XMM-NEWTON High resolution spectroscopy of NGC 5548

Abstract

Abstract. We analyze a 137 ks exposure X-ray spectrum of the Seyfert 1 galaxy NGC 5548 obtained with the XMM-Newton Reflection Grating Spectrometer. Due to the long exposure time, the spectrum is of higher statistical quality than the previous observations of this AGN. Therefore, we detect for the first time in NGC 5548 inner-shell transitions from O  to O  ions, and the Unresolved Transition Array of M-shell iron. The warm absorber found from this X-ray observation spans three orders of magnitude in ionization parameter. We detect O , which is as lowly ionized as the warm absorber detected in the UV band, to Fe . For O  the column density determined from our X-ray data is an order of magnitude larger than the column density measured in previous UV observations. We conclude that there is substantially more low ionized material than previously deduced from UV observations. However, only a few percent of the warm absorber detected in the X-rays is lowly ionized. A 99.9% significant increase in the derived absorbing column density with higher ionization states is observed. The outflow velocities determined from the X-ray absorption lines are consistent with those deduced from the UV lines, evidence, together with the detection of O , that the X-ray and UV warm absorber are different manifestations of the same phenomenon. From a simple mass conservation argument, we indicate that our data set is consistent with an outflow with small opening angle formed due to instabilities in the accretion disk. Possible due to uncertainties in the radiative transport mechanism, an apparent deviant iron to oxygen abundance is detected. No strong relativistically broadened emission lines of O , N  and C  were detected.

Multiwavelength campaign on Mrk 509

“…For the 40 ks RGS spectrum of NGC 3783, Blustin et al (2002) measured the abundances to be consistent with solar, with the exception of Fe. Similar abundances were measured by Steenbrugge et al (2003) for NGC 5548 using a 137 ks RGS spectrum, as well as by Blustin et al (2007) for a 160 ks RGS spectrum of NGC 7469. Holczer et al (2007) determined the abundances for IRAS 13349+2438 and NGC 3783 using the updated dielectronic recombination rates and determined abundances relative to Fe consistent with proto-solar ratios for O, Ne, Mg, Si, and S (NGC 3783 only).…”

“…For instance, Schmidt et al (2006) and Nahar et al (2009) performed detailed atomic calculations of the di-electronic recombination rates. Schmidt et al (2004) measured the wavelengths of the O v lines, after Steenbrugge et al (2003) had noted that the wavelength used for the 22 Å line was likely to be wrong. In their Appendix 1, Detmers et al (2011) list the atomic data that has been updated prior to the analysis of the RGS and LETGS spectra of Mrk 509.…”

K-shell photoionization ofO+andO2+ions: Experiment and theory

“…K-shell photoabsorption of oxygen and its ions is often responsible for prominent features in the interstellar medium (ISM) absorption spectra in the 500-600-eV photon energy range. Indeed oxygen K-shell absorption lines have been observed towards both low-mass x-ray binaries [1][2][3][4][5] and active nucleus of Seyfert galaxies [6][7][8].…”

Anatomy of the AGN in NGC 5548

“…From a dynamical modeling of the BLR (Pancoast et al 2014), it is inferred that this source is observed at an inclination angle of ∼30 • and hosts a supermassive black hole (SMBH) of ∼3 × 10 7 M in its center. Previously, high resolution UV (Crenshaw & Kraemer 1999;Crenshaw et al 2003a) and X-ray (Kaastra et al , 2002Steenbrugge et al 2003Steenbrugge et al , 2005) spectra have revealed several deep NAL that can be ascribed to a moderate velocity (v out = 200−1200 km s −1 ) ionized outflow.…”