710 research outputs found
CBM Performance for Anisotropic Flow Measurements
Compressed Baryonic Matter experiment (CBM) at FAIR has a potential of discoveries in the area of QCD phase diagram with high net baryon densities and moderate temperatures. Anisotropic transverse flow is one of the key observables to study the properties of matter created in heavy-ion collisions. CBM performance for anisotropic flow measurements is studied with Monte-Carlo simulations of gold ions at SIS-100 energies using heavy-ion event generators. Different combinations of the CBM detector subsystems are used to investigate the possible systematic biases in flow measurement and to study effects of detector azimuthal non-uniformity. Resulting performance of the CBM for flow measurements is demonstrated for directed flow of identified charged hadrons as a function of rapidity and transverse momentum in different centrality classes
Performance Studies for Strange Hadron Flow Measurements in CBM at FAIR
Measurements of the directed and elliptic flow of strange and multi-strange hadrons are an important part of the physics program of the Compressed Baryonic Matter experiment (CBM) at the future accelerator complex FAIR in Darmstadt, Germany. We present recent results from the CBM performance studies for measurements of the directed
Synthesis of Ni/NiO Nanopowder by Thermal Decomposition of Nickel Acetate Amine
Ni/NiO nanopowders have been synthesized using thermal decomposition of nickel acetate hexaammine in air. Obtained powders have been characterized by IR-spectroscopy, XRD and TG, DTA, DTG and
HR TEM. Thermal decomposition of nickel ammine complexes occurs with forming nickel hydroxide, carbonate and hydroxocarbonate ammines precursors. Mean particle size of nickel and nickel oxide phases in
powders depends on temperature. In the temperature range from 350 to 500 degrees Celsius the particle size of nickel
oxide has grown from 5 to 25 nm and nickel from 50 to 55 nm. Particle size of 5 nm for nickel hydroxide
ammine remained unchanged with temperature.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3481
Analyzing X-Ray Pulsar Profiles: Geometry and Beam Pattern of EXO 2030+375
The pulse profiles of the transient Be/X-ray binary EXO 2030+375 show strong
dependence on energy, as well as on its luminosity state, and are asymmetric in
shape. We want to identify the emission components of the two magnetic poles in
the pulsed emission to understand the geometry of the neutron star and its beam
pattern. We utilize a pulse-profile decomposition method that enables us to
find two symmetric pulse profiles from the magnetic poles of the neutron star.
The symmetry characteristics of these single-pole pulse profiles give
information about the position of the magnetic poles of the neutron star
relative to its rotation axis. We find a possible geometry for the neutron star
in EXO 2030+375 through the decomposition of the pulse profiles, which suggests
that one pole gets closer to the line of sight than the other and that, during
the revolution of the neutron star, both poles disappear behind the horizon for
a short period of time. A considerable fraction of the emission arises from a
halo while the pole is facing the observer and from the accretion stream of the
other pole while it is behind the neutron star, but the gravitational line
bending makes the emission visible to us.Comment: 8 pages, 9 figures, accepted for publication in A&
Procedure for Event Characterization in Pb-Pb Collisions at 40A GeV in the NA49 Experiment at the CERN SPS
The time evolution of the strongly interacting matter created in a heavy-ion collision depends on the initial geometry and the collision centrality. This makes important the experimental determination of the collision geometry. In this paper a procedure for event classification and estimation of the geometrical parameters in inelastic Pb-Pb collisions at the beam energy of 4
Tracking the Orbital and Super-orbital Periods of SMC X-1
The High Mass X-ray Binary (HMXB) SMC X-1 demonstrates an orbital variation
of 3.89 days and a super-orbital variation with an average length of 55 days.
As we show here, however, the length of the super-orbital cycle varies by
almost a factor of two, even across adjacent cycles. To study both the orbital
and super-orbital variation we utilize lightcurves from the Rossi X-ray Timing
Explorer All Sky Monitor (RXTE-ASM). We employ the orbital ephemeris from
Wojdowski et al. (1998) to obtain the average orbital profile, and we show that
this profile exhibits complex modulation during non-eclipse phases.
Additionally, a very interesting ``bounceback'' in X-ray count rate is seen
during mid-orbital eclipse phases, with a softening of the emission during
these periods. This bounceback has not been previously identified in pointed
observations. We then define a super-orbital ephemeris (the phase of the
super-orbital cycle as a function of date) based on the ASM lightcurve and
analyze the trend and distribution of super-orbital cycle lengths. SMC X-1
exhibits a bimodal distribution of these lengths, similar to what has been
observed in other systems (e.g., Her X-1), but with more dramatic changes in
cycle length. There is some hint, but not conclusive evidence, for a dependence
of the super-orbital cycle length upon the underlying orbital period, as has
been observed previously for Her X-1 and Cyg X-2. Using our super-orbital
ephemeris we are also able to create an average super-orbital profile over the
71 observed cycles, for which we witness overall hardening of the spectrum
during low count rate times. We combine the orbital and super-orbital
ephemerides to study the correlation between the orbital and super-orbital
variations in the system.Comment: 10 pages, using emulateapj style. To be published in the
Astrophysical Journa
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