Astrophysical letters & communications最新文献

{"title":"X-ray and Optical Wavelet Maps in the Central Region of Coma","authors":"A. Biviano, F. Durret, D. Gerbal, O. Fèvre, C. Lobo, A. Mazure, É. Slezak","doi":"10.1063/1.48336","DOIUrl":"https://doi.org/10.1063/1.48336","url":null,"abstract":"We have applied a wavelet transform analysis on ROSAT images and on an optical catalouge of the Coma cluster of galaxies. The comparison of these two sets of images allows us a detection of X‐ray emitting galaxies as well as particular emitting regions.","PeriodicalId":80579,"journal":{"name":"Astrophysical letters & communications","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1996-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1063/1.48336","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"58775396","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":"Turbulence: The Legacy of A. N. Kolmogorov","authors":"U. Frisch","doi":"10.1063/1.881555","DOIUrl":"https://doi.org/10.1063/1.881555","url":null,"abstract":"Preface 1. Introduction 2. Symmetries and conservation laws 3. Why a probabilistic description of turbulence? 4. Probabilistic tools: a survey 5. Two experimental laws of fully developed turbulence 6. The Kolmogorov 1941 theory 7. Kolmogorov and Landau: the lack of universality 8. Phenomenology of turbulence in the sense of Kolmogorov 1941 9. Intermittency 10. Further reading: a guided tour References Author index Subject index.","PeriodicalId":80579,"journal":{"name":"Astrophysical letters & communications","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1996-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1063/1.881555","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59099351","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":"AN HI STUDY OF URSA-MAJOR SPIRALS","authors":"M. Verheijen","doi":"10.1007/978-94-009-1726-2_16","DOIUrl":"https://doi.org/10.1007/978-94-009-1726-2_16","url":null,"abstract":"","PeriodicalId":80579,"journal":{"name":"Astrophysical letters & communications","volume":"31 1","pages":"349-352"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51510850","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":"Instabilities of Magnetic Flux Tubes in a Stellar Convection Zone","authors":"A. Ferriz-Mas, M. Schüssler","doi":"10.1080/03091929508229066","DOIUrl":"https://doi.org/10.1080/03091929508229066","url":null,"abstract":"Abstract Motivated by the problems of magnetic flux storage and dynamo action in stars with convection zones, we study the equilibrium and stability of magnetic flux tubes under the influence of differential rotation and stratification. The formalism developed in the first paper in this series is applied to axisymmetric, toroidal flux tubes (flux rings) lying in planes parallel to the equator at an arbitrary latitude. We assume mechanical force equilibrium, which requires neutral buoyancy of the flux tube and a longitudinal internal flow in the direction of stellar rotation. Stability against isentropic perturbations is investigated by considering both axisymmetric and non-axisymmetric, three-dimensional displacements of the equilibrium configuration. For axisymmetric modes, we find qualitative differences between the stability criteria for flux tubes within and outside the equatorial plane, where instability is generally easier to excite and overstable modes appear. In the case of non-axisymmetric pertur...","PeriodicalId":80579,"journal":{"name":"Astrophysical letters & communications","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1995-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/03091929508229066","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59775768","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":"Coronal Loop Oscillations Driven by Footpoint Motions: Analytical Results for a Model Problem","authors":"D. Berghmans, P. Bruyne","doi":"10.1086/176410","DOIUrl":"https://doi.org/10.1086/176410","url":null,"abstract":"","PeriodicalId":80579,"journal":{"name":"Astrophysical letters & communications","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1995-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60533406","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":"MIXED PAIRS OF GALAXIES","authors":"Duilia Fernandes de Mello","doi":"10.1086/133668","DOIUrl":"https://doi.org/10.1086/133668","url":null,"abstract":"According to many schemes for galaxy formation, galaxy morphology should depend strongly on the environment in which a galaxy resides and, especially, in which it was formed. Therefore, in pairs of galaxies one expects to find members of similar morphological type. However, morphological studies of paired galaxies show two different categories: pairs formed by galaxies with similar morphology (EE and SS) and pairs of mixed morphology (ES), where E represents early--type galaxies and S represents late--types. Actually a significant percentage of pairs in reasonably complete samples of binary galaxies (e.g. Catalog of Isolated Pairs of Galaxies by Karachentsev) are of mixed type. Moreover, the distribution of radial velocity differences between components of mixed pairs is similar to that for concordant type (especially SS) pairs. This is further support for the contention that most are physical binaries. We used imaging, spectroscopy and stellar population synthesis to study the interaction effects in 5 mixed pairs of galaxies (AM0327-285, AM1806-852, AM1907-504, AM2016-330, AM2055-492). The present pair sample originated from a sample of 126 candidate mixed pairs that were found during a visual search on the ESO sky surveys. An isolation criterion was employed that required the distance to the nearest neighbor (with major axis diameter ≥ the diameters of the pair components) to be at least five times the pair component separation. Many of these pairs are also found in the Catalogue of Southern Peculiar Galaxies and Associations by Arp & Madore. We find that one of them, AM1907--504, is unlikely to be a physical pair because of the large velocity difference. The other 4 pairs are most likely physically bound with Delta-V ≤ 600 km/s. They can also be classified as true ES pairs since the photometric profiles for the early-type components obey an r1/4 law. We find diverse signs of interaction in our pair sample ranging from direct collisions to small distortions. In principle, this evidence is less ambiguous in mixed pairs because we are dealing with a single gas rich component. A strong but indirect form of evidence for interaction between the galaxies involves the detection of a young stellar component in the early-type members. We used Bica's stellar synthesis approach in order to detect the young stellar population in these pairs. We find that 10% to 37% of their fluxes arises from a young age population (< 5 x 108 years). We suggest that a transfer of gas appears to be the most likely way for the E components to acquire fuel for star formation activity. The only other alternative would be to invoke an unusual star formation history in ellipticals that inhabit mixed pairs.","PeriodicalId":80579,"journal":{"name":"Astrophysical letters & communications","volume":"107 1","pages":"1129 - 1129"},"PeriodicalIF":0.0,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60509661","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":"A Redshift Survey in the South Galactic Pole Region","authors":"G. Vettolani, E. Zucca, A. Cappi, R. Merighins, M. Mignoli, G. Stirpe, G. Zamorani, H. Macgillivray, C. Collins, C. Balkowski, J. Alimi, A. Blanchard, V. Cayatte, P. Felenbok, S. Maurogordato, D. Proust, G. Chincarini, L. Guzzo, D. Maccagni, R. Scaramella, M. Ramella","doi":"10.1007/978-94-011-1146-1_145","DOIUrl":"https://doi.org/10.1007/978-94-011-1146-1_145","url":null,"abstract":"","PeriodicalId":80579,"journal":{"name":"Astrophysical letters & communications","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51663941","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":"Comparison of the open cluster and surface brightness distance scales for galactic classical cepheids","authors":"P. Fouqué, W. Gieren","doi":"10.1086/116679","DOIUrl":"https://doi.org/10.1086/116679","url":null,"abstract":"We have derived a new period-luminosity (PL) relation for galactic Cepheids in open clusters and associations from the Zero-Age Main-Sequence (ZAMS)-fitting method, using the most reliable cluster photometric data and Cepheid reddening data available, and homogeneous treatment of absorption corrections. For about half of the cluster Cepheid sample (17 stars) we also derive distances and absolute magnitudes from the surface-brightness method. From a comparison we find that the surface-brightness PL relation has a zero point about 0.15 mag brighter than the cluster ZAMS-fitting PL relation, but in view of the sources of systematic error involved in both methods, this discrepancy is clearly not significant","PeriodicalId":80579,"journal":{"name":"Astrophysical letters & communications","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1993-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60836144","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":"A Reference Catalogue and Atlas of Galactic Novae","authors":"H. Durbeck","doi":"10.1007/978-94-017-0596-7","DOIUrl":"https://doi.org/10.1007/978-94-017-0596-7","url":null,"abstract":"","PeriodicalId":80579,"journal":{"name":"Astrophysical letters & communications","volume":"32 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"1988-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50989181","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":"Book-Review - the Role of Dust in Dense Regions of Interstellar Matter","authors":"T. Henning, B. Stecklum","doi":"10.1007/978-94-009-3785-7","DOIUrl":"https://doi.org/10.1007/978-94-009-3785-7","url":null,"abstract":"","PeriodicalId":80579,"journal":{"name":"Astrophysical letters & communications","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1986-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51530220","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}