129 research outputs found
Diffuse Light in Hickson Compact Groups: The Dynamically Young System HCG 44
Compact groups are associations of a few galaxies in which the environment
plays an important role in galaxy evolution. The low group velocity dispersion
favors tidal interactions and mergers, which may bring stars from galaxies to
the diffuse intragroup light. Numerical simulations of galaxy clusters in
hierarchical cosmologies show that the amount of the diffuse light increases
with the dynamical evolution of the cluster. We search for diffuse light in the
galaxy group HCG 44 in order to determine its luminosity and luminosity
fraction. Combining with literature data, we aim to constrain the dynamical
status of Hickson compact groups. We use Intra Group planetary nebulae (IGPNe)
as tracers of diffuse light. These are detected by the so-called on band-off
band technique. We found 12 emission line objects in HCG 44, none of them
associated with the galaxies of the group. 6/12 emission line objects are
consistent with being IGPNe in HCG 44, but are also consistent with being
Ly background galaxies. Thus we derive an upper limit to the diffuse
light fraction in HCG 44 of 4.7%. We find a correlation between the fraction of
elliptical galaxies and the amount of diffuse light in Hickson compact groups.
Those with large fraction of diffuse light are those with large fractions in
number and luminosity of E/S0 galaxies. We propose an evolutionary sequence for
Hickson compact groups in which the amount of diffuse light increases with the
dynamical evolution of the group.Comment: 9 pages, 4 figures, accepted for publication at A&
Fast and slow rotators in the densest environments: a FLAMES/GIRAFFE IFS study of galaxies in Abell 1689 at z=0.183
We present FLAMES/GIRAFFE integral field spectroscopy of 30 galaxies in the
massive cluster Abell 1689 at z = 0.183. Conducting an analysis similar to that
of ATLAS3D, we extend the baseline of the kinematic morphology-density relation
by an order of magnitude in projected density and show that it is possible to
use existing instruments to identify slow and fast rotators beyond the local
Universe. We find 4.5 +- 1.0 slow rotators with a distribution in magnitude
similar to those in the Virgo cluster. The overall slow rotator fraction of our
Abell 1689 sample is 0.15 +- 0.03, the same as in Virgo using our selection
criteria. This suggests that the fraction of slow rotators in a cluster is not
strongly dependent on its density. However, within Abell 1689, we find that the
fraction of slow rotators increases towards the centre, as was also found in
the Virgo cluster.Comment: Accepted by MNRA
A twelve-image gravitational lens system in the z ~ 0.84 cluster Cl J0152.7-1357
Gravitational lens modeling is presented for the first discovered example of
a three-component source for which each component is quadruply imaged. The lens
is a massive galaxy member of the cluster Cl J0152.7-1357 at z ~ 0.84. Taking
advantage of this exceptional configuration and of the excellent angular
resolution of the HST/ACS, we measure the properties of the lens. Several
parametric macroscopic models were developed for the lens galaxy, starting from
pointlike to extended image models. For a lens model in terms of a singular
isothermal sphere with external shear, the Einstein radius is found to be R_{E}
= (9.54 +/- 0.15) kpc. The external shear points to the cluster's northern mass
peak. The unknown redshift of the source is determined to be higher than 1.9
and lower than 2.9. Our estimate of the lensing projected total mass inside the
Einstein radius, M_{len}(R < 9.54 kpc), depends on the source distance and lies
between 4.6 and 6.2 x 10^{11} M_{Sun}. This result turns out to be compatible
with the dynamical estimate based on an isothermal model. By considering the
constraint on the stellar mass-to-light ratio that comes from the evolution of
the Fundamental Plane, we can exclude the possibility that at more than 4 sigma
level the total mass enclosed inside the Einstein ring is only luminous matter.
Moreover, the photometric-stellar mass measurement within the Einstein radius
gives a minimum value of 50% (1 sigma) for the dark-to-total matter fraction.
The lensing analysis has allowed us to investigate the distribution of mass of
the deflector, also providing some interesting indications on scales that are
larger and smaller than the Einstein radius of the lens galaxy. The combination
of different diagnostics has proved to be essential in determining quantities
that otherwise would have not been directly measurable with the current data.Comment: 10 pages, 9 figures, accepted by Astronomy & Astrophysic
ĐŃŃĐ»Đ”ĐŽĐŸĐČĐ°ĐœĐžĐ” ĐžĐœŃĐ”ŃŃĐ”ĐčŃĐ° ĐŒĐŸĐ·Đł-ĐșĐŸĐŒĐżŃŃŃĐ”Ń ĐœĐ° ĐŸŃĐœĐŸĐČĐ” ŃлДĐșŃŃĐŸŃĐœŃĐ”ŃĐ°Đ»ĐŸĐłŃĐ°ŃОО
ĐбŃĐ”ĐșŃĐ°ĐŒĐž ĐžŃŃĐ»Đ”ĐŽĐŸĐČĐ°ĐœĐžŃ ŃĐČĐ»ŃŃŃŃŃ ĐœĐ°ŃŃŃĐ”ĐœĐžŃ ĐŽĐČОгаŃДлŃĐœĐŸĐč Đ°ĐșŃĐžĐČĐœĐŸŃŃĐž, ŃĐžŃŃĐ”ĐŒĐ°, ŃŃĐŸĐ±Ń ĐżĐŸĐŒĐŸŃŃ Đ»ŃĐŽŃĐŒ ĐŽĐČОгаŃŃŃŃ. ЊДлŃŃ ŃĐ°Đ±ĐŸŃŃ ŃĐČĐ»ŃĐ”ŃŃŃ ŃĐ°Đ·ŃĐ°Đ±ĐŸŃĐșĐ° ĐžĐœŃĐ”ŃŃĐ”ĐčŃĐ° ĐŒĐŸĐ·Đł-ĐșĐŸĐŒĐżŃŃŃĐ”Ń ĐœĐ° ĐŸŃĐœĐŸĐČĐ” ŃлДĐșŃŃĐŸŃĐœŃĐ”ŃĐ°Đ»ĐŸĐłŃĐ°ŃОО. Đ ŃĐ°Đ±ĐŸŃĐ” ŃĐ°Đ·ŃабаŃŃĐČĐ°Đ”ŃŃŃ ĐžĐœŃĐ”ŃŃĐ”ĐčŃŃ ĐŒĐŸĐ·Đł-ĐșĐŸĐŒĐżŃŃŃĐ”Ń ĐŽĐ»Ń ŃĐ±ĐŸŃĐ° Đž ĐŸĐ±ŃĐ°Đ±ĐŸŃĐșĐž ĐŒĐŸĐ·ĐłĐŸĐČŃŃ
ĐČĐŸĐ»Đœ ĐŽĐ»Ń Đ°ĐœĐ°Đ»ĐžĐ·Đ° ŃĐ”Đ»ĐŸĐČĐ”ŃĐ”ŃĐșĐžŃ
ĐœĐ°ĐŒĐ”ŃĐ”ĐœĐžĐč Đž ĐŽĐŸŃŃĐžĐ¶Đ”ĐœĐžŃ ŃĐ”Đ»ĐŸĐČĐ”ŃĐ”ŃĐșĐžŃ
ĐżĐŸŃŃĐ”Đ±ĐœĐŸŃŃĐ”Đč Ń ĐżĐŸĐŒĐŸŃŃŃ ĐșĐŸĐŒĐżŃŃŃĐ”ŃĐœŃŃ
ОлО ĐŽŃŃгОŃ
ŃлДĐșŃŃĐŸĐœĐœŃŃ
ŃŃŃŃĐŸĐčŃŃĐČ ĐžĐ»Đž ĐŽĐ»Ń ŃĐŸĐłĐŸ, ŃŃĐŸĐ±Ń ĐżĐŸĐŒĐŸŃŃ ĐžĐŒ ĐŸĐ±ŃĐ°ŃŃŃŃ Ń ĐČĐœĐ”ŃĐœĐžĐŒ ĐŒĐžŃĐŸĐŒ.The objects of study are mobility impaired, a system to help people move. The aim of this work is the development of an interface for brain-computer on the basis of electroencephalography. The article describes development of interfaces brain-computer for collection and processing of brain waves for the analysis of human intentions and achievements of human needs with the help of computer or other electronic devices or in order to help them communicate with the outside world
Data and 2D scaling relations for galaxies in Abell 1689: a hint of size evolution at z~0.2
{abridged} We present imaging and spectroscopy of Abell 1689 (z=0.183) from
GEMINI/GMOS-N and HST/ACS. We measure integrated photometry from the GMOS g'
and r' images (for 531 galaxies) and surface photometry from the HST F625W
image (for 43 galaxies) as well as velocities and velocity dispersions from the
GMOS spectra (for 71 galaxies). We construct the Kormendy relation (KR),
Faber-Jackson relation (FJR) and colour-magnitude relation (CMR) for early-type
galaxies in Abell 1689 using this data and compare them to those of the Coma
cluster. We measure the intrinsic scatter of the CMR in Abell 1689 to be 0.054
\pm 0.004 mag which places degenerate constraints on the ratio of the assembly
timescale to the time available (beta) and the age of the population. Making
the assumption that galaxies in Abell 1689 will evolve into those of Coma over
an interval of 2.26 Gyr breaks this degeneracy and limits beta to be > 0.6 and
the age of the red sequence to be > 5.5 Gyr (formed at z > 0.55). Without
corrections for size evolution but accounting for magnitude cuts and selection
effects, the KR & FJR are inconsistent and disagree at the 2 sigma level
regarding the amount of luminosity evolution in the last 2.26 Gyr. However,
after correcting for size evolution the KR & FJR show similar changes in
luminosity (0.22 \pm 0.11 mag) that are consistent with the passive evolution
of the stellar populations from a single burst of star formation 10.2 \pm 3.3
Gyr ago (z = 1.8+inf-0.9). Thus the changes in the KR, FJR & CMR of Abell 1689
relative to Coma all agree and suggest old galaxy populations with little or no
synchronisation in the star formation histories. Furthermore, the weak evidence
for size evolution in the cluster environment in the last 2.26 Gyr places
interesting constraints on the possible mechanisms at work, favouring
harassment or secular processes over merger scenarios.Comment: Accepted for publication in MNRA
Multiple Facets of Biodiversity Drive the Diversity-Stability Relationship
A significant body of evidence has demonstrated that biodiversity stabilizes ecosystem functioning over time in grassland ecosystems. However, the relative importance of different facets of biodiversity underlying the diversityâstability relationship remains unclear. Here we used data from 39 biodiversity experiments and structural equation modeling to investigate the roles of species richness, phylogenetic diversity, and both the diversity and community-weighted mean of functional traits representing the âfastâslowâ leaf economics spectrum in driving the diversityâstability relationship. We found that high species richness and phylogenetic diversity stabilize biomass production via enhanced asynchrony. Contrary to our hypothesis, low phylogenetic diversity also enhances ecosystem stability directly, albeit weakly. While the diversity of fastâslow functional traits has a weak effect on ecosystem stability, communities dominated by slow species enhance ecosystem stability by increasing mean biomass production relative to the standard deviation of biomass over time. Our results demonstrate that biodiversity influences ecosystem stability via a variety of facets, thus highlighting a more multicausal relationship than has been previously acknowledged
Upper limits on the strength of periodic gravitational waves from PSR J1939+2134
The first science run of the LIGO and GEO gravitational wave detectors
presented the opportunity to test methods of searching for gravitational waves
from known pulsars. Here we present new direct upper limits on the strength of
waves from the pulsar PSR J1939+2134 using two independent analysis methods,
one in the frequency domain using frequentist statistics and one in the time
domain using Bayesian inference. Both methods show that the strain amplitude at
Earth from this pulsar is less than a few times .Comment: 7 pages, 1 figure, to appear in the Proceedings of the 5th Edoardo
Amaldi Conference on Gravitational Waves, Tirrenia, Pisa, Italy, 6-11 July
200
Improving the sensitivity to gravitational-wave sources by modifying the input-output optics of advanced interferometers
We study frequency dependent (FD) input-output schemes for signal-recycling
interferometers, the baseline design of Advanced LIGO and the current
configuration of GEO 600. Complementary to a recent proposal by Harms et al. to
use FD input squeezing and ordinary homodyne detection, we explore a scheme
which uses ordinary squeezed vacuum, but FD readout. Both schemes, which are
sub-optimal among all possible input-output schemes, provide a global noise
suppression by the power squeeze factor, while being realizable by using
detuned Fabry-Perot cavities as input/output filters. At high frequencies, the
two schemes are shown to be equivalent, while at low frequencies our scheme
gives better performance than that of Harms et al., and is nearly fully
optimal. We then study the sensitivity improvement achievable by these schemes
in Advanced LIGO era (with 30-m filter cavities and current estimates of
filter-mirror losses and thermal noise), for neutron star binary inspirals, and
for narrowband GW sources such as low-mass X-ray binaries and known radio
pulsars. Optical losses are shown to be a major obstacle for the actual
implementation of these techniques in Advanced LIGO. On time scales of
third-generation interferometers, like EURO/LIGO-III (~2012), with
kilometer-scale filter cavities, a signal-recycling interferometer with the FD
readout scheme explored in this paper can have performances comparable to
existing proposals. [abridged]Comment: Figs. 9 and 12 corrected; Appendix added for narrowband data analysi
Studium der Theologie: Eine enzyklopÀdische Orientierung
Gerhard Ebelings aus einer Vorlesung entstandenes Buch eignet sich nach wie vor hervorragend als grundsĂ€tzliche EinfĂŒhrung in das Theologiestudium. Das Grundanliegen des Autors ist es, eine Orientierungshilfe zu leisten, welche ĂŒber die zunehmende Spezialisierung hinaus die Einheit der Theologie reflektiert. âDer Schwerpunkt liegt nicht in der Mitteilung von Fachwissen der einzelnen Disziplinen, sondern in deren VerknĂŒpfung untereinanderâ (Vorwort).
Ebeling wĂ€hlt eine eigenstĂ€ndige Reihenfolge und integriert auch nahestehende auĂertheologische Disziplinen wie Philosophie, Natur- und Geisteswissenschaften sowie Humanwissenschaften. Diese Neuausgabe zum 100. Geburtstag des Autors wird durch ein Nachwort ergĂ€nzt, das Ebelings Schrift in ihrem historischen Kontext prĂ€sentiert und mit BeitrĂ€gen der letzten Jahrzehnte in diesem Arbeitsfeld vergleicht
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