<i>INTEGRAL</i>and<i>XMM‐Newton</i>Spectral Studies of NGC 4388

Beckmann, V.; Gehrels, N.; Favre, Pascal; Walter, R.; Courvoisier, T. J. L.; Petrucci, P.-O.; Malzac, J.

doi:10.1086/423708

Cited by 50 publications

(56 citation statements)

References 35 publications

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“…At the adopted 5-σ confidence level, a broadened relativistic line is detected in only two sources. In both cases, this detection has been reported A131, page 4 of 13 Beckmann et al 2004), and NGC 5252 (Dadina et al 2010). The detection fraction in GREDOS ( 15%) is nominally smaller than for unobscured AGN.…”

Section: Spectral Resultsmentioning

confidence: 52%

On the driver of relativistic effect strength in Seyfert galaxies

Guainazzi¹,

Bianchi²,

Pérez³

et al. 2011

A&A

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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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Section: Spectral Resultsmentioning

confidence: 52%

On the driver of relativistic effect strength in Seyfert galaxies

Guainazzi¹,

Bianchi²,

Pérez³

et al. 2011

A&A

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“…Combined analysis from several missions shows a simple PL above a few keV absorbed by a column N H = 2.7×10 23 cm −2 , but with highly variable fluxes and obscuring column (Beckmann et al 2004;Cappi et al 2006;Iwasawa et al 2003;Risaliti et al 2002). Using the mean of the broad range found in XMM-Newton by Cappi et al (2006) and recent INTEGRAL results by Beckmann et al (2006), for a distance of 16.7 Mpc, results in a mean logL 2−10 = 42.24, to which we attach a large 1-σ error in dex of 0.3.…”

Section: A15 Ngc 4388mentioning

confidence: 98%

Resolving the mid-infrared cores of local Seyferts

Gandhi

Horst

Smette

et al. 2009

A&A

394

112

647

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We present new photometry of 16 local Seyferts including 6 Compton-thick sources in N-band filters around 12-μm, obtained with the VISIR instrument on the 8-m Very Large Telescope. The near-diffraction-limited imaging provides the least-contaminated core fluxes for these sources to date. Augmenting these with our previous observations and with published intrinsic X-ray fluxes, we form a total sample of 42 sources for which we find a strong mid-infrared:X-ray (12.3 μm:2-10 keV) luminosity correlation. Performing a physically-motivated subselection of sources in which the Seyfert torus is likely to be best-resolved results in the correlation L MIR ∝ L X 1.11±0.07 , with a reduction of the scatter in luminosities as compared to the full sample. Consideration of systematics suggests a range of 1.02-1.21 for the correlation slope. The mean 2-keV:12.3-μm spectral index (α IX ) is found to be −1.10 ± 0.01, largely independent of luminosity. Indirectly-computed 12-μm bolometric corrections range over ≈10-30 if a known luminosity trend of X-ray bolometric corrections is assumed. Comparison with ISO data spanning a wider luminosity range suggests that our correlation can be extended into the quasar regime. That unobscured, obscured, and Compton-thick sources all closely follow the same luminosity correlation has important implications for the structures of Seyfert cores. The typical resolution-limit of our imaging corresponds to ∼70 pc at a median z = 0.01, and we use the tightness of the correlation to place constraints on the dominance of any residual emission sources within these physical scales. An upper-limit for any contaminating star formation of ≈40% of the unresolved flux is inferred, on average. We suggest that uncontaminated mid-IR continuum imaging of AGN is an accurate proxy for their intrinsic power.

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“…The elliptical galaxy M84, west of M86, shows complicated structure in the diffuse emission in the core related to the radio outburst, and a tail extending to the south ( Finoguenov & Jones 2002). Also visible are NGC 4388 (south-southwest of M86; Beckmann et al 2004) and NGC 4438 (east of M86; Machacek et al 2004;Vollmer et al 2005). Both also have diffuse tails, which likely indicate their projected direction of motion with respect to the Virgo ICM.…”

Section: The X-ray Imagementioning

confidence: 98%

Chandra’s View of the Ram Pressure Stripped Galaxy M86

Randall

Nulsen

Forman

et al. 2008

Astrophysical Journal

131

167

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We present results from a mosaic of nine Chandra observations of M86 and the surrounding field. We detect three main diffuse components: the Virgo intracluster medium (ICM), the extended halo of M86, and the cooler central and stripped gas of M86. The most striking feature is a long tail of emission, which consists of a plume $4 0 north of M86 and two main extensions emanating from the plume. We conclude that it is formed by ram pressure stripping of M86 as it falls into the Virgo Cluster and interacts with the Virgo ICM, in agreement with earlier work. The tail is 150 kpc in projection, and a simple estimate gives a lower limit on the true length of the tail of 380 kpc, making this the longest ram pressure stripped tail currently known. The total gas mass in the plume ($7 ; 10 8 M ) and tail ($1 ; 10 9 M ) is about 3 times that in the core of M86, which supports the scenario where most of the gas was stripped rapidly and recently. The projected position of the plume can be understood if M86 has an aspherical potential. Ram pressure stripping from an aspherical potential can also explain the split ''double tails'' seen in M86 and in other Virgo Cluster galaxies in the field. The large line-of-sight velocity of M86 (1550 km s À1 with respect to M87), its position relative to the Virgo Cluster, and the orientation of the tail tightly constrain its orbital parameters.

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INTEGRALandXMM‐NewtonSpectral Studies of NGC 4388

Cited by 50 publications

References 35 publications

On the driver of relativistic effect strength in Seyfert galaxies

On the driver of relativistic effect strength in Seyfert galaxies

Resolving the mid-infrared cores of local Seyferts

Chandra’s View of the Ram Pressure Stripped Galaxy M86

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