Search results for "STARS"
showing 10 items of 798 documents
The Gaia-ESO Survey: evidence of atomic diffusion in M67?
2018
Investigating the chemical homogeneity of stars born from the same molecular cloud at virtually the same time is very important for our understanding of the chemical enrichment of the interstellar medium and with it the chemical evolution of the Galaxy. One major cause of inhomogeneities in the abundances of open clusters is stellar evolution of the cluster members. In this work, we investigate variations in the surface chemical composition of member stars of the old open clusterM67 as a possible consequence of atomic diffusion effects taking place during the main-sequence phase. The abundances used are obtained from high-resolution UVES/FLAMES spectra within the framework of the Gaia-ESO S…
Search for intermediate mass black hole binaries in the first and second observing runs of the Advanced LIGO and Virgo network
2019
Gravitational wave astronomy has been firmly established with the detection of gravitational waves from the merger of ten stellar mass binary black holes and a neutron star binary. This paper reports on the all-sky search for gravitational waves from intermediate mass black hole binaries in the first and second observing runs of the Advanced LIGO and Virgo network. The search uses three independent algorithms: two based on matched filtering of the data with waveform templates of gravitational wave signals from compact binaries, and a third, model-independent algorithm that employs no signal model for the incoming signal. No intermediate mass black hole binary event was detected in this sear…
All-sky search in early O3 LIGO data for continuous gravitational-wave signals from unknown neutron stars in binary systems
2021
Rapidly spinning neutron stars are promising sources of continuous gravitational waves. Detecting such a signal would allow probing of the physical properties of matter under extreme conditions. A significant fraction of the known pulsar population belongs to binary systems. Searching for unknown neutron stars in binary systems requires specialized algorithms to address unknown orbital frequency modulations. We present a search for continuous gravitational waves emitted by neutron stars in binary systems in early data from the third observing run of the Advanced LIGO and Advanced Virgo detectors using the semicoherent, GPU-accelerated, binaryskyhough pipeline. The search analyzes the most s…
Dynamics of boson stars and fermion-boson stars: a numerical-relativity panorama
2022
Los albores de la astronomía de ondas gravitacionales, actualmente liderada por la Colaboración LIGO-Virgo-KAGRA, abren un nuevo canal para inspeccionar la verdadera naturaleza de los objetos compactos oscuros. Los miembros más convincentes de esta categoría son los agujeros negros, de los que se cree ampliamente que están bien descritos por la métrica de Kerr cerca del equilibrio. Se han propuesto varias posibilidades teóricas más exóticas, denominadas imitadores de agujeros negros, ya que sus propiedades y dinámica se parecen en ciertos aspectos a las de los agujeros negros. Entre esos objetos compactos oscuros alternativos, las estrellas bosónicas, descritas por un campo escalar o vector…
Meistara Ekharta mācība D. T. Sudzuki transcendentālfilozofijas interpretācijā
2021
Maģistra darbs “Meistara Ekharta mācība D. T. Sudzuki transcendentālfilozofijas interpretācijā” ir veltīts tam, lai pētītu 20.gadsimta japāņu domātāja Daisecu Teitaro Sudzuki (Daisetz Teitaro Suzuki) darbos pausto Meistara Ekharta – 13.gadsmta vācu filozofa, teologa un mistiķa – domas salīdzinājumu ar budisma mācību. D. T. Sudzuki ir domātājs, kurš izvirza pieņēmumu, ka Meistars Ekharts savos darbos pauž uzskatus, kas ir ļoti tuvi vai pat vienādi ar budisma filozofiju, kaut arī 13.gadsimtā Eiropā budisms nebija zināms.
Observatory science with eXTP
2019
Disponible preprint en: arXiv:1812.04023v1 [astro-ph.HE] [v1] Mon, 10 Dec 2018 19:00:52 UTC (4,376 KB)
2018
Star-shaped polymers show a continuous change of properties from flexible linear chains to soft colloids, as the number of arms is increased. To investigate the effect of macromolecular architecture on the flow properties, we employ computer simulations of single chain and star polymers as well as of their mixtures under Poiseuille flow. Hydrodynamic interactions are incorporated through the multi-particle collision dynamics (MPCD) technique, while a bead-spring model is used to describe the polymers. For the ultradilute systems at rest, the polymers are distributed uniformly in the slit channel, with a weak dependence on their number of arms. Once flow is applied, however, we find that the…
Time-domain effective-one-body gravitational waveforms for coalescing compact binaries with nonprecessing spins, tides and self-spin effects
2018
We present TEOBResumS, a new effective-one-body (EOB) waveform model for nonprecessing (spin-aligned) and tidally interacting compact binaries.Spin-orbit and spin-spin effects are blended together by making use of the concept of centrifugal EOB radius. The point-mass sector through merger and ringdown is informed by numerical relativity (NR) simulations of binary black holes (BBH) computed with the SpEC and BAM codes. An improved, NR-based phenomenological description of the postmerger waveform is developed.The tidal sector of TEOBResumS describes the dynamics of neutron star binaries up to merger and incorporates a resummed attractive potential motivated by recent advances in the post-Newt…
Mass-Metallicity Relation from Cosmological Hydrodynamical Simulations and X-ray Observations of Galaxy Groups and Clusters
2018
Recent X-ray observations of galaxy clusters show that the distribution of intra-cluster medium (ICM) metallicity is remarkably uniform in space and time. In this paper, we analyse a large sample of simulated objects, from poor groups to rich clusters, to study the dependence of the metallicity and related quantities on the mass of the systems. The simulations are performed with an improved version of the Smoothed-Particle-Hydrodynamics \texttt{GADGET-3} code and consider various astrophysical processes including radiative cooling, metal enrichment and feedback from stars and active galactic nuclei (AGN). The scaling between the metallicity and the temperature obtained in the simulations ag…
Możliwości rozwoju przedsiębiorstw świadczących osobom starszym usługi zdrowotne i opiekuńcze w poszczególnych województwach w Polsce
2018
Postępujący proces starzenia się polskiego społeczeństwa wpływa na zwiększające się zapotrzebowanie na usługi zdrowotne i opiekuńcze. Aby wykazać, w których regionach kraju istnieją największe możliwości rozwoju prywatnej inicjatywy w zakresie świadczenia usług zdrowotnych i opiekuńczych, opracowano diagnozę stopnia zaspokojenia tych potrzeb osób starszych (65+) w poszczególnych województwach w Polsce w 2015 r. Wykorzystując syntetyczną miarę rozwoju (SMR) [Panek, 2009], wykazano, że najmniejsze możliwości rozwoju prywatnych przedsiębiorstw występują w województwie małopolskim, w dalszej kolejności podkarpackim i lubelskim. Najwięcej niepublicznych placówek powinno powstawać z kolei w wojew…