Enhanced X-ray Emission from the Most Radio-Powerful Quasar in the Universe’s First Billion Years
Thomas Connor, Eduardo Bañados, Daniel Stern, Chris Carilli, Andrew Fabian, Emmanuel Momjian, Sofía Rojas-Ruiz, Roberto Decarli, Emanuele Paolo Farina, Chiara Mazzucchelli, Hannah P. Earnshaw
We present deep (265 ks) Chandra X-ray observations of PSO J352.4034−15.3373, a quasar at z=5.831 that, with a radio-to-optical flux ratio of R>1000, is one of the radio-loudest quasars in the early universe and is the only quasar with observed extended radio jets of kpc-scale at z≳6. Modeling the X-ray spectrum of the quasar with a power law, we find a best fit of Γ=1.99+0.29−0.28, leading to an X-ray luminosity of L2−10=1.26+0.45−0.33×1045 erg s−1 and an X-ray to UV brightness ratio of αOX=−1.36±0.11. We identify a diffuse structure 50 kpc (∼8′′) to the NW of the quasar along the jet axis that corresponds to a 3σ enhancement in the angular density of emission and can be ruled out as a background fluctuation with a probability of P=0.9985. While with few detected photons the spectral fit of the structure is uncertain, we find that it has a luminosity of L2−10∼1044 erg s−1. These observations therefore potentially represent the most distant quasar jet yet seen in X-rays. We find no evidence for excess X-ray emission where the previously-reported radio jets are seen (which have an overall linear extent of 0.′′28), and a bright X-ray point source located along the jet axis to the SE is revealed by optical and NIR imaging to not be associated with the quasar.
Comments: 16 pages, 7 Figures. Accepted for publication the Astrophysical Journal
Subjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
Cite as: arXiv:2103.03879 [astro-ph.GA] (or arXiv:2103.03879v1 [astro-ph.GA] for this version)
Submission history
From: Thomas Connor
[v1] Fri, 5 Mar 2021 19:00:00 UTC (1,824 KB)
