885 research outputs found
Detection of the compressed primary stellar wind in eta Carinae
A series of three HST/STIS spectroscopic mappings, spaced approximately one
year apart, reveal three partial arcs in [Fe II] and [Ni II] emissions moving
outward from eta Carinae. We identify these arcs with the shell-like
structures, seen in the 3D hydrodynamical simulations, formed by compression of
the primary wind by the secondary wind during periastron passages.Comment: Accepted for publication in the Astrophysical Journal Letter
LITTLE THINGS in 3D: robust determination of the circular velocity of dwarf irregular galaxies
Dwarf Irregular galaxies (dIrrs) are the smallest stellar systems with
extended HI discs. The study of the kinematics of such discs is a powerful tool
to estimate the total matter distribution at these very small scales. In this
work, we study the HI kinematics of 17 galaxies extracted from the `Local
Irregulars That Trace Luminosity Extremes, The HI Nearby Galaxy Survey' (LITTLE
THINGS). Our approach differs significantly from previous studies in that we
directly fit 3D models (two spatial dimensions plus one spectral dimension)
using the software BAROLO, fully exploiting the information in the
HI datacubes. For each galaxy we derive the geometric parameters of the HI disc
(inclination and position angle), the radial distribution of the surface
density, the velocity-dispersion () profile and the rotation curve.
The circular velocity (V), which traces directly the galactic
potential, is then obtained by correcting the rotation curve for the asymmetric
drift. As an initial application, we show that these dIrrs lie on a baryonic
Tully-Fisher relation in excellent agreement with that seen on larger scales.
The final products of this work are high-quality, ready-to-use kinematic data
( and ) that we make publicly available. These
can be used to perform dynamical studies and improve our understanding of these
low-mass galaxies.Comment: 36 pages, 28 figures, 2 tables. Submitted to MNRAS (revised version
after the referee report). The final rotation curves can be downloaded from
http://www.filippofraternali.com/styled-9/index.htm
Socioeconomic and territorial impact of the ski industry in the Spanish Pyrenees: mountain development and leisure induced urbanization
26 páginas, 8 figuras.[EN] This article assesses the territorial impact of the ski industry in
two areas of the Spanish Pyrenees (Aragon Pyrenees and the Catalan High
Pyrenees). By analyzing the changes on demographic dynamics and structure,
economic portfolio, and evolution of the built structure of these areas since the
construction of the ski resorts, we, firstly, identify a trend towards urbanization
emerging in these areas, and secondly, that this trend unfolds in two different
models: around the ski resorts at the northern end of valleys in the Aragon study site,
and in regional centers at the bottom of the main valleys in the Catalan High
Pyrenees. In this fashion the ski industry, which offers seasonal services to a mostly
urban clientele, contributes to the redefinition of peripheral rural areas taking into
account urban needs. The towns, by the ski resorts in Aragon, and in the bottom of
the valleys in Catalonia, have grown to become small nodes of a large network that
expands the physical, economic and cultural influence of the low lands cities over the
Spanish mountains.[ES] Se evalúa el impacto territorial de la actividad del esquà en los
Pirineos españoles (Pirineos Aragoneses y Alto Pirineo Catalán). A partir del
análisis de los cambios registrados en la dinámica y estructura demográfica y de las
prácticas económicas, desde la instalación de las estaciones de esquÃ, se identifica, en
primer lugar, una tendencia urbanizadora emergente y, en segundo lugar, que dicha
tendencia se manifiesta en dos modelos diferentes: en el Pirineo aragonés se limita a
las cabeceras de los valles, mientras que en el Pirineo Catalán se expande a los fondos
de valle y cabeceras comarcales. De esta manera, la actividad del esquà contribuye a
redefinir las zonas rurales periféricas, teniendo en cuenta las necesidades urbanas.
Los pueblos próximos a las estaciones de esquà en Aragón y de los fondos de valle en
Cataluña han crecido hasta convertirse en pequeños núcleos de una gran red que
expande la influencia fÃsica, económica y cultural de las ciudades de las tierras bajas
hacia las montañas españolas.This work has been supported by the research projects: PROBASE
(CGL2006-11619/HID), INDICA (CGL2011-27753-CO2-01 y 02) and
HIDROCAES (CGL2011-27574-CO2-02), financed by Spanish Commission of
Science and Technology.Peer reviewe
Creación de unidades de análisis forense en bibliotecas
Las técnicas de análisis forense digital, de aplicación en investigación criminal, también se pueden usar en las bibliotecas para acceder a información digital almacenada en soportes o formatos obsoletos. Se analizan distintos ejemplos de departamentos de análisis forense creados por bibliotecas y se describen los elementos de hardware y software mÃnimos con los que se podrÃa montar una unidad de análisis forense en cualquier biblioteca. Con este fin se presentan dos posibles configuraciones de equipamiento y se dan recomendaciones sobre organización del flujo de trabajo para la recuperación de antiguos discos duros y disquetes. Forensic analysis techniques, usually applied in criminal research, could also be used in libraries to access digital information stored in obsolete formats or storage devices. This article analyses some examples of forensic research departments created by libraries, and describes the minimal hardware and software elements required to set up a library unit specialized in forensic analysis. Two possible equipment settings are introduced and recommendations are given on how to organize a workflow to recover information stored in floppy disks, diskettes and old hard drives
A highly-ionized region surrounding SN Refsdal revealed by MUSE
Supernova (SN) Refsdal is the first multiply-imaged, highly-magnified, and
spatially-resolved SN ever observed. The SN exploded in a highly-magnified
spiral galaxy at z=1.49 behind the Frontier Fields Cluster MACS1149, and
provides a unique opportunity to study the environment of SNe at high z. We
exploit the time delay between multiple images to determine the properties of
the SN and its environment, before, during, and after the SN exploded. We use
the integral-field spectrograph MUSE on the VLT to simultaneously target all
observed and model-predicted positions of SN Refsdal. We find MgII emission at
all positions of SN Refsdal, accompanied by weak FeII* emission at two
positions. The measured ratios of [OII] to MgII emission of 10-20 indicate a
high degree of ionization with low metallicity. Because the same high degree of
ionization is found in all images, and our spatial resolution is too coarse to
resolve the region of influence of SN Refsdal, we conclude that this high
degree of ionization has been produced by previous SNe or a young and hot
stellar population. We find no variability of the [OII] line over a period of
57 days. This suggests that there is no variation in the [OII] luminosity of
the SN over this period, or that the SN has a small contribution to the
integrated [OII] emission over the scale resolved by our observations.Comment: 5 pages, 4 figures, accepted for publication in A&
The three-dimensional structure of the Eta Carinae Homunculus
We investigate, using the modeling code SHAPE, the three-dimensional
structure of the bipolar Homunculus nebula surrounding Eta Carinae, as mapped
by new ESO VLT/X-Shooter observations of the H2 micron
emission line. Our results reveal for the first time important deviations from
the axisymmetric bipolar morphology: 1) circumpolar trenches in each lobe
positioned point-symmetrically from the center and 2) off-planar protrusions in
the equatorial region from each lobe at longitudinal (~55 degrees) and
latitudinal (10-20 degrees) distances from the projected apastron direction of
the binary orbit. The angular distance between the protrusions (~110 degrees)
is similar to the angular extent of each polar trench (~130 degrees) and nearly
equal to the opening angle of the wind-wind collision cavity (~110 degrees). As
in previous studies, we confirm a hole near the centre of each polar lobe and
no detectable near-IR H2 emission from the thin optical skirt seen prominently
in visible imagery. We conclude that the interaction between the outflows
and/or radiation from the central binary stars and their orientation in space
has had, and possibly still has, a strong influence on the Homunculus. This
implies that prevailing theoretical models of the Homunculus are incomplete as
most assume a single star origin that produces an axisymmetric nebula. We
discuss how the newly found features might be related to the Homunculus
ejection, the central binary and the interacting stellar winds. We also include
a 3D printable version of our Homunculus model.Comment: 14 pages, 7 color figures, 1 interactive 3D figure (Figure 5,
requires Adobe Reader), published in MNRAS. A 3D printable version of our
Homunculus model can be downloaded from
http://svs.gsfc.nasa.gov/vis/a010000/a011500/a011568/Eta_Car_Homunuculus_3D_model.zip
or from the 'Supporting Information' link in the electronic version of the
MNRAS articl
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