發(fā)布時間：2018-04-08 10:30

  本文選題：活動星系核　切入點：黑洞　出處：《中國科學技術大學》2016年博士論文

【摘要】：塵埃環(huán)是活動星系核統(tǒng)一模型的關鍵結構成分。然而,人們對塵埃環(huán)的研究主要局限在塵埃的紅外熱輻射上,而對塵埃環(huán)中的氣體輻射了解很少。在統(tǒng)一模型的框架下,塵埃環(huán)處的氣體在電離連續(xù)譜的照射下,通過光致電離過程可以產(chǎn)生豐富的紫外、光學發(fā)射線。發(fā)射線的寬度(FWHM～2000 km s-1)介于寬發(fā)射線(broad emission lines,縮寫B(tài)ELs)和窄發(fā)射線(narrow emission lines,縮寫NELs)之間。我們稱之為中等寬度發(fā)射線(intermediate-width emission lines,縮寫IELs).本文在前人對IEL研究的基礎之上，展開以下系列工作。IEL研究的最大困難在于譜線輪廓分解的不確定性。我們借鑒日冕儀原理,在一個部分遮蔽類星體OI 287中,利用塵埃環(huán)作為天然“日冕儀”將紫外波段BEL嚴重消光,從而探測到顯著的IEL。在維里化假設下,我們發(fā)現(xiàn)中等寬度發(fā)射線區(qū)(intermediate-width emission line region,縮寫IELR)到中心黑洞的距離(～1.3 pc)與塵埃環(huán)內(nèi)半徑基本吻合。光致電離模型計算表明,IELR氣體的密度(～108.8-109.4 cm-3),與通常塵埃環(huán)內(nèi)表面處的密度基本一致。這些結果表明IEL很可能是產(chǎn)生于塵埃環(huán)內(nèi)表面被中心電離源照射的氣體。類似OI 287的天體可以在半遮蔽類星體中大量發(fā)現(xiàn)。這說明IEL是可以廣泛存在的,并為IEL的深入研究奠定了觀測基礎。IEL提供了診斷塵埃環(huán)處氣體物理性質(zhì)新的途徑。在類星體SDSS J2324-0946的光譜中,一個線寬FWHM≈2000km s-1的IEL成分同時出現(xiàn)允許線Lyαγ1216、CⅣλ1549、半禁線CⅢ]λ1909、以及禁線[OⅢ]λλ4959,5007中。借助光致電離模型計算,我們估計這個類星體塵埃環(huán)處發(fā)射氣體的物理性質(zhì),如氫的密度nH～106.2-6.3 cm-3、距離中心電離源的距離35～35-50pc、覆蓋因子CF～6%、以及～4%倍小麥云的塵氣比。IEL拓寬了人們了解塵埃環(huán)的手段,與傳統(tǒng)紅外SED擬合方法相比,可以獲取更多關于塵埃環(huán)的物理特性。利用HST和SDSS等光譜數(shù)據(jù),我們在低紅移構建了同時有靜止系紫外和光學光譜的Ⅰ型活動星系核樣本。對該樣本的分析結果顯示,在維里化假設下IELR到中心黑洞的距離與塵埃環(huán)內(nèi)半徑在統(tǒng)計意義上基本一致。這表明塵埃環(huán)的內(nèi)表面是產(chǎn)生IEL的主要位置。根據(jù)這個結果,我們進而得到利用IEL測量黑洞質(zhì)量的公式。由于IEL可以在Lya和C IV等紫外發(fā)射線中得到,這種方法對于在高紅移宇宙測量黑洞質(zhì)量尤為重要。此外,IEL影響使用BEL線寬對黑洞質(zhì)量的測量。將IEL從發(fā)射線中扣除可以顯著改善利用BEL線寬測量黑洞質(zhì)量的精度。
[Abstract]:Dust ring is a key structural component of the unified model of active galactic nuclei (AGNs).However, the study of dust ring is mainly confined to the infrared thermal radiation of dust, but little is known about the gas radiation in dust ring.In the framework of the unified model, the gas in the dust ring can produce abundant ultraviolet and optical emission lines by photoionization under the irradiation of continuous ionization spectrum.The width of the emission line is between broad emission lines (abbreviated as BELs) and narrow emission lines (abbreviated as NELs).We call it intermediate-width emission lines.On the basis of previous studies on IEL, the main difficulty of the following series of work, I. e., is the uncertainty of spectral contour decomposition.Based on the principle of coronal apparatus, in a partially obscured quasar OI287, we use the dust ring as a natural coronal instrument to seriously extinction the ultraviolet band BEL and detect the remarkable BEL.On the assumption of virization, we find that the distance from intermediate width emission line region (IELR) to the central black hole is 1.3 pc.) and the inner radius of the dust ring is basically consistent.The calculation of photoionization model shows that the density of IELR gas is 108.8-109.4 cm ~ (-3), which is basically consistent with the density at the inner surface of the dust ring.These results suggest that IEL probably originated from the inner surface of the dust ring irradiated by a central ionization source.Objects like OI 287 can be found in a large number of semi-shadowed quasars.This indicates that IEL can exist widely and provides a new way to diagnose the physical properties of gas in the dust ring for the further study of IEL.In the spectra of quasar SDSS J2324-0946, an IEL component with a linewidth of FWHM 鈮，

本文編號：1721215