X-ray Properties of Young Radio Quasars at z > 4.5. (arXiv:2007.01342v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Snios_B/0/1/0/all/0/1">Bradford Snios</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Siemiginowska_A/0/1/0/all/0/1">Aneta Siemiginowska</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sobolewska_M/0/1/0/all/0/1">Małgosia Sobolewska</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cheung_C/0/1/0/all/0/1">C. C. Cheung</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kashyap_V/0/1/0/all/0/1">Vinay Kashyap</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Migliori_G/0/1/0/all/0/1">Giulia Migliori</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schwartz_D/0/1/0/all/0/1">Daniel A. Schwartz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stawarz_L/0/1/0/all/0/1">Łukasz Stawarz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Worrall_D/0/1/0/all/0/1">Diana M. Worrall</a>
We present a comprehensive analysis of Chandra X-ray observations of 15 young
radio quasars at redshifts $4.5 < z < 5.0$. All sources are detected in the
$0.5-7.0$ keV energy band. Emission spectra are extracted, and the average
photon index for the sample is measured to be $1.5pm0.1$. Unabsorbed
rest-frame $2-10$ keV luminosities are found to range between $(0.5-23.2)
times 10^{45}$ erg s$^{-1}$. The optical-X-ray power-law spectral index
$alpha_{ox}$ is calculated for each source using optical/UV data available in
the literature. The $alpha_{ox}$-UV relationship is compared with other quasar
surveys, and an anti-correlation is observed that agrees with independent
estimates. Rest-frame radio and X-ray luminosities are established for the
sample, and a correlation between the luminosities is detected. These
multiwavelength results reinforce a lack of spectral evolution for quasars over
a broad redshift range. We additionally identify three quasars from our
multiwavelength analysis that are statistically significant outliers, with one
source being a Compton-thick candidate in the early Universe, and discuss each
in detail.
We present a comprehensive analysis of Chandra X-ray observations of 15 young
radio quasars at redshifts $4.5 < z < 5.0$. All sources are detected in the
$0.5-7.0$ keV energy band. Emission spectra are extracted, and the average
photon index for the sample is measured to be $1.5pm0.1$. Unabsorbed
rest-frame $2-10$ keV luminosities are found to range between $(0.5-23.2)
times 10^{45}$ erg s$^{-1}$. The optical-X-ray power-law spectral index
$alpha_{ox}$ is calculated for each source using optical/UV data available in
the literature. The $alpha_{ox}$-UV relationship is compared with other quasar
surveys, and an anti-correlation is observed that agrees with independent
estimates. Rest-frame radio and X-ray luminosities are established for the
sample, and a correlation between the luminosities is detected. These
multiwavelength results reinforce a lack of spectral evolution for quasars over
a broad redshift range. We additionally identify three quasars from our
multiwavelength analysis that are statistically significant outliers, with one
source being a Compton-thick candidate in the early Universe, and discuss each
in detail.
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