Chandra X-Rays from the Redshift 7.54 Quasar ULAS J1342+0928

Eduardo Banados; Thomas Connor; Daniel Stern; John Mulchaey; Xiaohui Fan; Roberto Decarli; Emanuele P. Farina; Chiara Mazzucchelli; Bram P. Venemans; Fabian Walter; Feige Wang; Jinyi Yang

doi:10.3847/2041-8213/aab61e

Chandra X-Rays from the Redshift 7.54 Quasar ULAS J1342+0928

Eduardo Banados
, Thomas Connor
, Daniel Stern
, John Mulchaey
, Xiaohui Fan
, Roberto Decarli
, Emanuele P. Farina
, Chiara Mazzucchelli
, Bram P. Venemans
, Fabian Walter
, Feige Wang
, Jinyi Yang

Astronomy

Research output: Contribution to journal › Article › peer-review

35 Scopus citations

Abstract

We present a 45 ks Chandra observation of the quasar ULAS J1342+0928 at z = 7.54. We detect counts from the quasar in the observed-frame energy range 0.5-7.0 keV (6σ detection), representing the most distant non-transient astronomical source identified in X-rays to date. The present data are sufficient only to infer rough constraints on the spectral parameters. We find an X-ray hardness ratio of between the 0.5-2.0 keV and 2.0-7.0 keV ranges and derive a power-law photon index of . Assuming a typical value for high-redshift quasars of Γ = 1.9, ULAS J1342+0928 has a 2-10 keV rest-frame X-ray luminosity of . Its X-ray-to-optical power-law slope is , consistent with the general trend indicating that the X-ray emission in the most bolometrically powerful quasars is weaker relative to their optical emission.

Original language	English (US)
Article number	L25
Journal	Astrophysical Journal Letters
Volume	856
Issue number	2
DOIs	https://doi.org/10.3847/2041-8213/aab61e
State	Published - Apr 1 2018

Keywords

cosmology
individual (ULAS J134208.10+092838.61)
observations-early universe-quasars

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.3847/2041-8213/aab61e

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title = "Chandra X-Rays from the Redshift 7.54 Quasar ULAS J1342+0928",

abstract = "We present a 45 ks Chandra observation of the quasar ULAS J1342+0928 at z = 7.54. We detect counts from the quasar in the observed-frame energy range 0.5-7.0 keV (6σ detection), representing the most distant non-transient astronomical source identified in X-rays to date. The present data are sufficient only to infer rough constraints on the spectral parameters. We find an X-ray hardness ratio of between the 0.5-2.0 keV and 2.0-7.0 keV ranges and derive a power-law photon index of . Assuming a typical value for high-redshift quasars of Γ = 1.9, ULAS J1342+0928 has a 2-10 keV rest-frame X-ray luminosity of . Its X-ray-to-optical power-law slope is , consistent with the general trend indicating that the X-ray emission in the most bolometrically powerful quasars is weaker relative to their optical emission.",

keywords = "cosmology, individual (ULAS J134208.10+092838.61), observations-early universe-quasars",

author = "Eduardo Banados and Thomas Connor and Daniel Stern and John Mulchaey and Xiaohui Fan and Roberto Decarli and Farina, \{Emanuele P.\} and Chiara Mazzucchelli and Venemans, \{Bram P.\} and Fabian Walter and Feige Wang and Jinyi Yang",

year = "2018",

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doi = "10.3847/2041-8213/aab61e",

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T1 - Chandra X-Rays from the Redshift 7.54 Quasar ULAS J1342+0928

AU - Banados, Eduardo

AU - Connor, Thomas

AU - Stern, Daniel

AU - Mulchaey, John

AU - Fan, Xiaohui

AU - Decarli, Roberto

AU - Farina, Emanuele P.

AU - Mazzucchelli, Chiara

AU - Venemans, Bram P.

AU - Walter, Fabian

AU - Wang, Feige

AU - Yang, Jinyi

PY - 2018/4/1

Y1 - 2018/4/1

N2 - We present a 45 ks Chandra observation of the quasar ULAS J1342+0928 at z = 7.54. We detect counts from the quasar in the observed-frame energy range 0.5-7.0 keV (6σ detection), representing the most distant non-transient astronomical source identified in X-rays to date. The present data are sufficient only to infer rough constraints on the spectral parameters. We find an X-ray hardness ratio of between the 0.5-2.0 keV and 2.0-7.0 keV ranges and derive a power-law photon index of . Assuming a typical value for high-redshift quasars of Γ = 1.9, ULAS J1342+0928 has a 2-10 keV rest-frame X-ray luminosity of . Its X-ray-to-optical power-law slope is , consistent with the general trend indicating that the X-ray emission in the most bolometrically powerful quasars is weaker relative to their optical emission.

AB - We present a 45 ks Chandra observation of the quasar ULAS J1342+0928 at z = 7.54. We detect counts from the quasar in the observed-frame energy range 0.5-7.0 keV (6σ detection), representing the most distant non-transient astronomical source identified in X-rays to date. The present data are sufficient only to infer rough constraints on the spectral parameters. We find an X-ray hardness ratio of between the 0.5-2.0 keV and 2.0-7.0 keV ranges and derive a power-law photon index of . Assuming a typical value for high-redshift quasars of Γ = 1.9, ULAS J1342+0928 has a 2-10 keV rest-frame X-ray luminosity of . Its X-ray-to-optical power-law slope is , consistent with the general trend indicating that the X-ray emission in the most bolometrically powerful quasars is weaker relative to their optical emission.

KW - cosmology

KW - individual (ULAS J134208.10+092838.61)

KW - observations-early universe-quasars

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VL - 856

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JF - Astrophysical Journal Letters

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ER -

Chandra X-Rays from the Redshift 7.54 Quasar ULAS J1342+0928

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