射电类星体黑洞质量和射电特性的研究

收集了117个类星体(20个射电宁静类星体和97个射电噪类星体)的红移、热光度、H_β发射线宽度、5 100 A的单色光度、射电噪度.利用反响映射法计算了样本的黑洞质量和爱丁顿比,利用总的5 GHz流量密度计算出射电光度.分析了它们之间的相关性,得到的结论如下:(1)射电宁静类星体的黑洞质量和热光度、射电噪度、射电光度之间具有弱相关性,而射电噪类星体黑洞质量和热光度、射电噪度、射电光度之间具有强相关性;(2)射电宁静类星体热光度和射电光度、5 100 A的单色光度之间具有弱的相关性,而射电噪类星体热光度和射电光度、5 100 A的单色光度之间具有强的相关性;(3)射电宁静和射电噪类星体的黑洞质量、发射线宽度和爱丁顿比分布有差异.基于这些结果得到:射电宁静和射电噪类星体发射线宽度的差异可能是导致它们黑洞质量不同的原因;射电宁静和射电噪类星体本质的不同是由于内秉物理性质的不同造成的;黑洞质量、黑洞自旋、爱丁顿比和寄主星系形态是解释射电噪度起源和双峰状分布的重要参量;射电喷流和盘的吸积率之间具有紧密的关系.     

射电类星体的演化与宇宙学红移

收集了142个射电类星体(28个射电宁静类星体、114个射电噪类星体)、43个核占优型射电类星体、82个瓣占优型射电类星体和80个Seyfert星系的样本,基于Logistic非线性回归分析的方法对红移和热光度、黑洞质量、5 GHz射电光度、爱丁顿吸积率、核主导参数R的关系进行研究,拟合出相应的演化曲线,得到如下结论:(1)射电类星体的演化是从射电噪类星体(RLQ)演化到射电宁静类星体(RQQ),当演化到一定阶段射电类星体过渡到Seyfert星系;(2)核占优型射电类星体(CDQ)和瓣占优型射电类星体(LDQ)之间并没有明显的随红移演化.     

射电类星体黑洞自旋与射电噪相关性研究

黑洞自旋及其参量能提供射电类星体射电噪度的信息。从文献资料中收集了69个射电类星体源。这些源包含了37个陡谱射电类星体(SSRQs),32个平谱射电类星体(FSRQs)。通过样本数据研究黑洞自旋能量与射电类星体射电噪的相关性。研究结果表明:(1)37个陡谱射电类星体与射电噪存在明显的相关性。这种相关性在3种磁场条件下都存在(B=BEDD,B=104G,B∝j);(2)陡谱射电类星体与射电噪之间的相关性不受相对论聚束效应的影响;(3)32个平谱射电类星体与射电噪之间不存在相关性,这说明黑洞自旋与射电噪的相关性与射电类星体的类型有很大关系;(4)陡谱射电类星体黑洞自旋与射电噪的强相关性表明,黑洞自旋能量在一定程度上给出陡谱射电类星体射电噪度的信息。这些研究结果与其他人提出的理论是一致的。     

黑洞自转和类星体喷流射电辐射的相关性

利用Ｂｌａｎｄｆｏｒｄ－Ｚｎａｊｅｋ过程,得出了黑洞自转与活动星系核射电噪度的关系.在假设ＡＧＮ喷流的射电功率主要来自于所提取的黑洞旋转能量后,根据Ｆａｌｃｋｅ和Ｂｉｅｒ－ｍａｎｎ提出的喷流－吸积盘耦合机制,估算了ＡＧＮ喷流的最大射电辐射功率．通过与ＰＧ类星体样本中强射电源观测结果的比较,进一步证实强射电类星体除了其喷流方向与视向的夹角很小外,其中心的超大质量黑洞很可能是自转很快的旋转黑洞．     

X线选射电噪活动星系核的多波段性质

基于被ROSAT全天区巡天观测和射电4．85GHz巡天观测同时探测到的活动星系核的大样本,研究了X射线选的射电噪活动星系核的多波段性质．通过分析该样本中的活动星系核的宽波段能量分布,确认了来自射电、光学和X射线波段的辐射光度之间的显著相关性．这种相关性对于类星体、赛弗特、蝎虎座天体和射电星系是有区别的．同时,探讨了从光学到X射线波段之间的谱指数与红移以及5000A和4．85GHz处的单色光度的相关性．     

黑洞自转和类星体喷流射电辐射的相关性

利用Ｂｌａｎｄｆｏｒｄ－Ｚｎａｊｅｋ过程,得出了黑洞自转与活动星系核射电噪度的关系,在假设ＡＧＮ喷流的射电功率来自于所提取的黑洞旋转能量后,根据Ｆａｌｃｋｅ和Ｂｉｅｒｍａｎｎ提出的喷流－吸积耦合机制,估算了ＡＧＮ喷流的最大射电辐射功率,通过与ＰＧ类星体样本强射电源观测结果的比较,进一步证实强射电类星体除了其喷流方向与视向的夹角很小外,其中心的超大质量黑洞很可能是自转很快的旋转黑洞。     

X射线选射电噪活动星系核的多波段性质(英文)

基于被ROSAT全天区巡天观测和射电 4.85GHz巡天观测同时探测到的活动星系核的大样本 ,研究了X射线选的射电噪活动星系核的多波段性质 .通过分析该样本中的活动星系核的宽波段能量分布 ,确认了来自射电、光学和X射线波段的辐射光度之间的显著相关性 .这种相关性对于类星体、赛弗特、蝎虎座天体和射电星系是有区别的 .同时 ,探讨了从光学到X射线波段之间的谱指数与红移以及 50 0 0 和 4.85GHz处的单色光度的相关性     

由NVSS证认的射电类星体

通过对２０００年版Ｖｅｒｏｎ类星体星表和ＮＶＳＳ巡天数据进行交叉证认,得到了３０１颗新发现有射电辐射的类星体,计算了射电类星体的射电谱指数、射电光度、偏振度等物理量并进行了统计分析,讨论了射电类星体所理比例随红移和绝对星等的分布,以及夺度随红移的演化关系。结果发现,强射电类星体在所有类星体中所占的比例Ｆ（ＲＬＱ）随着ＭＢ的增加而增大,随红移的演化是ｚ＝０．０到ｚ＝０．８逐渐上升,在ｚ＝１．５附近开     

一个耀变体样本在射电波段的Jurkevich周期分析

利用欧文斯谷射电天文台(Owens Valley Radio Observatory, OVRO) 15 GHz的观测数据,通过Jurkevich理论分析了78个耀变体样本的光变曲线,结果表明,射电源显示了显著的光变周期,范围为0.83–2.55 yr.另外,通过估算射电源光变的调制指数,发现蝎虎天体的调制指数较平谱射电类星体有更大的高斯分布峰值.     

由NVSS证认的射电类星体

通过对２０００年版Ｖｅｒｏｎ类星体星表和ＮＶＳＳ巡天数据进行交叉证认,得到了３０１颗新发现有射电辐射的类星体．计算了射电类星体的射电话指数、射电光度、偏振度等物理量并进行了统计分析,讨论了射电类星体所占比例随红移和绝对星等的分布,以及偏振度随红移的演化关系．结果发现,强射电类星体在所有类星体中所占的比例Ｆ（ＲＬＱ）随着ＭＢ的增加而增大,随红移的演化是从。＝０．０到ｚ＝０．８逐渐上升,在ｚ＝１．５附近开始缓慢下降,到ｚ＝ ２．０附近降到谷底,然后又有上升趋势．射电偏振度大部分小于 ４．０％,偏振度越小,类星体数目越多．而射电偏振度与红移之间似乎没有相关性．     

射电活动星系核中盘与喷流联系

本文收集了射电源表１Ｊｙ,Ｓ４ ,Ｓ５ 中的活动星系核的宽发射线数据,发现射电活动星系核的宽发射线与５ＧＨｚ 射电辐射强相关。ＢＬＬａｃ 天体具有较弱的宽发射线辐射,但具有与其它活动星系核类似的统计行为。结果表明射电活动星系核中的喷流与吸积过程存在本质联系。     

The radio properties of a sample of optically selected radio-loud quasars

We searched for identification between the Large Bright Quasar Survey and the latest whole-sky survey catalog of 4.85 GHz radio sources. We found 34 quasars to have radio counterparts and they proved to be radio-loud objects. We found a nearly linear correlation between their radio and optical luminosities in this, probably the largest so far, sample of radio-loud quasars.     

A Statistical Study of XBLs, RBLs and FSRQs at 1.5 GHz

BL Lac objects are similar to the fiat spectrum radio quasars in many aspects except regarding the emission lines.In order to study their relationship,we selected 56 BL Lacertae objects(33 X-ray-selected,23 radio-selected)and 45 flat spectrum radio quasars,analyzed their radio luminosities and core-dominance parameters.We found that the radio luminosities of the radio selected BL Lac objects located in between the X-ray selected BL Lac objects and the fiat spectrum radio quasars.However,this intermediate position does not bold for the core-dominance parameter:the RBLs have the largest core-dominance parameters.This sug- gests that the core-dominance parameter can not be taken as a sequencing criterion.We also investigated the correlation between the luminosity and the core-dominance parameter for the three subclasses.We concluded that,here,the sequence XBL-RBL—FSRQ still exists.     

Properties of radio-detected broad absorption line quasars from the Sloan Digital Sky Survey

We investigate the optical colors and radio morphologies of 214 broad absorption line (BAL) quasars with FIRST detections in the redshift range 1.68≤z≤4.93 drawn from the Sloan Digital Sky Survey (SDSS) Data Release 5 (DR5) quasar catalog. The radio-detected SDSS BAL quasars are found to have Δ(g?i) colors significantly redder than their non-BAL counterparts, with a mean color difference of 0.52 mag, in good agreement with the O–E (roughly B–R) color difference between radio-selected BAL and non-BAL quasars in the FIRST Bright Quasar Survey (FBQS). The vast majority (～90 %) of the radio-detected BAL quasars are found to be core-only sources, most of which show compact radio morphologies, consistent with the morphological results for the FBQS sample. Moreover, within the FIRST-detected SDSS sample, BAL quasars with GB6 detections are found to span a wide range in radio spectral indices, indistinguishable from that of non-BAL quasars, indicating no special line of sight for the presence of BALs. The properties of the present SDSS sample are more consistent with the evolutionary model, in which BALs are at an early evolutionary stage of quasars.     

The large-scale distribution of quasars identified with strong radio sources at 5 GHz

The large-scale angular distribution of quasars from a complete sample of extragalactic radio sources is examined at different redshifts. The sample contains 264 quasars which have been found so far among the complete sample of 518 radio sources stronger than. 1 Jy at 5 GHz. Of these, 19 quasars have redshift z > 2. Dividing the entire sky into three separate declination zones of equal area, the counts of quasars seem to indicate a deficit of high redshift quasars in the northernmost declination zone. On the other hand, the Iow-redshift quasars (z < 1) appear fairly uniformly distributed. We discuss some possible selection effects that might have led to the apparent anomaly at high redshifts and estimate the expected number of high-redshift quasars amongst the radio sources in the sample for which redshifts are presently not available.     

A search for distant radio-loud quasars in the CLASS survey: three new radio-selected quasars at z > 4

We report on the search for distant radio-loud quasars in the Cosmic Lens All Sky Survey (CLASS) of flat spectrum radio sources with S _5GHz>30 mJy . Unresolved optical counterparts were selected from APM scans of POSS-I plates, with e <19.0 and red o − e >2.0 colours, in an effective area of ∼6400 deg². Four sources were found to be quasars with z >4 , of which one was previously known. This sample bridges the gap between the strong radio surveys with S _5GHz>200 mJy and the samples of radio-weak quasars that can be generated via radio observations of optically selected quasars. In addition, four new quasars at z >3 have been found. The selection criteria result in a success-rate of ∼1:7 for radio-loud quasars at z >4 , which is a significant improvement over previous studies. This search yields a surface density of 1 per 1600 deg², which is about a factor of ∼15 lower than that found in a similar search for radio-quiet quasars at z >4 . The study presented here is strongly biased against quasars beyond z >4.5 , since the e -passband of the POSS-I only samples the spectra shortward of 1200 Å at these redshifts.     

Radio Luminosity, Black Hole Mass and Eddington Ratio for Quasars from the Sloan Digital Sky Survey

We investigate the MBH-O'.relation for radio-loud quasars with redshift z＜0.83 in Data Release 3 of the Sloan Digital Sky Survey (SDSS).The sample consists of 3772 quasars with better models of the H/~ and [O III] lines and available radio luminosity,including 306 radio-loud quasars,3466 radio-quiet quasars with measured radio luminosity or upper-limit of radio luminosity (181 radio-quiet quasars with measured radio luminosity).The virial supermassive black hole mass (MBH) is calculated from the broad H/line,and the host stellar velocity dispersion (σ*) is traced by the core [O III] gaseous velocity dispersion.The radio luminosity and radio loudness are derived from the FIRST catalog.Our results are as follows:(1) For radio-quiet quasars,we confirm that there is no obvious deviation from the MBH-O".relation defined for inactive galaxies when the uncertainties in MBH and the luminosity bias are concerned.(2) We find that the radio-loud quasars deviate more from the MBH-σ.relation than do the radio-quiet quasars.This deviation is only partly due to a possible cosmological evolution of the MBH-σ* relation and the luminosity bias.(3) The radioluminosity is proportional to M128 0.23-0.16 BH(LBol/LEdd)1.29 0.31-0.24 for radio-quiet quasars and to M3.10 0.6.-0.70(LBol.LEdd)4.18 1.40-1.10 for radio-loud quasars.The weaker dependence of the radio luminosity on the mass and the Eddington ratio for radio-loud quasars shows that other physical effects would account for their radio luminosities,such as the spin of the black hole.     

An X-Ray Study of Lobe-Dominated Radio-Loud Quasars with XMM-Newton

We report on our results of X-ray spectral analysis for a sample of radio-loud quasars covering a wide range of the radio core-dominance parameter, R, from core-dominated to lobe-dominated objects, using data obtained mostly with the XMM-Newton Observatory. We find that the spectral shape of the underlying power-law continuum is flat even for the lobe-dominated objects (average photon index ～ 1.5), indistinguishable from that of core-dominated quasars. For lobe-dominated objects, contribution of X-rays from the jets is expected to be very small based on previous unification schemes, more than one order of magnitude lower than the observed X-ray luminosities. Assuming that radio-loud quasars follow the same X-ray-UV/optical luminosity relation for the disk-corona emission as found for radio-quiet quasars, we estimate the X-ray flux contributed by the disk-corona component from the optical/UV continuum. We find that neither the luminosity, nor the spectral shape, of the disk-corona X-ray emission can account for the bulk of the observed X-ray properties. Thus in lobe-dominated quasars, either the disk-corona X-ray emission is much enhanced in strength and flatter in spectral shape (photon index～1.5) compared to normal radio-quiet quasars, or their jet X-ray emission is much enhanced compared to their weak radio core-jet emission. If the latter is the case, our result may imply that the jet emission in X-rays is less Doppler beamed than that in the radio. As a demonstrating example, we test this hypothesis by using a specific model in which the X-ray jet has a larger opening angle than the radio jet.     

Observational manifestations and intrinsic properties of the RCR sources in terms of a unified model

We present a summary results of the study of radio sources showing significant variations of integral flux density using the data from the RATAN-600 surveys of 1980–1994 at a frequency of 7.6 cm. The majority of the detected variable sources have flat radio spectra, although there are also all other spectrum types found. Point and compact sources predominate, although all known morphological structures are found in the sample. Variability is detected both in quasars and galaxies. Using the catalog data, we found brightness variations in the optical and/or infrared ranges for a half of host objects of radio sources. We analyzed the properties of nonvariable and variable RCR sources. We compared the ratio of absolute magnitude to radio luminosity for sources with the active nucleus types determined from the optical data. It is found that this parameter is approximately the same for quasars with different radio luminosity. It isminimum for the strongest radio galaxies and grows up to the level characteristic of quasars with the decrease of radio luminosity. Considering that the ratio depends on obscuring properties of a dust torus, such behavior can be explained if we assume that the torus geometry and its optical depth depend on the source long. This parameter is slightly higher among variable sources than among nonvariable ones which counts in favor of the nucleus more open to an observer.     

Compact steep-spectrum sources from the S4 sample

We present the results of 5-GHz observations with the VLA A-array of a sample of candidate compact steep‐spectrum (CSS) sources selected from the S4 survey. We also estimate the symmetry parameters of high-luminosity CSS sources selected from different samples of radio sources, and compare these with the larger sources of similar luminosity to understand their evolution and the consistency of the CSS sources with the unified scheme for radio galaxies and quasars. The majority of CSS sources are likely to be young sources advancing outwards through a dense asymmetric environment. The radio properties of CSS sources are found to be consistent with the unified scheme, in which the axes of the quasars are observed close to the line of sight, while radio galaxies are observed close to the plane of the sky.