RE J1034+396 (z = 0.0433), as a Narrow Line Seyfert 1 galaxy (NLS1), is the first source which unquestionably shows the Quasi-Periodic Oscillations (QPO) in the X-ray emission with the period of 2.7 × 10−4 Hz, which hosts a Black Hole in the center of active galactic nuclei (AGN). The measurement of the black hole mass is extremely important for the studies of the individual objects in many perspectives. The ratio of the luminosity to the Eddington luminosity is a key parameter determining the properties of the type 1 unobscured AGN, while the Eddington luminosity is defined based on the black hole mass. Moreover, in cosmology, the determination of the black hole mass range as a function of redshift puts strong constraints on the galaxy evolution, i.e., if the massive black holes come from the galaxies merger or accretion of the intergalactic medium (IGM).
However, the black hole mass of RE J1034+396 is still not well constrained. In recent study by Czerny, B. and collaborators from the Copernicus Astronomical Center in Poland and Key Laboratory for Particle Astrophysics in China, the black hole mass is measured with a number of different ways, namely X-ray variability, optical reverberation method, stellar dispersion, broad band spectrum fitting and low/high frequency QPO. It turns out that the black hole mass is in more acceptable range of 4.4 × 105 to 8.8 × 106 solar mass, which may imply that the black hole in RE J1034+396 is still at the stage of rapid black hole growth. In addition, the optical/ultraviolet observed spectrum is found to be strongly dominated by the starlight emission from the host galaxy in which consists of young population (~ 100 million years) and old population (~ 5 - 10 billion years) of stars.
Figure: The summary of various determinations of the black hole mass in RE J1034+396.Article: “The summary of various determinations of the black hole mass in RE J1034+396”, Czerny, B.; You, B.; Kurcz, A.; Sredzinska, J.; Hryniewicz, K.; Nikolajuk, M.; Krupa, M.; Wang, J.-M.; Hu, C., which is submitted to Astronomy & Astrophysics, arXiv:1601.0
