We present results from a potentially powerful new method for modeling two‐dimensional radiative transfers in anisotropic systems. The method is highly efficient, allowing inclusion of radiative attenuation in dynamical simulations. Comparisons are made with a detailed radiative transfer code. As a first application, we compute self‐consistent models of Compton‐heated coronae in systems with luminosities up to 0.6 LEdd. Lower luminosity models are used to compare with the results of earlier work.We present results from a potentially powerful new method for modeling two‐dimensional radiative transfers in anisotropic systems. The method is highly efficient, allowing inclusion of radiative attenuation in dynamical simulations. Comparisons are made with a detailed radiative transfer code. As a first application, we compute self‐consistent models of Compton‐heated coronae in systems with luminosities up to 0.6 LEdd. Lower luminosity models are used to compare with the results of earlier work.
{"title":"Models of accretion disk coronae in high luminosity systems","authors":"S. Murray, R. Klein, J. Castor, C. McKee","doi":"10.1063/1.46011","DOIUrl":"https://doi.org/10.1063/1.46011","url":null,"abstract":"We present results from a potentially powerful new method for modeling two‐dimensional radiative transfers in anisotropic systems. The method is highly efficient, allowing inclusion of radiative attenuation in dynamical simulations. Comparisons are made with a detailed radiative transfer code. As a first application, we compute self‐consistent models of Compton‐heated coronae in systems with luminosities up to 0.6 LEdd. Lower luminosity models are used to compare with the results of earlier work.We present results from a potentially powerful new method for modeling two‐dimensional radiative transfers in anisotropic systems. The method is highly efficient, allowing inclusion of radiative attenuation in dynamical simulations. Comparisons are made with a detailed radiative transfer code. As a first application, we compute self‐consistent models of Compton‐heated coronae in systems with luminosities up to 0.6 LEdd. Lower luminosity models are used to compare with the results of earlier work.","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"221 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115654446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The x‐ray source in high mass x‐ray binaries (HMXB’s) provides a unique ‘‘active’’ probe of the winds of massive stars. As the binary system orbits around the center of mass, our line of sight changes continuously, allowing us to map the distribution of x‐ray absorbing gas in the system. At the same time, the strong x‐ray flux alters the local dynamics of the wind, providing us with an opportunity to study the physics of radiatively‐driven winds. Some HMXB systems even provide a variable x‐ray source, from which we can measure the effects of a local x‐ray flux. New hydrodynamic models, coupled with recent observations, allow us to take advantage of this natural x‐ray machine, providing new insight into the dynamics of radiatively driven winds. The various physical processes that affect the wind dynamics will be reviewed, as well as the observational consequences of these processes as gleaned from multidimensional hydrodynamic models.
{"title":"Hydrodynamics of winds in high mass x‐ray binaries","authors":"J. Blondin","doi":"10.1063/1.45942","DOIUrl":"https://doi.org/10.1063/1.45942","url":null,"abstract":"The x‐ray source in high mass x‐ray binaries (HMXB’s) provides a unique ‘‘active’’ probe of the winds of massive stars. As the binary system orbits around the center of mass, our line of sight changes continuously, allowing us to map the distribution of x‐ray absorbing gas in the system. At the same time, the strong x‐ray flux alters the local dynamics of the wind, providing us with an opportunity to study the physics of radiatively‐driven winds. Some HMXB systems even provide a variable x‐ray source, from which we can measure the effects of a local x‐ray flux. New hydrodynamic models, coupled with recent observations, allow us to take advantage of this natural x‐ray machine, providing new insight into the dynamics of radiatively driven winds. The various physical processes that affect the wind dynamics will be reviewed, as well as the observational consequences of these processes as gleaned from multidimensional hydrodynamic models.","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125589983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents a simple kinematic model of the so‐called ‘‘very high state’’ of black hole candidates, during which several QPO observations have been made. The model is based upon the viscous and thermal instabilities that are believed to be present in accretion disks. In this model, the very high state is a transition phase between the high (thermal, quiescent) state and low (power law, highly variable) state that is characterized by a quasi‐stable disk oscillating on the local instability timescales. The disk can be stablized by a hot wind that could feed a Compton cloud, which in turn could produce the hard tail in the observed x‐ray spectra. The model is able to reproduce both the overall shape and the amplitude of the power spectral density and the observed frequency dependent lags between the hard and soft x‐rays. In addition, the required energetics of the hot wind is shown to be consistent with the energy required to feed the hypothesized Compton cloud. Specific comparisons between the model and data taken during the very high state of GX339‐4 are made.
{"title":"Modeling black hole x‐ray power spectra","authors":"M. Nowak","doi":"10.1063/1.45937","DOIUrl":"https://doi.org/10.1063/1.45937","url":null,"abstract":"This paper presents a simple kinematic model of the so‐called ‘‘very high state’’ of black hole candidates, during which several QPO observations have been made. The model is based upon the viscous and thermal instabilities that are believed to be present in accretion disks. In this model, the very high state is a transition phase between the high (thermal, quiescent) state and low (power law, highly variable) state that is characterized by a quasi‐stable disk oscillating on the local instability timescales. The disk can be stablized by a hot wind that could feed a Compton cloud, which in turn could produce the hard tail in the observed x‐ray spectra. The model is able to reproduce both the overall shape and the amplitude of the power spectral density and the observed frequency dependent lags between the hard and soft x‐rays. In addition, the required energetics of the hot wind is shown to be consistent with the energy required to feed the hypothesized Compton cloud. Specific comparisons between the model and data taken during the very high state of GX339‐4 are made.","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122706819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Neutron stars in x‐ray binaries have strong magnetic fields, those in old binaries usually weak magnetic fields, but exceptions confute simple explanations. Observational evidence claimed to prove spontaneous field decay in single radio pulsars is found wanting on closer scrutiny. Some detailed properties of the z‐distributions of radio pulsars are described; these may explain the contradictory results of apparently similar population synthesis studies.
{"title":"Do magnetic fields of neutron stars decay","authors":"F. Verbunt","doi":"10.1063/1.45968","DOIUrl":"https://doi.org/10.1063/1.45968","url":null,"abstract":"Neutron stars in x‐ray binaries have strong magnetic fields, those in old binaries usually weak magnetic fields, but exceptions confute simple explanations. Observational evidence claimed to prove spontaneous field decay in single radio pulsars is found wanting on closer scrutiny. Some detailed properties of the z‐distributions of radio pulsars are described; these may explain the contradictory results of apparently similar population synthesis studies.","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"337 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122751351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Rosat observations of cataclysmic variables","authors":"A. V. Teeseling, F. Verbunt","doi":"10.1063/1.46005","DOIUrl":"https://doi.org/10.1063/1.46005","url":null,"abstract":"","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122757876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We review the various radio surveys which have been designed primarily for discovering recycled pulsars. In the 11 years since the first millisecond pulsar, PSR 1937+21, was found, a total of about 55 have been discovered, although most of these have only been found since 1988. Around that time, the first millisecond pulsar was found in a globular cluster and by now a total of 34 pulsars have been found in these objects. These include a total of 29 pulsars with period less than 50 ms and 14 are in binary systems. New galactic surveys have now discovered 21 millisecond pulsars, mostly discovered in the past 2 years. These constitute a very nearby population which has a space density similar to that of normal pulsars. However, their formation rate is only one every 104–105 years.
{"title":"Recycled radio pulsars","authors":"A. Lyne","doi":"10.1063/1.46039","DOIUrl":"https://doi.org/10.1063/1.46039","url":null,"abstract":"We review the various radio surveys which have been designed primarily for discovering recycled pulsars. In the 11 years since the first millisecond pulsar, PSR 1937+21, was found, a total of about 55 have been discovered, although most of these have only been found since 1988. Around that time, the first millisecond pulsar was found in a globular cluster and by now a total of 34 pulsars have been found in these objects. These include a total of 29 pulsars with period less than 50 ms and 14 are in binary systems. New galactic surveys have now discovered 21 millisecond pulsars, mostly discovered in the past 2 years. These constitute a very nearby population which has a space density similar to that of normal pulsars. However, their formation rate is only one every 104–105 years.","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"195 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114252550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The increase in the orbital period of X 1822–371 with a timescale of 3×106 yrs is confirmed by a new ROSAT observation. In contrast to some other LMXBs, a simple quadratic ephemeris remains a good fit to the eclipse timings.
X 1822-371轨道周期的增加(时间尺度为3×106年)被ROSAT的新观测证实。与其他一些lmxb相比，简单的二次星历表仍然很适合日食时间。
{"title":"An ephemeris update for X 1822–371","authors":"C. Hellier, A. Smale","doi":"10.1063/1.46038","DOIUrl":"https://doi.org/10.1063/1.46038","url":null,"abstract":"The increase in the orbital period of X 1822–371 with a timescale of 3×106 yrs is confirmed by a new ROSAT observation. In contrast to some other LMXBs, a simple quadratic ephemeris remains a good fit to the eclipse timings.","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122203599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The rapid x‐ray variability of black hole candidates and neutron stars with high, low, and very low magnetic fields is compared. Similarities in the properties of the variability between source types suggest that similar physical mechanisms underly some power spectral components seen in common in neutron stars with various magnetic‐field strengths and black hole candidates. Other components appear to be unique for magnetized neutron stars. Suggestions are made for the sites of origin and generation mechanisms of these power spectral components.
{"title":"Rapid variability in neutron stars and black holes - Comparison and attempt at unification","authors":"M. Klis","doi":"10.1063/1.45930","DOIUrl":"https://doi.org/10.1063/1.45930","url":null,"abstract":"The rapid x‐ray variability of black hole candidates and neutron stars with high, low, and very low magnetic fields is compared. Similarities in the properties of the variability between source types suggest that similar physical mechanisms underly some power spectral components seen in common in neutron stars with various magnetic‐field strengths and black hole candidates. Other components appear to be unique for magnetized neutron stars. Suggestions are made for the sites of origin and generation mechanisms of these power spectral components.","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121300784","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
EXOSAT observations of three absorption dips in Hercules X‐1 are presented. A partial covering model is employed, and qualitative differences between the three dips are highlighted. The behavior of the pulse profile during the dips is discussed. A transition between different phase states of the absorbing medium is observed within one dip, consistent with the cooling and condensation of an ionized cloud into discrete absorbing clumps.
{"title":"Exosat studies of dips in Hercules X‐1","authors":"A. Reynolds, A. Parmar","doi":"10.1063/1.46035","DOIUrl":"https://doi.org/10.1063/1.46035","url":null,"abstract":"EXOSAT observations of three absorption dips in Hercules X‐1 are presented. A partial covering model is employed, and qualitative differences between the three dips are highlighted. The behavior of the pulse profile during the dips is discussed. A transition between different phase states of the absorbing medium is observed within one dip, consistent with the cooling and condensation of an ionized cloud into discrete absorbing clumps.","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121637019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Wolinski, J. Dolan, P. Boyd, J. Elliot, M. Nelson, J. Percival, L. Townsley, G. W. Citters
Variable linear polarization has previously been observed in the visible Tapia, 1984), Vela XR‐1 (Dolan & Tapia, 1988), and Cyg XR‐1 (Kemp et al., 1976, 1978). We present the first linear polarization observations of these systems in the ultraviolet (UV), using the High Speed Photometer (HSP) aboard the Hubble Space Telescope. The UV polarimetric light curves obtained from Vela XR‐1 and 4U1700‐37 display an added component of polarization at first quadrature inconsistent with the standard model of Brown et al. (1978) for scattering in binary systems. However, the UV polarimetric light curves toward Cyg XR‐1 are well fit by the standard model. Variations attributable to changes in scattering structure from one orbit to the next are also detected in two of the systems. Possible origins of the additional polarization detected at first quadrature in Vela XR‐1 and 4U1700‐37 are evaluated.
{"title":"UV polarimetry of the x‐ray binary systems 4U1700‐37, Vela XR‐1, and Cygnus XR‐1","authors":"K. Wolinski, J. Dolan, P. Boyd, J. Elliot, M. Nelson, J. Percival, L. Townsley, G. W. Citters","doi":"10.1063/1.45970","DOIUrl":"https://doi.org/10.1063/1.45970","url":null,"abstract":"Variable linear polarization has previously been observed in the visible Tapia, 1984), Vela XR‐1 (Dolan & Tapia, 1988), and Cyg XR‐1 (Kemp et al., 1976, 1978). We present the first linear polarization observations of these systems in the ultraviolet (UV), using the High Speed Photometer (HSP) aboard the Hubble Space Telescope. The UV polarimetric light curves obtained from Vela XR‐1 and 4U1700‐37 display an added component of polarization at first quadrature inconsistent with the standard model of Brown et al. (1978) for scattering in binary systems. However, the UV polarimetric light curves toward Cyg XR‐1 are well fit by the standard model. Variations attributable to changes in scattering structure from one orbit to the next are also detected in two of the systems. Possible origins of the additional polarization detected at first quadrature in Vela XR‐1 and 4U1700‐37 are evaluated.","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127591202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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