63,582 research outputs found

    Far infra-red emission lines in high redshift quasars

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    We present Plateau de Bure Interferometer observations of far infra-red emission lines in BRI 0952-0115, a lensed quasar at z=4.4 powered by a super-massive black hole (M_BH=2x10^9 M_sun). In this source, the resolved map of the [CII] emission at 158 micron allows us to reveal the presence of a companion galaxy, located at \sim 10 kpc from the quasar, undetected in optical observations. From the CO(5-4) emission line properties we infer a stellar mass M*<2.2x10^10 M_sun, which is significantly smaller than the one found in local galaxies hosting black holes with similar masses (M* \sim 10^12 M_sun). The detection of the [NII] emission at 205 micron suggests that the metallicity in BRI 0952-0115 is consistent with solar, implying that the chemical evolution has progressed very rapidly in this system. We also present PdBI observations of the [CII] emission line in SDSSJ1148+5251, one of the most distant quasar known, at z=6.4. We detect broad wings in the [CII] emission line, indicative of gas which is outflowing from the host galaxy. In particular, the extent of the wings, and the size of the [CII] emitting region associated to them, are indicative of a quasar-driven massive outflow with the highest outflow rate ever found (dM/dt>3500 M_sun/yr).Comment: 5 pages, 4 figures, proceedings of the NRAO meeting: The Interstellar Medium in High Redshift galaxies Comes of Age, September 201

    Blocking Sets in the complement of hyperplane arrangements in projective space

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    It is well know that the theory of minimal blocking sets is studied by several author. Another theory which is also studied by a large number of researchers is the theory of hyperplane arrangements. We can remark that the affine space AG(n,q)AG(n,q) is the complement of the line at infinity in PG(n,q)PG(n,q). Then AG(n,q)AG(n,q) can be regarded as the complement of an hyperplane arrangement in PG(n,q)PG(n,q)! Therefore the study of blocking sets in the affine space AG(n,q)AG(n,q) is simply the study of blocking sets in the complement of a finite arrangement in PG(n,q)PG(n,q). In this paper the author generalizes this remark starting to study the problem of existence of blocking sets in the complement of a given hyperplane arrangement in PG(n,q)PG(n,q). As an example she solves the problem for the case of braid arrangement. Moreover she poses significant questions on this new and interesting problem

    The integer cohomology of toric Weyl arrangements

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    A referee found an error in the proof of the Theorem 2 that we could not fix. More precisely, the proof of Lemma 2.1 is incorrect. Hence the fact that integer cohomology of complement of toric Weyl arrangements is torsion free is still a conjecture. ----- A toric arrangement is a finite set of hypersurfaces in a complex torus, every hypersurface being the kernel of a character. In the present paper we prove that if \Cal T_{\wdt W} is the toric arrangement defined by the \textit{cocharacters} lattice of a Weyl group \wdt W, then the integer cohomology of its complement is torsion free

    What role for health in the new Commission? EPC Policy Brief 4 February 2020

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    The Juncker Presidency came to an end two months ago, giving experts the chance to analyse the achievements of EU action in the field of health over the past five years and speculate on what Europe’s health policy will look like in the future. Despite little space for manoeuvre, the past European Commission mandate did gain some significant wins. Nevertheless, more efforts are needed if Europe is to tackle the unprecedented challenges affecting people’s health, such as demographic changes, environmental degradation and the rapidly changing world of work

    A stability-like theorem for cohomology of pure braid groups of the series A, B and D

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    Consider the ring R:=\Q[\tau,\tau^{-1}] of Laurent polynomials in the variable Ï„\tau. The Artin's Pure Braid Groups (or Generalized Pure Braid Groups) act over R,R, where the action of every standard generator is the multiplication by Ï„\tau. In this paper we consider the cohomology of such groups with coefficients in the module RR (it is well known that such cohomology is strictly related to the untwisted integral cohomology of the Milnor fibration naturally associated to the reflection arrangement). We give a sort of \textit{stability} theorem for the cohomologies of the infinite series AA, BB and D,D, finding that these cohomologies stabilize, with respect to the natural inclusion, at some number of copies of the trivial RR-module \Q. We also give a formula which compute this number of copies.Comment: 17 pages; added reference for section
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