Doppler tomography and photometry of the cataclysmic variable 1RXS J064434.5+334451

We have obtained simultaneous photometric and spectroscopic observations of the cataclysmic variable 1RXS J064434.5+334451. We have calibrated the spectra for slit losses using simultaneous photometry, allowing us to construct reliable Doppler images from H? and He?ii 4686-Å emission lines. We have improved the ephemeris of the object based on new photometric eclipse timings, obtaining HJD = 245?3403.759?533 + 0.269?374?46E. Some eclipses present a clear internal structure, which we attribute to a central He?ii emission region surrounding the white dwarf, a finding supported by Doppler tomography. This indicates that the system has a large inclination angle i = 78 ± 2°. We have also analysed the radial velocity curve from the emission lines to measure its semi-amplitude, K1, from H? and He?ii 4686 and derive the masses of the components M1 = 0.82 ± 0.06 M?, M2 = 0.78 ± 0.04 M? and their separation a = 2.01 ± 0.06 R?. The Doppler tomography and other observed features in this nova-like system strongly suggest that this is a SW Sex type system

Aneurisma de arteria renal como causa de hipertensión arterial en paciente joven

Renal artery aneurysms are a rare cause of arterial hypertension. The diagnosis is made usually with imaging techniques during the evaluation of secondary hypertension. Their resolution, by percutaneous procedures or surgery, drives mostly to remission of hypertension.Los aneurismas de arteria renal son una causa poco frecuente de hipertensión arterial. Se diagnostican mediante pruebas de imagen durante el cribado de hipertensión arterial secundaria. Su reparación, tanto por vía percutánea como quirúrgica, conduce en la mayoría de los casos a la resolución de la hipertensión arterial

U Geminorum: a test case for orbital parameters determination

High-resolution spectroscopy of U Gem was obtained during quiescence. We did not find a hot spot or gas stream around the outer boundaries of the accretion disk. Instead, we detected a strong narrow emission near the location of the secondary star. We measured the radial velocity curve from the wings of the double-peaked H$\alpha$ emission line, and obtained a semi-amplitude value that is in excellent agreement with the obtained from observations in the ultraviolet spectral region by Sion et al. (1998). We present also a new method to obtain K_2, which enhances the detection of absorption or emission features arising in the late-type companion. Our results are compared with published values derived from the near-infrared NaI line doublet. From a comparison of the TiO band with those of late type M stars, we find that a best fit is obtained for a M6V star, contributing 5 percent of the total light at that spectral region. Assuming that the radial velocity semi-amplitudes reflect accurately the motion of the binary components, then from our results: K_em = 107+/-2 km/s; K_abs = 310+/-5 km/s, and using the inclination angle given by Zhang & Robinson(1987); i = 69.7+/-0.7, the system parameters become: M_WD = 1.20+/-0.05 M_sun,; M_RD = 0.42+/-0.04 M_sun; and a = 1.55+/- 0.02 R_sun. Based on the separation of the double emission peaks, we calculate an outer disk radius of R_out/a ~0.61, close to the distance of the inner Lagrangian point L_1/a~0.63. Therefore we suggest that, at the time of observations, the accretion disk was filling the Roche-Lobe of the primary, and that the matter leaving the L_1 point was colliding with the disc directly, producing the hot spot at this location.Comment: 36 pages, 14 figures, ccepted for publication in A