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We present a spectral analysis of two XMM-Newton observations of thenarrow-line Seyfert 1 galaxy UGC 11763. UGC 11763 shows very different softX-ray spectral shapes in the two observations separated by 12 years. Threespectral models are considered to explain the multi-epoch X-ray variability ofUGC 11763, one based on the relativistic disc reflection model, one based onmultiple partially-covering absorbers combined with the warm corona model, anda hybrid model. In the first model, the X-ray variability of UGC 11763 iscaused by the emission from a compact coronal region with a variable size. Theresulting disc reflection component changes accordingly. A warm absorptionmodel with a modest column density is required in this model too. In thepartially-covering absorption scenario, the X-ray variability of UGC 11763 iscaused by the variable covering factors of two absorbers located within aregion of $r<\approx100r_{\rm g}$. Moreover, the temperature and strength ofthe warm corona have to change significantly too to explain the variableunderlying soft X-ray emission. Lastly, we investigate the possibility ofvariable intrinsic power-law emission from the hot corona combined withvariable absorption in UGC 11763 without changing the geometry of the corona inthe third model. This hybrid model provides a slightly better fit than thepartially-covering absorption model with improvements in fitting the ironemission band. Current CCD-resolution data cannot distinguish these spectralmodels for UGC 11763. Future high-resolution X-ray missions, e.g. Athena andXRISM, will test them by resolving different spectral components.

Comparing Reflection and Absorption Models for the Soft X-ray Variability in the NLS1 AGN UGC 11763