Constraining the black hole mass and accretion rate in the narrow-line Seyfert 1 RE J1034+396

We present a comprehensive study of the spectrum of the narrow-line Seyfert 1 galaxy RE J1034+396, summarizing the information obtained from the optical to X-rays with observations from the William Herschel 4.2m Telescope (WHT), the Hubble Space Telescope, the Extreme UltraViolet Explorer, ROSAT, ASCA and BeppoSAX. The BeppoSAX spectra reveal a soft component which is well-represented by two blackbodies with kT of about 60 eV and 160 eV, mimicking that expected from a hot, optically-thick accretion disc around a low-mass black hole. This is borne out by our modeling of the optical to X-ray nuclear continuum, which constrains the physical parameters of a NLS1 for the first time. The models demonstrate that RE J1034+396 is likely to be a system with a nearly edge-on accretion disk (60 to 75 degrees from the disk axis), accreting at nearly Eddington rates (0.3 to 0.7 L_edd) onto a low mass (about 2 million solar masses) black hole (abridged).