Through their research study of radiation produced by supermassive great voids in quasars, researchers discovered that spectral energy circulation is not affected by a quasar’s intrinsic brightness, challenging recognized beliefs. Their research study shows that the basic accretion disk theory might not totally represent observed phenomena, stressing the possible function of accretion disk winds.
Astronomers have actually found that a quasar’s spectral energy circulation isn’t impacted by its brightness, challenging standard theories and stressing the function of accretion disk winds.
Associate Professor Zhenyi Cai and Professor Junxian Wang from the Department of Astronomy at the University of Science and Technology of China (USTC) of the Chinese Academy of Sciences (CAS), through the research study of the optical to severe ultraviolet radiation created by the accretion of supermassive great voids at the centers of quasars, have actually found that their spectral energy circulation is independent to the intrinsic brightness of quasars, reversing the standard understanding in this field.
Furthermore, their research study reveals a significant departure of the typical severe ultraviolet spectral energy circulation of quasars from the forecasts of the classical accretion disk theory. This discovery challenges the classical design and supplies significant assistance for designs that integrate prevalent accretion disk winds. The outcomes were released online on October 5, 2023, in Nature Astronomy
Figure 1: Artist’s illustration of a supermassive great void accreting gas and shining in the accretion disc. Credit: NASA/JPL-Caltech
Quasar Background
Quasars are a class of exceptionally intense extragalactic things where huge supermassive great voids at their centers continually feast on the gas in the core areas of their host galaxies. The enormous gravitational possible energy is launched on the accretion disk formed by the gas, transforming it into thermal energy and electro-magnetic radiation, leading to an unusually intense nucleus of the galaxy. Quasars are likewise described as “cosmic behemoths” due to their remarkably high intrinsic luminosity.
According to the basic accretion disk theory, accretion disks produce the widely known “big blue bump” in the spectral energy circulation, with the peak anticipated in the severe ultraviolet. The bigger the main < period class ="glossaryLink" aria-describedby ="tt" data-cmtooltip ="<div class=glossaryItemTitle>black hole</div><div class=glossaryItemBody>A black hole is a place in space where the gravitational field is so strong that not even light can escape it. Astronomers classify black holes into three categories by size: miniature, stellar, and supermassive black holes. Miniature black holes could have a mass smaller than our Sun and supermassive black holes could have a mass equivalent to billions of our Sun.</div>" data-gt-translate-attributes="[{"attribute":"data-cmtooltip", "format":"html"}]" > great void‘s mass, the lower the anticipated temperature level of the accretion disk, and the softer the severe ultraviolet spectrum. Observations have actually exposed that more luminescent quasars( with bigger supermassive great void masses) display fairly weaker emission lines( described by softer severe ultraviolet spectra), called the well-knownBaldwinEffect, which seems constant with the classical accretion disk design.
Figure 2:The ultraviolet spectral energy circulation slope of quasars (best axis, hollow information points) is independent of intrinsic brightness, which can not describe theBaldwin result( left axis, strong information points).Credit:University ofScience andTechnology ofChina
ChallengingClassicalTheories
AssociateProfessorZhenyi Cai andProfessorJunxian(****************************************************************************************************************************************** )’s research study focuses straight on the optical-to-ultraviolet spectral energy circulation of big sample quasars.(********************************************************************************************************************************************** )research study makes use of observational information from the ground-based SDSS and space-based GALEX, managing for the incompleteness of the ultraviolet detection.
(******** )They discovered that the typical ultraviolet spectral energy circulation of quasars does not depend upon their intrinsic brightness, which not just recommends that distinctions in intrinsic brightness can not describe the Baldwin result however likewise challenges the forecasts of basic accretion disk theory.
At the very same time, the scientists propose a possible brand-new physical origin for theBaldwin result: more luminescent quasars have weaker accretion disk temperature level changes, hence not able to release more emission line clouds.
Figure 3:Average intrinsic optical-to-ultraviolet spectral energy circulation of quasars( red information points), substantially softer than the basic accretion disk forecasts( left panel), however constant with disk wind design forecasts( best panel).Credit:University ofScience andTechnology ofChina
Proposing aNewModel
In addition, the research study fixes for the results of intergalactic medium absorption and discovers that the typical severe ultraviolet spectrum of quasars is softer than all previous research study outcomes.(********************************************************************************************************************************************** )disparity postures a substantial difficulty to the basic accretion disk design however lines up well with forecasts from the design including an accretion disk wind, recommending the frequency of disk winds in quasars.
(************************************************************************************************************************************************** )outcomes of this research study have broad ramifications for a much deeper understanding of different elements of supermassive great void accretion physics, great void mass development, cosmic reionization, the origin of broad-line areas, severe ultraviolet dust termination, and more.In the future, satellite tasks with ultraviolet detection abilities, such as theChineseSpaceStationTelescope( CSST), will considerably boost our understanding of the physical homes of quasars and comparable celestial things.
Reference:“A universal average spectral energy distribution for quasars from the optical to the extreme ultraviolet” by Zhen-Yi Cai, andJun-Xian Wang, 5October 2023,NatureAstronomy
DOI:101038/ s41550-023-02088 -5
