We present deep pointed observations of ten globular clusters obtained with the ROSAT PSPC, and one with the ROSAT HRI. X‐ray sources are detected in the cores of seven of them, at luminosities of ∼1–6×1032 erg s−1. At least two of these are multiple. Four have colors indicating soft spectra, with blackbody temperatures kT≲0.3 keV. Soft spectra can be excluded for the other three sources. The sources outside the cores are probably not associated with the cluster. The most likely counterparts for these sources are soft x‐ray transients (SXTs).
{"title":"ROSAT observations of globular clusters","authors":"H. Johnston, F. Verbunt, G. Hasinger","doi":"10.1063/1.45952","DOIUrl":"https://doi.org/10.1063/1.45952","url":null,"abstract":"We present deep pointed observations of ten globular clusters obtained with the ROSAT PSPC, and one with the ROSAT HRI. X‐ray sources are detected in the cores of seven of them, at luminosities of ∼1–6×1032 erg s−1. At least two of these are multiple. Four have colors indicating soft spectra, with blackbody temperatures kT≲0.3 keV. Soft spectra can be excluded for the other three sources. The sources outside the cores are probably not associated with the cluster. The most likely counterparts for these sources are soft x‐ray transients (SXTs).","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"75 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":"116355246","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":"Lithium in quiescent x‐ray novae","authors":"P. Charles, J. Casares, E. Martín, R. Rebolo","doi":"10.1063/1.45971","DOIUrl":"https://doi.org/10.1063/1.45971","url":null,"abstract":"","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"3 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":"125171565","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}
B. Vaughan, M. Klis, K. Wood, J. Norris, P. Hertz, P. Michelson, J. Paradijs, W. Lewin, K. Mitsuda
Coherent millisecond x‐ray pulsations are expected from low‐mass x‐ray binaries (LMXB), but remain undetected. Using the single‐parameter Quadratic Coherence Recovery Technique (QCRT) to correct for unknown binary orbital motion we have performed Fourier transform searches for coherent oscillations in all long, continuous segments of data obtained at 1 millisecond time resolution during Ginga observations of LMXB. We have searched the six known Z‐sources (GX 5‐1, Cyg X‐2, Sco X‐1, GX 17+2, GX 340+0, and GX 349+2), seven of the ten known atoll sources (GX 3+1, GX 9+1, GX 9+9, 1728‐33, 1820‐30, 1636‐53, and 1608‐52), the ‘‘peculiar’’ source Cir X‐1, and the high mass binary Cyg X‐3. We find no evidence for coherent pulsations in any of these sources, with 99% confidence limits on the pulsed fraction between 0.3% and 5.0% at frequencies below the Nyquist frequency of 512 Hz.
{"title":"Searches for millisecond pulsations in low‐mass x‐ray binaries with Ginga data","authors":"B. Vaughan, M. Klis, K. Wood, J. Norris, P. Hertz, P. Michelson, J. Paradijs, W. Lewin, K. Mitsuda","doi":"10.1063/1.45939","DOIUrl":"https://doi.org/10.1063/1.45939","url":null,"abstract":"Coherent millisecond x‐ray pulsations are expected from low‐mass x‐ray binaries (LMXB), but remain undetected. Using the single‐parameter Quadratic Coherence Recovery Technique (QCRT) to correct for unknown binary orbital motion we have performed Fourier transform searches for coherent oscillations in all long, continuous segments of data obtained at 1 millisecond time resolution during Ginga observations of LMXB. We have searched the six known Z‐sources (GX 5‐1, Cyg X‐2, Sco X‐1, GX 17+2, GX 340+0, and GX 349+2), seven of the ten known atoll sources (GX 3+1, GX 9+1, GX 9+9, 1728‐33, 1820‐30, 1636‐53, and 1608‐52), the ‘‘peculiar’’ source Cir X‐1, and the high mass binary Cyg X‐3. We find no evidence for coherent pulsations in any of these sources, with 99% confidence limits on the pulsed fraction between 0.3% and 5.0% at frequencies below the Nyquist frequency of 512 Hz.","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"37 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":"133329781","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}
P. Roche, M. Coe, C. Everall, J. Fabregat, V. Reglero, T. Prince, D. Chakrabarty, Lars Bildsen, A. Norton, S. Unger, D. Buckley
We present a summary of the Southampton/Valencia/Caltech/SAAO campaign for long‐term, multiwavelength monitoring of high mass x‐ray binaries. A number of sources have been observed in unusual states, including detailed studies of the Be/x‐ray transients X Persei (4U0352+309: disk loss state, 1988–1990), 3A1118‐616 (transient outburst, Jan. 1991), GX 1+4 (outburst Sept. 1993) and EXO2030+375 (periastron passsage, June 1993).
{"title":"Long term multiwavelength monitoring of high mass X-ray binaries","authors":"P. Roche, M. Coe, C. Everall, J. Fabregat, V. Reglero, T. Prince, D. Chakrabarty, Lars Bildsen, A. Norton, S. Unger, D. Buckley","doi":"10.1063/1.45926","DOIUrl":"https://doi.org/10.1063/1.45926","url":null,"abstract":"We present a summary of the Southampton/Valencia/Caltech/SAAO campaign for long‐term, multiwavelength monitoring of high mass x‐ray binaries. A number of sources have been observed in unusual states, including detailed studies of the Be/x‐ray transients X Persei (4U0352+309: disk loss state, 1988–1990), 3A1118‐616 (transient outburst, Jan. 1991), GX 1+4 (outburst Sept. 1993) and EXO2030+375 (periastron passsage, June 1993).","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"43 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":"127479624","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 present the results of evolutionary computational for the low‐mass binary (LMB) with 1.4 M⊙ neutron star (NS) as a compact companion and 1 M⊙ red dwarf as a donor star. At the moment of filling of the Roche lobe by the red dwarf an orbital system of a system is 9.h4. We take into account the illumination of the donor star by energetic quanta and particles from the NS. We focus on a regime of ‘‘non‐catastrophic’’ heating when at the beginning of mass‐transfer phase the pulsar’s illumination activates the mass loss by a donor star rather than vaporizes its outer layers. We also incorporate the effect of sweeping of overflowing plasma out of the system by the pulsar’s magneto‐dipole radiation. One issue is that the evolution of such a system may result in the formation of the LMB with rapidly rotating NS and 0.2 M⊙ red‐dwarf companion, and having orbital period ∼(6–7)h. Another issue we investigate is the regime of episodic mass loss (with approximately Eddington rate) by the donor star commencing at the ...
{"title":"Evolutionary Scheme for Low-Mass Binary with Millisecond Pulsar","authors":"A. Muslimov, M. Sarna","doi":"10.1063/1.46034","DOIUrl":"https://doi.org/10.1063/1.46034","url":null,"abstract":"We present the results of evolutionary computational for the low‐mass binary (LMB) with 1.4 M⊙ neutron star (NS) as a compact companion and 1 M⊙ red dwarf as a donor star. At the moment of filling of the Roche lobe by the red dwarf an orbital system of a system is 9.h4. We take into account the illumination of the donor star by energetic quanta and particles from the NS. We focus on a regime of ‘‘non‐catastrophic’’ heating when at the beginning of mass‐transfer phase the pulsar’s illumination activates the mass loss by a donor star rather than vaporizes its outer layers. We also incorporate the effect of sweeping of overflowing plasma out of the system by the pulsar’s magneto‐dipole radiation. One issue is that the evolution of such a system may result in the formation of the LMB with rapidly rotating NS and 0.2 M⊙ red‐dwarf companion, and having orbital period ∼(6–7)h. Another issue we investigate is the regime of episodic mass loss (with approximately Eddington rate) by the donor star commencing at the ...","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"31 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":"129726428","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 structure and stability of the inner regions of accretion disks surrounding neutron stars and black holes have been studied. Within the framework of the α viscosity prescription for optically thick disks, we assume the viscous stress scales with gas pressure only, and the α parameter, which is less than or equal to unity, is formulated as α0(h/r)n, where h is the local scale height and n and α0 are constants. We neglect advective energy transport associated with radial motions and construct the vertical disk structures by assuming a Keplerian rotation law and local hydrostatic and thermal equilibrium. The vertical structures have been calculated with and without convective energy transport, and it is found that convection is important especially for mass accretion rates greater than about 0.1 times the Eddington value, MEdd. Although convective efficiency is low, convection does help to stabilize the disk. The results show that the disk can be locally unstable and that for n≳0.75, an S‐shaped relatio...
{"title":"The vertical structure and stability of accretion disks surrounding black holes and neutron stars","authors":"J. Milsom, Xingming Chen, R. Taam","doi":"10.1063/1.46014","DOIUrl":"https://doi.org/10.1063/1.46014","url":null,"abstract":"The structure and stability of the inner regions of accretion disks surrounding neutron stars and black holes have been studied. Within the framework of the α viscosity prescription for optically thick disks, we assume the viscous stress scales with gas pressure only, and the α parameter, which is less than or equal to unity, is formulated as α0(h/r)n, where h is the local scale height and n and α0 are constants. We neglect advective energy transport associated with radial motions and construct the vertical disk structures by assuming a Keplerian rotation law and local hydrostatic and thermal equilibrium. The vertical structures have been calculated with and without convective energy transport, and it is found that convection is important especially for mass accretion rates greater than about 0.1 times the Eddington value, MEdd. Although convective efficiency is low, convection does help to stabilize the disk. The results show that the disk can be locally unstable and that for n≳0.75, an S‐shaped relatio...","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"16 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124469405","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}
Energy spectra of the black hole candidate GX339‐4 in the low intensity state were observed on four occasions through 1989 to 1991 with the Large Area Counters onboard the GINGA satellite. The spectra showed significant deviations from a power‐law, with an iron Kα emission line at ∼6.4 keV and broad iron K‐edge structure above ∼7 keV. The energy spectra above 4 keV were successfully explained with a reflection model, in which a part of the incident x‐rays with a power‐law spectrum is Compton reflected by optically thick matter. The line equivalent width with respect to the reflection component decreases as the source flux increases, consistent with an increase in the ionization state of the material so that resonant absorption followed by Auger ionization depletes the line.
{"title":"Spectral study of GX339‐4 in the low intensity state observed with GINGA","authors":"Y. Ueda, K. Ebisawa, C. Done","doi":"10.1063/1.46003","DOIUrl":"https://doi.org/10.1063/1.46003","url":null,"abstract":"Energy spectra of the black hole candidate GX339‐4 in the low intensity state were observed on four occasions through 1989 to 1991 with the Large Area Counters onboard the GINGA satellite. The spectra showed significant deviations from a power‐law, with an iron Kα emission line at ∼6.4 keV and broad iron K‐edge structure above ∼7 keV. The energy spectra above 4 keV were successfully explained with a reflection model, in which a part of the incident x‐rays with a power‐law spectrum is Compton reflected by optically thick matter. The line equivalent width with respect to the reflection component decreases as the source flux increases, consistent with an increase in the ionization state of the material so that resonant absorption followed by Auger ionization depletes the line.","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"144 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123260359","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}
C. Wilson, B. A. Harmon, R. Wilson, G. Fishman, C. Meegan, D. Chakrabarty, J. Grunsfeld, T. Prince, M. Finger, W. Paciesas, G. Pendleton
GS 0834‐430 has been observed in seven outbursts with the Large Area Detectors (LAD’s) of the Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory. We have fit observed pulse frequencies and total flux with a model that assumes binary motion and a relationship between the total flux and accretion induced torque. In addition, we have fit the first five harmonics of 4–6 day summed pulse profiles with a template pulse profile for each channel to detect changes in pulse shape. We present the history of the total flux and the pulsed frequency, pulse profiles, and orbital parameters.
{"title":"BATSE observations of GS 0834‐430","authors":"C. Wilson, B. A. Harmon, R. Wilson, G. Fishman, C. Meegan, D. Chakrabarty, J. Grunsfeld, T. Prince, M. Finger, W. Paciesas, G. Pendleton","doi":"10.1063/1.44303","DOIUrl":"https://doi.org/10.1063/1.44303","url":null,"abstract":"GS 0834‐430 has been observed in seven outbursts with the Large Area Detectors (LAD’s) of the Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory. We have fit observed pulse frequencies and total flux with a model that assumes binary motion and a relationship between the total flux and accretion induced torque. In addition, we have fit the first five harmonics of 4–6 day summed pulse profiles with a template pulse profile for each channel to detect changes in pulse shape. We present the history of the total flux and the pulsed frequency, pulse profiles, and orbital parameters.","PeriodicalId":101857,"journal":{"name":"The evolution of X‐ray binaries","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123307246","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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