{"title":"Obituary: Earle B. Mayfield (1923-2007)","authors":"Gary Chapman","doi":"10.3847/BAASOBIT2011018","DOIUrl":"https://doi.org/10.3847/BAASOBIT2011018","url":null,"abstract":"","PeriodicalId":9423,"journal":{"name":"Bulletin of the American Astronomical Society","volume":"27 1","pages":"018"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89828418","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 : 1998-01-01DOI: 10.1007/978-94-011-4778-1_134
A. Ingersoll, A. Vasavada
{"title":"Dynamics of Jupiter's Atmosphere","authors":"A. Ingersoll, A. Vasavada","doi":"10.1007/978-94-011-4778-1_134","DOIUrl":"https://doi.org/10.1007/978-94-011-4778-1_134","url":null,"abstract":"","PeriodicalId":9423,"journal":{"name":"Bulletin of the American Astronomical Society","volume":"48 1","pages":"1042-1049"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90393256","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":"The effect of velocity gradients on Cepheid spectra: models.","authors":"R. Paul Butler, Roger A. Bell, R. Hindsley","doi":"10.1086/177064","DOIUrl":"https://doi.org/10.1086/177064","url":null,"abstract":"","PeriodicalId":9423,"journal":{"name":"Bulletin of the American Astronomical Society","volume":"100 1","pages":"1429"},"PeriodicalIF":0.0,"publicationDate":"1995-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73617272","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 is the fourth study in a series to determine the direct trigonometric parallaxes of four of the nearest open star clusters, the Hyades, the Pleiades, the Praesepe, and the nearby cluster in Coma (Gatewood et al. 1990; Gatewood et al. 1992); Gatewood & Kiewiet de Jonge 1994). The results for the open star cluster in Coma are compared with those of the other three clusters, and the members are found to be significantly subluminous. The trigonometric parallax of the cluster is estimated from that of three members studied with the Multichannel Astrometric Photometer (MAP) at the Thaw Refractor of the University of Pittsburgh's Allegheny Observatory. The weighted mean parallax of the cluster is +13.53 +/- 0.54 mass (0.00054 min), corresponding to a distance modulus of 4.34 +/- 0.09 mag. The U-B excess of the Coma cluster members may be used to adjust the observed absolute magnitudes and the B-V measurements as suggested by Sandage & Eggen (1959). The agreement obtained in this manner suggests that, like subdwarf stars, the stars of the Coma cluster appear subluminous because of line blanketing. One of the three members observed in this study was recognized as a member by its parallax and is the faintest known member of the cluster.
这是一系列研究中的第四项，旨在确定最近的四个疏散星团的直接三角视差，它们是毕宿星团、昴宿星团、前宿星团和附近的彗发星团(Gatewood et al. 1990;Gatewood et al. 1992);Gatewood & Kiewiet de Jonge 1994)。将后发星疏散星团的结果与其他三个星团的结果进行了比较，发现其成员明显是亚发光的。星团的三角视差是通过匹兹堡大学阿勒格尼天文台的多通道天文光度计(MAP)研究的三个成员的视差估计出来的。星团的加权平均视差为+13.53 +/- 0.54质量(0.00054分钟)，对应的距离模量为4.34 +/- 0.09等。后发星团成员的U-B余量可以用来调整观测到的绝对星等和B-V测量，如Sandage & Eggen(1959)所建议的。以这种方式获得的一致表明，像亚矮星一样，后发星团的恒星由于线覆盖而显得亚光。在这项研究中观测到的三个成员中，有一个是通过视差被识别出来的，它是星团中已知最模糊的成员。
{"title":"Map-based trigonometric parallaxes of open clusters: Coma","authors":"G. Gatewood","doi":"10.1086/175733","DOIUrl":"https://doi.org/10.1086/175733","url":null,"abstract":"This is the fourth study in a series to determine the direct trigonometric parallaxes of four of the nearest open star clusters, the Hyades, the Pleiades, the Praesepe, and the nearby cluster in Coma (Gatewood et al. 1990; Gatewood et al. 1992); Gatewood & Kiewiet de Jonge 1994). The results for the open star cluster in Coma are compared with those of the other three clusters, and the members are found to be significantly subluminous. The trigonometric parallax of the cluster is estimated from that of three members studied with the Multichannel Astrometric Photometer (MAP) at the Thaw Refractor of the University of Pittsburgh's Allegheny Observatory. The weighted mean parallax of the cluster is +13.53 +/- 0.54 mass (0.00054 min), corresponding to a distance modulus of 4.34 +/- 0.09 mag. The U-B excess of the Coma cluster members may be used to adjust the observed absolute magnitudes and the B-V measurements as suggested by Sandage & Eggen (1959). The agreement obtained in this manner suggests that, like subdwarf stars, the stars of the Coma cluster appear subluminous because of line blanketing. One of the three members observed in this study was recognized as a member by its parallax and is the faintest known member of the cluster.","PeriodicalId":9423,"journal":{"name":"Bulletin of the American Astronomical Society","volume":"80 1","pages":"1330"},"PeriodicalIF":0.0,"publicationDate":"1995-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83952163","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 : 1995-01-01DOI: 10.1007/978-94-011-0069-4_81
L. Taff, J. Morrison, R. Smart
{"title":"Precision Vs. Accuracy in Star Catalogs","authors":"L. Taff, J. Morrison, R. Smart","doi":"10.1007/978-94-011-0069-4_81","DOIUrl":"https://doi.org/10.1007/978-94-011-0069-4_81","url":null,"abstract":"","PeriodicalId":9423,"journal":{"name":"Bulletin of the American Astronomical Society","volume":"23 1","pages":"372-372"},"PeriodicalIF":0.0,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85476630","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":"High-redshift radio galaxies","authors":"G. Miley","doi":"10.1007/BFB0102579","DOIUrl":"https://doi.org/10.1007/BFB0102579","url":null,"abstract":"","PeriodicalId":9423,"journal":{"name":"Bulletin of the American Astronomical Society","volume":"52 1","pages":"42-52"},"PeriodicalIF":0.0,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73706873","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 : 1994-07-01DOI: 10.1103/revmodphys.66.699
R. Hulse, R. Hulse
Exactly 20 years ago today, on December 8, 1973, I was at the Arecibo Observatory in Puerto Rico recording in my notebook the confirming observation of the first pulsar discovered by the search which formed the basis for my Ph.D. thesis. As excited as I am sure I was at that point in time, I certainly had no idea of what lay in store for me in the months ahead, a path which would ultimately lead me here today. I would like to take you along on a scientific adventure, a story of intense preparation, long hours, serendipity, and a certain level of compulsive behavior that tries to make sense out of everything that one observes. The remarkable and unexpected result of this detective story was a discovery which is still yielding fascinating scientific results to this day, nearly 20 years later, as Professor Taylor will describe for you in his lecture. I hope that by sharing this story with you, you will be able to join me in reliving the challenges and excitement of this adventure, and that we will all be rewarded with some personal insights as to the process of scientific discovery and the nature of science as a human endeavor.
{"title":"THE DISCOVERY OF THE BINARY PULSAR","authors":"R. Hulse, R. Hulse","doi":"10.1103/revmodphys.66.699","DOIUrl":"https://doi.org/10.1103/revmodphys.66.699","url":null,"abstract":"Exactly 20 years ago today, on December 8, 1973, I was at the Arecibo Observatory in Puerto Rico recording in my notebook the confirming observation of the first pulsar discovered by the search which formed the basis for my Ph.D. thesis. As excited as I am sure I was at that point in time, I certainly had no idea of what lay in store for me in the months ahead, a path which would ultimately lead me here today. I would like to take you along on a scientific adventure, a story of intense preparation, long hours, serendipity, and a certain level of compulsive behavior that tries to make sense out of everything that one observes. The remarkable and unexpected result of this detective story was a discovery which is still yielding fascinating scientific results to this day, nearly 20 years later, as Professor Taylor will describe for you in his lecture. I hope that by sharing this story with you, you will be able to join me in reliving the challenges and excitement of this adventure, and that we will all be rewarded with some personal insights as to the process of scientific discovery and the nature of science as a human endeavor.","PeriodicalId":9423,"journal":{"name":"Bulletin of the American Astronomical Society","volume":"20 1","pages":"971"},"PeriodicalIF":0.0,"publicationDate":"1994-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81235292","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 have obtained velocity fields of the Giant H II complexes NGC 5471 in M101, NGC 2363 in NGC 2366, and the largest H II region in NGC 2403 from H-alpha observations using the TAURUS imaging Fabry-Perot interferometer. We have detected five H-alpha sources with velocity profiles which are broad when compared with the surrounding H II region. Region B in NGC 5471 has been previously determined to contain a supernova remnant by the presence of nonthermal radio continuum radiation and enhanced (O I) and (S II) emission (Skillman 1985) and broad H-alpha emission (Chu & Kennicutt 1986). Two broad H-alpha sources in NGC 2363 coincide with regions where strong splitting has been found in the (O III) line (Roy et al. 1991). Two more broad H-alpha sources have been identified in the largest H II region in NGC 2403. Very Large Array (VLA) radio continuum observations with a resolution of 2 sec at lambda(6) and lambda(20) cm of all 3 H II complexes are presented. In addition, high resolution (subarcsecond) VLA images of NGC 5471 were made at lambda(2) and lambda(6) cm. The presence of a nonthermal source in region NGC 5471 B was confirmed while region NGC 5471 A appears to be dominated by thermal emission. The nonthermal spectral index in NGC 2363 A indicates the existence of none or more supernova remnants at the position of a large velocity width source detected in H-alpha emission. No similar nonthermal sources were detected in NGC 2403 #1. Supernovae explosions and stellar winds are considered as causes for these large velocity width sources (LVWS). If the emission from the LVWSs is attributed to single supernova remnants, they are unusually luminous in both nonthermal radio continuum and H-alpha emision. The very large H-alpha luminosities could be a result of high velocity gas being ionized by the neighboring stellar cluster.
{"title":"A kinematic search for supernova remnants in giant extragalactic H II regions","authors":"Hui Yang, E. Skillman, R. Sramek","doi":"10.1086/116885","DOIUrl":"https://doi.org/10.1086/116885","url":null,"abstract":"We have obtained velocity fields of the Giant H II complexes NGC 5471 in M101, NGC 2363 in NGC 2366, and the largest H II region in NGC 2403 from H-alpha observations using the TAURUS imaging Fabry-Perot interferometer. We have detected five H-alpha sources with velocity profiles which are broad when compared with the surrounding H II region. Region B in NGC 5471 has been previously determined to contain a supernova remnant by the presence of nonthermal radio continuum radiation and enhanced (O I) and (S II) emission (Skillman 1985) and broad H-alpha emission (Chu & Kennicutt 1986). Two broad H-alpha sources in NGC 2363 coincide with regions where strong splitting has been found in the (O III) line (Roy et al. 1991). Two more broad H-alpha sources have been identified in the largest H II region in NGC 2403. Very Large Array (VLA) radio continuum observations with a resolution of 2 sec at lambda(6) and lambda(20) cm of all 3 H II complexes are presented. In addition, high resolution (subarcsecond) VLA images of NGC 5471 were made at lambda(2) and lambda(6) cm. The presence of a nonthermal source in region NGC 5471 B was confirmed while region NGC 5471 A appears to be dominated by thermal emission. The nonthermal spectral index in NGC 2363 A indicates the existence of none or more supernova remnants at the position of a large velocity width source detected in H-alpha emission. No similar nonthermal sources were detected in NGC 2403 #1. Supernovae explosions and stellar winds are considered as causes for these large velocity width sources (LVWS). If the emission from the LVWSs is attributed to single supernova remnants, they are unusually luminous in both nonthermal radio continuum and H-alpha emision. The very large H-alpha luminosities could be a result of high velocity gas being ionized by the neighboring stellar cluster.","PeriodicalId":9423,"journal":{"name":"Bulletin of the American Astronomical Society","volume":"86 1","pages":"1410"},"PeriodicalIF":0.0,"publicationDate":"1994-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78098531","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 a comprehensive nonequilibrium ionization (NEI) analysis of X-ray spectral data from the Einstein Observatory and EXOSAT for the supernova remnant G292.0+1.8. The spectra are well described by a single-temperature, single-timescale NEI model with kT = 1.64(sub -0.19)(sup +0.29) keV and n(sub e)t = (5.55(sub -1.12)(sup +1.2) x 10(exp 10)s/cu cm, which establishes that this remnant is indeed young and in the ionizing phase of evolution of its X-ray spectrum. We determine the abundances of the elements O, Ne, Mg, Si, S, Ar, and Fe and examine their variation over the allowed range of column density, kT, and n(sub e)t. Numerical calculations of the nucleosynthesis expected for a 25 solar mass progenitor agree best with the fitted abundances; in fact the minimum rms percent difference between this model and the derived abundances is only 15%. From the fitted emission measure and a simple geometric model of the remnant we estimate the mass of X-ray-emitting plasma to be 9.3(sub -6.2)(sup +1.19) solar mass, for an assumed distance of 4.8 +/- 1.6 kpc. Additional errors on this mass estimate, from clumping of the ejecta, for example, may be substantial. No evidence was found for a difference in the thermodynamic state of the plasma as a function of elemental composition based on analysis of the individual ionization timescales of the various species. In this sense then, G292.0+1.8 resembles the remnant Cas A (another product of a massive star supernova), while it is different from the remnants of SN 1572 (Tycho) and SN 1006, both of which are believed to be from Type Ia supernovae.
{"title":"Elemental abundances of the supernova remnant G292.0+1.8: evidence for a massive progenitor","authors":"J. Hughes, K. P. Singh","doi":"10.1086/173710","DOIUrl":"https://doi.org/10.1086/173710","url":null,"abstract":"We present a comprehensive nonequilibrium ionization (NEI) analysis of X-ray spectral data from the Einstein Observatory and EXOSAT for the supernova remnant G292.0+1.8. The spectra are well described by a single-temperature, single-timescale NEI model with kT = 1.64(sub -0.19)(sup +0.29) keV and n(sub e)t = (5.55(sub -1.12)(sup +1.2) x 10(exp 10)s/cu cm, which establishes that this remnant is indeed young and in the ionizing phase of evolution of its X-ray spectrum. We determine the abundances of the elements O, Ne, Mg, Si, S, Ar, and Fe and examine their variation over the allowed range of column density, kT, and n(sub e)t. Numerical calculations of the nucleosynthesis expected for a 25 solar mass progenitor agree best with the fitted abundances; in fact the minimum rms percent difference between this model and the derived abundances is only 15%. From the fitted emission measure and a simple geometric model of the remnant we estimate the mass of X-ray-emitting plasma to be 9.3(sub -6.2)(sup +1.19) solar mass, for an assumed distance of 4.8 +/- 1.6 kpc. Additional errors on this mass estimate, from clumping of the ejecta, for example, may be substantial. No evidence was found for a difference in the thermodynamic state of the plasma as a function of elemental composition based on analysis of the individual ionization timescales of the various species. In this sense then, G292.0+1.8 resembles the remnant Cas A (another product of a massive star supernova), while it is different from the remnants of SN 1572 (Tycho) and SN 1006, both of which are believed to be from Type Ia supernovae.","PeriodicalId":9423,"journal":{"name":"Bulletin of the American Astronomical Society","volume":"36 1","pages":"918"},"PeriodicalIF":0.0,"publicationDate":"1994-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90706277","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 : 1994-01-01DOI: 10.1007/978-94-011-0752-5_34
R. O’Connell
{"title":"The Ages of Elliptical Galaxies","authors":"R. O’Connell","doi":"10.1007/978-94-011-0752-5_34","DOIUrl":"https://doi.org/10.1007/978-94-011-0752-5_34","url":null,"abstract":"","PeriodicalId":9423,"journal":{"name":"Bulletin of the American Astronomical Society","volume":"93 1","pages":"255-266"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90505733","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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