Several AM Her objects show low amplitude, 1 Hz quasi‐periodic oscillations in power spectra of their optical emission. Wolff, Wood, and Imamura, in a recent series of papers, show that accretion noise driven radiative shocks are a plausible model for this phenomenon. Here, we discuss how two‐temperature effects can play an important role in regulating the frequency of the shock oscillations within the formalism outlined by Wolff et al. We argue that two‐temperature effects can be important in accretion flows onto white dwarfs with masses as low as 0.6 M⊙ if cyclotron radiation is an important energy loss process in the shocked gas. The planned USA x‐ray timing experiment on the ARGOS satellite should be able to detect the quasi‐periodic x‐ray oscillations predicted by our shock oscillation model.
{"title":"Dynamics of accretion shocks in AM Herculis systems: Models for high mass white dwarfs","authors":"M. Wolff, K. Wood, J. Imamura","doi":"10.1063/1.45927","DOIUrl":"https://doi.org/10.1063/1.45927","url":null,"abstract":"Several AM Her objects show low amplitude, 1 Hz quasi‐periodic oscillations in power spectra of their optical emission. Wolff, Wood, and Imamura, in a recent series of papers, show that accretion noise driven radiative shocks are a plausible model for this phenomenon. Here, we discuss how two‐temperature effects can play an important role in regulating the frequency of the shock oscillations within the formalism outlined by Wolff et al. We argue that two‐temperature effects can be important in accretion flows onto white dwarfs with masses as low as 0.6 M⊙ if cyclotron radiation is an important energy loss process in the shocked gas. The planned USA x‐ray timing experiment on the ARGOS satellite should be able to detect the quasi‐periodic x‐ray oscillations predicted by our shock oscillation model.","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"27 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":"122590243","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 study numerically the quasi‐spherical accretion of matter on to a compact object (neutron star or black hole). Anisotropic x‐ray luminosity, powered by mass accretion, heats the accreting gas through Compton scattering. When the gas temperature increases above the local escape temperature, part of the accreting gas will flow outwards as a result of the action of buoyancy force. The direction of the outflow coincides with the maximum of the x‐ray luminosity. The depth of outflow is correlated with the energy of x‐ray quanta. In spite of its quantum nature, Compton heating markedly affects the gas, forcing the matter outflow at x‐ray luminosities as small as three or four orders of magnitude less than the Eddington limit. The phenomenon of hot gas outflow takes place in the case of accretion on to a wind‐fed x‐ray source in a wide binary with massive OB or Be‐star. We propose a new spin‐down mechanism for accreting neutron stars that explains the existence of a number of long‐period (p∼100–1000 s) x‐ray ...
{"title":"The Outflowing Regime of Quasi-Spherical Accretion on to X-Ray Objects and the Spin-Down Mechanism for Wind-Fed X-ray Pulsars","authors":"A. Illarionov, I. Igumenshchev, D. Kompaneets","doi":"10.1063/1.45946","DOIUrl":"https://doi.org/10.1063/1.45946","url":null,"abstract":"We study numerically the quasi‐spherical accretion of matter on to a compact object (neutron star or black hole). Anisotropic x‐ray luminosity, powered by mass accretion, heats the accreting gas through Compton scattering. When the gas temperature increases above the local escape temperature, part of the accreting gas will flow outwards as a result of the action of buoyancy force. The direction of the outflow coincides with the maximum of the x‐ray luminosity. The depth of outflow is correlated with the energy of x‐ray quanta. In spite of its quantum nature, Compton heating markedly affects the gas, forcing the matter outflow at x‐ray luminosities as small as three or four orders of magnitude less than the Eddington limit. The phenomenon of hot gas outflow takes place in the case of accretion on to a wind‐fed x‐ray source in a wide binary with massive OB or Be‐star. We propose a new spin‐down mechanism for accreting neutron stars that explains the existence of a number of long‐period (p∼100–1000 s) x‐ray ...","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":"132245582","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 briefly review the processes by which Thorne‐Żytkow objects (TŻOs), i.e., red supergiants with neutron cores, are believed to form. The energy source in massive TŻOs is nuclear burning, provided by a modified rapid p process. After ≲106 yr, this process is expected to break down, leading to a neutrino runaway and the collapse of the TŻO envelope. Part of the envelope will be accreted by the neutron‐star core, which will be spun up and may be transformed into a black hole. The rest of the envelope is likely to form a centrifugally supported disk. This disk will ultimately become gravitationally unstable, possibly forming one or more self‐gravitating objects (planets or low‐mass stars) in the process. The final system may be a spun‐up pulsar surrounded by planets, a low‐mass x‐ray binary, or a low‐mass black‐hole binary like V404 Cygni.
{"title":"The fate of Thorne‐Żytkow objects","authors":"P. Podsiadlowski, R. Cannon, M. Rees","doi":"10.1063/1.45980","DOIUrl":"https://doi.org/10.1063/1.45980","url":null,"abstract":"We briefly review the processes by which Thorne‐Żytkow objects (TŻOs), i.e., red supergiants with neutron cores, are believed to form. The energy source in massive TŻOs is nuclear burning, provided by a modified rapid p process. After ≲106 yr, this process is expected to break down, leading to a neutrino runaway and the collapse of the TŻO envelope. Part of the envelope will be accreted by the neutron‐star core, which will be spun up and may be transformed into a black hole. The rest of the envelope is likely to form a centrifugally supported disk. This disk will ultimately become gravitationally unstable, possibly forming one or more self‐gravitating objects (planets or low‐mass stars) in the process. The final system may be a spun‐up pulsar surrounded by planets, a low‐mass x‐ray binary, or a low‐mass black‐hole binary like V404 Cygni.","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"6 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":"132574768","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":"X‐ray transitions of black hole binaries and variable α‐parameter disks","authors":"C. Luo, C. Meirelles, E. Liang","doi":"10.1063/1.45991","DOIUrl":"https://doi.org/10.1063/1.45991","url":null,"abstract":"","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"6 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":"130610487","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 PSR 1259−63 system is unique in that it is the first radio pulsar found to be in a binary system with a massive main sequence companion. As such, it may be the evolutionary missing link connecting the radio pulsars to the x‐ray emitting Be‐binaries. In this paper, we consider the conditions under which PSR 1259−63 may be the progenitor of the less eccentric, more slowly rotating x‐ray Be‐binaries such as 4U0115+63, A0535+26, and A0538−66. Scenarios invoking the interaction of pulsar with the stellar wind of the companion, are proposed to account for the rapid spin down phase which must occur in this system, if it is evolutionarily linked to accreting x‐ray binaries. The unexpected x‐ray emission observed from PSR 1259−63 may indicate that the interaction between the pulsar and the Be star occurs at greater distances and produces a greater spin down efficiency than has been previously calculated.
PSR 1259−63系统的独特之处在于，它是第一个在双星系统中发现的具有大质量主序伴星的射电脉冲星。因此，它可能是连接射电脉冲星和发射x射线的be -双星的进化中缺失的一环。在本文中，我们考虑了PSR 1259 - 63可能是较小偏心、旋转较慢的x射线be -双星(如4U0115+63、A0535+26和A0538 - 66)的祖先的条件。假设脉冲星与伴星的恒星风相互作用，可以解释在这个系统中必须发生的快速自旋下降阶段，如果它在进化上与吸积x射线双星有关的话。从PSR 1259−63观测到的意想不到的x射线发射可能表明脉冲星和Be星之间的相互作用发生在更远的距离上，并且产生比先前计算的更高的自旋下降效率。
{"title":"The evolutionary status of PSR 1259−63","authors":"L. Cominsky","doi":"10.1063/1.45959","DOIUrl":"https://doi.org/10.1063/1.45959","url":null,"abstract":"The PSR 1259−63 system is unique in that it is the first radio pulsar found to be in a binary system with a massive main sequence companion. As such, it may be the evolutionary missing link connecting the radio pulsars to the x‐ray emitting Be‐binaries. In this paper, we consider the conditions under which PSR 1259−63 may be the progenitor of the less eccentric, more slowly rotating x‐ray Be‐binaries such as 4U0115+63, A0535+26, and A0538−66. Scenarios invoking the interaction of pulsar with the stellar wind of the companion, are proposed to account for the rapid spin down phase which must occur in this system, if it is evolutionarily linked to accreting x‐ray binaries. The unexpected x‐ray emission observed from PSR 1259−63 may indicate that the interaction between the pulsar and the Be star occurs at greater distances and produces a greater spin down efficiency than has been previously calculated.","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"73 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":"127391960","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 Einstein X‐ray Observatory Satellite provided the first detection of isolated x‐ray sources in the Andromeda Galaxy. Recent ROSAT observations have provided observations of the x‐ray binaries in M31 complete to Lx∼1034 erg sec−1, and are sensitive enough to detect many supernova remnants and other x‐ray sources. Optical identifications are crucial to identify or confirm the identifications of these sources. This article reviews the search for optical counterparts to the Einstein x‐ray sources and discusses the ongoing efforts of the MIT‐UvA‐MPE group to identify optical counterparts to the ROSAT x‐ray sources.
{"title":"Optical identifications of M31 sources","authors":"E. Magnier","doi":"10.1063/1.46031","DOIUrl":"https://doi.org/10.1063/1.46031","url":null,"abstract":"The Einstein X‐ray Observatory Satellite provided the first detection of isolated x‐ray sources in the Andromeda Galaxy. Recent ROSAT observations have provided observations of the x‐ray binaries in M31 complete to Lx∼1034 erg sec−1, and are sensitive enough to detect many supernova remnants and other x‐ray sources. Optical identifications are crucial to identify or confirm the identifications of these sources. This article reviews the search for optical counterparts to the Einstein x‐ray sources and discusses the ongoing efforts of the MIT‐UvA‐MPE group to identify optical counterparts to the ROSAT x‐ray sources.","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127044781","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}
R. W. Nelson, J. C. Wang, E. Salpeter, I. Wasserman
Simple estimates indicate there should be ≳103 low luminosity x‐ray pulsars (L≳1034 erg s−1) in the Galaxy undergoing ‘‘low‐state’’ wind accretion in Be/x‐ray binary systems, and ∼108–109 isolated neutron stars which may be accreting directly from the interstellar medium. Despite their low effective temperatures (kTe≲300 eV), we predict the low luminosity accreting neutron stars with magnetic fields B∼(0.7−7)×1012 G should emit a substantial fraction (0.5–5%) of their total luminosity in a narrow (E/ΔE∼2–4) cyclotron emission line which peaks in the energy range ∼5–20 keV. In sharp contrast to the underlying thermal emission, this nonthermal cyclotron component will not be strongly absorbed by the intervening H i gas, and consequently it may be the only observable signature for the bulk of these low luminosity sources. We propose a search for this cyclotron emission feature in long pointed observations by ASCA of the Be/x‐ray transient pulsars V0331+53 and 4U0115+63 in their quiescent ‘‘low state’’.
{"title":"A potential cyclotron line signature in low luminosity x-ray pulsars","authors":"R. W. Nelson, J. C. Wang, E. Salpeter, I. Wasserman","doi":"10.1063/1.45944","DOIUrl":"https://doi.org/10.1063/1.45944","url":null,"abstract":"Simple estimates indicate there should be ≳103 low luminosity x‐ray pulsars (L≳1034 erg s−1) in the Galaxy undergoing ‘‘low‐state’’ wind accretion in Be/x‐ray binary systems, and ∼108–109 isolated neutron stars which may be accreting directly from the interstellar medium. Despite their low effective temperatures (kTe≲300 eV), we predict the low luminosity accreting neutron stars with magnetic fields B∼(0.7−7)×1012 G should emit a substantial fraction (0.5–5%) of their total luminosity in a narrow (E/ΔE∼2–4) cyclotron emission line which peaks in the energy range ∼5–20 keV. In sharp contrast to the underlying thermal emission, this nonthermal cyclotron component will not be strongly absorbed by the intervening H i gas, and consequently it may be the only observable signature for the bulk of these low luminosity sources. We propose a search for this cyclotron emission feature in long pointed observations by ASCA of the Be/x‐ray transient pulsars V0331+53 and 4U0115+63 in their quiescent ‘‘low state’’.","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128959368","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 gathering of a wealth of precise quantitative observational data on x‐ray binaries and recycled radio pulsars during the last decades has allowed the testing of many theoretical ideas on the physics, formation, and evolution of neutron stars and black holes, which could never have been tested on single compact objects. Also, new observations often have led to new theories and models which again can be tested observationally. In this talk I give a personal view of this development over the past thirty years.
{"title":"Three decades of x‐ray binaries, from the point of view of a theoretician","authors":"E. Heuvel","doi":"10.1063/1.46006","DOIUrl":"https://doi.org/10.1063/1.46006","url":null,"abstract":"The gathering of a wealth of precise quantitative observational data on x‐ray binaries and recycled radio pulsars during the last decades has allowed the testing of many theoretical ideas on the physics, formation, and evolution of neutron stars and black holes, which could never have been tested on single compact objects. Also, new observations often have led to new theories and models which again can be tested observationally. In this talk I give a personal view of this development over the past thirty years.","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133999479","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}
Objects with temperatures on the order of 30 eV and luminosities around 1038 erg/s have been established as a separate class by the recent ROSAT observations. The prototype supersoft x‐ray source (SSS) is the well‐known x‐ray binary CAL83 in the LMC, which has an orbital period of 1.04d. In the meantime about 10 SSS have been found in the Magellanic Clouds and at least 15 in the Andromeda Nebula. Two uncatalogued galactic supersoft sources have recently been discovered, but also the nova Muscae 1984 could be detected in a supersoft state 9 years after the explosion. In several cases dramatic time variability is found, with x‐ray on‐ and off‐states. The observations are summarized here. Several models have been suggested to explain the high luminosity and low temperature of SSS, all of them require very high mass accretion rates, which are also indicated in some of the optical spectra. In one interpretation the compact object is a neutron star (or black hole) shrouded by super‐Eddington accretion and the l...
{"title":"Supersoft x‐ray sources","authors":"G. Hasinger","doi":"10.1063/1.45948","DOIUrl":"https://doi.org/10.1063/1.45948","url":null,"abstract":"Objects with temperatures on the order of 30 eV and luminosities around 1038 erg/s have been established as a separate class by the recent ROSAT observations. The prototype supersoft x‐ray source (SSS) is the well‐known x‐ray binary CAL83 in the LMC, which has an orbital period of 1.04d. In the meantime about 10 SSS have been found in the Magellanic Clouds and at least 15 in the Andromeda Nebula. Two uncatalogued galactic supersoft sources have recently been discovered, but also the nova Muscae 1984 could be detected in a supersoft state 9 years after the explosion. In several cases dramatic time variability is found, with x‐ray on‐ and off‐states. The observations are summarized here. Several models have been suggested to explain the high luminosity and low temperature of SSS, all of them require very high mass accretion rates, which are also indicated in some of the optical spectra. In one interpretation the compact object is a neutron star (or black hole) shrouded by super‐Eddington accretion and the l...","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"322 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127758269","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}
In recent years, the discovery of orbital period changes and eclipses in binaries with neutron stars has led to a new wave of excitement over these systems. They have also led to speculation that the traditional views of x‐ray binary evolution may be incomplete. Here I briefly discuss the observed orbital period derivatives and possible analogies between these binaries and other types of compact binary. I conclude that stellar activity in a late‐type companion is the most likely cause for the anomalous orbital period changes, and that it is also a strong candidate for explaining the eclipse phenomenon in at least some observed systems.
{"title":"Evolution versus variability in neutron star binaries","authors":"R. Wijers","doi":"10.1063/1.45977","DOIUrl":"https://doi.org/10.1063/1.45977","url":null,"abstract":"In recent years, the discovery of orbital period changes and eclipses in binaries with neutron stars has led to a new wave of excitement over these systems. They have also led to speculation that the traditional views of x‐ray binary evolution may be incomplete. Here I briefly discuss the observed orbital period derivatives and possible analogies between these binaries and other types of compact binary. I conclude that stellar activity in a late‐type companion is the most likely cause for the anomalous orbital period changes, and that it is also a strong candidate for explaining the eclipse phenomenon in at least some observed systems.","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"126 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116716926","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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