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在早期的文章中,基于耀变体(Blazar)的知识,我们预言了在射电噪活动星系核(AGN)中心10kpc范围内X射线喷流的存在。钱得拉(Chandra)卫星最近对低功率射电星系的X射线观测与我们的预言相一致。在本文中我们研究了kpc尺度喷流中的电子加速,并建议通过对强的FRⅡ射电星系中所预言的X射线喷流的钱得拉卫星的X射线的观测,来研究红的耀变体中的康普顿冷却以及在内部致密喷流和大尺度延伸喷流间环境的不同。以上的研究可以进一步检验我们的关于射电噪活动星系核中kpc尺度X射线喷流的模型。 相似文献
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喷流的研究是天文学和天体物理学中最使人兴趣的课题之一。在本文中,陈述了河外射电源中喷流在现阶段的观测阶段,讨论了某些典型的高能天体中喷流的特性。第一部分所涉及的内容包括喷流的定义,产生和传播;也包括喷流的不对称性和统一的解释模式的讨论。 相似文献
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自从人们获得河外射电源的第一个结构图像以来,30多年时间已经过去了。在这段时间的后半期,人们对许多源中的喷流状结构作了大量研究。目前,我们正在分析所获得的有关喷流的第一代结果。这包括高分辨率观测,数值模拟和理论研究等诸方面的成就。在本文 详细地讨论河外射电源中的喷流。 相似文献
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在早期的文章中,基于耀变体(Blazar)的知识,我们预言了在射电噪活动星系核(AGN)中心10
kpc范围内X射线喷流的存在.钱得拉(Chandra)卫星最近对低功率射电星系的X射线观测与我们的预言相一致.在本文中我们研究了kpc尺度喷流中的电子加速,并建议通过对强的FR
Ⅱ射电星系中所预言的X射线喷流的钱得拉卫星的X射线的观测,来研究红的耀变体中的康普顿冷却以及在内部致密喷流和大尺度延伸喷流间环境的不同.以上的研究可以进一步检验我们的关于射电噪活动星系核中kpc尺度X射线喷流的模型. 相似文献
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本文总结最近从Xray 观测得到的关于宽吸收线类星体一些新结果, 我们和人家的结果都表明吸收物质的柱密度比原来从紫外估计的高三个量级, 在PG1411 + 442 中, 我们发现Xray 除了吸收成分外, 还有散射成分, 其量级和UV 吸收的剩余流量一致, 从而说明以前从UV 推断的结论是有问题的。此外, 对PG1126041 的研究表明从宽吸收线类星体到Seyfert 星系的窄本征吸收线其物理性质是连续过渡的。 相似文献
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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。 相似文献
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为了研究ROSAT X射线选亮近类星体巡天的选择判据,从1995年4月至1996年10月期间,利用北京天台2.16米望远镜进行了试验观测,发现了73个类星体,27个赛弗特星系,1个BL Lac侯选体,1个白矮星和1个激变变星。 相似文献
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I. S. Glass 《Astrophysics and Space Science》1995,230(1-2):215-223
The term Active Galactic Nuclei includes QSOs (Quasi-Stellar Objects), Seyfert galaxies, BL Lac objects and nuclei showing unusual amounts of star formation. South African work has centred on the photometric properties of these objects, both in the optical(UBVRI) and the infrared(JHKL). Photometry has been used to investigate the nature of the relevant emission mechanisms by studying both the colours of the nuclear components and their variations. In particular, it has been demonstrated convincingly that circumnuclear dust shells are present in several Seyfert 1 galaxies at temperatures of around 1500 K.It has also been shown that the variable component in many Seyfert 1 galaxies retains a constant spectral shape independent of its actual flux at a given time. Further, there is evidence that this shape is largely the same in all Seyfert 1 galaxies. Other studies have concentrated on surveys of morphological, spectroscopic and photometric characteristics of certain classes of galaxies such as those found by the IRAS satellite and those listed in the Arp-Madore catalogue of interacting galaxies. 相似文献
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Martin Haas Peter Biermann Rolf Chini Jochen Heidt Wolfram Kollatschny Helmut Meusinger Ralf Siebenmorgen 《Astronomische Nachrichten》2005,326(7):535-558
D01 Direct evidence of the receding ‘torus’ around active galactic nuclei of FRII radio galaxies and quasars D02 Infrared emission from a clumpy and dusty torus around AGN D03 Size and properties of AGN narrow–line regions from emission–line diagnostics D04 Structural Variability of Intraday Variable Sources D05 Stability of self‐gravitating accretion disks in galactic centers D06 Supermassive Binary Black Holes in AGN D07 The extreme flare in III Zw 2: Evolution of a radio jet in a Seyfert galaxy D08 Radio Linear and Circular Polarization from M81* D09 A fundamental relation between Supermassive Black Holes and Dark Matter Haloes D10 Hunting for radio‐quiet BL Lacs – the 2dF BL Lac survey D11 The Eddington limit in accretion discs D12 Molecular Tori in AGN: A search using excited states of OH D13 The X‐Ray Properties of Radio‐Loud Core‐Dominated AGN: The 2 cm‐X‐Sample D14 The X‐Ray Properties of Radio‐Loud Core‐Dominated AGN: Extension to the High Redshift Regime D15 Line Profile Variability in AGN D16 Jet Superwind Interaction D17 Radio Interferometric Observations of AGN – Probing the Nucleus of M87 with 20 Schwarzschild radii resolution D18 The ISO–2MASS AGN survey D19 Supermassive binary black holes driving the activity of galactic nuclei D20 Proton acceleration at quasi‐perpendicular shocks: A case study for Active Galactic Nuclei D21 Super‐luminal shocks in Active Galactic Nuclei D22 Unconventional quasars from the variability and proper motion survey D23 Radio observations of starburst and AGN activity in Ultraluminous Infrared Galaxies D24 Kinematics in Active Galactic Nuclei at Parsec Scales: the VLBA 2cm Survey D25 Three‐dimensional models of clumpy tori in Seyfert galaxies D26 Silicate emission in active galaxies ‐ From LINERs to QSOs D27 Discovery of 10 µm silicate emission in quasars. – Evidence of the AGN unification scheme. D28 Near‐IR adaptive optics imaging of luminous infrared galaxies D29 Interferometric observations of the Circinus galaxy with MIDI D30 Infrared Interferometry of the Seyfert Galaxy NGC 1068 相似文献
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Martin Haas Peter Biermann Rolf Chini Jochen Heidt Wolfram Kollatschny Helmut Meusinger Ralf Siebenmorgen 《Astronomische Nachrichten》2007,328(7):665-680
F11 Jets, supernovae, gammabursts – more light for theory? F35 A Direct Comparison of the QSO Samples from VPMS and SDSS F36 Gravitational Microlensing Simulations and Ensemble Broad‐Band Variability of the QSOs from VPMS F42 Luminosity function of low redshift quasars F43 Star Formation around Active Galactic Nuclei – Results from near infrared observations F58 High‐Redshift Quasars as Probes of Early Star Formation F66 On the dust emission of Seyfert nuclei F72 Propagation of Very Light MHD Jets F78 Giant Outflows in MassiveHigh‐z Radio Galaxies: Direct Evidence for AGNFeedback in the Early Universe F89 Lowfrequency mapping of ‘normal’ FR II radio galaxies: Resolving the puzzle of X‐shaped radio sources F90 Nature of X‐shaped radio sources: A statistical approach F100 Cosmological growth of Supermassive Black Holes: constraints on kinetic and radiative energy feedback F107 Molecular Tori in AGN F136 Electron‐Ion Recombination Rate Coefficients of Iron M‐Shell Ions for X‐Ray Astronomy F139 Hydrodynamic models of obscuring tori F145 The unique BL Lac Object S5 0716+714 F158 On the Cluster Environment of the BL Lac Object OJ 287 F179 The circumnuclear dust in nearby AGN resolved by mid‐infrared interferometry F184 NIR‐imaging of SDSS BL Lac objects F190 Blazar Observations in the TeV energy range with the MAGIC Telescope F198 Gas Inflow Rates in Nearby AGN Galaxies F202 Two zone SSC model for blazar jets F215 Long‐termVHE γ ‐ray monitoring of bright blazars with a dedicated telescope F218 Long termmonitoring of bright TeV Blazars with the MAGIC telescope F220 Fifteen Blazars in Very‐High Energy Gamma Rays: A Comparative Study F229 Numerical calculation of blazar spectra. Application to 1 ES 1218+30.4 F230 Blazar spectral energy distributions corrected for gamma ray attenuation F240 Observation of PG 1553+113 with the MAGIC Telescope F243 VHE Gamma‐Ray Flare of PKS2155‐304 detected by the MAGIC telescope F245 Observations of 3C279 with the MAGIC Telescope F258 Diffraction limited near infrared imaging spectroscopy of the NLR of NGC4151 相似文献
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M. Matsuoka 《Astrophysics and Space Science》1993,210(1-2):245-257
AGN (Active Galactic Nuclei) have their profound time variability over a wide range of time scales. Although many results of AGN variability have been provided from wide band wavelength observations, I would like to concentrate the recent problems concerning a nearby region of their central engine based on the X-ray observations which are most efficient to investigate this region. In this paper we will investigate mainly the result of Seyfert galaxies which would be generalized to other AGN. 相似文献
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对活动星系核中的喷流加速机制、观测特征有目前研究近况进行了评述。磁场在喷流加速过程中起重要作用,对磁场加速喷流模型中喷流加速区域的大小进行了估计。比较了不同的磁场加速喷流模型,并讨论了有序吸积盘磁场的形成与维持过程。简要地评述了活动星系核中吸积盘与喷流存在内在联系的观测证据,及中央黑洞与活动星系核的射电辐射特征的关系。 相似文献
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Biman B. Nath 《Journal of Astrophysics and Astronomy》2011,32(4):545-548
The Intracluster Medium (ICM) is believed to have been affected by feedback from Active Galactic Nuclei (AGN) and/or supernovae-driven
winds. These sources are supposed to have injected entropy into the ICM gas. The recently determined universal pressure profile
of the ICM gas has been used and after comparing with the entropy profile of the gas from gravitational effects of the dark
matter halo, the additional entropy injected by non-gravitational sources, as a function of the total cluster mass is determined.
The current observational data of red-shift evolution of cluster scaling relation is shown that allow models in which the
entropy injection decreases at high red-shift. 相似文献
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R. D. Blandford 《Astrophysics and Space Science》1998,261(1-4):245-252
There is now little doubt that the nuclei of most galaxies contain massive black holes with 106M⊙< M < 1010M⊙and that these are ultimately responsible for most nuclear activity when they are supplied with gas. Parallel observations
of Galactic X-ray sources are providing small scale counterparts that have similar properties except that they vary far more
rapidly. As we can now determine the masses of these black holes in several instances, we can ask much more quantitative questions
about the mode of accretion and the origin and collimation of outflows. In this contribution, I will emphasize the importance
of magnetic field for extracting the angular momentum from the flow and explain how the radiative efficiency is controlled
by the mass accretion rate and the actual properties of magnetized, plasma.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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通过搜集了457个活动星系核样本,根据活动星系核的演化实质是指宇宙时标上的变化,讨论了红移量与活动星系核演化的关系,最终证明了活动星系核的演化分为两个序列:(1)从类星体到Seyfert星系之间的演化;(2)平谱射电类星体(FSRQ)—BL Lac天体—射电星系(RG)的演化。 相似文献
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Astronomy Letters - Based on SDSS data, we consider the fraction of active galactic nuclei among polar-ring galaxies. We have found evidence for an excess of Seyfert galaxies and LINERS among... 相似文献
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