6,205 research outputs found
A spectrophotometric catalogue of HII galaxies
We present a spectrophotometric catalogue of 90 emission-line galaxies (ELGs)
discovered during an objective - prism survey that aimed to search for dwarf
galaxies within the voids (Popescu et al. 1996, 1998). The paper presents line
ratios, equivalent widths and absolute fluxes for the emission-lines seen in
the spectra of the galaxies. A list of newly discovered Wolf-Rayet galaxies is
presented. Many objects included in the catalogue have low metallicity and the
extreme cases are proposed as candidates for very low metallicity galaxies.Comment: 14 pages, to appear in Astronomy and Astrophysics Suppl. Serie
Modelling the spectral energy distribution of galaxies from the ultraviolet to submillimeter
We present results from a new modelling technique which can account for the
observed optical/NIR - FIR/submm spectral energy distributions (SEDs) of normal
star-forming galaxies in terms of a minimum number of essential parameters
specifying the star-formation history and geometrical distribution of stars and
dust. The model utilises resolved optical/NIR images to constrain the old
stellar population and associated dust, and geometry-sensitive colour
information in the FIR/submm to constrain the spatial distributions of young
stars and associated dust. It is successfully applied to the edge-on spirals
NGC891 and NGC5907. In both cases the young stellar population powers the bulk
of the FIR/sub-mm emission. The model also accounts for the observed surface
brightness distribution and large-scale radial brightness profiles in NGC891 as
determined using the Infrared Space Observatory (ISO) at 170 and 200 mcrions
and at 850 micron using SCUBA.Comment: 20 pages (Latex), Highlight talk at the Joint European and National
Astronomical Meeting JENAM 2001, to be published in Reviews in Modern
Astronomy 15: Five Days of Creation: Astronomy with Large Telescopes from
Ground and Base. Germany : Astronomische Gesellschaft, 200
Milnor open books and Milnor fillable contact 3-manifolds
We say that a contact manifold is Milnor fillable if it is contactomorphic to
the contact boundary of an isolated complex-analytic singularity (X,x).
Generalizing results of Milnor and Giroux, we associate to each holomorphic
function f defined on X, with isolated singularity at x, an open book which
supports the contact structure. Moreover, we prove that any 3-dimensional
oriented manifold admits at most one Milnor fillable contact structure up to
contactomorphism.
* * * * * * * *
In the first version of the paper, we showed that the open book associated to
f carries the contact structure only up to an isotopy. Here we drop this
restriction. Following a suggestion of Janos Kollar, we also give a simplified
proof of the algebro-geometrical theorem 4.1, central for the uniqueness
result.Comment: 17 page
Entanglement entropy of multipartite pure states
Consider a system consisting of -dimensional quantum particles and
arbitrary pure state of the whole system. Suppose we simultaneously
perform complete von Neumann measurements on each particle. One can ask: what
is the minimal possible value of the entropy of outcomes joint
probability distribution? We show that coincides with entanglement
entropy for bipartite states. We compute for two sample multipartite
states: the hexacode state () and determinant states (). The
generalization of determinant states to the case is considered.Comment: 7 pages, REVTeX, corrected some typo
The economic and social dimensions of Romania’s metallurgical industry
The purpose of this paper is to enhance the understanding of both the economic and social dimensions belonging to Romania’s metallurgical industry and how they contribute to generating business value. The approach of this subject became of utmost necessity in turbulent times such as the one Romania is facing nowadays
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