摘要:

The results of some new QED calculations are presented. We consider two-photon emission by electrons, and determine magnetic field, spin and polarization dependence of the transition rates. We utilize the electron wave functions of Sokolov and Ternov (1968, Synchrotron Radiation, Berlin: Akademie), rather than those of Johnson and Lippmann (1949, Physical Review D, 76, 828). As pointed out by Graziani (1993, Astrophysical Journal, 412, 351), use of the former wave functions is necessary to obtain results valid outside the weak field limit. The results are of particular interest for processes in magnetars, for which the magnetic field is near, or can exceed, the critical value(Bcr=4.414×1013&hthinsp;G).©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1361656

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

All magnetic fields are produced electrically, also the field of magnetars. Their new electric model was partly published by the author in the book The Electric Universe in 1998. The new model is based on the positive charge which is collected in the pre-supernovas core via the different masses and sizes of proton and electron. The supernova implosion produces neutrons, but only from proton-electron pairs. The protons in overbalance will be fixed on the surface of the neutron body and create a magnetic field and synchrotron-radiation via rotation. The enclosed proton-bubbles swim upwards. The biggest proton bubbles surface first, and explode into space. This “proton-volcano” kicks the neutron star from the center of the SNR. The later proton-explosions produce only proton-jets. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1361657

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

A procedure to estimate temporal locations, amplitudes, widths, rise and decay times of pulses occurring within a large sample of GRB light curves, using BATSE 64-ms concatenated data, is based on an improved version of Bayesian Blocks. It determines the maximum likelihood value of the number of blocks by marginalizing over all the other parameters (block locations and sizes). The blocks are then used to obtain objective, automatic estimates of pulse parameters, which can either be used to study pulse-attribute correlations or as the starting solution for iterative, nonlinear fits of parametric models. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1361658

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

We describe the design of a suite of software tools to allow users to query Gamma Ray Burst (GRB) data and perform data mining expeditions. We call this suite of tools a shed (SHell forExpeditions usingDatamining). Our schedule is to have a completed prototype (funded via the NASA AISRP) by February, 2002. Meanwhile, interested users will find a partially functioning tool shed at http:/grb.mankato.msus.edu. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1361659

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

This work deals with the use of Karhunen-Loeve Expansion (KLE) for astronomical image compression. A mathematical algorithm of KLE has been derived using characteristics of(N×N)-dimensional Hilbert space. The KLE frequency domains and their reductions leading to image compression have been studied in comparison with other integral transforms. The following important results have been obtained during accuracy and suitability testing of KLE in astronomical photometry measurements. The achieved results show that KLE is suitable and probably the best method of astronomical image compression. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1361660

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

Digital data transmission or data storage are branches often using data compression. In this paper we describe a simple and fast lossless compression algorithm for CCD images of star fields which reduces the amount of data by roughly 50&percent;. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1361661

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

Most Americans learn about modern science from press reports, while such articles have a bad reputation among scientists. We have performed a study of 148 news articles on gamma-ray astronomy to quantitatively answer the questions “How accurate are press reports of gamma-ray astronomy?” and “What fraction of the basic claims in the press are correct?” We have taken all articles on the topic from five news sources (UPI, New York Times, Sky & Telescope, Science News, and five middle-sized city newspapers) for one decade (1987–1996) We found an average rate of roughly one trivial error every two articles, while none of our 148 articles significantly mislead the reader or misrepresented the science. This quantitative result is in stark contrast to the nearly universal opinion among scientists that the press frequently butchers science stories. So a major result from our study is that reporters should be rehabilitated into the good graces of astrophysicists, since they actually are doing a good job. For our second question, we rated each story with the probability that its basic new science claim is correct. We found that the average probability over all stories is 70&percent;. Since the reporters and the scientists are both doing good jobs, then why is 30&percent; of the science you read in the press wrong? The reason is that the nature of news reporting is to present front-line science and the nature of front-line science is that reliable conclusions have not yet been reached. The combination of these two natures forces fast breaking science news to have frequent incorrect ideas that are subsequently identified and corrected. So a second major result from our study is to make the distinction between textbook science (with reliabilities near 100&percent;) and front-line science which you read about in the press (with reliabilities near 70&percent;). ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1361662

出版商:AIP    

年代:1900

数据来源: AIP