Highly ionized disc and transient outflows in the Seyfert galaxy IRAS 18325–5926

Abstract

We report on strong X-ray variability and the Fe K-band spectrum of the Seyfert galaxy IRAS 18325-5926 obtained from the 2001 XMM-Newton EPIC pn observation with a duration of ∼120 ks. While the X-ray source is highly variable, the 8-10 keV band shows larger variability than that of the lower energies. Amplified 8-10 keV flux variations are associated with two prominent flares of the X-ray source during the observation. The Fe K emission is peaked at 6.6 keV with moderate broadening. It is likely to originate from a highly ionized disc with an ionization parameter of log ξ 3. The Fe K line flux responds to the main flare, which supports its disc origin. A short burst of the Fe line flux has no relation to the continuum brightness, for which we have no clear explanation. We also find transient, blueshifted Fe K absorption features that can be identified with high-velocity (∼0.2 c) outflows of highly ionized gas, as found in other active galaxies. The deepest absorption feature appears only briefly (∼1 h) at the onset of the main flare and disappears when the flare declines. The rapid evolution of the absorption spectrum makes this source peculiar among the active galaxies with high-velocity outflows. Another detection of the absorption feature also precedes the other flare. The variability of the absorption feature partly accounts for the excess variability in the 8-10 keV band where the absorption feature appears. Although no reverberation measurement is available, the black hole mass of ∼2 × 10 6 M is inferred from the X-ray variability. When this mass is assumed, the black hole is accreting at around the Eddington limit, which may fit the highly ionized disc and strong outflows observed in this galaxy.

Searching for ultra-fast outflows in AGN using variability spectra

“…IRAS 18325-5926 is studied by Iwasawa et al (2016), reporting a UFO at ∼ 0.2c, also obtained from XMM-Newton EPIC-pn, which is similar to the result obtained here of 0.15 +0.02 −0.05 c. This UFO is likely to be responding to the changes in ionization levels and flares of the source.…”

WISDOM Project – XIII. Feeding molecular gas to the supermassive black hole in the starburst AGN-host galaxy Fairall 49

“…Previous indirect estimates of 𝑀 • used empirical scaling relations. Iwasawa et al (2016) found 2 × 10 6 M from X-ray variability; this value is in strong disagreement with our value being 50 times smaller. Dasyra et al (2011) found 7×10 8 M using the velocity dispersion of narrow-line 2019) and the WISDOM papers, respectively.…”

“…Finally, Véron-Cetty & Véron (2006) gave a Sy1h classification: a Sy2 spectra that shows a Sy1 behaviour in polarized light. The X-ray emission from the AGN shows flux variability (Iwasawa et al 1995) and a broad Iron Fe k emission line (Iwasawa et al 1996(Iwasawa et al , 2016.…”

AGN Coronae through a Jet Perspective

“…& Katz (2015), 9 gas dynamics massesMarconi & Hunt (2003), 10 stellar-velocity dispersion, M-L BWoo & Urry (2002), 11 stellar-velocity dispersionPapadakis (2004), 12 X-ray scalingKara et al (2015), 13 M-L BMarchesini et al (2004), 14 M-L BMalizia et al (2008), 15 X-ray scalingIwasawa et al (2016),16 O III FWHMWandel & Mushotzky (1986), 17 X-ray scalingNardini et al (2015), 18 X-ray scalingMcHardy et al (2005), 19 M-L BPonti et al (2012), 20 gas dynamicsSchulz et al (1994), 21 velocity dispersionMarconi et al (2008), 22 X-ray scalingAlston et al (2015), 23 X-ray scalingAlston et al (2014), 24 M-L BFabian et al (2005), 25Keck et al (2015), 26Steenbrugge et al (2003), 27Gallo et al (2015), 28Brenneman & Reynolds (2009), 29Lobban et al (2016), 30Ballantyne et al (2001), 31Walton et al (2014), 32Jorstad et al (2005), 33McKernan & Yaqoob (2004), 34Giovannini et al (2001),35 Fürst et al (2016), 36 Hasenkopf et al (2002,37 Matt et al (2015),38 Rosario et al (2010), 39 Ruschel-Dutra et al (2014, 40Walton et al (2010), 41 Lanzuisi et al (2016), 42 Guainazzi et al (2016,43 Noda et al (2016),44 Zoghbi et al (2013) ,45 García et al (2014), 46 Marinucci et al (2014b, 47Marinucci et al (2014a), 48 Lohfink et al (2016,49 Fabian et al (2012), 50Guainazzi et al (1999), 51Boissay et al (2014), 52Chainakun et al (2016),53 Kara et al (2014), 54Czerny et al (2010),55 Patrick et al (2011), 56 Leighly (1999, 57Brenneman et al (2011), 58 Bennert et al (2006), 59 Agís-González et al (2014, 60 no inclination was found; we therefore used the average viewing angle from the ti...…”