In x‐ray pulsars, the emission from the bottom of the accretion column in the magnetic pole propagates to the observers through the surrounding environment: the magnetosphere, the accretion disk and the disk corona, the stellar wind, the companion’s atmosphere, and finally the interstellar medium. The photoionization zone of the stellar wind, which is formed surrounding the neutron star by x‐ray irradiation, plays an important role as a reprocessing site. The spectrum originating from the polar caps is modified by the photoelectric absorption and subsequent fluorescent emission, Thomson/Compton scattering and synchrotron resonant scattering that occur in these environments. Modifications in the spectrum due to the reprocessing are briefly reviewed based on the recent results obtained from observations by Tenma, EXOST, and Ginga. A preliminary result from Vela X‐1 with ASCA is presented, exhibiting a new aspect in studying x‐ray pulsars.
{"title":"X‐ray scattering in x‐ray binary pulsars","authors":"F. Nagase","doi":"10.1063/1.46033","DOIUrl":"https://doi.org/10.1063/1.46033","url":null,"abstract":"In x‐ray pulsars, the emission from the bottom of the accretion column in the magnetic pole propagates to the observers through the surrounding environment: the magnetosphere, the accretion disk and the disk corona, the stellar wind, the companion’s atmosphere, and finally the interstellar medium. The photoionization zone of the stellar wind, which is formed surrounding the neutron star by x‐ray irradiation, plays an important role as a reprocessing site. The spectrum originating from the polar caps is modified by the photoelectric absorption and subsequent fluorescent emission, Thomson/Compton scattering and synchrotron resonant scattering that occur in these environments. Modifications in the spectrum due to the reprocessing are briefly reviewed based on the recent results obtained from observations by Tenma, EXOST, and Ginga. A preliminary result from Vela X‐1 with ASCA is presented, exhibiting a new aspect in studying x‐ray pulsars.","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"30 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":"133852093","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 properties of accreting x‐ray pulsars are reviewed paying particular attention to their pulse and orbital periods and high‐energy x‐ray spectra. The importance of making broad‐band x‐ray measurements of these systems is demonstrated.
{"title":"The properties of accreting x‐ray pulsars","authors":"A. Parmar","doi":"10.1063/1.45982","DOIUrl":"https://doi.org/10.1063/1.45982","url":null,"abstract":"The properties of accreting x‐ray pulsars are reviewed paying particular attention to their pulse and orbital periods and high‐energy x‐ray spectra. The importance of making broad‐band x‐ray measurements of these systems is demonstrated.","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"5 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":"128247759","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 I‐band light curve of GX 9+9 shows a roughly sinusoidal modulation. The best fitting sine‐wave has a period and formal error of 4.1744±0.0002 hours. When the data are folded on this period, however, clear variations in the shape of the light curve are apparent from night to night. The modulation in the mean light‐curve has a semi‐amplitude of 10.6%.
{"title":"The I band light curve of the low mass x‐ray binary GX 9+9","authors":"C. Haswell, T. Abbott","doi":"10.1063/1.46009","DOIUrl":"https://doi.org/10.1063/1.46009","url":null,"abstract":"The I‐band light curve of GX 9+9 shows a roughly sinusoidal modulation. The best fitting sine‐wave has a period and formal error of 4.1744±0.0002 hours. When the data are folded on this period, however, clear variations in the shape of the light curve are apparent from night to night. The modulation in the mean light‐curve has a semi‐amplitude of 10.6%.","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"42 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":"121857668","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}
Modern stellar evolutionary tracks are used to calculate the evolution of a very large number of massive binary star systems (Mtot≳15M⊙) which cover a wide range of total masses, mass ratios, and starting preparations. Each binary is evolved accounting for mass and angular momentum loss (due to wind mass loss, mass loss during Roche lobe overflow of the primary, mass loss during a common envelope phase should it occur), through the supernova of the primary to the x‐ray binary phase. Using the observed rate of star formation in our galaxy and the properties of massive binaries, we calculated the expected high mass x‐ray binary (HMXRB) population in the Galaxy. We test various massive binary evolutionary scenarios by comparing the resulting predictions to the x‐ray observations. Our principle result is that approximately 70% of the overflow matter is lost from a massive binary system during mass transfer in the Roche lobe overflow phase.
{"title":"The galactic high mass x‐ray binary population","authors":"William W. Dalton, C. Sarazin","doi":"10.1063/1.45953","DOIUrl":"https://doi.org/10.1063/1.45953","url":null,"abstract":"Modern stellar evolutionary tracks are used to calculate the evolution of a very large number of massive binary star systems (Mtot≳15M⊙) which cover a wide range of total masses, mass ratios, and starting preparations. Each binary is evolved accounting for mass and angular momentum loss (due to wind mass loss, mass loss during Roche lobe overflow of the primary, mass loss during a common envelope phase should it occur), through the supernova of the primary to the x‐ray binary phase. Using the observed rate of star formation in our galaxy and the properties of massive binaries, we calculated the expected high mass x‐ray binary (HMXRB) population in the Galaxy. We test various massive binary evolutionary scenarios by comparing the resulting predictions to the x‐ray observations. Our principle result is that approximately 70% of the overflow matter is lost from a massive binary system during mass transfer in the Roche lobe overflow phase.","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"29 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":"124995870","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}
E. Harlaftis, Derek Jones, P. Charles, Andrew J. Martin
We present new photometric observations of the GRO transient J0422+32 which show a two‐hour and a five‐hour variation of only 0.1 magnitude in amplitude. Spectroscopic observations during the late decline of the August 1992 outburst and during the August 1993 outburst show variability in the double‐peaked Balmer and He ii profiles on a timescale of hours and reveal red‐shifted emission components at two epochs.
{"title":"ING photometry and spectroscopy of the optical counterpart of the x‐ray transient GRO J0422+32","authors":"E. Harlaftis, Derek Jones, P. Charles, Andrew J. Martin","doi":"10.1063/1.45995","DOIUrl":"https://doi.org/10.1063/1.45995","url":null,"abstract":"We present new photometric observations of the GRO transient J0422+32 which show a two‐hour and a five‐hour variation of only 0.1 magnitude in amplitude. Spectroscopic observations during the late decline of the August 1992 outburst and during the August 1993 outburst show variability in the double‐peaked Balmer and He ii profiles on a timescale of hours and reveal red‐shifted emission components at two epochs.","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"31 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":"130190101","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 investigate pulsations of the red‐dwarf companion of the neutron star (NS) in a low‐mass binary (LMB). The illumination of the donor star by the pulsar’s high‐energy, non‐thermal radiation and relativistic wind may substantially affect its structure. We present a quantitative analysis of the oscillation spectrum of a red dwarf which evolved in an LMB and underwent a stage of evaporation. We calculate the p‐ and g‐modes for red dwarfs of masses within the interval 0.2–0.6 M⊙. For comparison, we present similar calculations for ZAMS stars of the same masses. In the case of less massive donor stars (∼0.2 M⊙) the oscillation spectrum becomes qualitatively different from that of their ZAMS counterparts. We also consider tidally forced g‐modes and perform a linear analysis of these oscillations for different degrees of the non‐synchronization between the orbital rotation and spin rotation of the red‐dwarf component. We discuss the triggering by these oscillations of the Roche‐lobe overflow and sudden mass lo...
{"title":"Evolution of LMBs and Asteroseismology","authors":"M. Sarna, U. Lee, A. Muslimov","doi":"10.1063/1.45963","DOIUrl":"https://doi.org/10.1063/1.45963","url":null,"abstract":"We investigate pulsations of the red‐dwarf companion of the neutron star (NS) in a low‐mass binary (LMB). The illumination of the donor star by the pulsar’s high‐energy, non‐thermal radiation and relativistic wind may substantially affect its structure. We present a quantitative analysis of the oscillation spectrum of a red dwarf which evolved in an LMB and underwent a stage of evaporation. We calculate the p‐ and g‐modes for red dwarfs of masses within the interval 0.2–0.6 M⊙. For comparison, we present similar calculations for ZAMS stars of the same masses. In the case of less massive donor stars (∼0.2 M⊙) the oscillation spectrum becomes qualitatively different from that of their ZAMS counterparts. We also consider tidally forced g‐modes and perform a linear analysis of these oscillations for different degrees of the non‐synchronization between the orbital rotation and spin rotation of the red‐dwarf component. We discuss the triggering by these oscillations of the Roche‐lobe overflow and sudden mass lo...","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"24 1 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":"131288766","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 vertical oscillation of an accretion disk surrounding a neutron star is studied by using the OPAL opacities. We have found that the vertical structure of the model disk is vibrationally unstable when we use new opacities instead of the Los Alamos opacities.
{"title":"Effect of new opacities on the disk instability","authors":"M. Takeuti, R. Kanetake","doi":"10.1063/1.45938","DOIUrl":"https://doi.org/10.1063/1.45938","url":null,"abstract":"The vertical oscillation of an accretion disk surrounding a neutron star is studied by using the OPAL opacities. We have found that the vertical structure of the model disk is vibrationally unstable when we use new opacities instead of the Los Alamos opacities.","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"118 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":"128128691","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 derive a constraint on the pair density ratio, z+=n+/np in an electron‐positron pair wind flowing away from the central region of an accretion disk around a compact object under the assumption of a coupling between electrons, positrons, and protons. The observed annihilation flux per unit volume is used to determine a minimum mass loss rate per unit area, M*, for a given pair density ratio at the base of the streamline. The requirement that M*
{"title":"A lower limit on the pair density ratio (z+) in an electron‐positron pair wind","authors":"M. D. Moscoso, J. Wheeler","doi":"10.1063/1.45993","DOIUrl":"https://doi.org/10.1063/1.45993","url":null,"abstract":"We derive a constraint on the pair density ratio, z+=n+/np in an electron‐positron pair wind flowing away from the central region of an accretion disk around a compact object under the assumption of a coupling between electrons, positrons, and protons. The observed annihilation flux per unit volume is used to determine a minimum mass loss rate per unit area, M*, for a given pair density ratio at the base of the streamline. The requirement that M*<M*,Edd (the mean Eddington mass loss rate per unit area) then places a lower limit on the pair density ratio at the base of the wind, z+,min. The GRANAT/SIGMA experiment observed a positron annihilation line in Nova Muscae 1991. The narrow width and redshift of the line suggest that the pair production and annihilation regions are physically distinct. We hypothesize that an electron‐positron pair wind transports the pairs from the production to the annihilation region and calculate z+,min.","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"48 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":"122708186","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}
An ultraviolet spectrum of the long‐period low‐mass x‐ray binary 2S 0921‐630 was obtained with IUE near the time of partial eclipse of the accretion disk by its G‐giant companion star. The short‐wavelength spectrum shows a very weak continuum, with emission lines of N v, Si iv, C iv, and He iv. The strength of these lines during eclipse implies that the volume of the line‐emitting region must be larger than that which is eclipsed in the optical light curve. The UV spectrum is similar to that of Cyg X‐2 (when it is on the x‐ray flaring branch of x‐ray color‐color plots) although the weakness of N v may indicate a lower abundance for that element. Alternatively, the apparent absence of N iii and N iv in 2S 0921‐630 suggests the upper portion of the accretion disk in 2S 0921‐630 may be hotter than that in Cyg X‐2.
{"title":"The ultraviolet spectrum of 2S 0921‐630","authors":"P. Schmidtke","doi":"10.1063/1.46015","DOIUrl":"https://doi.org/10.1063/1.46015","url":null,"abstract":"An ultraviolet spectrum of the long‐period low‐mass x‐ray binary 2S 0921‐630 was obtained with IUE near the time of partial eclipse of the accretion disk by its G‐giant companion star. The short‐wavelength spectrum shows a very weak continuum, with emission lines of N v, Si iv, C iv, and He iv. The strength of these lines during eclipse implies that the volume of the line‐emitting region must be larger than that which is eclipsed in the optical light curve. The UV spectrum is similar to that of Cyg X‐2 (when it is on the x‐ray flaring branch of x‐ray color‐color plots) although the weakness of N v may indicate a lower abundance for that element. Alternatively, the apparent absence of N iii and N iv in 2S 0921‐630 suggests the upper portion of the accretion disk in 2S 0921‐630 may be hotter than that in Cyg X‐2.","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"16 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":"132055336","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 concept of the black hole was derived from the Schwarzchild metric which was then the only exact and reliable solution of Einstein’s field equations (Rμσ=0). That metric gives a coordinate velocity for electromagnetic radiation (EMR) that goes to zero at the Schwarzchild radius, thereby resulting in the black hole. This analysis shows that inherent in the Schwarzchild solution is the assumption that the velocity of EMR in a gravitational field is independent of wavelength and frequency. An alternate exact solution is derived making the opposite assumption. The resulting metric’s properties include: a) the coordinate velocity of light is frequency dependent and does not predict a black hole and b) the mass parameter has dimensions of volume unlike Schwarzchild’s geometric mass parameter. The implications of these results are discussed.
{"title":"Analysis of the assumption of frequency independence of light velocity in a gravitational field","authors":"C. A. Gall","doi":"10.1063/1.45994","DOIUrl":"https://doi.org/10.1063/1.45994","url":null,"abstract":"The concept of the black hole was derived from the Schwarzchild metric which was then the only exact and reliable solution of Einstein’s field equations (Rμσ=0). That metric gives a coordinate velocity for electromagnetic radiation (EMR) that goes to zero at the Schwarzchild radius, thereby resulting in the black hole. This analysis shows that inherent in the Schwarzchild solution is the assumption that the velocity of EMR in a gravitational field is independent of wavelength and frequency. An alternate exact solution is derived making the opposite assumption. The resulting metric’s properties include: a) the coordinate velocity of light is frequency dependent and does not predict a black hole and b) the mass parameter has dimensions of volume unlike Schwarzchild’s geometric mass parameter. The implications of these results are discussed.","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":"133899720","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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