1 / 21

Multi-epoch X-ray observations of Seyfert 1 galaxies

Multi-epoch X-ray observations of Seyfert 1 galaxies. Luigi Gallo Saint Mary’s University. Thanks to a long list of collaborators!. Case 1: 1H0707-495. 2000 XMM-Newton, Boller et al (2002). First discovery of a sharp spectral drop in a NLS1. Several models to describe the

alicen
Download Presentation

Multi-epoch X-ray observations of Seyfert 1 galaxies

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Multi-epoch X-ray observations of Seyfert 1 galaxies Luigi Gallo Saint Mary’s University Thanks to a long list of collaborators! Luigi Gallo

  2. Case 1: 1H0707-495 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. Luigi Gallo

  3. 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 Luigi Gallo

  4. 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 Luigi Gallo

  5. 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 Luigi Gallo

  6. 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. Luigi Gallo

  7. 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 Luigi Gallo

  8. 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 Luigi Gallo

  9. 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 Luigi Gallo

  10. 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 Luigi Gallo

  11. 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 Luigi Gallo

  12. 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 Luigi Gallo

  13. Re-examining the Fe line in 2002 Luigi Gallo

  14. Re-examining the Fe line in 2002 Luigi Gallo

  15. 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 Luigi Gallo

  16. Distinct modes of variability (Gallo et al. 2007b) post-dip pre-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 Luigi Gallo

  17. 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 Luigi Gallo

  18. 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! Luigi Gallo

  19. Luigi Gallo

  20. Luigi Gallo

  21. Summary 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! Luigi Gallo

More Related