text: 273,117,1447618499656966148,3422471637,Elias Kammoun,"#new_paper Check out our paper where we present a new model of the Optical/UV/X-ray spectral energy distribution of AGN, within the context of thermal reverberation. The model adopts an iterative interaction between the disc and the corona (<LINK>) 1/n <LINK> In this context, part of the X-rays irradiating the accretion disc will be emitted as an X-ray reflection. The other part will be absorbed by the disc and re-emitted in the form of thermal radiation with a certain time delay. 2/n We assume the presence of two coronæ, located above and below the disc, responsible of this radiation. We also assume that below a given transition radius (rtrans) all the accretion disc power is transferred to the corona. The transferred fraction is set by the BH spin. 3/n <LINK> We explored the effects of various parameter on the SED: spin, accretion rate, corona height, transferred power, inclination, etc. The model conserves the energy and the number of photons in the disc-corona system. Here's an example of the effect of the corona height 4/n <LINK> Finally, we applied the model to the average broadband SED of NGC 5548. 5/n <LINK> We combined the results of the SED fitting to the ones from time-lag analysis (<LINK>). We confirmed that the BH in NGC 5548 is rapidly spinning. The model calculates a posteriori the size of the corona for a given accretion rate, height, and X-ray spectrum 6/n <LINK> Final remark: this model cannot be applied to any simultaneous Optical/UV/X-ray SED. The observed optical/UV spectra are the response of the X-ray activity hours and days before the time of the observations (depending on the time lags). 7/n Final remark Cont'd:Thus, applying the model to observations that are shorter than the time delays may lead to erroneous results. n/n @lmallick_astro It is indeed.. it was kind of surprising when we found out this.",https://arxiv.org/abs/2110.01249,"We develop a new physical model for the broadband spectral energy distribution (SED) of X-ray illuminated accretion discs, that takes into account the mutual interaction of the accretion disc and the X-ray corona, including all relativistic effects. We assume a Keplerian, optically thick and geometrically thin accretion disc and an X-ray source in the lamp-post geometry that emits an isotropic power-law spectrum with a high-energy cut-off. We assume that all the energy that would be released by thermal radiation in the standard disc model in its innermost part, is transported to the corona, effectively cooling the disc in this region. We include the disc heating due to thermalisation of the absorbed part of the disc illumination by X-ray corona. The X-ray reflection from the disc is also included. We compute the X-ray luminosity and the low-energy X-ray cut-off through an iterative process, taking full account of the interplay between the X-ray illumination of the disc and the resulting accretion disc spectrum which enters the corona so that the energy balance is preserved. The corona radius is also computed from the conservation of the photon's number during Comptonization. We discuss the model SEDs and their dependence on system parameters. The disc-corona interaction has profound effects - it constrains the X-ray luminosity and changes the shape and normalisation of the UV/optical blue bump. We use the new code to fit the broad-band SED of a typical Seyfert 1 galaxy, NGC 5548. We infer a high black-hole spin, an intermediate system inclination, and an accretion rate below 10% of Eddington. The X-ray luminosity in this source could be supported by 45-70% of the accretion energy dissipated in the disc. The new model, named KYNSED, is publicly available to be used for fitting AGN SEDs inside the XSPEC spectral analysis tool. ","A physical model for the broadband energy spectrum of X-ray illuminated