NuSTAR unveils a Compton-thick Type 2 quasar in Mrk 34

摘要: We present Nustar 3-40 keV observations of the optically selected Type 2 quasar (QSO2) SDSS J1034+6001 or Mrk 34. The high-quality hard X-ray spectrum and archival XMM-Newton data can be fitted self-consistently with a reflection-dominated continuum strong Fe Kalpha fluorescence line equivalent-width >1 keV. Prior spectral fitting below 10 showed source to consistent being obscured by Compton-thin column densities gas along line-of-sight, despite evidence for much higher columns from multiwavelength data. NuSTAR now enables direct measurement this column, shows that Nh lies in Compton-thick (CT) regime. new also show high intrinsic 2-10 luminosity L_{2-10}~10^{44} erg/s, contrast previous low-energy measurements which L_{2-10}<~10^{43} erg/s (i.e. selection does not pick up as an intrinsically luminous quasar). Both obscuring power are about order magnitude (or more) larger than inferred pre-NuSTAR fitting. Mrk34 is thus 'gold standard' CT QSO2 nearest non-merging system class, other local NGC6240 currently undergoing major merger coupled star-formation. For typical bolometric correction factors, accretion enough potentially total infrared luminosity. thermal emission related star-formation unlikely drive observed bright soft component ~3 keV, favoring photionization instead.