384 research outputs found

    A Gamma Doradus Candidate In Eclipsing Binary BD And?

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    The BVR photometric light curves of the eclipsing binary BD And were obtained in 2008 and 2009. We estimated the mass ratio of the system as 0.97 and the photometric solutions were derived. The results show that BD And is a detached binary system, whose components have a little temperature difference of about 40 K. By analyzing photometric available light minimum times, we also derived an update ephemeris and found for the first time a possible periodic oscillation with an amplitude of 0.011 days and a period of 9.6 years. The results indicate that the periodic oscillation could be caused by a third component physically attached to the eclipsing binary. After removing the light variations due to the eclipses and proximity effects, the light-curve distortions are further explained by the pulsation of the primary component with a dominant period of 1 day. In accordance with the position of the primary component on the Hertzsprung-Russell diagram and its pulsation period, the primary component of BD And could be an excellent gamma Doradus candidate. It is rarely phenomenon that a component of the eclipsing binary system is a gamma Doradus variable.Comment: 34 pages, 8 figures. arXiv admin note: text overlap with arXiv:1112.1916 by other authors without attributio

    Absolute Properties of An Overcontact Binary HH Boo

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    We obtained multi-colour light curves of HH Boo. We analysed the orbital period variation of the system. The analysis indicated that there is possible mass transfer from the second component to the primary or mass loss with -5.04x10-7 Msun per year. Re-analysing the available radial velocity curve, we analysed the light curves. The inclination (i) of the system was found to be 69.71(0.16) deg, while the semi-major axis (a) was computed as 2.246(0.064) Rsun. The mass of the primary component was found to be 0.92(0.08) Msun, while it was obtained as 0.58(0.06) Msun for the secondary component. The radius of the primary component was computed as 0.98(0.03) Rsun, while it was computed as 0.80(0.02) Rsun for the secondary component. We demonstrated that HH Boo should be a member of the A-type subclass of W UMa binaries.Comment: 20 pages, 5 figures, 4 table

    V1135 Herculis: a double-lined eclipsing binary with an Anomalous Cepheid

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    BVR light curves and radial velocities for the double-lined eclipsing binary V1135\,Her were obtained. The brighter component of V1135\,Her is a Cepheid variable with a pulsation period of 4.22433±\pm0.00026 days. The orbital period of the system is about 39.99782±\pm0.00233 days, which is the shortest value among the known Type\,II Cepheid binaries. The observed B, V, and R magnitudes were cleaned for the intrinsic variations of the primary star. The remaining light curves, consisting of eclipses and proximity effects, are obtained. Our analyses of the multi-colour light curves and radial velocities led to the determination of fundamental stellar properties of both components of the interesting system V1135\,Her. The system consists of two evolved stars, G1+K3 between giants and supergiants, with masses of M1_1=1.461±\pm0.054 \Msun ~and M2_2=0.504±\pm0.040 {\Msun} and radii of R1_1=27.1±\pm0.4 {\Rsun} and R2_2=10.4±\pm0.2 {\Rsun}. The pulsating star is almost filling its corresponding Roche lobe which indicates the possibility of mass loss or transfer having taken place. We find an average distance of d=7500±\pm450 pc using the BVR magnitudes and also the V-band extinction. Location in the Galaxy and the distance to the galactic plane with an amount of 1300 pc indicate that it probably belongs to the thick-disk population. Most of the observed and calculated parameters of the V1135\,Her and its location on the color-magnitude and period-luminosity diagrams lead to a classification of an Anomalous Cepheid.Comment: 25 pages, 9 Tables, 9 Figures, Accepted Revista Mexicana de Astronom\'ia y Astrof\'isica. arXiv admin note: substantial text overlap with arXiv:1211.120

    Systematic study of magnetic linear dichroism and birefringence in (Ga,Mn)As

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    Magnetic linear dichroism and birefringence in (Ga,Mn)As epitaxial layers is investigated by measuring the polarization plane rotation of reflected linearly polarized light when magnetization lies in the plane of the sample. We report on the spectral dependence of the rotation and ellipticity angles in a broad energy range of 0.12-2.7 eV for a series of optimized samples covering a wide range on Mn-dopings and Curie temperatures and find a clear blue shift of the dominant peak at energy exceeding the host material band gap. These results are discussed in the general context of the GaAs host band structure and also within the framework of the k.p and mean-field kinetic-exchange model of the (Ga,Mn)As band structure. We find a semi-quantitative agreement between experiment and theory and discuss the role of disorder-induced non-direct transitions on magneto-optical properties of (Ga,Mn)As.Comment: 18 page

    The CSU Accelerator and FEL Facility

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    The Colorado State University (CSU) Accelerator Facility will include a 6-MeV L-Band electron linear accelerator (linac) with a free-electron laser (FEL) system capable of producing Terahertz (THz) radiation, a laser laboratory, a microwave test stand, and a magnetic test stand. The photocathode drive linac will be used in conjunction with a hybrid undulator capable of producing THz radiation. Details of the systems used in CSU Accelerator Facility are discusse

    Metastatic Serous Carcinoma Initially Presented As An Incarcerated And Strangulated Umbilical Hernia: A Rare Case Report

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    Introduction: We report a rare case of a metastatic serous ovarian carcinoma presented as an incarcerated and strangulated umbilical hernia.Presentation of case: A 54 year-old female was admitted to the hospital with a painful mass around the umblical region. It was elucidated during clinical history that the mass had been present for 3 to 4 years without pain. An incarcerated and strangulated umbilical hernia including a solid mass and mesenteric fat was detected on physical examination. She underwent an urgent operation for strangulated umbilical hernia. The pathological diagnosis of the hernia material was reported as carcinoma compatible with serous ovarian carcinoma metastasis. Concurrently, total abdominal histerectomy and bilateral salphingo-oopherectomy, pelvic and paraaortic lymph node dissection, omentectomy and sigmoid colon resection were performed. Histopathological evaluation confirmed the serous carcinoma originated from the left ovary.Conclusion: In the literature, some metastatic tumors have been reported to be presented as umbilical metastasis rarely. However, the present case is the first metastatic ovarian cancer that initially presented as an incarcerated and strangulated umbilical hernia in the literature, to the best of our knowledge. 

    Charge and spin distributions in GaMnAs/GaAs Ferromagnetic Multilayers

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    A self-consistent electronic structure calculation based on the Luttinger-Kohn model is performed on GaMnAs/GaAs multilayers. The Diluted Magnetic Semiconductor layers are assumed to be metallic and ferromagnetic. The high Mn concentration (considered as 5% in our calculation) makes it possible to assume the density of magnetic moments as a continuous distribution, when treating the magnetic interaction between holes and the localized moment on the Mn(++) sites. Our calculation shows the distribution of heavy holes and light holes in the structure. A strong spin-polarization is observed, and the charge is concentrated mostly on the GaMnAs layers, due to heavy and light holes with their total angular momentum aligned anti-parallel to the average magnetization. The charge and spin distributions are analyzed in terms of their dependence on the number of multilayers, the widths of the GaMnAs and GaAs layers, and the width of lateral GaAs layers at the borders of the structure.Comment: 12 pages,7 figure
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