1,323 research outputs found

    The Discovery of a Molecular Complex in the Tidal Arms near NGC 3077

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    We present the discovery of a giant molecular complex (r=350 pc, M_ vir=10^7 M_sun) in the tidal arms south-east of NGC 3077, a member of the M 81 triplet. The complex is clearly detected in the 12CO (J=1-0) transition at five independent positions. The position relative to NGC 3077, the systemic velocity (v_hel=14km/s) and the cloud averaged line width (15km/s) indicate that the object is not related to Galactic cirrus but is extragalactic. The tidal HI arm where the molecular complex is located has an total HI mass of M_HI=3x10^8 M_sun. This tidal material was presumably stripped off the outer parts of NGC 3077 during the closest encounter with M 81, about 3x10^8 years ago. After the complex detected along a torn-out spiral arm of M 81 by Brouillet et al., it is the second of its kind reported so far. Based on published optical observations, we have no evidence for on--going star formation in the newly detected molecular complex. Since the system has all the ingredients to form stars in the future, we speculate that it might eventually resemble the young dwarf galaxies in the M 81 group.Comment: 12 pages (including 3 figures), accepted for publication in the ApJ Letter

    Star Forming Objects in the Tidal Tails of Compact Groups

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    A search for star forming objects belonging to tidal tails has been carried out in a sample of deep Halpha images of 16 compact groups of galaxies. A total of 36 objects with Halpha luminosity larger than 10^38 erg s-1 have been detected in five groups. The fraction of the total Halpha luminosity of their respective parent galaxies shown by the tidal objects is always below 5% except for the tidal features of HCG95, whose Halpha luminosity amounts to 65% of the total luminosity. Out of this 36 objects, 9 star forming tidal dwarf galaxy candidates have been finally identified on the basis of their projected distances to the nuclei of the parent galaxies and their total Halpha luminosities. Overall, the observed properties of the candidates resemble those previously reported for the so-called tidal dwarf galaxies.Comment: 5 gif figures. Accepted for publication in Astrophysical Journa

    The orbital poles of Milky Way satellite galaxies: a rotationally supported disc-of-satellites

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    Available proper motion measurements of Milky Way (MW) satellite galaxies are used to calculate their orbital poles and projected uncertainties. These are compared to a set of recent cold dark-matter (CDM) simulations, tailored specifically to solve the MW satellite problem. We show that the CDM satellite orbital poles are fully consistent with being drawn from a random distribution, while the MW satellite orbital poles indicate that the disc-of-satellites of the Milky Way is rotationally supported. Furthermore, the bootstrapping analysis of the spatial distribution of theoretical CDM satellites also shows that they are consistent with being randomly drawn. The theoretical CDM satellite population thus shows a significantly different orbital and spatial distribution than the MW satellites, most probably indicating that the majority of the latter are of tidal origin rather than being DM dominated sub-structures. A statistic is presented that can be used to test a possible correlation of satellite galaxy orbits with their spatial distribution.Comment: Accepted for publication in Ap

    Challenges and successes in the treatment of hemophilia: the story of a patient with severe hemophilia A and high-titer inhibitors

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    In the past, patients with severe hemophilia have suffered a substantially reduced quality of life with frequent bleeding episodes, disabling arthropathy, and shorter life expectancy. In addition, methods of treatment and management have been costly and time-consuming, and have placed a considerable burden on patients’ physical and psychological well-being. With the advent of the on-demand therapy and prophylactic treatment paradigm, patients have been able to receive care with less interruption of daily activities. Treatments may be more challenging for hemophiliacs with inhibitors to replacement factor; however, recent advances in the use of bypassing agents and immune tolerance therapy have enabled them to aggressively manage their disease while maintaining their independence. This review focuses on the challenges of treating such a severe hemophiliac through examination of the lifetime experience of a young adult male with a severe form of congenital hemophilia A. At this stage of his life, the patient has minimal disabilities and is inhibitor-free through optimal care and strong family support. His aspiration to pursue a productive life has led him to a career in medicine. After receiving his medical degree, he pursued a specialty in the treatment of hemophilia. By assisting other hemophilia patients, he exemplifies both the rewards of persevering through episodes of bleeding and other complications and the fact that disabilities can be minimized when managed meticulously and in a timely fashion to enable a productive and dignified life

    Computing the Weil representation of a superelliptic curve

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    We study the Weil representation ρ\rho of a curve over a pp-adic field with potential reduction of compact type. We show that ρ\rho can be reconstructed from its stable reduction. For superelliptic curves of the form yn=f(x)y^n=f(x) at primes pp whose residue characteristic is prime to the exponent nn we make this explicit

    Magnetic properties of Gd_xY_{1-x}Fe_2Zn_{20}: dilute, large, S\textbf {S} moments in a nearly ferromagnetic Fermi liquid

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    Single crystals of the dilute, rare earth bearing, pseudo-ternary series, Gd_xY_{1-x}Fe_2Zn_{20} were grown out of Zn-rich solution. Measurements of magnetization, resistivity and heat capacity on Gd_xY_{1-x}Fe_2Zn_{20} samples reveal ferromagnetic order of Gd^{3+} local moments across virtually the whole series (x0.02x \geq 0.02). The magnetic properties of this series, including the ferromagnetic ordering, the reduced saturated moments at base temperature, the deviation of the susceptibilities from Curie-Weiss law and the anomalies in the resistivity, are understood within the frame work of dilute, S\textbf {S} moments (Gd^{3+}) embedded in a nearly ferromagnetic Fermi liquid (YFe_2Zn_{20}). The s-d model is employed to further explain the variation of TCT_{\mathrm{C}} with x as well as the temperature dependences of of the susceptibilities
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