Broadband X-ray properties of Narrow-Line Seyfert 1 galaxies

We present a study of 52 Narrow-Line Seyfert 1 (NLS1) galaxies using archival data from XMM-Newton, Swift, and NuSTAR to investigate their coronal properties. The sample spans a redshift range of 0.002 < z < 0.965, black hole masses between 6 < log(M/Msolar) < 9, and bolometric luminosities from 39.5 < log(Lbol) < 45.5. We modeled the X-ray spectra using a combination of a blackbody component, ionized local absorbers, and a reflection model with an embedded cutoff power-law to extract key physical parameters. For a subset (~47 %) of observations, we obtained well-constrained coronal temperatures and high-energy cut-off values, while for the remaining observations, only lower limits could be determined. The mean coronal temperature and cutoff energy across the sample are found to be around 55 keV and 153 keV, respectively. From spectral fitting, we also derived the average photon index and optical depth to be 2.05 and 2.09, respectively. A statistically significant (Pearson's correlation coefficient 0.38 with p-value < 0.00001) positive correlation between the photon index and the Eddington ratio supports the scenario of high accretion rates in NLS1 galaxies. Moreover, the compactness-temperature diagram shows that all the sources lie away from the pair-production limit, thus indicating that corona in NLS1s are not pair dominated plasma rather normal hybrid plasma.