Revealing the Dusty Warm Absorber in MCG −6-30-15 with the [ITAL]Chandra[/ITAL] High-Energy Transmission Grating

Lee, Julia C.; Ogle, Patrick; Canizares, C. R.; Marshall, Herman L.; Schulz, Norbert S.; Morales, Raquel; Fabian, A. C.; Iwasawa, K.

doi:10.1086/320912

Cited by 177 publications

(233 citation statements)

References 34 publications

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“…This suggests that the dust is similar to Galactic dust and resides within the warm ionized gas, and may significantly affect the observed soft X-ray spectrum (Komossa & Fink 1997 and references therein;Komossa & Bade 1998). Spectroscopic evidence for dust in X-ray warm absorbers has now been found by Lee et al (2001) in the Chandra gratings observation of MCG-6-30-15 (this seems to have been confirmed by the very recent XMM-Newton data of Turner et al 2003). This high resolution spectrum exhibited a sharp drop 2 at ∼0.7 keV consistent with the L3 absorption edge from neutral Fe.…”

Section: Introductionsupporting

confidence: 65%

“…Of the three models shown here, the depth of the O  edge is greatest when r = 175 pc, with τ OVII = 0.15. The Fe  edge from the dust is noticeable as a small notch just redward of the O  edge, as was observed by Lee et al (2001). The majority of the opacity below 0.3 keV is due to absorption by He , as was found in the lukewarm absorber of Kraemer et al (2000).…”

Section: The Location Of the Dwasupporting

confidence: 54%

“…In particular, the O  edge was found to anticorrelate with the source luminosity while the O  edge seemed to remain constant (Otani et al 1996;Orr et al 1997). The Chandra observations found a strong O  edge (τ OVII ∼ 0.7) and a series of O  absorption lines within 200 km s −1 of the systemic velocity of MCG-6-30-15 (Lee et al 2001). An updated analysis presented by Lee et al (2002) showed that many of the other low-ionization absorption lines also have very small outflow velocities.…”

Section: Introductionmentioning

confidence: 97%

“…Currently, the study of the warm absorber is being revolutionized with observations from the dispersion gratings onboard Chandra and XMM-Newton which have been able to resolve individual absorption lines from a myriad of metals and charge states in the warm gas (e.g., Kaastra et al 2000;Kaspi et al 2001;Collinge et al 2001;Lee et al 2001;Kaspi et al 2002). Photoionization modeling has then shown that, in many cases, more than one ionization parameter 1 is needed to describe the observed spectrum (e.g, Morales et al 2000;Kaspi et al 2001;Kaastra et al 2002).…”

Section: Introductionmentioning

confidence: 99%

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On the location and composition of the dust in the MCG–6-30-15 warm absorber

Ballantyne¹,

Weingartner²,

Murray³

2003

A&A

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Abstract. The warm absorber observed in the Seyfert 1 galaxy MCG-6-30-15 is known to consist of at least two zones and very likely contains dust. Hubble Space Telescope images of MCG-6-30-15 show a dust lane crossing the galaxy just below the nucleus. In this paper, we argue that this dust lane is responsible for the observed reddening of the nuclear emission and the Fe  edge hinted at in the Chandra spectrum of MCG-6-30-15. We further suggest that the gas within the dust lane can comprise much of the low ionization component (i.e., the one contributing the O  edge) of the observed warm absorber. Moreover, placing the warm absorbing material at such distances (hundreds of pc) can account for the small outflow velocities of the low ionization absorption lines as well as the constancy of the O  edge. Photoionization models of a dusty interstellar gas cloud (with a column appropriate for the reddening toward MCG-6-30-15) using a toy Seyfert 1 spectral energy distribution show that it is possible to obtain a significant O  edge (τ ∼ 0.2) if the material is ∼150 pc from the ionizing source. For MCG-6-30-15, such a distance is consistent with the observed dust lane. We emphasize the point first made by Kraemer et al.: dusty interstellar material will likely contribute to the warm absorber, and should be included in spectral modeling. The current data on MCG-6-30-15 is unable to constrain the dust composition within the warm absorber. Astronomical silicate is a viable candidate, but there are indications of a very low O abundance in the dust, which is inconsistent with a silicate origin. If true, this may indicate that there were repeated cycles of grain destruction and growth from shocks in the interstellar medium of MCG-6-30-15. Pure iron grains are an unlikely dust constituent due to the limit on their abundance in the Galaxy, yet they cannot be ruled out. The high column densities inferred from the highly ionized zone of the warm absorber implies that this gas is dust-free.

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Section: Introductionsupporting

confidence: 65%

Section: The Location Of the Dwasupporting

confidence: 54%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

On the location and composition of the dust in the MCG–6-30-15 warm absorber

Ballantyne¹,

Weingartner²,

Murray³

2003

A&A

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“…ref [8]) often strictly focused on data 2 keV, as the main effect of these warm absorbers are below this energy (e.g. ref [58]), notably the two strong edges of O VII and O VIII at ∼ 0.74 keV and ∼ 0.87 keV, respectively [59] (note that for RX J1131-1231 at z = 0.658, this restricts the bulk effect of any possible WA to energies 0.5 keV). However, subsequent detailed analyses accounting for the multizone warm absorber present in this source still obtained consistent spin measurements [55,52,60] and concluded that the relativistic iron line is robust to the precise details of the WA (e.g.…”

Section: No Evidence For Complex Absorption In Rx J1131-1231mentioning

confidence: 99%

Reflection from the strong gravity regime in a lensed quasar at redshift z = 0.658

Reis

Reynolds

Miller

et al. 2014

Nature

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The co-evolution of a supermassive black hole with its host galaxy[1] through cosmic time is encoded in its spin[2, 3, 4]. At z > 2, supermassive black holes are thought to grow mostly by merger-driven accretion leading to high spin. However, it is unknown whether below z ∼ 1 these black holes continue to grow via coherent accretion or in a chaotic manner [5], though clear differences are predicted [3,4] in their spin evolution. An established method[6] to measure the spin of black holes is via the study of relativistic reflection features [7] from the inner accretion disk. Owing to their greater distances, there has hitherto been no significant detection of relativistic reflection features in a moderateredshift quasar. Here, we use archival data together with a new, deep observation of a gravitationally-lensed quasar at z = 0.658 to rigorously detect and study reflection in this moderate-redshift quasar. The level of relativistic distortion present in this reflection spectrum enables us to constrain the emission to originate within 3 gravitational radii from the black hole, implying a spin parameter a = 0.87 +0.08 −0.15 at the 3σ level of confidence and a > 0.66 at the 5σ level. The high spin found here is indicative of growth via coherent accretion for this black hole, and suggests that black hole growth between 0.5 z 1 occurs principally by coherent rather than chaotic accretion episodes. 1When optically-thick material, e.g. an accretion disc, is irradiated by hard X-rays, some of the flux is reprocessed into an additional 'reflected' emission component, which contains both continuum emission and atomic features. The most prominent signature of reflection from the inner accretion disc is typically the relativistic iron Kα line (6.4-6.97 keV; rest frame) [8] and the Compton reflection hump [7] often peaking at 20 − 30 keV (rest-frame). However, the deep gravitational potential and strong Doppler shifts associated with regions around black holes will also cause the forest of soft X-ray emission lines in the ∼ 0.7 − 2.0 keV range to be blended into a smooth emission feature, providing a natural explanation for the "soft-excess" observed in the X-ray spectra of nearby active galactic nuclei (AGNs) [9,10]. Indeed, both the iron line and the soft excess can be used to provide insight into the nature of the central black hole and to measure its spin [10]. Prior studies have revealed the presence of a soft-excess in 90% of quasars at[11, 12] z 1.7, and broad Fe-lines are also seen in 25% of these objects [11,13], suggesting that reflection is also prevalent in these distant AGNs. However, due to the inadequate S/N resulting from their greater distances, the X-ray spectra of these quasars were necessarily modeled using simple phenomenological parameterizations [12,14].Gravitational lensing offers a rare opportunity to study the innermost relativistic region in distant quasars [15,16], by acting as a natural telescope and magnifying the light from these sources. Quasars located between 0.5 z 1 are considerably ...

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A short review of relativistic iron lines from stellar‐mass black holes

Miller

2006

Astron Nachr

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In this contribution, I briefly review recent progress in detecting and measuring the properties of relativistic iron lines observed in stellar-mass black hole systems, and the aspects of these lines that are most relevant to studies of similar lines in Seyfert-1 AGN. In particular, the lines observed in stellar-mass black holes are not complicated by complex low-energy absorption or partial-covering of the central engine, and strong lines are largely independent of the model used to fit the underlying broad-band continuum flux. Indeed, relativistic iron lines are the most robust diagnostic of black hole spin that is presently available to observers, with specific advantages over the systematics-plagued disk continuum. If accretion onto stellar-mass black holes simply scales with mass, then the widespread nature of lines in stellar-mass black holes may indicate that lines should be common in Seyfert-1 AGN, though perhaps harder to detect.

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Revealing the Dusty Warm Absorber in MCG −6-30-15 with the [ITAL]Chandra[/ITAL] High-Energy Transmission Grating

Cited by 177 publications

References 34 publications

On the location and composition of the dust in the MCG–6-30-15 warm absorber

On the location and composition of the dust in the MCG–6-30-15 warm absorber

Reflection from the strong gravity regime in a lensed quasar at redshift z = 0.658

A short review of relativistic iron lines from stellar‐mass black holes

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