Peering Through the Dust: NuSTAR Observations of Two FIRST-2MASS Red Quasars

Some reddened quasars appear to be transitional objects in the paradigm of merger-induced black hole growth/galaxy evolution, where a heavily obscured nucleus starts to be unveiled by powerful quasar winds evacuating the surrounding cocoon of dust and gas. Hard X-ray observations are able to peer through this gas and dust, revealing the properties of circumnuclear obscuration. Here, we present NuSTAR and XMM-Newton/Chandra observations of FIRST-2MASS-selected red quasars F2M 0830+3759 and F2M 1227+3214. We find that though F2M 0830+3759 is moderately obscured (N_H,Z = (2.1 ± 0.2) × 10²² cm^-2) and F2M 1227+3214 is mildly absorbed ({N}_{{H},{{Z}}}={3.4}_-0.7^+0.8× {10}²¹ cm^-2) along the line of sight, heavier global obscuration may be present in both sources, with {N}_{{H},{{S}}}={3.7}_-2.6^+4.1× {10}²³ cm^-2 and <5.5 × 10²³ cm^-2 for F2M 0830+3759 and F2M 1227+3214, respectively. F2M 0830+3759 also has an excess of soft X-ray emission below 1 keV, which is well accommodated by a model where 7% of the intrinsic X-ray emission from the active galactic nucleus (AGN) is scattered into the line of sight. While F2M 1227+3214 has a dust-to-gas ratio (E(B - V)/N_H) consistent with the Galactic value, the value of E(B - V)/N_H for F2M 0830+3759 is lower than the Galactic standard, consistent with the paradigm that the dust resides on galactic scales while the X-ray reprocessing gas originates within the dust sublimation zone of the broad-line region. The X-ray and 6.1 μm luminosities of these red quasars are consistent with the empirical relations derived for high-luminosity, unobscured quasars, extending the parameter space of obscured AGNs previously observed by NuSTAR to higher luminosities.