2019ApJ...884..166S -
Astrophys. J., 884, 166-166 (2019/October-3)
First hard X-ray observation of a compact symmetric object: a broadband X-ray study of a radio galaxy OQ+208 with NuSTAR and Chandra.
SOBOLEWSKA M., SIEMIGINOWSKA A., GUAINAZZI M., HARDCASTLE M., MIGLIORI G., OSTORERO L. and STAWARZ L.
Abstract (from CDS):
Compact symmetric objects (CSOs) have been observed with Chandra and XMM-Newton to gain insights into the initial stages of a radio source evolution and to probe the black hole activity at the time of relativistic outflow formation. However, there have been no CSO observations to date at the hard X-ray energies (>10 keV), impeding our ability to robustly constrain the properties of the intrinsic X-ray emission and of the medium surrounding the young expanding jets. We present the first hard X-ray observation of a CSO performed with the Nuclear Spectroscopic Telescope Array (NuSTAR). Our target, OQ +208, is detected up to 30 keV, and thus we establish CSOs as a new class of the NuSTAR sources. We analyze the NuSTAR data jointly with our new Chandra and archival XMM-Newton data and find that a young (∼250 yr old) radio jet spanning the length of 10 pc coexists with cold obscuring matter, consistent with a dusty torus, with an equivalent hydrogen column density of NH = 1023-1024 cm–2. The primary X-ray emission is characterized by a photon index of Γ ∼ 1.45 and an intrinsic 0.5-30 keV luminosity of L ≃ 1043 erg s–1. The results of our spectral modeling and broad-line optical classification of the source suggest a porous structure of the obscuring torus. Alternatively, the source may belong to the class of optically unobscured/X-ray-obscured active galactic nucleus. The observed X-ray emission is too weak compared to that predicted by the expanding radio lobes model, leaving an accretion disk corona or jets as the possible origins of the X-ray emission from this young radio galaxy.
Abstract Copyright:
© 2019. The American Astronomical Society. All rights reserved.
Journal keyword(s):
galaxies: active - galaxies: evolution - galaxies: jets - X-rays: galaxies
Simbad objects:
2
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