337 research outputs found
Impacto social y distributivo de la revisión de la Directiva sobre Fiscalidad Energética en España
Este documento busca evaluar los impactos distributivos directos de la reforma del ETD en los hogares españoles. Para ello, se han usado los resultados de un modelo de microsimulaciĂłn desarrollado por BC3 con el IEEP y otros socios de la red Think Sustainable Europe (TSE). El objetivo de este estudio es explorar si los instrumentos propuestos a nivel de la UE pueden ser diseñados de manera que sean progresivos y no afecten a colectivos vulnerables, e identificar opciones polĂticas para asegurar que fortalezcan y no socaven la justicia social
Search for associations containing young stars (SACY) VIII. An updated census of spectroscopic binary systems showing hints of non-universal multiplicity among these associations
We seek to update the spectroscopy binary fraction of the SACY (Search for
Associations Containing Young stars) sample taking in consideration all
possible biases in our identification of binary candidates, such as activity
and rotation. Using high-resolution spectroscopic observations we have produced
1300 cross-correlation functions (CCFs) to disentangle the previously
mentioned sources of contamination. The radial velocity values obtained were
cross-matched with the literature and were used to revise and update the
spectroscopic binary (SB) fraction in each of the SACY association. In order to
better describe the CCF profile, we calculated a set of high-order
cross-correlation features to determine the origin of the variations in radial
velocities. We identified 68 SB candidates from our sample of 410 objects. Our
results hint that the youngest associations have a higher SB fraction.
Specifically, we found sensitivity-corrected SB fractions of for ~Cha , for TW Hya and
for ~Pictoris, in contrast with the five
oldest ( Myr) associations we have sampled which are
or lower. This result seems independent of the methodology used to asses
membership to the associations. The new CCF analysis, radial velocity estimates
and SB candidates are particularly relevant for membership revision of targets
in young stellar associations. These targets would be ideal candidates for
follow-up campaigns using high-resolution techniques in order to confirm
binarity, resolve the orbits, and ideally calculate dynamical masses.
Additionally, if the results on SB fraction in the youngest associations are
confirmed, it could hint of non-universal multiplicity among SACY associations.Comment: The paper has been accepted in A&
The central engine of GRB 130831A and the energy breakdown of a relativistic explosion
Gamma-ray bursts (GRBs) are the most luminous explosions in the universe, yet
the nature and physical properties of their energy sources are far from
understood. Very important clues, however, can be inferred by studying the
afterglows of these events. We present optical and X-ray observations of GRB
130831A obtained by Swift, Chandra, Skynet, RATIR, Maidanak, ISON, NOT, LT and
GTC. This burst shows a steep drop in the X-ray light-curve at s
after the trigger, with a power-law decay index of . Such a rare
behaviour cannot be explained by the standard forward shock (FS) model and
indicates that the emission, up to the fast decay at s, must be of
"internal origin", produced by a dissipation process within an
ultrarelativistic outflow. We propose that the source of such an outflow, which
must produce the X-ray flux for day in the cosmological rest frame,
is a newly born magnetar or black hole. After the drop, the faint X-ray
afterglow continues with a much shallower decay. The optical emission, on the
other hand, shows no break across the X-ray steep decrease, and the late-time
decays of both the X-ray and optical are consistent. Using both the X-ray and
optical data, we show that the emission after s can be explained
well by the FS model. We model our data to derive the kinetic energy of the
ejecta and thus measure the efficiency of the central engine of a GRB with
emission of internal origin visible for a long time. Furthermore, we break down
the energy budget of this GRB into the prompt emission, the late internal
dissipation, the kinetic energy of the relativistic ejecta, and compare it with
the energy of the associated supernova, SN 2013fu.Comment: Accepted for publication by MNRAS. 21 pages, 3 figures, 8 tables.
Extra table with magnitudes in the sourc
From Nuevo LeĂłn to the USA and Back Again: Transnational Students in Mexico
The movement of Mexicans to the United States is both longstanding and long studied and from that study we know that for many newcomers the attachment to the receiving community is fraught and tentative. The experience of immigrant children in U.S. schools is also relatively well studied and reveals challenges of intercultural communication as well as concurrent and contradictory features of welcome and unwelcome. What is less well known, in the study of migration generally and of transnational students in particular, is how students moving in a less common direction â from the U.S. to Mexico â experience that movement. Based on visits to 173 randomly selected classrooms in the state of Nuevo LeĂłn Mexico, this study shares survey and interview data from 208 of the 242 students encountered who had previous experience attending school in the United States
Por D. Luysa Iosepha de Guzman, marquesa de Villamanrique, y de Ayamonte con D. Manuel Luys de Guzman Manrique de Zuñiga, su hijo mayor ... y con Don Manuel de Zuñiga, Duque de Beiar ... y con Don Baltasar de Guzman, marques de Valero ... sobre la succession de el estado de Ayamonte y sus agregados, en el juyzio en fauor del Duque, y que se absuelva å la Marquesa de sus demandas
Al final del texto consta: "Licenc. D. Gaspar de Santoyo Ruyz de Contreras"Precede al tĂt.: "christus"Sign.: A-Z\p2\s, 2A\p1\sCapital xil
Young and Intermediate-age Distance Indicators
Distance measurements beyond geometrical and semi-geometrical methods, rely
mainly on standard candles. As the name suggests, these objects have known
luminosities by virtue of their intrinsic proprieties and play a major role in
our understanding of modern cosmology. The main caveats associated with
standard candles are their absolute calibration, contamination of the sample
from other sources and systematic uncertainties. The absolute calibration
mainly depends on their chemical composition and age. To understand the impact
of these effects on the distance scale, it is essential to develop methods
based on different sample of standard candles. Here we review the fundamental
properties of young and intermediate-age distance indicators such as Cepheids,
Mira variables and Red Clump stars and the recent developments in their
application as distance indicators.Comment: Review article, 63 pages (28 figures), Accepted for publication in
Space Science Reviews (Chapter 3 of a special collection resulting from the
May 2016 ISSI-BJ workshop on Astronomical Distance Determination in the Space
Age
A First Search for coincident Gravitational Waves and High Energy Neutrinos using LIGO, Virgo and ANTARES data from 2007
We present the results of the first search for gravitational wave bursts
associated with high energy neutrinos. Together, these messengers could reveal
new, hidden sources that are not observed by conventional photon astronomy,
particularly at high energy. Our search uses neutrinos detected by the
underwater neutrino telescope ANTARES in its 5 line configuration during the
period January - September 2007, which coincided with the fifth and first
science runs of LIGO and Virgo, respectively. The LIGO-Virgo data were analysed
for candidate gravitational-wave signals coincident in time and direction with
the neutrino events. No significant coincident events were observed. We place
limits on the density of joint high energy neutrino - gravitational wave
emission events in the local universe, and compare them with densities of
merger and core-collapse events.Comment: 19 pages, 8 figures, science summary page at
http://www.ligo.org/science/Publication-S5LV_ANTARES/index.php. Public access
area to figures, tables at
https://dcc.ligo.org/cgi-bin/DocDB/ShowDocument?docid=p120000
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