Multiple Scattered Sight Lines to the Red QSO 2MASX J10494334+5837501

Abstract

The reddened, highly polarized QSO 2MASX J1049334+5837501 (2M 1049+5837) shows a strong IR dust signature with a spectral energy distribution peaked at ~20 μm and a luminosity of ~1011 L☉, but the active nucleus is outshone at optical wavelengths by the host galaxy. Remarkable variations with wavelength in the degree and position angle of polarization require two primary sources of scattered flux from the active nucleus. These are: (1) a reddened component with P ≥ 8% that we identify with material near the axis of a presumed obscuring dust torus in the context of orientation-dependent unification schemes for active galactic nuclei (AGNs); and (2) a faint, very blue source that is only important at λ 4500 A. The latter component is only revealed because of its extremely high polarization (P = 20%-30%) and the fact that flux from the nucleus and the scattering is nearly completely extinguished in this spectral region. High-resolution images show extensions approximately orthogonal to the two position angles of polarization. Consideration of these characteristics suggests refinements to the standard, first-order picture offered by the unified scheme for AGNs. Namely, that there can be multiple scattered sight lines within some AGNs, and that it is possible that the polar scattering lobes can provide sufficient scattering optical depth that the emergent nuclear spectrum is highly reddened. These deviations are useful in explaining the existence of highly polarized, red, type 1 AGNs that form a significant fraction of the QSOs found in near-IR surveys. Importantly, the utility of the type 1/type 2 spectral signature as an indicator of orientation becomes less effective as the dust covering factor increases and nuclear radiation is more effectively scattered into all sight lines.