![]() They suppose that this source may be a standard radio-quiet quasar rather than a high-Eddington quasi-stellar object. The researchers underlined that the X-ray and optical properties of J1144 are different from many high-Eddington sources. However, the astronomers noted that If the black hole spin is relatively low, the accretion rate can even exceed the Eddington limit. The observations indicate that J1144 seems to accrete at a rate larger than 40% of the Eddington limit. According to the authors of the study, the large X-ray variability is due to intrinsic changes in the X-ray luminosity of the source accompanied with changes in the absorption in the line of sight. Moreover, the results indicate also a shorter timescale variability of the order of approximately 2.7 within 40 days. The observational campaign found that J1144 exhibits an X-ray variability by a factor of about 10 within a year. These four space observatories allowed them to gain more insights into the properties of J1144. This value, together with the high bolometric luminosity, yields an Eddington ratio at a level of 1.4 for this quasar.Ī group of astronomers led by Elias Kammoun of the University of Toulouse, France, has conducted X-ray observations of this quasar using Spektr-RG, Swift, NuSTAR and XMM-Newton space telescopes. It is estimated that the mass of the black hole in J1144 is approximately 2.6 billion solar masses. It is also the optically brightest (unbeamed) quasar at a redshift greater than 0.4. ![]() It has a bolometric luminosity of about 470 quattuordecillion erg/s, which makes it the most luminous quasar over the last 9 billion years of cosmic history. J1144 was detected in June 2022 at a redshift of 0.83. They also improved our understanding of the dynamics of supermassive black holes and the intergalactic medium. For instance, quasars have been used to investigate the large-scale structure of the universe and the era of reionization. They are among the brightest and most distant objects in the known universe, and serve as fundamental tools for numerous studies in astrophysics as well as cosmology. The Candela (cd) unit is also used for Luminous Intensity, and 1cd=1lm/sr.Quasars, or quasi-stellar objects (QSOs) are active galactic nuclei (AGN) of very high luminosity, emitting electromagnetic radiation observable in radio, infrared, visible, ultraviolet and X-ray wavelengths. The unit for Radiant Intensity is Watt/steradian (W/sr) and Luminous Intensity is Lumens/steradian (lm/sr). The coned shaped sector is known as a steradian. Now picture an imaginary sphere that surrounds the light source, and the light source is emitting a countable amount of individual rays within a small conical angle in a specific direction.īoth Radiant & Luminous Intensity represent the total amount of optical power within this coned shaped sector of the total space around the light source however Luminous Intensity factors in the human eye response. An integrating sphere is often used to collect the light emitted in all directions. The unit for Radiant Flux is watt (W), and Luminous Flux is lumen(lm). Both Radiant & Luminous Flux represent the total power of a light source however Luminous Flux factors in the human eye response. ![]() The total number of these light rays represents the total optical power (electromagnetic energy) of that light source. Imagine the rays are straight lines extending equally in every possible direction from the bulb. Radiant/Luminous Intensity is the amount of emitted optical power generated by a light source in a specific direction and conical shape angle directed toward the observer.Įxpressed in watts (radiometric flux) or lumens (luminous flux) Radiant / Luminous Fluxįor ease of understanding, picture an incandescent bulb as a light source that emits a finite amount of individual light rays. Stated briefly, Radiant/Luminous Flux represents the total emitted optical power generated by a light source that is collected and measured with no regard to the direction of the flux. ![]()
0 Comments
Leave a Reply. |