18,600 research outputs found
Asymmetric nuclear matter and neutron-skin in extended relativistic mean field model
The density dependence of the symmetry energy, instrumental in understanding
the behaviour of the asymmetric nuclear matter, is investigated within the
extended relativistic mean field (ERMF) model which includes the contributions
from the self and mixed interaction terms for the scalar-isoscalar (),
vector-isoscalar () and vector-isovector () mesons upto the
quartic order. Each of the 26 different parameterizations of the ERMF model
employed are compatible with the bulk properties of the finite nuclei. The
behaviour of the symmetry energy for several parameter sets are found to be
consistent with the empirical constraints on them as extracted from the
analyses of the isospin diffusion data. The neutron-skin thickness in the
Pb nucleus for these parameter sets of the ERMF model lie in the range
of fm which is in harmony with the ones predicted by the
Skyrme Hartree-Fock model. We also investigate the role of various mixed
interaction terms which are crucial for the density dependence of the symmetry
energy.Comment: 14 pages, 4 figures, Physical Review C (in press
A preliminary study of a very large space radiometric antenna
An approach used to compute the size of a special radiometric reflector antenna is presented. Operating at 1 GHz, this reflector is required to produce 200 simultaneous contiguous beams, each with a 3 dB footprint of 1 km from an assumed satellite height of 650 km. The overall beam efficiency for each beam is required to be more than 90%
Discovery of a Quasi-Periodic Oscillation in the Ultraluminous X-ray Source IC 342 X-1: XMM-Newton Results
We report the discovery of a quasi-periodic oscillation (QPO) at 642 mHz in
an {\it XMM-Newton} observation of the ultraluminous X-ray source (ULX) IC 342
X-1. The QPO has a centroid at mHz, a coherence factor
of , and an amplitude (rms) of 4.1\% with significance of
. The energy dependence study shows that the QPO is stronger in the
energy range 0.3 - 5.0 keV. A subsequent observation (6 days later) does not
show any signature of the QPO in the power density spectrum. The broadband
energy spectra (0.3 - 40.0 keV) obtained by quasi-simultaneous observations of
{\it XMM-Newton} and {\it NuSTAR} can be well described by an absorbed {\it
diskbb} plus {\it cutoffpl} model. The best fitted spectral parameters are
power-law index () 1.1, cutoff energy () 7.9 keV and
disc temperature () 0.33 keV, where the QPO is detected. The
unabsorbed bolometric luminosity is 5.34 10 erg~s.
Comparing with the well known X-ray binary GRS 1915+105, our results are
consistent with the mass of the compact object in IC 342 X-1 being in the range
. We discuss the possible implications of our results.Comment: 7 pages, 3 figures (2 colour), in press (MNRAS
A generalization of starlike functions of order alpha
For every and we define a class of analytic
functions, the so-called -starlike functions of order , on the open
unit disk. We study this class of functions and explore some inclusion
properties with the well-known class of starlike functions of order .
The paper is also devoted to the discussion on the Herglotz representation
formula for analytic functions when is -starlike of
order . As an application we also discuss the Bieberbach conjecture
problem for the -starlike functions of order . Further application
includes the study of the order of -starlikeness of the well-known basic
hypergeometric functions introduced by Heine.Comment: 13 pages, 4 figures, submitted to a journa
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