摘要:

We present results from simultaneous observations of Cyg X‐1 withINTEGRALandRXTEin 2002 November and December, employing the newRXTEcalibration fromHEASOFT5.3. The broad‐band X‐ray/&ggr;‐ray spectrum is well described by Comptonization spectra with an additional reflection component. The temperature of the Comptonizing plasma iskTe∼ 60–80 keV and its optical depth is &tgr; ∼ 0.8–1.2. The covering factor of the reflector is &OHgr;/2&pgr; ∼ 0.1. There is a possible soft excess below 10 keV, interpreted as emission from the accretion disk. The spectral parameters are slightly different from those obtained by us earlier due to the differentRXTE‐PCA calibration. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1781011

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

Cygnus X‐3, among the X‐ray binaries, is one of the brightest in the radio band, repeatedly exhibiting huge radio flares. The X‐ray spectra shows two definite states, low (correspondingly hard) and high (correspondingly soft). During the hard state the X‐ray spectra shows a pivoting behaviour correlated to the radio emission. In the high state the X‐ray spectra shows a gamut of behaviour which controls the radio flaring activity of the source. The complete evolution of the X‐ray spectra along with the radio flaring activity is reported here, for the first time for this source. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1781012

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

Since the launch of the Rossi X‐ray Timing Explorer in 1995 our understanding of jetted outflows has significantly improved. Indeed, relativistic jets are now believed to be a fairly ubiquitous property of accreting compact objects, that are intimately coupled with the accretion history. In this review, we summarize the observational connections in X‐ray binaries between accretion flows and relativistic outflows (especially the relation with the X‐ray states). We emphasize those aspects that have significantly benefited from the RXTE experiment, including the role that jets could play at high energies. We also review recent observations of large scale relativistic jets that could point to their long term effects on the interstellar medium. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1781013

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

Time‐dependent x‐ray and radio observations of accreting sources give considerable insight into how jets might be produced, both in low‐luminosity and high‐luminosity situations. I discuss recent observations of binary x‐ray sources and AGN that may have a direct bearing on jet production, and I review the theoretical efforts that have been made to understand them. While it is certainly true that jet production can be understood only with a good accretion model, I also argue that accretion onto compact objects cannot be understood without fully taking into account the production of a jet. Jets are probably a fundamental aspect of some accretion modes.In a quest for an integrated model for accretion and jet production I introduce a new accretion concept, the magnetically‐dominated accretion flow or MDAF, as an alternative to current models for the low/hard/plateau state of accreting black holes (and the atoll source island state). Although much quantitative work needs to be performed before the concept can evolve into a true model, MDAFs have a number of phenomenological advantages. In addition to providing explanations for several X‐ray timing and radio properties of accreting sources, the MDAF suggests a model for the infrared flares in the Galactic center. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1781014

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

I discuss some potential contributions of future X‐ray timing missions to understanding relativistic jet systems. I focus particularly on stellar‐mass black hole systems, as other authors in this proceedings cover AGN, etc. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1781015

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

We have taken optical and infrared observations during the 2002 outburst of the soft X‐ray transient, 4U 1543‐47. A secondary maximum occurs in the lightcurves during the outburst decline. This feature is much stronger at infrared wavelengths than optical. We have applied single blackbody, multicolor blackbody and broken‐power law models to the optical/infrared spectral energy distribution of the secondary maximum and find that the broken power‐law provides the best fit. We therefore conclude that the secondary maximum emission originates from a jet. We also show the most recent lightcurves of the 2002/2003 outburst of GX 339‐4 in which a secondary maximum appears. This leads us to the conclusion that secondary maxima may be a common occurrence in soft X‐ray transients during outburst decline which appear after the object transitions into the low‐hard state. Infrared observations of such phenomena will give reliable triggers for multiwavelength observations, allowing us to greatly improve our knowledge of jet formation and behavior, and how this relates to the accretion geometry. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1781016

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

We present simultaneous X‐ray and radio views of accretion during jet outflow. Previously, we imaged superluminal ejecta after X‐ray/radio flares, and discovered an AU‐scale nuclear jet. Recently, we identified trends in RXTE ASM data to predict the flares, and so captured the evolution of the accretion disk with pointed PCA observations. We also observed in three radio bands with the VLBA on scales of 10–1000 AU, on 3 consecutive days.The radio images show two distinct types of outflow, and the corresponding X‐ray properties are clearly identified. We discuss the evolution of the disk/corona system (viz. X‐ray flux, spectral hardness, frequency of the 1–10 Hz QPO, and time lag between fluctuations in the soft & hard bands) as the relativistic outflow is launched. We believe these X‐ray/radio data represent strong constraints on models for the disk/jet connection. Considerable work remains, however, to decode the physical conditions operating in the disk from their observational signatures. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1781017

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

We formulate and solve the diffusion problem of line photon propagation in a bulk outflow from a compact object (black hole or neutron star) using a generic assumption regarding the distribution of line photons within the outflow. Thomson scattering of the line photons within the expanding flow leads to a decrease of their energy which is of first order inv/c, wherevis the outflow velocity andcthe speed of light. We demonstrate that the emergent line profile is closely related to the time distribution of photons diffusing through the flow (the light curve) and consists of a broad redshifted feature. We analyzed the line profiles for the general case of outflow density distribution. We emphasize that the redshifted lines are intrinsic properties of the powerful outflow that are supposed to be in many compact objects. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1781018

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

We present a disk instability model for unusually short, but intense and chaotic, flares of a few days observed in a black hole microquasar V4641 Sgr= SAX J1819.3‐2525, a multiple component relativistic jet source. To reproduce the observed short duration of the flare, a ring‐like, truncated Keplerian disk is required. We discuss causes of such a truncated accretion disk based on the disk instability model, and implication to short‐duration flare events observed in other microquasars and fast X‐ray transients. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1781019

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

Microquasars, nearby stellar‐scale analogy of quasars, are producing jets at speeds very close to the speed of light up to 0.98 c. Microquasars are also accreting transient or persistent X‐ray binaries. For a decade since its discovery, the phenomena of microquasars have had a great deal of attention. The observation of transient flares and accompanied jet phenomena is one of the highlights in the fields of X‐ray, radio and, very recently, infrared astronomy. The recent observations have indicated that the superluminal jets probably are the common nature of the black hole X‐ray binaries and, in part, of the neutron star binary sources. The recent development in observational techniques has made it possible to study detailed feature of jet phenomena. In the radio the very long baseline interferometry (VLBI) is required to map images of jets. The first Korean VLBI Network (KVN), recently proposed for the mm‐wave multi‐channel receiver system of 2.5, 8.5, 23, 43, 86–129 GHz, therefore, can be a promising tool of probing the nature of microquasars. In this paper, we present the strategy of observing microquasar phenomena with radio telescopes in Korea, including KVN, and international collaboration with Japanese VLBI system, VERA. Monitoring program for microquasars with 6–14–21 m array is also presented. As an example radio timing of frequently flaring, radio‐bright microquasars such as GRS 1915+105 and Cyg X‐3 are discussed. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1781020

出版商:AIP    

年代:1904

数据来源: AIP