Mrk 1014: an AGN-dominated ultraluminous infrared galaxy

In this paper we report on an XMM-Newton observation of the ultraluminous infrared QSO Mrk 1014. The X-ray observation reveals a power-law-dominated (Γ~ 2.2) spectrum with a slight excess in the soft energy range. Active galactic nucleus (AGN) and starburst emission models fit the soft excess emission equally well, however, the most plausible explanation is an AGN component as the starburst model parameter, temperature and luminosity appear physically unrealistic. The mean luminosity of Mrk 1014 is about 2 × 10⁴⁴ erg s^-1. We have also observed excess emission at energies greater than 5 keV. This feature could be attributed to a broadened and redshifted iron complex, but deeper observations are required to constrain its origin. The light curve shows small-scale variability over the ~11-ks observation. There is no evidence of intrinsic absorption in Mrk 1014. The X-ray observations support the notion of an AGN-dominated central engine. We establish the need for a longer observation to constrain more precisely the nature of the X-ray components.