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首頁> 外文學(xué)位 >Kinematics of the narrow-line regions in the Seyfert galaxies NGC 4151 and NGC 1068.
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Kinematics of the narrow-line regions in the Seyfert galaxies NGC 4151 and NGC 1068.

機(jī)譯：塞弗特星系NGC 4151和NGC 1068中的細(xì)線區(qū)域的運(yùn)動(dòng)學(xué)。

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摘要

We present a study of high-resolution long-slit spectra of the narrow-line regions (NLRs) of NGC 4151 (a Seyfert 1 galaxy) and NGC 1068 (a Seyfert 2 galaxy) obtained with the Space Telescope Imaging Spectrograph (STIS) aboard the Hubble Space Telescope (HST). The spectra were retrieved from the Multimission Archive at Space Telescope (MAST) and were obtained from five and seven orbits of HST time resulting in five and seven parallel slit configurations at position angles of 52° and 38° for NGC 4151 and NGC 1068 respectively. The spectra have a spatial resolution of 0&inches;.2 across and 0&inches;.1 along each slit. Observations of [O III] emission from the NLRs were made using the medium resolution G430M grating aboard HST. The spectral resolving power of the grating, R=lDl≃90 00 , resulted in the detection of multiple kinematic components of the [O III] emission line gas along each slit. Radial velocities of the components were measured using a Gaussian fitting procedure.; Biconical outflow models were generated to match the data and for comparison to previous models done with lower dispersion observations. The general trend is an increase in radial velocity roughly proportional to distance from the nucleus, followed by a linear decrease after roughly 100 pc. This is similar to that seen in other Seyfert galaxies, indicating common acceleration and deceleration mechanisms. The full-width at half-maximum (FWHM) of the emission lines reaches a maximum of 1000 kms-1 near the nucleus, and generally decreases with increasing distance to about 100 kms-1 in the extended narrow-line region (ENLR), starting at about 400 pc from the nucleus. In addition to the bright emission knots, which generally fit our model, there are faint high velocity clouds that do not fit the biconical outflow pattern of our kinematic model.; A comparison of our observations with high-resolution radio maps shows that the kinematics of the faint NLR clouds may be affected by the radio lobes that comprise the inner jet. However, the bright NLR clouds show a smooth transition across the radio knots in radial velocity and velocity dispersion plots and remain essentially undisturbed in their vicinity, indicating that the radio jet is not the principal driving force on the outflowing NLR clouds.; A dynamical model was developed for NGC 1068; it includes forces of radiation pressure, gravity, and drag due an ambient medium, simultaneously acting on the NLR clouds. The velocity profile from this model was too steep to fit the data, which show a more slowly increasing velocity profile. Gravity alone was not able to slow down the clouds but with the drag forces included, the clouds could slow down, reaching systemic velocities at distances that depend on the column densities of the NLR gas and density of the intercloud medium. A biconical model using the geometric parameters from our kinematic fit, and the velocity law from the dynamic fit, was used to match the data. The resulting dynamic model represented a poor fit to the data, indicating the need for additional dynamical considerations.
機(jī)譯：我們提供了利用太空望遠(yuǎn)鏡成像光譜儀（STIS）獲得的NGC 4151（塞弗特1星系）和NGC 1068（塞弗特2星系）的窄線區(qū)域（NLR）的高分辨率長縫光譜的研究哈勃太空望遠(yuǎn)鏡（HST）。光譜是從太空望遠(yuǎn)鏡的多任務(wù)檔案庫（MAST）中檢索到的，并且是從HST時(shí)間的五個(gè)和七個(gè)軌道獲得的，分別導(dǎo)致NGC 4151和NGC 1068在位置角分別為52°和38°的五個(gè)和七個(gè)平行狹縫構(gòu)型。光譜的空間分辨率為0英寸; 0.2跨，0英寸; .1沿每個(gè)狹縫。使用HST上的中分辨率G430M光柵對NLR的[O III]發(fā)射進(jìn)行了觀測。光柵的光譜分辨能力R ＝ IDl＆sime; 90 00，導(dǎo)致沿著每個(gè)狹縫檢測到[O III]發(fā)射線氣體的多個(gè)運(yùn)動(dòng)學(xué)分量。使用高斯擬合程序測量部件的徑向速度。生成雙曲線流出模型以匹配數(shù)據(jù)，并與使用較低色散觀測值進(jìn)行的先前模型進(jìn)行比較?？偟内厔菔菑较蛩俣鹊脑黾哟笾屡c離核的距離成正比，然后在大約100 pc之后線性減小。這與在其他塞弗特星系中看到的相似，表明常見的加速和減速機(jī)制。發(fā)射線的半峰全寬（FWHM）在原子核附近最大達(dá)到1000 kms-1，并且通常在擴(kuò)展的窄線區(qū)域（ENLR）中隨著距離增加到約100 kms-1而減小，從原子核開始約400 pc。除了通常適合我們模型的明亮發(fā)射結(jié)之外，還有不適合我們運(yùn)動(dòng)模型的雙錐形流出模式的微弱高速云。將我們的觀測結(jié)果與高分辨率的無線電圖進(jìn)行比較，結(jié)果表明，微弱的NLR云的運(yùn)動(dòng)學(xué)可能會(huì)受到構(gòu)成內(nèi)部射流的無線電波瓣的影響。然而，明亮的NLR云在徑向速度和速度色散圖中顯示出穿過無線電結(jié)的平滑過渡，并且在它們附近基本保持不受干擾，表明無線電射流不是流出NLR云的主要驅(qū)動(dòng)力。為NGC 1068開發(fā)了一個(gè)動(dòng)力學(xué)模型。它包括輻射壓力，重力和環(huán)境介質(zhì)引起的阻力，同時(shí)作用于NLR云上。該模型的速度曲線太陡而無法擬合數(shù)據(jù)，這表明速度曲線的增加更為緩慢。僅靠重力并不能使云團(tuán)減速，但是如果加上阻力，云團(tuán)可能會(huì)減速，在達(dá)到一定距離時(shí)的系統(tǒng)速度取決于NLR氣體的柱密度和云間介質(zhì)的密度。使用來自我們的運(yùn)動(dòng)學(xué)擬合的幾何參數(shù)和來自動(dòng)態(tài)擬合的速度定律的雙圓錐模型來匹配數(shù)據(jù)。生成的動(dòng)態(tài)模型表示與數(shù)據(jù)的擬合度較差，表明需要進(jìn)行其他動(dòng)力學(xué)考慮。

著錄項(xiàng)

  • 作者

    Das, Varendra.;

  • 作者單位

    Georgia State University.;

  • 授予單位 Georgia State University.;
  • 學(xué)科 Physics Astronomy and Astrophysics.
  • 學(xué)位 Ph.D.
  • 年度 2006
  • 頁碼 214 p.
  • 總頁數(shù) 214
  • 原文格式 PDF
  • 正文語種 eng
  • 中圖分類 天文學(xué);
  • 關(guān)鍵詞

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