Multi-epoch X-ray observations of Seyfert 1 galaxies Luigi Gallo Saint Mary’s University Thanks to a long list of collaborators! The X-ray Universe Granada, 27 May 2008 Luigi Gallo

Case 1: 1H0707-495 First discovery of a sharp spectral drop in a NLS1. 2000 XMM-Newton, Boller et al (2002) First discovery of a sharp spectral drop in a NLS1. Several models to describe the single-epoch spectra (Boller et al. 2002; Fabian et al. 2002; Tanaka et al 2004; Done et al. 2008; Sobolewska & Done 2008…..) More information is needed. The X-ray Universe Granada, 27 May 2008 Luigi Gallo

Drop structure changes within 2 years Case 1: 1H0707-495 Gallo et al. (2004) Drop structure changes within 2 years Can still be described by multiple models but becomes more challenging (Gallo et al. 2004; Fabian et al. 2004) 2002 2000 The X-ray Universe Granada, 27 May 2008 Luigi Gallo

Case 1: 1H0707-495 2007 observations < 2 days Drop structure changes on scales of at least 2 days! Drop depth appears to depend on continuum flux. ~ 30 days ~ 15 days The X-ray Universe Granada, 27 May 2008 Luigi Gallo

Level of complexity depends on X-ray weakness Gallo 2006 Strateva et al. (2005) aox-Luv relation No 2-10 keV complexity (i.e. power law) 2-10 keV complexity Need to catch objects in low-X-ray flux state The X-ray Universe Granada, 27 May 2008 Luigi Gallo

1H0707-495: Recap -- New data shows that the drop structure is changing on rapid time scales (days). Starts to challenge some models. -- Several models can describe single-epoch observations. With more data, these models can be scrutinized better and probably eliminated. The X-ray Universe Granada, 27 May 2008 Luigi Gallo

Case 2: I Zw 1 (pre XMM) “modest” variability -- steep spectrum (~2.4), but weak soft excess -- notable intrinsic cold absorption -- strong, broad and ionised Fe K emission The X-ray Universe Granada, 27 May 2008 Luigi Gallo

2002 XMM-Newton observations Case 2: I Zw 1 2002 XMM-Newton observations (Gallo et al. 2004) -- steep spectrum -- weak soft excess -- intrinsic neutral (5-101020 cm-2) and ionised absorption -- broad, ionised Fe K emission The X-ray Universe Granada, 27 May 2008 Luigi Gallo

2002 XMM-Newton observations Case 2: I Zw 1 2002 XMM-Newton observations (Gallo et al. 2004) -- steep spectrum -- weak soft excess -- intrinsic neutral (5-101020 cm-2) and ionised absorption -- broad, ionised Fe K emission -- multiple emission lines? -- narrow 6.4 keV (from torus?) plus broad-ish, ionised line The X-ray Universe Granada, 27 May 2008 Luigi Gallo

2002 XMM-Newton observations Case 2: I Zw 1 2002 XMM-Newton observations (Gallo et al. 2004) -- modest amplitude flare concentrated at high energies -- spectral variability due to power law normalisation fluctuations The X-ray Universe Granada, 27 May 2008 Luigi Gallo

2005 XMM-Newton observation Average spectral properties (Gallo et al. 2007a) 2005 spectrum -- flux diminished since 2002 -- steep spectrum (as always) -- intensity of soft excess increases -- intrinsic neutral absorption diminishes (1.51020 cm-2) -- changes in the ionised absorber (see Costantini et al. 2007) -- broad, ionised Fe K emission seems unchanged -- likely emitted from ~ 20-60 rg -- no 6.4 keV emission line 2002 2005 The X-ray Universe Granada, 27 May 2008 Luigi Gallo

2005 XMM-Newton observation Average spectral properties (Gallo et al. 2007a) 2005 2002 2005  the same 2-component model fits mean continuum in 2002 and 2005 well, but requires different relative contributions to the 0.3-10 keV band The X-ray Universe Granada, 27 May 2008 Luigi Gallo

Re-examining the Fe line in 2002 The X-ray Universe Granada, 27 May 2008 Luigi Gallo

Re-examining the Fe line in 2002 The X-ray Universe Granada, 27 May 2008 Luigi Gallo

Re-examining the Fe line in 2002 Black: 2-12 keV continuum -- ionised line does not respond to hard continuum flare -- redder component arises during the flare The X-ray Universe Granada, 27 May 2008 Luigi Gallo

Distinct modes of variability (Gallo et al. 2007b) pre-dip post-dip flux-correlated spectral variability change in ff-plot pre-dip spectral hardening onset of hard X-ray lag rms changes pre- and post-dip  pre-dip: variability from changes in spectral shape post-dip: variability from changes in normalisation The X-ray Universe Granada, 27 May 2008 Luigi Gallo

I Zw 1: Recap -- mean spectrum at two epochs separated by 3 years can be described by a 2-component model (modified by a warm absorber) -- broad, ionised Fe K originates from ~ 40 rg -- transient Fe K emission originates much closer and its flux is correlated with a hard X-ray flare -- change in the mode of variability occurs on dynamical timescales The X-ray Universe Granada, 27 May 2008 Luigi Gallo

Thank you! Why do we need multi-epoch observations of AGN? * multi-epoch observations are necessary to understand the whole story - what is changing? - how fast are things changing? - accurately constrain what is NOT changing (e.g. inclination, abundances) * catching AGN/NLS1 in a low X-ray flux state reveals the nature of the complexity --> can potentially distinguish absorption/reflection Thank you! The X-ray Universe Granada, 27 May 2008 Luigi Gallo

The X-ray Universe Granada, 27 May 2008 Luigi Gallo

The X-ray Universe Granada, 27 May 2008 Luigi Gallo

Summary Thank you! Multi-epoch observations of AGN are needed to constrain the physics in the X-ray region 1H0707-495: new data shows variations in the drop structure on much more rapid times scales then previously seen (in progress….) I Zw 1: both observations “may” be understood if the corona exists in two states: (1) one centrally located and rapidly variable (2) the other: more constant and distant -- several other objects not discussed, come see me if interested (e.g. Mrk 335, IRAS13224-3809, UGC 3973) Thank you! The X-ray Universe Granada, 27 May 2008 Luigi Gallo