* Astronomy

Title: Discovery of the Most-Distant Double-Peaked Emitter at z=1.369
Authors: B. Luo, W. N. Brandt, J. D. Silverman, I. V. Strateva, F. E. Bauer, P. Capak, J. Kartaltepe, B. D. Lehmer, V. Mainieri, M. Salvato, G. Szokoly, D. P. Schneider, C. Vignali

We report the discovery of the most-distant double-peaked emitter, CXOECDFS J033115.0-275518, at z=1.369. A Keck/DEIMOS spectrum shows a clearly double-peaked broad Mg II \lambda2799 emission line, with FWHM 11000 km/s for the line complex. The line profile can be well fit by an elliptical relativistic Keplerian disk model. This is one of a handful of double-peaked emitters known to be a luminous quasar, with excellent multiwavelength coverage and a high-quality X-ray spectrum. CXOECDFS J033115.0-275518 is a radio-loud quasar with two radio lobes (FR II morphology) and a radio loudness of f_{5 GHz}/f_{4400 \AA}~429. The X-ray spectrum can be modelled by a power law with photon index 1.72 and no intrinsic absorption; the rest-frame 0.5-8.0 keV luminosity is 5.0 x 10^{44} erg/s. The spectral energy distribution (SED) of CXOECDFS J033115.0-275518 has a shape typical for radio-loud quasars and double-peaked emitters at lower redshift. The local viscous energy released from the line-emitting region of the accretion disk is probably insufficient to power the observed line flux, and external illumination of the disk appears to be required. The presence of a big blue bump in the SED along with the unexceptional X-ray spectrum suggest that the illumination cannot arise from a radiatively inefficient accretion flow.

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