Detection of blueshifted emission and absorption and a relativistic iron line in the X-ray spectrum of ESO 323−G077^★

Abstract

We report on the X‐ray observation of the Seyfert 1 galaxy ESO 323−G077 performed with XMM–Newton. The EPIC spectra show a complex spectrum with conspicuous absorption and emission features. The continuum emission can be modelled with a power law with an index of 1.99 ± 0.02 in the whole XMM–Newton energy band, marginally consistent with typical values of type I objects. An absorption component with an uncommonly high equivalent hydrogen column (nH= 5.82+0.12−0.11× 1022 cm−2) is affecting the soft part of the spectrum. Additionally, two warm absorption components are also present in the spectrum. The lower ionized one, mainly imprinting the soft band of the spectrum, has an ionization parameter of log U= 2.14+0.06−0.07 and an outflowing velocity of v= 3200+600−200 km s−1. Two absorption lines located at ∼6.7 and ∼7.0 keV can be modelled with the highly ionized absorber. The ionization parameter and outflowing velocity of the gas measured are log U= 3.26+0.19−0.15 and v= 1700+600−400 km s−1, respectively. Four emission lines were also detected in the soft energy band. The most likely explanation for these emission lines is that they are associated with an outflowing gas with a velocity of ∼2000 km s−1. The data suggest that the same gas which is causing the absorption could also being responsible of these emission features. Finally, the XMM–Newton spectrum shows the presence of a relativistic iron emission line likely originated in the accretion disc of a Kerr black hole with an inclination of ∼25°. We propose a model to explain the observed X‐ray properties which invokes the presence of a two‐phase outflow with cone‐like structure and a velocity of the order of 2000– 4000 km s−1. The inner layer of the cone would be less ionized, or even neutral, than the outer layer. The inclination angle of the source would be lower than the opening angle of the outflowing cone.

Evidence for ultra-fast outflows in radio-quiet AGNs

“…ESO 323-G77: the detailed XMM-Newton EPIC pn spectral analysis of this source has been published by Jiménez-Bailón et al (2008). We confirm their detection of a couple of narrow absorption features at the rest-frame energy of ∼6.7 keV and ∼7 keV ascribable to Fe XXV Heα and Fe XXVI Lyα resonant absorption.…”

X-RAY WARM ABSORPTION AND EMISSION IN THE POLAR-SCATTERED SEYFERT 1 GALAXY Mrk 704

“…They also detected an iron line with an equivalent width of 160 eV. As part of a systematic study of a sample, Jiménez-Bailón et al (2008) have studied the reflection grating spectrometer (RGS) spectra of Mrk 704 obtained from a short (∼25 ks) XMMNewton observation and found two distinct components of warm absorbers. Here, we perform a detailed X-ray spectral study of Mrk 704, both medium and high resolutions, based on a long ∼100 ks XMM-Newton observation.…”

A CORRELATION BETWEEN THE HIGHEST ENERGY COSMIC RAYS AND NEARBY ACTIVE GALACTIC NUCLEI DETECTED BYFERMI

“…Given the available information on these AGNs, our analysis suggests that Centaurus A is the primary candidate for the production site of several UHECRs observed in the direction of its group of galaxies. We note that ESO 323−G77 shows evidence of the presence of a relativistically broadened Fe Kα (Jiménez-Bailón et al 2008), which suggests that the supermassive black hole in this galaxy could be rapidly spinning, with the Kerr black hole being a potential UHECR accelerator (Boldt & Ghosh 1999;van Putten 2008;Dermer & Menon 2009). …”

“…NGC 4945 is classified as either a starburst galaxy or an obscured Seyfert 2 nucleus showing no signs of the presence of relativistic outflows (e.g., Spoon et al 2000;Chou et al 2007), while ESO 323−G77 is a Seyfert 1 galaxy that displays evidence for the presence of a mildly relativistic outflow in its X-ray spectrum (Jiménez-Bailón et al 2008). We have to be careful when associating these galaxies with the nearby PAO events since neither of them display powerful outflows or are energetically impressive (but see Boldt & Ghosh 1999;Pe'Er et al 2009).…”