Comparing reflection and absorption models for the soft X-ray variability in the NLS1 AGN UGC 11763. Issue 3 (29th August 2022)

• Record Type: Journal Article
• Authors: Jiang, Jiachen; Gallo, Luigi C; Grupe, Dirk; Parker, Michael L
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 516:Issue 3(2022)
• Page Start: 4256
• Page End: 4268
• Publication Date: 2022-08-29
• Subjects: accretion, accretion discs -- black hole physics -- galaxies: Seyfert; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stac2434
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We present a spectral analysis of two XMM–Newton observations of the narrow-line Seyfert 1 galaxy UGC 11763. UGC 11763 shows very different soft X-ray spectral shapes in the two observations separated by 12 yr. Three spectral models are considered to explain the multi-epoch X-ray variability of UGC 11763, one based on the relativistic disc reflection model, one based on multiple partially covering absorbers combined with the warm corona model, and a hybrid model. In the first model, the X-ray variability of UGC 11763 is caused by the emission from a compact coronal region with a variable size. The resulting disc reflection component changes accordingly. A warm absorption model with a modest column density is required in this model too. In the partially covering absorption scenario, the X-ray variability of UGC 11763 is caused by the variable covering factors of two absorbers located within a region of r < ≈100 r g . Moreover, the temperature and strength of the warm corona have to change significantly too to explain the variable underlying soft X-ray emission. Lastly, we investigate the possibility of variable intrinsic power-law emission from the hot corona combined with variable absorption in UGC 11763 without changing the geometry of the corona in the third model. This hybrid model provides a slightly better fit than the partially covering absorption model with improvements in fitting the iron emission band. Current CCD-resolution data cannot distinguish these spectral models for UGC 11763. Future high-resolution X-ray missions, e.g. Athena and XRISM, will test them by resolving different spectral components.