Ultraviolet Spectra of Two Magnetic White Dwarfs and Ultraviolet Spectra of Subluminous Objects Found in the Kiso Schmidt Survey

Low resolution International Ultraviolet Explorer (IUE) spectroscopic observations of two magnetic white dwarfs BPM25114 and K813-14 were obtained using both the SWP and LWP cameras. The first object has an observed magnetic field of 4 x 10(7) Gauss and the second has one of 3 x 10(7) Gauss. Both objects have overall spectral energy distributions appropriate for cool DA white dwarfs with T(eff) near 10,000 K and accordingly show strong lambda lambda 1400 and 1600 absorption in their spectra. Compared to non-magnetic DA white dwarfs of comparable effective temperature, there are some differences in the profiles, presumably produced by the magnetic fields in these objects. In addition, the ultraviolet spectra of a number of hot subluminous stars in the Kiso Schmidt survey were observed

A Study of the Ultraviolet Absorptions in the Spectra of DA White Dwarfs and Ultraviolet Spectra of the Star HR6560

Two projects in conjunction with the International Ultraviolet Explorer Satellite are discussed. These projects were to: (1) study the properties of the H2 and H2+ quasi-molecular absorption features at lambda lambda 1600 and 1400 in the ultraviolet spectra of the hydrogen-rich DA white dwarfs and to search for additional spectroscopic features in the spectra of these stars; and (2) use the ultraviolet portion of the spectrum of the peculiar rare earth-rich late F type star, HR6560 (HD159870), to establish whether or not the element abundance anomalies are produced in conjunction with its having a white dwarf binary companion. The data show that HR6560 is probably not associated with any hot subluminous or degenerate star

Ultraviolet Spectra of Two Magnetic White Dwarfs and Ultraviolet Spectra of Subluminous Objects Found in the Kiso Schmidt Survey and Ultraviolet Absorptions in the Spectra of DA White Dwarfds

Research under NASA Grant NAG5-287 has carried out a number of projects in conjunction with the International Ultraviolet Explorer (IUE) satellite. These include: (1) studies of the UV spectra of DA white dwarfs which show quasi-molecular bands of H2 and H2(+); (2) the peculiar star HR6560; (3) the UV spectra of two magnetic white dwarfs that also show the quasi-molecular features; (4) investigations of the UV spectra of subluminous stars, primarily identified from visual wavelength spectroscopy in the Kiso survey of UV excess stars, some of which show interesting metal lines in their UV spectra; and (5) completion of studies of UV spectra of DB stars. The main result of this research has been to further knowledge of the structure and compositions of subluminous stars which helps cast light on their formation and evolution

Higgs shifts from electron-positron annihilations near neutron stars

We discuss the potential for using neutron stars to determine bounds on the Higgs-Kretschmann coupling by looking at peculiar shifts in gamma-ray spectroscopic features. In particular, we reanalyse multiple lines observed in GRB781119 detected by two gamma-ray spectrometers, and derive an upper bound on the Higgs-Kretschmann coupling that is much more constraining than the one recently obtained from white dwarfs. This calls for targeted analyses of spectra of gamma-ray bursts from more recent observatories, dedicated searches for differential shifts on electron-positron and proton-antiproton annihilation spectra in proximity of compact sources, and signals of electron and proton cyclotron lines from the same neutron star.Comment: 7 pages, 2 figure

Using the Fundamental Plane to Estimate the Total Binding Mass in A2626

We use fundamental plane (FP) distance estimates to the components of the double cluster A2626 (cz~17,500 km/s) to constrain cluster kinematics and estimate total binding mass. The FP coefficients for a sample of 24 early type and S0 cluster members (alpha=1.30+/-0.36 and beta=0.31+/-0.06) are consistent with others reported in the literature. We examine the Mg_b distributions within both subclusters and find them to be indistinguishable. Lacking evidence for stellar population differences, we interpret the FP zeropoint offset (\log(D_B/D_A)=-0.037+/-0.046, where D_{cl} is distance to subcluster cl) as a measure of the distance difference. This measurement is consistent with the subclusters being at the same distance, and it rules out the Hubble flow hypothesis (distances proportional to velocity) with 99% confidence; analysis of the subcluster galaxy magnitude distributions rules out Hubble flow at 93% confidence. Both results favor a kinematic model where the subclusters are bound and infalling. We estimate the total cluster binding mass by modelling the subcluster merger as radial infall. The minimum possible total binding mass is 1.65 times higher than the sum of the standard virial masses, a difference statistically significant at the ~3sigma level. We discuss explanations for the inconsistency including (1) biases in the standard virial mass estimator, (2) biases in our radial infall mass estimate, and (3) mass beyond the virialized cluster region; if the standard virial mass is significantly in error, the cluster has an unusually high mass to light ratio (~1000h). Because observational signatures of departures from radial infall are absent, we explore the implications of mass beyond the virialized, core regions. (abridged)Comment: 14 pages and 5 figures, Latex, Accepted for publication in A

Experiential Learning: Theory and Postulates as Reflected in John Dewey\u27s Theories of Learning and Experience

There is a need to integrate the experiences that take place through in-school activities and the exper snces that take place elsewhere in orde\u27 to make the si nts1 learning more educative. This can be accomplished through the velopment and implementation of experiential learning programs within the school setting. This study was undertaken to develop a philosophical and theoretical foundation for experiential learning programs and to present postulates for the development and implementation of experiential learning programs in school settings. The philosophical and theoretical foundation has been developed in the theories of learning and experience of John Dewey. The postxilates evolved from the study of the writings of John Dewey and a review of experience-based programs. John Dewey advocated an education based on experience but did not view ail experiences as educative. An educative experience is one in which there is continuity, interaction, purpose, and reflection. In order to provide the conditions for educative experiences, the educator must know the student, his needs, interests, capacities, and past experiences. The. educator should guide the student in his reorganizing or reconstructing of experiences. The educator must select the conditions for experiences based on the student’s past experiences, capacities- needs, and interests and with consideration of future experiences. Dewey believed that the student should be the starting point in ’earning. If the objective conditions are arranged meaningfully, the student will feel a need or desire to obtain the subject-matter. The student will seek the information that, has relevance to his experiences. An education of experience is an active education. The activity is purposeful* The student\u27s impulsion originates from a need. The need can originate because of internal conditions\u3e external conditions or the relationship of the two. As the impulsion develops, it confronts obstacles in the environment. This confrontation forces the impulsion to search for its meaning or significance. This search takes place through inquiry and reflection. The educator provides guidance and direction during the inquiry arid reflection. During an education of experience, the student, is stimulated to interact with the environment. The environment or external conditions are arranged so that growth of the student is possible and so that this growth creates conditions for further growth. When education is based on a philosophy of experience, learning is experiencing. Education is then ... a process of living and not a preparation for life. The postulates presented evolved from the study of John Dewey\u27s theories of learning and. experience and a review of experience-based programs. The postulates were not intended as a curriculum for an experiential learning program.. These postulates provide? direction for the development and implementation of experiential learning programs in school settings. The postulates, were developed from the perspective of a classroom teacher. The postulates are: 1. The community can be a valueable resource for educative experiences. 2. T\u27he experiences of the student should he educative. 3. Subject-matter should be the medium of learning rather than the object of learning. 4. The teacher should direct through indirection. 5. A positive environment should be provided. 6. Planning is necessary for success in an experiential learning program. 7. Activity should be utilized as a means of progression rather than as an end in itself. 8. An experiential learning program should provide opportunities for group as well as individual experiences. 9. An experiential learning program should provide opportunities for experiences In the areas of adventure, creativity, service, practical skills, and logical inquiry

Star Formation and Relaxation in 379 Nearby Galaxy Clusters

We investigate the relationship between star formation (SF) and level of relaxation in a sample of 379 galaxy clusters at z < 0.2. We use data from the Sloan Digital Sky Survey to measure cluster membership and level of relaxation, and to select star-forming galaxies based on mid-infrared emission detected with the Wide-Field Infrared Survey Explorer. For galaxies with absolute magnitudes M_r < -19.5, we find an inverse correlation between SF fraction and cluster relaxation: as a cluster becomes less relaxed, its SF fraction increases. Furthermore, in general, the subtracted SF fraction in all unrelaxed clusters (0.117 +/- 0.003) is higher than that in all relaxed clusters (0.097 +/- 0.005). We verify the validity of our SF calculation methods and membership criteria through analysis of previous work. Our results agree with previous findings that a weak correlation exists between cluster SF and dynamical state, possibly because unrelaxed clusters are less evolved relative to relaxed clusters.Comment: 6 pages, 4 figures, accepted for publication in Ap

Ultraviolet Spectra of Subluminous Objects Found in the Kiso Schmidt Survey and Systematic Reanalysis of the Archived Ultraviolet Spectra of White Dwarfs Observed with the IUE Satellite Under the Astrophysics Data Program (ADP)

Recent research under NASA grant NAG5-971 consisted of the performance of two projects in conjunction with the International Ultraviolet Explorer (IUE) satellites. These are: (1) to look at the ultraviolet spectra of subluminous stars identified from visual wavelength spectroscopy that had been originally discovered from the Kiso Schmidt survey for ultraviolet excess stars and (2) to carry out a systematic reanalysis of the archived IUE spectra of white dwarfs. This report presents information on the progress of the re-reduction of over 600 IUE white dwarf spectra and their subsequent analysis employing model atmospheres and the observation of the Kiso ultraviolet excess stars