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Spectrum analysis at 3 mm of the central region (r≈800 pc) of NGC 4303 showed molecular gas lines of both dense gas tracers (HCN, HNC, HCO+, and C2H) and diffuse gases (13CO and C18O). Molecular gas parameters: H2 mass MH2=(1.75±0.32)×108M☉; radial velocity Vdense=178±60 km s-1, and VCO=151±29 km s-1; HCN luminosity LHCN=(7.38±1.40)×106 K km s-1 pc2; dense gas mass Mdense=(4.7±0.3)×107 M☉, indicating a significant contribution of dense to total molecular gas mass. To explore the AGN nature and central dusty torus of the galaxy, CIGALE was used to fit the integrated spectral energy distribution. Large torus properties are estimated: luminosity LTORUS=(7.1±2.8)×1043 erg s-1 and line of sight inclination of 67±16°, which is consistent with a Type 2 AGN; total infrared luminosity LIR=(3.51± 0.30)×1044 erg s-1; star formation rate SFR=6.0±0.3 M☉ yr-1. A marginal AGN contribution of ≈20% was found. 

ABSTRACT We present a revised analysis of the photometric reverberation mapping campaign of the narrow-line Seyfert 1 galaxy PKS 0558 − 504 carried out with the Swift Observatory during 2008–2010. Previously, Gliozzi et al. (2013) found using the Discrete Correlation Function (DCF) method that the short-wavelength continuum variations lagged behind variations at longer wavelengths, the opposite of the trend expected for thermal reprocessing of X-rays by the accretion disc, and they interpreted their results as evidence against the reprocessing model. We carried out new DCF measurements that demonstrate that the inverted lag-wavelength relationship found by Gliozzi et al. resulted from their having interchanged the order of the driving and responding light curves when measuring the lags. To determine the inter-band lags and uncertainties more accurately, we carried out new measurements with four independent methods. These give consistent results showing time delays increasing as a function of wavelength, as expected for the disc reprocessing scenario. The slope of the re-analysed delay spectrum appears to be roughly compatible with the predicted τ ∝ λ4/3 relationship for reprocessing by an optically thick and geometrically thin accretion disc, although the data points exhibit a large scatter about the fitted power-law trend.