PEERING THROUGH THE DUST: NuSTAR OBSERVATIONS OF TWO FIRST-2MASS RED QUASARS

Abstract

ABSTRACT 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.