Multiwavelength campaign on Mrk 509

Abstract

Context. We report on a detailed study of the Fe K emission/absorption complex in the nearby, bright Seyfert 1 galaxy Mrk 509. The study is part of an extensive XMM-Newton monitoring consisting of 10 pointings (∼60 ks each) about once every 4 days, and includes a reanalysis of previous XMM-Newton and Chandra observations. Aims. We aim at understanding the origin and location of the Fe K emission and absorption regions. Methods. We combine the results of time-resolved spectral analysis on both short and long time-scales including model-independent rms spectra. Results. Mrk 509 shows a clear (EW = 58±4 eV) neutral Fe Kα emission line that can be decomposed into a narrow (σ = 0.027 keV) component (found in the Chandra HETG data) plus a resolved (σ = 0.22 keV) component. We find the first successful measurement of a linear correlation between the intensity of the resolved line component and the 3-10 keV flux variations on time scales of years down to a few days. The Fe Kα reverberates the hard X-ray continuum without any measurable lag, suggesting that the region producing the resolved Fe Kα component is located within a few light days to a week (r < ∼ 10 3 r g ) from the black hole (BH). The lack of a redshifted wing in the line poses a lower limit of ≥40 r g for its distance from the BH. The Fe Kα could thus be emitted from the inner regions of the BLR, i.e. within the ∼80 light days indicated by the Hβ line measurements. In addition to these two neutral Fe Kα components, we confirm the detection of weak (EW ∼ 8-20 eV) ionised Fe K emission. This ionised line can be modelled with either a blend of two narrow Fe xxv and Fe xxvi emission lines (possibly produced by scattering from distant material) or with a single relativistic line produced, in an ionised disc, down to a few r g from the BH. In the latter interpretation, the presence of an ionised standard α-disc, down to a few r g , is consistent with the source high Eddington ratio. Finally, we observe a weakening/disappearing of the mediumand high-velocity high-ionisation Fe K wind features found in previous XMM-Newton observations. Conclusions. This campaign has made the first reverberation measurement of the resolved component of the Fe Kα line possible, from which we can infer a location for the bulk of its emission at a distance of r ∼ 40-1000 r g from the BH.

Multiwavelength campaign on Mrk 509

“…The lack of a similar absorption line during the non-simultaneous Suzaku campaign was interpreted by Ponti et al (2009) as being due to intrinsic variability in the absorber properties. Moreover, the stacked XMM-Newton pn spectrum from the deep exposure taken in 2009 does not show any significant (>3σ) evidence of ultra-fast outflows in the Fe-K band (Ponti et al 2013).…”

“…Yaqoob & Padmanabhan (2004) detected a narrow iron line in a shorter, 59 ks HETGS spectrum taken in 2001. The analysis of the XMM-Newton pn spectrum (Ponti et al 2013) shows that the neutral Fe-K emission line has two components: a narrow component that remains constant in flux over time, and a broader component with a constant equivalent width from days to years timescales. In addition, the XMM-Newton spectrum shows excess flux between 6.7-7.0 keV that can be modelled well with two different models: a weak relativistically broadened emission line or weak highly-ionised line emission from H-like or He-like iron, possibly produced by scattering from distant material.…”

Multiwavelength campaign on Mrk 509

“…The soft-excess was first identified in this object thanks to HEAO1-A2 (Singh et al 1985); the iron line was detected for the first time in 1987 with EXOSAT (Morini et al 1987), and the reflection component was initially revealed by Ginga (Pounds et al 1994). EPIC data from XMM-Newton observations (in 2000, 2001, 2005, and 2006) show evidence of a complex Fe K emission line, with a narrow and a neutral component possibly produced far from the source, plus a broad and variable component possibly originating in the accretion disk (Pounds et al 2001;Page et al 2003;Ponti et al 2009Ponti et al , 2013. Using XMM-Newton observations of Mrk 509, Cappi et al (2009) detected the presence of lines, at ∼8-8.5 keV and ∼9.7 keV, consistent with being produced by Fe Kα and Kβ shell absorptions associated with mildly relativistic and variable outflow.…”

“…In Mrk 509, the complex iron line at ∼6.4 keV is decomposed into a narrow line, which is constant on a several-year time scale, probably originating in remote neutral material (see De Rosa et al 2004;Ponti et al 2009Ponti et al , 2013) and a resolved component, varying with the continuum on a time scale of a few days , which is most probably produced in the broad line region or outer disk. The ionized FeK line (6.7-6.97 keV) might be produced in the inner accretion disk.…”

“…Since the ionization parameter required by the reflection component to fit the soft-excess is low, it cannot produce the (possibly relativistic) Fe XXV and Fe XXVI lines observed in Ponti et al (2013). Instead it will contribute to the low ionization emission of the Fe Kα line at 6.4 keV.…”