ray spectrum. Piconcelli et al (2006) suggested the presence of a partially covering absorber to explain a remarkably flat power law describing the data. A combined analysis of the XMM-Newton and INTEGRAL observation was later done by Panessa et al (2008) who concluded that the spectrum is affected by one fully and two partially covering absorbers with substantial column densities (N pc1 H ≈ 5 × 10 22 cm −2 , and N pc2 H ≈ 4 × 10 23 cm −2 ) and covering fractions around 50%.…”

Section: Introductionmentioning

confidence: 85%

“…Because our spectral results with the Suzaku observation differ from that reported by Piconcelli et al (2006) we also reanalysed the archival XMM-Newton data and performed a simultaneous fit to both data sets. We used the recent version of the SAS software (11.0.0) 3 .…”

Section: Data Reduction and Analysismentioning

confidence: 99%

“…In the XMM-Newton observation of Centaurus B, 4U 1344-60 appeared at the edge of the field (Obs.ID: 0092140101). Piconcelli et al (2006) studied the EPIC-pn spectrum together with the optical observations of the source. The optical spectrum allowed for a classification of the source as an active galaxy of an intermediate type.…”

Section: Introductionmentioning

confidence: 99%

“…4U 1344-60 was observed by INTEGRAL (Bird et al 2010) with its hard X-ray flux f (Cusumano et al 2010). Residuals in the energy range, where emission features by iron line are expected, were formerly analysed by Piconcelli et al (2006) in the XMM-Newton observation. A model consisting of the power-law continuum plus a narrow unresolved Gaussian line gave an unacceptable fit.…”

Section: Introductionmentioning

confidence: 99%

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Active galaxy 4U 1344-60: did the relativistic line disappear?

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Bianchi

Guainazzi

et al. 2012

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Context. X-ray bright active galactic nuclei represent a unique astrophysical laboratory for studying accretion physics around supermassive black holes. Aims. 4U 1344-60 is a bright Seyfert galaxy which revealed relativistic reflection features in the archival XMM-Newton observation. Methods. We present the spectroscopic results of new data obtained with the Suzaku satellite and compare them with the previous XMM-Newton observation.Results. The X-ray continuum of 4U 1344-60 can be well described by a power-law component with the photon index ≈1.7 modified by a fully and a partially covering local absorbers. We measured a substantial decrease of the fraction of the partially absorbed radiation from around 45% in the XMM-Newton observation to less than 10% in the Suzaku observation while the power-law slope remains constant within uncertainties. The iron line in the Suzaku spectrum is relatively narrow, σ = (0.08 ± 0.02) keV, without any suggestion for relativistic broadening. Regarding this, we interpret the iron line in the archival XMM-Newton spectrum as a narrow line of the same width plus an additional red-shifted emission around 6.1 keV. Conclusions. No evidence of the relativistic reflection is present in the Suzaku spectra. The detected red-shifted iron line during the XMM-Newton observation could be a temporary feature either due to locally enhanced emission or decreased ionisation in the innermost accretion flow.

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Section: Introductionmentioning

confidence: 70%

Section: Introductionmentioning

confidence: 85%

Section: Data Reduction and Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Active galaxy 4U 1344-60: did the relativistic line disappear?

Svoboda

Bianchi

Guainazzi

et al. 2012

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Relativistic Fe Kα features in the XMM‐Newton spectrum of the intermediate Seyfert galaxy 4U 1344‐60

et al. 2006

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We present the analysis of optical and X-ray XMM-Newton data of the source 4U 1344-60. On the basis of the optical data we propose to classify 4U 1344-60 as a Seyfert 1.5 galaxy and we measured a redshift value z=0.012±0.001. The observed X-ray spectrum is complex. The continuum emission can be described as a power law obscured by two neutral absorption components. 4U 1344-60 exhibits a broad and skewed iron line at 6.4 keV most likely originated in a few gravitational radius of an accretion disc. The analysis also reveals the presence of two narrow emission line-like features at ∼4.9 keV and ∼5.3 keV. Assuming that hot spots on the surface of the accretion disc, orbiting very close to the black hole is responsible of these emission lines, the accretion disc would present an inclination of 20• and the active regions would be located in the 6-10 Rg radius range.

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On the driver of relativistic effect strength in Seyfert galaxies

Guainazzi¹,

Bianchi²,

Pérez³

et al. 2011

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Context. Spectroscopy of X-ray emission lines emitted from accretion discs around supermassive black holes is one of the most powerful probes of the accretion flow physics and geometry, while also providing in principle observational constraints on the black hole spin. Previous studies have suggested that relativistically broadened line profiles are fairly common in nearby unobscured Seyfert galaxies. Their strength, as parametrised by the equivalent width (EW) against the total underlying continuum, spans a range of almost two orders of magnitude. Aims. We attempt to determine the ultimate physical driver of the strength of this relativistic reprocessing feature. Methods. We first extend the hard X-ray flux-limited sample of Seyfert galaxies studied so far in the framework of the FERO (Finding Extreme Relativistic Objects) project to obscured objects up to a column density N H = 6 × 10 23 cm −2 . We verify that none of the line properties depends on the AGN optical classification, as expected from the Seyfert unification scenarios. There is also no correlation between the accretion disc inclination, as derived from formal fits of the line profiles, and the optical type or host galaxy aspect angle, suggesting that the innermost regions of the accretion disc and the host galaxy plane are not aligned. We use this extended sample to study the dependence of the EW on various observables, and compare it with the predictions of Monte Carlo accretion-disc reprocessing simulation. Results. The behaviour of the EW as a function of disc inclination, shape of the intrinsic power-law nuclear continuum, or iron abundance does not agree with the simulation predictions. Our observational data are not sensitive enough to the detailed ionisation state of the line-emitting disc. However, the lack of dependence of the line EW on either the luminosity or the rest-frame centroid energy rules out disc ionisation playing an important role on the EW dynamical range in Seyferts.Conclusions. The dynamical range of the relativistically broadened K α iron line EW in nearby Seyferts appears to be mainly determined by the properties of the innermost accretion flow. We discuss several mechanisms (disc ionisation, disc truncation, and aberration due to a mildly relativistic outflowing corona) that can explain this. We stress that the above results represent neither a falsification or proof of the relativistically blurring scenario. Observational data still do not contradict scenarios invoking different mechanisms for the spectral complexity around the iron line, most notably the "partial covering" absorption scenario.

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4U 1344-60: a bright intermediate Seyfert galaxy atz= 0.012 with a relativistic Fe K$\mathsf{\alpha}$ emission line

Cited by 16 publications

References 60 publications

Active galaxy 4U 1344-60: did the relativistic line disappear?

Active galaxy 4U 1344-60: did the relativistic line disappear?

Relativistic Fe Kα features in the XMM‐Newton spectrum of the intermediate Seyfert galaxy 4U 1344‐60

On the driver of relativistic effect strength in Seyfert galaxies

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