{"title":"Hickson's compact groups of galaxies: Far-infrared enhancement","authors":"V. R. Venugopal","doi":"10.1093/MNRAS/277.2.455","DOIUrl":"https://doi.org/10.1093/MNRAS/277.2.455","url":null,"abstract":"","PeriodicalId":50722,"journal":{"name":"Bulletin of the Astronomical Society of India","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1995-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/MNRAS/277.2.455","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61022686","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}
Pub Date : 1995-09-01DOI: 10.1007/978-94-011-5220-4_47
T. Kosugi
{"title":"Magnetic reconnection and particle acceleration in solar flares as revealed by YOHKOH","authors":"T. Kosugi","doi":"10.1007/978-94-011-5220-4_47","DOIUrl":"https://doi.org/10.1007/978-94-011-5220-4_47","url":null,"abstract":"","PeriodicalId":50722,"journal":{"name":"Bulletin of the Astronomical Society of India","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1995-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51711774","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}
Pub Date : 1993-01-01DOI: 10.1007/978-94-011-0880-5_72
T. Chandrasekhar, N. Ashok, S. Ragland
{"title":"Near infrared high angular resolution observations of stars and circumstellar regions by the technique of lunar occultations","authors":"T. Chandrasekhar, N. Ashok, S. Ragland","doi":"10.1007/978-94-011-0880-5_72","DOIUrl":"https://doi.org/10.1007/978-94-011-0880-5_72","url":null,"abstract":"","PeriodicalId":50722,"journal":{"name":"Bulletin of the Astronomical Society of India","volume":"21 1","pages":"376-378"},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51650301","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":"Solar neutrino flux variation and its implications","authors":"P. Raychaudhuri","doi":"10.4006/1.3035857","DOIUrl":"https://doi.org/10.4006/1.3035857","url":null,"abstract":"","PeriodicalId":50722,"journal":{"name":"Bulletin of the Astronomical Society of India","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1989-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70136447","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}
A formula for stellar mass-loss rate has been derived using conservation equations of mass and momentum for coronal and continuum radiation-driven wind. The derived mass-loss rate formula has been found to be consistent with the observed mass-loss rates for stars from O to M spectral type. Two constant parameters appearing in the mass-loss rate formula have been found to have values for special group of stars such as Be-stars, which are different from the majority of stars. 24 references.
{"title":"A unified formula for mass loss rate of O to M stars.","authors":"S. Tarafdar","doi":"10.1086/166610","DOIUrl":"https://doi.org/10.1086/166610","url":null,"abstract":"A formula for stellar mass-loss rate has been derived using conservation equations of mass and momentum for coronal and continuum radiation-driven wind. The derived mass-loss rate formula has been found to be consistent with the observed mass-loss rates for stars from O to M spectral type. Two constant parameters appearing in the mass-loss rate formula have been found to have values for special group of stars such as Be-stars, which are different from the majority of stars. 24 references.","PeriodicalId":50722,"journal":{"name":"Bulletin of the Astronomical Society of India","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1988-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60533668","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}
V. Bhatia, N. Chopra, B. Majumdar, N. Panchapakesan
The general relativistic effects on the pulse shapes, arrival times of pulses, and brightness temperatures of fast pulsars are investigated. The Kerr metric is employed for this purpose and the results are compared with those of Kapoor and Datta (1985, 1986), who used the rotationally perturbed spherical metric derived by Hartle and Thorne (1968). It is found that generally the results of Kapoor and Datta need very little modification. However, a difference in the values of deflection angles is found that is due to a different interpretation. More importantly, it is found that the width of the pulse increases, if emitted close to the surface, but decreases, if emitted from further away. This has an important bearing on the estimate of brightness temperatures from observed widths (and related intensity) of the pulsars. 11 references.
{"title":"Dependence of pulsar characteristics on the space-time metric.","authors":"V. Bhatia, N. Chopra, B. Majumdar, N. Panchapakesan","doi":"10.1086/166068","DOIUrl":"https://doi.org/10.1086/166068","url":null,"abstract":"The general relativistic effects on the pulse shapes, arrival times of pulses, and brightness temperatures of fast pulsars are investigated. The Kerr metric is employed for this purpose and the results are compared with those of Kapoor and Datta (1985, 1986), who used the rotationally perturbed spherical metric derived by Hartle and Thorne (1968). It is found that generally the results of Kapoor and Datta need very little modification. However, a difference in the values of deflection angles is found that is due to a different interpretation. More importantly, it is found that the width of the pulse increases, if emitted close to the surface, but decreases, if emitted from further away. This has an important bearing on the estimate of brightness temperatures from observed widths (and related intensity) of the pulsars. 11 references.","PeriodicalId":50722,"journal":{"name":"Bulletin of the Astronomical Society of India","volume":"80 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1988-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60533605","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}
General relativistic effects, due to spacetime curvature and rotation, on the arrival times of pulsar signals are investigated using a rotationally perturbed spherical metric. For the millisecond pulsar PSR 1937 + 214, the advancement in arrival time (assuming the usual polar cap model for emission mechanism and a radius-to-frequency mapping) due to these effects is found to be nontrivial. The results are compared with recent multifrequency timing measurements on PSR 1937 + 214, and the implications regarding emission region thickness and emission mechanism for fast pulsars are discussed. 19 references.
{"title":"Effect of Spacetime Curvature and Rotation on Arrival Times of Pulses from Fast Pulsars","authors":"R. Kapoor, B. Datta","doi":"10.1086/164806","DOIUrl":"https://doi.org/10.1086/164806","url":null,"abstract":"General relativistic effects, due to spacetime curvature and rotation, on the arrival times of pulsar signals are investigated using a rotationally perturbed spherical metric. For the millisecond pulsar PSR 1937 + 214, the advancement in arrival time (assuming the usual polar cap model for emission mechanism and a radius-to-frequency mapping) due to these effects is found to be nontrivial. The results are compared with recent multifrequency timing measurements on PSR 1937 + 214, and the implications regarding emission region thickness and emission mechanism for fast pulsars are discussed. 19 references.","PeriodicalId":50722,"journal":{"name":"Bulletin of the Astronomical Society of India","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1986-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60533041","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}
Pub Date : 1984-01-01DOI: 10.1007/springerreference_22768
T. Velusamy
{"title":"Radio detection of a","authors":"T. Velusamy","doi":"10.1007/springerreference_22768","DOIUrl":"https://doi.org/10.1007/springerreference_22768","url":null,"abstract":"","PeriodicalId":50722,"journal":{"name":"Bulletin of the Astronomical Society of India","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1984-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"52928438","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}
Pub Date : 1982-10-01DOI: 10.1088/0305-4470/15/10/022
S. Banerji, D. Mandal
The authors have set up the Klein-Gordon equation in the background of the Schwarzschild curved space-time and studied the scattering of radial tardyons and tachyons from a black hole. They also show that black holes of mass below 7*1014 g may contain bound states of tardyons of pion mass which will be unstable on account of the presence of an attractive r-4 term.
{"title":"Scattering of scalar tardyons and tachyons from a Schwarzschild black hole.","authors":"S. Banerji, D. Mandal","doi":"10.1088/0305-4470/15/10/022","DOIUrl":"https://doi.org/10.1088/0305-4470/15/10/022","url":null,"abstract":"The authors have set up the Klein-Gordon equation in the background of the Schwarzschild curved space-time and studied the scattering of radial tardyons and tachyons from a black hole. They also show that black holes of mass below 7*1014 g may contain bound states of tardyons of pion mass which will be unstable on account of the presence of an attractive r-4 term.","PeriodicalId":50722,"journal":{"name":"Bulletin of the Astronomical Society of India","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0305-4470/15/10/022","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60205022","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 problem of global stability and structure of a class of disk models, both cold and ''warm'' against axisymmetric and nonaxisymmetric perturbations has been reconsidered in the form of an eigenvalue problem involving a triply infinite matrix. Some large wavelength (or open), nonaxisymmetric modes are found to stabilize in centrally concentrated disks. Unstable ''leading'' modes of cold disks become, gradually, ''trailing'' as the thermal energy of the disk is increased. The growth rates of short wavelength modes are lowered significantly by pressure effects in warm disks.
{"title":"Global density waves in self gravitating flat disks.","authors":"A. Ambastha, R. Varma","doi":"10.1086/160608","DOIUrl":"https://doi.org/10.1086/160608","url":null,"abstract":"The problem of global stability and structure of a class of disk models, both cold and ''warm'' against axisymmetric and nonaxisymmetric perturbations has been reconsidered in the form of an eigenvalue problem involving a triply infinite matrix. Some large wavelength (or open), nonaxisymmetric modes are found to stabilize in centrally concentrated disks. Unstable ''leading'' modes of cold disks become, gradually, ''trailing'' as the thermal energy of the disk is increased. The growth rates of short wavelength modes are lowered significantly by pressure effects in warm disks.","PeriodicalId":50722,"journal":{"name":"Bulletin of the Astronomical Society of India","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1982-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60532857","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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