The team* led by Prof. Toru Misawa of the School of General Education, Shinshu University found for the first time that the internal donut-shaped structure of the central nuclei of bright galaxies in the distant universe can have an "anisotropic" effect on the gas distributed over a vast area around them.

Because luminous nuclei of distant galaxies (quasars) emit strong ultraviolet radiation, they ionize** hydrogen gas (intergalactic gas***) around them. If the quasar's UV radiation is isotropic, the "ionization level" of intergalactic gas should be almost constant regardless of the direction seen from the quasars. However, previous studies have reported that the ionization level is biased depending on the direction.

Therefore, the team investigated the origin of the anisotropic ionization level by targeting unique objects called "BAL quasars" whose direction of ultraviolet radiation can be estimated to some extent. Specifically, the team measured the ionization level of intergalactic gas in the transverse direction of a foreground BAL quasar, by observing another quasar in the background (Fig. 1).

As a result of new observations with the Subaru Telescope**** in addition to the existing data, the team have found that the donut-shaped shielding structure (dust torus) of quasars is likely to cause the anisotropy of the ionization level. The dust torus is the indispensable structure of the standard quasar model.

Thus, the above results observationally support the existence of a dust torus and suggest that its effects may extend to distant intergalactic gas. They are also important for exploring the history of ionization of the entire universe and studying the internal structure of quasars.

The results of this research were published in the academic journal "The Astrophysical Journal" (IF: 5.521) of the American Astronomical Society.

Research Report:Exploratory Study of the Transverse Proximity Effect around BAL Quasars

Related Links
Shinshu
Understanding Time and Space

Tweet

Thanks for being here; We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain. With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords. Our news coverage takes time and effort to publish 365 days a year. If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor $5 Billed Once credit card or paypal		SpaceDaily Monthly Supporter $5 Billed Monthly paypal only

Black Hole Hunters - A citizen science search for black hole self-lensing
London, UK (SPX) Jul 12, 2022
A research team from the Open University and the University of Southampton is asking for the public's help to find some of the most mysterious, elusive objects in the Universe - black holes. By examining data from the SuperWASP survey, the UK's leading extra-solar planet detection programme, the team hope to detect changes in starlight that may provide evidence for the existence of these black holes. The most massive stars explode when they get old, and what is left of the star after the explosion ... read more