65,222 research outputs found
Far infra-red emission lines in high redshift quasars
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
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 is the complement of the line at infinity in .
Then can be regarded as the complement of an hyperplane arrangement
in ! Therefore the study of blocking sets in the affine space
is simply the study of blocking sets in the complement of a finite
arrangement in . 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 . 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
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.
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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
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
Consider the ring R:=\Q[\tau,\tau^{-1}] of Laurent polynomials in the
variable . The Artin's Pure Braid Groups (or Generalized Pure Braid
Groups) act over where the action of every standard generator is the
multiplication by . In this paper we consider the cohomology of such
groups with coefficients in the module (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
, and finding that these cohomologies stabilize, with respect to
the natural inclusion, at some number of copies of the trivial -module \Q.
We also give a formula which compute this number of copies.Comment: 17 pages; added reference for section
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