我们使用380 ks XMM-牛顿高分辨率RGS光谱来寻找1H 0707 -495核环境中的窄光谱特征。我们没有发现任何证据的视线电离风（暖吸收）。然而，我们确实探测到了宽约5000 km s^-1的宽发射谱线，与O VIII Ly-alpha、N VII Ly-alpha、C VI Ly-alpha和Fe XIX/Fe XX/Ne IX He-alpha混合物相一致。有趣的是，这些谱线同时具有蓝移和红移分量，其速度位移与距黑洞约1600 R_g的吸积盘中的原点一致。这些特征可解释为圆盘反射谱的窄线核，从而为1H 0707 -495的X射线谱的圆盘解释提供了独立的支持。我们讨论的相关性，我们的研究结果的“X射线宽线区域”在其他Seyferts，和光学宽线区域本身的起源。
英文摘要：
We use a 380 ks XMM-Newton high-resolution RGS spectrum to look for narrow spectral features from the nuclear environment of 1H0707-495. We do not find any evidence of a line-of-sight ionized wind (warm absorber). We do, however, detect broad emission lines, of width ~5000 km s^-1, consistent with O VIII Ly-alpha, N VII Ly-alpha, C VI Ly-alpha and a Fe XIX/Fe XX/Ne IX He-alpha blend. Intriguingly, these lines have both blueshifted and redshifted components, whose velocity shifts are consistent with an origin in an accretion disc at ~1600 R_g from the black hole. The features can be interpreted as the narrow line cores of the disc reflection spectrum, thus providing independent support for the discline interpretation of the X-ray spectrum of 1H0707-495. We discuss the relevance of our findings for the `X-ray broad line region' in other Seyferts, and for the origins of the optical broad line region itself.
We investigate aperiodic X-ray flux variability in accreting highly magnetized neutron stars - X-ray pulsars (XRPs). The X-ray variability is largely determined by mass accretion rate fluctuations at the NS surface, which replicate accretion rate fluctuations at the inner radius of the accretion disc. The variability at the inner radius is due to fluctuations arising all over the disc and propagating inwards under the influence of viscous diffusion. The inner radius varies with mean mass accretion rate and can be estimated from the known magnetic field strength and accretion luminosity of XRPs…
We develop a new physical model for the broadband spectral energy distribution (SED) of X-ray illuminated accretion discs, that takes into account the mutual interaction of the accretion disc and the X-ray corona, including all relativistic effects. We assume a Keplerian, optically thick and geometrically thin accretion disc and an X-ray source in the lamp-post geometry that emits an isotropic power-law spectrum with a high-energy cut-off. We assume that all the energy that would be released by thermal radiation in the standard disc model in its innermost part, is transported to the corona, ef…
Active galactic nuclei are supermassive black holes surrounded by an accretion disk, two populations of clouds, bipolar jets, and a dusty torus. The clouds move in Keplerian orbits at high velocities. In particular, the broad-line region (BLR) clouds have velocities ranging from $1000$ to $10000$ km s$^{-1}$. Given the extreme proximity of these clouds to the supermassive black hole, frequent collisions with the accretion disk should occur. The impact of BLR clouds onto the accretion disk can produce strong shock waves where particles might be accelerated. The goal of this work is to investiga…
Here we present a detailed study of the broadband noise in the power density spectra of the black hole X-ray binary MAXI J1820+070 during the hard state of its 2018 outburst, using the Hard X-ray Modulation Telescope (Insight-HXMT) observations. The broadband noise shows two main humps, which might separately correspond to variability from a variable disk and two Comptonization regions. We fitted the two humps with multiple Lorentzian functions and studied the energy-dependent properties of each component up to 100--150 keV and their evolution with spectral changes. The lowest frequency compon…
Broadband spectral studies of Type-I X-ray bursts can put strong constraints on the physics of burst spectra as well as their interaction with the environment. We present the results obtained from the broadband time-resolved spectroscopy of 15 thermonuclear bursts detected simultaneously from the neutron star atoll source 4U 1636-536 using LAXPC and SXT onboard AstroSat. During the observations with AstroSat, the Low mass X-ray binary (LMXB) 4U 1636-536 is observed to show a modest spectral evolution within the island state. The broadband burst spectra are observed to show an excess in additio…
We analyze extensive spectroscopic and photometric data of the hypervariable quasar SDSS J131424+530527 (RMID 017) at z=0.456, an optical "changing look" quasar from the Sloan Digital Sky Survey Reverberation Mapping project that increased in optical luminosity by a factor of 10 between 2014 and 2017. The observed broad emission lines all respond in luminosity and width to the changing optical continuum, as expected for photoionization in a stratified, virialized broad emission line region. The luminosity changes therefore result from intrinsic changes in accretion power rather than variable o…
We present a broad-band X-ray timing study of the variations in pulse behavior with superorbital cycle in the low-mass X-ray binary Her X-1. This source shows a 35-day superorbital modulation in X-ray flux that is likely caused by occultation by a warped, precessing accretion disk. Our data set consists of four joint XMM-Newton and NuSTAR observations of Her X-1 which sample a complete superorbital cycle. We focus our analysis on the first and fourth observations, which occur during the bright "main-on" phase, because these observations have strongly detected pulsations. We added an archival X…
The Effects of Complex Accretion Disk Geometry on Broadened Iron K$α$ Lines
University of California, Santa Barbara（加州大学圣塔芭芭拉分校）；Stanford University（斯坦福大学）；Kavli Institute for Particle Astrophysics & Cosmology (KIPAC), Stanford University（斯坦福大学卡弗里粒子天体物理与宇宙学研究所）；The Ohio State University（俄亥俄州立大学）
XRISM/Resolve observations of Hercules X-1: a pulsating, highly broadened Fe K emission line from the neutron star accretion column
Center for Astrophysics — Harvard & Smithsonian（天体物理中心——哈佛与史密森尼学会）；MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology（麻省理工学院卡弗里天体物理与空间研究所）；INAF—IASF Palermo（意大利国家天体物理研究所巴勒莫天文物理研究所）；Department of Astronomy and Astrophysics, The University of Chicago（芝加哥大学天体物理学系）；Institut für Astronomie und Astrophysik, Universität Tübingen（蒂宾根大学天文学与天体物理研究所）；Centre for Astrophysics Research, University of Hertfordshire（赫特福德大学天体物理研究中心）；Università degli Studi di Palermo, Dipartimento di Fisica e Chimica（巴勒莫大学物理与化学系）；Institute of Astronomy, Madingley Road, Cambridge（剑桥大学天体物理研究所）；Department of Physics, Graduate School of Science, Kyoto University（京都大学理学研究科物理学系）；Department of Astronomy, University of Michigan（密歇根大学天文学系）
We use seven different methods to estimate broad-line and continuum reddenings of NGC 5548. We investigate two possible reddening curves considered for active galactic nuclei (AGNs): the mean AGN reddening curve of Gaskell & Benker (2007) which is relatively flat in the ultraviolet, and a curve that rises strongly into the ultraviolet like a Small Magellanic Cloud (SMC) reddening curve. We also consider a standard Milky Way curve. Regardless of the curve adopted, we find a total reddening ~14 times greater than the small amount of reddening due to dust in the solar neighbourhood. The UV-to-opt…
We report the detection of relativistically broadened iron K alpha emission in the X-ray spectra of AGN detected in the 4Ms CDF-S. Using the Bayesian X-ray analysis (BXA) package, we fit 199 hard band (2-7 keV) selected sources in the redshift range z=0.5--4 with three models: (i) an absorbed power-law, (ii) the first model plus a narrow reflection component, and (iii) the second model with an additional relativistic broadened reflection. The Bayesian evidence for the full sample of sources selects the model with the additional broad component as being 10^5 times more probable to describe the …
The accreting millisecond X-ray pulsar Swift J1756.9$-$2508 went into outburst in April 2018 and June 2019, 8.7 yr after the previous activity period. We investigated the temporal, timing and spectral properties of these two outbursts using data from NICER, XMM-Newton, NuSTAR, INTEGRAL, Swift and Insight-HXMT. The two outbursts exhibited similar broad-band spectra and X-ray pulse profiles. For the first time, we report the detection of the pulsed emission up to $\sim100$ keV observed by Insight-HXMT during the 2018 outburst. We also found the pulsation up to $\sim60$ keV observed by NICER and …
The profiles of the broad emission lines of active galactic nuclei (AGNs) and the time delays in their response to changes in the ionizing continuum ("lags") give information about the structure and kinematics of the inner regions of AGNs. Line profiles are also our main way of estimating the masses of the supermassive black holes (SMBHs). However, the profiles often show ill-understood, asymmetric structure and velocity-dependent lags vary with time. Here we show that partial obscuration of the broad-line region (BLR) by outflowing, compact, dusty clumps produces asymmetries and velocity-depe…
Broad iron emission lines in Seyfert Galaxies - re-condensation of gas onto an inner disk below the ADAF
最近用Chandra、XMM-Newton和Suzaku对Seyfert 1活动星系核进行的观测显示出宽的铁K_α发射线，有些相对论性地模糊了。对于银河系黑洞的X射线双星XMM-牛顿光谱在硬态也揭示了相对论铁发射线和热分量的存在下，解释为一个弱的内部冷吸积盘热日冕下的指示。这些热成分被发现后，从软到硬的光谱状态的过渡，可以理解为持续的气体从对流为主的流（ADAF）到磁盘上的再冷凝。鉴于恒星质量和超大质量黑洞周围吸积流的相似性，我们讨论了Seyfert 1活动星系核中的宽铁发射线是否可以理解为来自类似的吸积流几何。在Miller（2007）和Nandra et al.（2007）的样本中，我们推导了具有强线的Seyfert星系的Eddington标度吸积率。在评估中，我们使用了观测到的X射线光度，热辐射校正和文献中的黑洞质量，大多数值来自Fabian和Vasudevan（2009）。超过一半的来源得出的速率小于爱丁顿速率的0.1。对于塞弗特1活动星系核中10^7到10^8个太阳质量的黑洞来说，这个极限相当于每年0.01到0.2个太阳质量。我们的研究表明，对于相当多的Seyfert活动星系核在硬谱态铁的发射线可以产生于一个内部弱盘周围的ADAF的再凝聚模型预测。一些具有较高吸积率的剩余源可能处于与LMXB的“非常高”状态相当的光谱状态。（节略）
We have analyzed AstroSat observations of the galactic micro-quasar system GRS 1915+105, when the system exhibited C-type Quasi-periodic Oscillations (QPOs) in the frequency range of 3.4-5.4 Hz. The broad band spectra (1-50 keV) obtained from simultaneous LAXPC and SXT can be well described by a dominant relativistic truncated accretion disk along with thermal Comptonization and reflection. We find that while the QPO frequency depends on the inner radii with a large scatter, a much tighter correlation is obtained when both the inner radii and accretion rate of the disk are taken into account. …
A long-standing question in active galactic nucleus (AGN) research is how the corona is heated up to produce X-ray radiation much stronger than that arising from the viscous heating within the corona. In this paper, we carry out detailed investigations of magnetic-reconnection heating to the corona, specifically, studying how the disc and corona are self-consistently coupled with the magnetic field, and how the emergent spectra depend on the fundamental parameters of AGN. It is shown that diverse spectral shapes and luminosities over a broad bandpass from optical to X-ray can be produced from …
Due to the complexity of modeling the radiative transfer inside the accretion columns of neutron star binaries, their X-ray spectra are still commonly described with phenomenological models, for example, a cutoff power law. While the behavior of these models is well understood and they allow for a comparison of different sources and studying source behavior, the extent to which the underlying physics can be derived from the model parameters is very limited. During recent years, several physically motivated spectral models have been developed to overcome these limitations. Their application, ho…
Instituto de Astrofísica de Canarias（加那利天体物理研究所）；Universidad de La Laguna（拉古纳大学）；European Southern Observatory (ESO)（欧洲南方天文台）；University of Durham（杜伦大学）；INAF–Osservatorio Astronomico di Brera（意大利国家天体物理研究所布里耶拉天文台）；Max-Planck-Institut für Extraterrestrische Physik（马克斯·普朗克地外物理研究所）；Università degli Studi dell’Insubria（因苏布里亚大学）；Osaka University（大阪大学）
We present results from NuSTAR and XMM-Newton observations of the new black hole X-ray binary MAXI J1820+070 at low accretion rates (below 1% of the Eddington luminosity). We detect a narrow Fe K$α$ emission line, in contrast to the broad and asymmetric Fe K$α$ line profiles commonly present in black hole binaries at high accretion rates. The narrow line, with weak relativistic broadening, indicates that the Fe K$α$ line is produced at a large disk radius. Fitting with disk reflection models assuming standard disk emissivity finds a large disk truncation radius (a few tens to a few hundreds of…
We confirm that the spectra are best fit by a model containing two Compton reflection components, one from distant material, and the other displaying relativistic broadening, most likely from the inner accretion disk. The degree of relativistic broadening indicates a preference for high black hole spin, but the reflection is weaker than that expected for a flat disk illuminated by a point source. We investigate the Compton reflection signatures as a function of luminosity, redshift and obscuration, confirming an X-ray Baldwin effect for both the narrow and broad components of the iron line. An…
We present the first systematic broad-band X-ray study of super-Eddington accretion onto SMBHs with simultaneous {\it NuSTAR} and {\it XMM-Newton} or {\it Swift}/XRT observations of a sample of 8 super-Eddington accreting AGN with Eddington ratio $1<λ_{\rm Edd}<426$. We find that the SEAMBHs show a steep primary continuum slope as expected for sources accreting in the super Eddington regime, mostly dominated by relativistic reflection. The Iron K$α$ emission lines of the sources of our sample show relativistic broadening. In addition the equivalent widths of the narrow components of the Iron K…
