Distant quasar J0439+1634 explored in X-rays

Using ESA’s XMM-Newton spacecraft, a global staff of astronomers has performed X-ray observations of probably the most distant identified gravitationally lensed quasar—J0439+1634. Results of the research, revealed December 20 on the arXiv pre-print server, shed extra gentle on the properties of this supply.

Quasars, or quasi-stellar objects (QSOs), are extraordinarily luminous active galactic nuclei (AGN) containing supermassive central black holes with accretion disks. Their redshifts are measured from the sturdy spectral traces that dominate their seen and ultraviolet spectra.

Astronomers are particularly focused on finding out high-redshift quasars (at redshift larger than 5.0) as they’re probably the most luminous and most distant compact objects within the observable universe. Spectra of such QSOs can be utilized to estimate the mass of supermassive black holes that constrain the evolution and formation fashions of quasars. Therefore, high-redshift quasars may function a robust device to probe the early universe.

At a redshift of 6.52, J0439+1634 the primary identified gravitationally lensed high-redshift quasar. Its excessive lensing magnification makes it a wonderful goal for the research of X-ray emission from a reionization-era QSO that’s intrinsically much less luminous.

J0439+1634 can also be the so-called broad absorption line (BAL) quasar. In common, BAL quasars are assumed to be extremely absorbed within the delicate X-ray band and are typically X-ray weak in observations of low-redshift quasars. However, to this point no such research of high-redshift BAL QSOs have been carried out, resulting from their faint X-ray emission.

So a staff of researchers led by Jinyi Yang of the University of Arizona determined to discover J0439+1634 with the European Photon Imaging Camera (EPIC) system onboard XMM-Newton. They investigated the X-ray properties of this supply by spectral evaluation and in contrast the outcomes with different quasar populations.

J0439+1634 was recognized as an X-ray supply with XMM-Newton within the 0.5–10 keV band by all three EPIC cameras, whereas it was not detected within the 0.2–0.5 keV band. The EPIC spectra present that the quasar has a flat photon index—at a degree of roughly 1.45.

The observations discovered that the optical-to-X-ray spectral slope of J0439+1634 is about −2.07 suggesting that this quasar is underluminous by an element of 18 in X-rays, which is in line with the habits of BAL QSOs noticed at decrease redshift. The astronomers famous that their research marks the primary time when an X-ray weak BAL quasar at a redshift of above 6.0 has been noticed spectroscopically.

Furthermore, spectral becoming utilizing an absorbed power-law mannequin suggests a excessive intrinsic column density within the case of J0439+1634—greater than 200 sextillion cm^-2. This discovering, in accordance with the researchers, means that J0439+1634 is the primary extremely obscured quasar with X-ray spectroscopy within the reionization epoch. They assume that this supply could possibly be an intrinsically X-ray weak quasar.

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