1,704 research outputs found

    Note and Comment

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    The Domicile of a Wife - In 1908 Professor Dicey stated flatly, as a rule of the English law without exceptions, that the domicile of a married woman during coverture is the same as that of her husband, and changes with his. It is a rule which makes for hard cases and offers constant invitations for exceptions to meet the situations it creates. Must a deserted wife follow her husband to the ends of the earth to secure the domiciliary jurisdiction for divorce? May he, by shifting his own place of permanent residence, arbitrarily deprive her of capacity to make a will, or determine the law to govern the devolution of the property upon her dying intestate? Where can she vote

    Book Reviews

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    The Radio Afterglow and the Host Galaxy of the X-Ray Rich GRB 981226

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    We report the discovery of a radio transient VLA 232937.2-235553, coincident with the proposed X-ray afterglow for the gamma-ray burst GRB 981226. This GRB has the highest ratio of X-ray to gamma-ray fluence of all the GRBs detected by BeppoSAX so far and yet no corresponding optical transient was detected. The radio light curve of VLA 232937.2-235553 is qualitatively similar to that of several other radio afterglows. At the sub-arcsecond position provided by the radio detection, optical imaging reveals an extended R=24.9 mag object, which we identify as the host galaxy of GRB 981226. Afterglow models which invoke a jet-like geometry for the outflow or require an ambient medium with a radial density dependence, such as that produced by a wind from a massive star, are both consistent with the radio data. Furthermore, we show that the observed properties of the radio afterglow can explain the absence of an optical transient without the need for large extinction local to the GRB.Comment: Accepted for publication in the Astrophysical Journal Letters. Thirteen pages. Three Postscript figure

    Polarization of Broad Absorption Line QSOs I. A Spectropolarimetric Atlas

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    We present a spectropolarimetric survey of 36 broad absorption line quasi-stellar objects (BAL QSOs). The continuum, absorption trough, and emission line polarization of BAL QSOs yield clues about their structure. We confirm that BAL QSOs are in general more highly polarized than non-BAL QSOs, consistent with a more equatorial viewing direction for the former than the latter. We have identified two new highly-polarized QSOs in our sample (1232+1325 and 1333+2840). The polarization rises weakly to the blue in most objects, perhaps due to scattering and absorption by dust particles. We find that a polarization increase in the BAL troughs is a general property of polarized BAL QSOs, indicating an excess of scattered light relative to direct light, and consistent with the unification of BAL QSOs and non-BAL QSOs. We have also discovered evidence of resonantly scattered photons in the red wing of the C IV broad emission lines of a few objects. In most cases, the broad emission lines have lower polarization and a different position angle than the continuum. The polarization characteristics of low-ionization BAL QSOs are similar to those of high-ionization BAL QSOs, suggesting a similar BAL wind geometry.Comment: 39 pages, 6 figures (20 .gif files), accepted for publication in The Astrophysical Journal Supplement

    Charged-Particle Motion in Electromagnetic Fields Having at Least One Ignorable Spatial Coordinate

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    We give a rigorous derivation of a theorem showing that charged particles in an arbitrary electromagnetic field with at least one ignorable spatial coordinate remain forever tied to a given magnetic-field line. Such a situation contrasts the significant motions normal to the magnetic field that are expected in most real three-dimensional systems. It is pointed out that, while the significance of the theorem has not been widely appreciated, it has important consequences for a number of problems and is of particular relevance for the acceleration of cosmic rays by shocks.Comment: 7 pages, emulateapj format, including 1 eps figure, to appear in The Astrophysical Journal, Dec. 10 1998 issu

    Self-similar solution of a nonsteady problem of nonisothermal vapour condensation on a droplet growing in diffusion regime

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    This paper presents a mathematically exact self-similar solution to the joint nonsteady problems of vapour diffusion towards a droplet growing in a vapour-gas medium and of removal of heat released by a droplet into a vapour-gas medium during vapour condensation. An equation for the temperature of the droplet is obtained; and it is only at that temperature that the self-similar solution exists. This equation requires the constancy of the droplet temperature and even defines it unambiguously throughout the whole period of the droplet growth. In the case of strong display of heat effects, when the droplet growth rate decreases significantly, the equation for the temperature of the droplet is solved analytically. It is shown that the obtained temperature fully coincides with the one that settles in the droplet simultaneously with the settlement of its diffusion regime of growth. At the obtained temperature of the droplet the interrelated nonsteady vapour concentration and temperature profiles of the vapour-gas medium around the droplet are expressed in terms of initial (prior to the nucleation of the droplet) parameters of the vapour-gas medium. The same parameters are used to formulate the law in accordance with which the droplet is growing in diffusion regime, and also to define the time that passes after the nucleation of the droplet till the settlement of diffusion regime of droplet growth, when the squared radius of the droplet becomes proportionate to time. For the sake of completeness the case of weak display of heat effects is been studied.Comment: 12 pages, 4 figure

    Fermi Surface Properties of Low Concentration Cex_{x}La1x_{1-x}B6_{6}: dHvA

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    The de Haas-van Alphen effect is used to study angular dependent extremal areas of the Fermi Surfaces (FS) and effective masses of Cex_{x}La1x_{1-x}B6% _{6} alloys for xx between 0 and 0.05. The FS of these alloys was previously observed to be spin polarized at low Ce concentration (xx = 0.05). This work gives the details of the initial development of the topology and spin polarization of the FS from that of unpolarized metallic LaB6_{6} to that of spin polarized heavy Fermion CeB6_{6} .Comment: 7 pages, 9 figures, submitted to PR

    Below the Lyman Edge: UV Polarimetry of Quasars

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    The Lyman edge at 912 \AA is an important diagnostic region for studying quasi-stellar objects (QSOs). In particular, it reveals a great deal about the physical conditions within the atmospheres of accretion disks, a ubiquitous component of QSO theories. A robust prediction of accretion disk models is a significant polarization due to electron scattering just longward (in wavelength) of the Lyman edge because of the wavelength dependence of the Hydrogen absorption opacity. Observations of the Lyman edge regions of QSOs have shown scant evidence for the predicted features-few QSOs show the broad, partial Lyman edges expected to be common according to most theories, and none show the high polarizations expected longward of the Lyman edge. Still, polarization spectra of a small number of QSOs have shown a rising polarization (up to 20%) at wavelengths shortward of the Lyman edge. We have now doubled our sample of intermediate-redshift QSOs observed with the HST/FOS spectropolarimeter to determine the amount of polarization on both sides of the Lyman limit. For this new sample of six objects, polarizations are low and mostly consistent with zero below the Lyman edge. Another important result of the new data is that it strengthens the conclusion that quasars are generally not polarized significantly just longward of the Lyman edge at $\sim 1000 \AA. There is no significant statistical wavelength dependence to the polarization longward of the Lyman edge indicating that simple plane-parallel atmospheres with scattering-dominated opacity are not significant sources of UV flux in quasars.Comment: Accepted to Ap.J., 30 pages, 8 figure

    The Host Galaxy of GRB 990123

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    We present deep images of the field of gamma-ray burst (GRB) 990123 obtained in a broad-band UV/visible bandpass with the Hubble Space Telescope, and deep near-infrared images obtained with the Keck-I 10-m telescope. Both the HST and Keck images show that the optical transient (OT) is clearly offset by 0.6 arcsec from an extended object, presumably the host galaxy. This galaxy is the most likely source of the metallic-line absorption at z = 1.6004 seen in the spectrum of the OT. With magnitudes V_{C} ~ 24.6 +/- 0.2 and K = 21.65 +/- 0.30 mag this corresponds to an L ~ 0.7 L_* galaxy, assuming that it is located at z = 1.6. The estimated unobscured star formation rate is SFR ~ 6 M_sun/yr, which is not unusually high for normal galaxies at comparable redshifts. The strength of the observed metallic absorption lines is suggestive of a relatively high metallicity of the gas, and thus of a chemically evolved system which may be associated with a massive galaxy. It is also indicative of a high column density of the gas, typical of damped Ly-alpha systems at high redshifts. We conclude that this is the host galaxy of GRB 990123. No other obvious galaxies are detected within the same projected radius from the OT. There is thus no evidence for strong gravitational lensing magnification of this burst, and some alternative explanation for its remarkable energetics may be required. The observed offset of the OT from the center of its apparent host galaxy, 5.5 +/- 0.9 proper kpc (projected) in the galaxy's rest-frame, both refutes the possibility that GRBs are related to galactic nuclear activity and supports models of GRBs which involve the death and/or merger of massive stars. Further, the HST image suggests an intimate connection of GRB 990123 and a star-forming region.Comment: Updated references. 12 pages including 3 Postscript figures. Camera- ready reproductions of the figures can be found at http://astro.caltech.edu/~jsb/GRB/grb990123.htm
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