分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： Inflows at the dusty torus and smaller scales is crucial to investigate the process of supermassive black hole accretion. However, only few cases of inflowing gas at small scales have been reported through redshifted broad absorption lines so far. Here we report 9 redshifted narrow absorption lines (NALs) of \rm Mg^+ ions with inflowing speeds of 1071 -- 1979 km/s, which are likely along the directions close to the axes of accretion disks. The quasars showing inflowing Mg II NALs have on average slightly smaller Eddington ratios when compared to the sources with outflow Mg II NALs. The upper limits of locations of the detected NALs are at parsec scale, around the distances of dusty tori to central SMBHs. The one possible origin of these infalling NALs is from dusty tori. Of course, these infalling NALs can also be naturally explained by chaotic cold accretion resulted from the nonlinear interaction of active galactic nucleus (AGN) jets with the interstellar medium, and these cold gaseous blobs may originally precipitate in metal-rich trailing outflows uplifted by AGN jet ejecta. The infalling NALs may thus provide direct evidence for cold gas precipitation and accretion in AGN feedback processes, and provide the direct evidence of inflowing gas along the directions close to quasar jets and at parsec scale. It does not matter whether these infalling NALs are from the dusty tori or the interaction of AGN jets with the ISM, the infalling NALs cannot provide sufficient fuels to power the quasars.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： We have collected 10025 foreground-background quasar pairs with projected distances d_p0.15 \AAaround foreground quasars, including both the LOS (line-of-sights of foreground quasars) and transverse (TRA, perpendicular to the LOS) absorptions. Both the equivalent width (the correlation coefficient \rho=-0.915 and the probability P 4\sigma) greater than that of LOS \Mgii\ absorption lines at projected distances d_p200 kpc. The anisotropic radiation from quasars would be the most possible interpretation for the anisotropic absorption around quasars. This could also indicate that the quasar radiation is not obviously impacting the gas halos of quasars at scales d_p>200 kpc.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： We have collected 10025 foreground-background quasar pairs with projected distances d_p0.15 \AAaround foreground quasars, including both the LOS (line-of-sights of foreground quasars) and transverse (TRA, perpendicular to the LOS) absorptions. Both the equivalent width (the correlation coefficient \rho=-0.915 and the probability P 4\sigma) greater than that of LOS \Mgii\ absorption lines at projected distances d_p200 kpc. The anisotropic radiation from quasars would be the most possible interpretation for the anisotropic absorption around quasars. This could also indicate that the quasar radiation is not obviously impacting the gas halos of quasars at scales d_p>200 kpc.
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