477 research outputs found
Нарушение межличностных отношений супругов при отдаленных последствиях закрытой черепно−мозговой травмы у мужа
Методами психодиагностического исследования выявлены закономерности нарушения межличностной адаптации супругов при отдаленных последствиях военной закрытой черепно−мозговой травмы у мужа.The methods of psychodiagnosis were used to reveal the regularities of interpersonal adaptation disorders in spouses at long−term sequelae of military closed brain injury in the husband
On the pion electroproduction amplitude
We analyze amplitudes for the pion electroproduction on proton derived from
Lagrangians based on the local chiral SU(2) x SU(2) symmetries. We show that
such amplitudes do contain information on the nucleon axial form factor F_A in
both soft and hard pion regimes. This result invalidates recent Haberzettl's
claim that the pion electroproduction at threshold cannot be used to extract
any information regarding F_A.Comment: 14 pages, 6 figures, revised version, accepted for publication in
Phys. Rev.
The Blue Straggler population in the globular cluster M53 (NGC5024): a combined HST, LBT, CFHT study
We used a proper combination of multiband high-resolution and wide field
multi-wavelength observations collected at three different telescopes (HST, LBT
and CFHT) to probe Blue Straggler Star (BSS) populations in the globular
cluster M53. Almost 200 BSS have been identified over the entire cluster
extension. The radial distribution of these stars has been found to be bimodal
(similarly to that of several other clusters) with a prominent dip at ~60'' (~2
r_c) from the cluster center. This value turns out to be a factor of two
smaller than the radius of avoidance (r_avoid, the radius within which all the
stars of ~1.2 M_sun have sunk to the core because of dynamical friction effects
in an Hubble time). While in most of the clusters with a bimodal BSS radial
distribution, r_avoid has been found to be located in the region of the
observed minimum, this is the second case (after NGC6388) where this
discrepancy is noted. This evidence suggests that in a few clusters the
dynamical friction seems to be somehow less efficient than expected.
We have also used this data base to construct the radial star density profile
of the cluster: this is the most extended and accurate radial profile ever
published for this cluster, including detailed star counts in the very inner
region. The star density profile is reproduced by a standard King Model with an
extended core (~25'') and a modest value of the concentration parameter
(c=1.58). A deviation from the model is noted in the most external region of
the cluster (at r>6.5' from the center). This feature needs to be further
investigated in order to address the possible presence of a tidal tail in this
cluster.Comment: 25 pages, 9 figures, accepted for publication on Ap
GMRT HI observations of the Eridanus group of galaxies
The GMRT HI 21cm-line observations of galaxies in the Eridanus group are
presented. The Eridanus group, at a distance of ~23 Mpc, is a loose group of
\~200 galaxies. The group extends more than 10 Mpc in projection. The velocity
dispersion of the galaxies in the group is ~240 km/s. The galaxies are
clustered into different sub-groups. The overall population mix of the group is
30% (E+S0) and 70% (Sp+Irr). The observations of 57 Eridanus galaxies were
carried out with the GMRT for ~200 hour. HI emission was detected from 31
galaxies. The channel rms of ~1.0 mJy beam^{-1} was achieved for most of the
image-cubes made with 4 hour of data. The corresponding HI column density
sensitivity (3-sigma) is ~1x10^{20} cm^{-2} for a velocity-width of ~13.4 km/s.
The 3-sigma detection limit of HI mass is ~1.2x10^{7} M_sun for a line-width of
50 km/s. Total HI images, HI velocity fields, global HI line profiles, HI mass
surface densities, HI disk parameters and HI rotation curves are presented. The
velocity fields are analysed separately for the approaching and the receding
sides of the galaxies. This data will be used to study the HI and the radio
continuum properties, the Tully-Fisher relations, the dark matter halos, and
the kinematical and HI lopsidedness in galaxies.Comment: 75 pages including HI atlas; Accepted for publication in Journal of
Astroph. & Astron. March, 200
The Luminosity Function of M3
We present a high precision, large sample luminosity function (LF) for the
Galactic globular cluster M3. With a combination of ground based and Hubble
Space Telescope data we cover the entire radial extent of the cluster. The
observed LF is well fit by canonical standard stellar models from the red giant
branch (RGB) tip to below the main sequence turnoff point. Specifically,
neither the RGB LF-bump nor subgiant branch LF indicate any breakdown in the
standard models. On the main sequence we find evidence for a flat initial mass
function and for mass segregation due to the dynamical evolution of the
cluster.Comment: 18 pages, 13 figures. ApJ, in pres
Induced pseudoscalar coupling of the proton weak interaction
The induced pseudoscalar coupling is the least well known of the weak
coupling constants of the proton's charged--current interaction. Its size is
dictated by chiral symmetry arguments, and its measurement represents an
important test of quantum chromodynamics at low energies. During the past
decade a large body of new data relevant to the coupling has been
accumulated. This data includes measurements of radiative and non radiative
muon capture on targets ranging from hydrogen and few--nucleon systems to
complex nuclei. Herein the authors review the theoretical underpinnings of
, the experimental studies of , and the procedures and uncertainties
in extracting the coupling from data. Current puzzles are highlighted and
future opportunities are discussed.Comment: 58 pages, Latex, Revtex4, prepared for Reviews of Modern Physic
A helium spread among the main sequence stars in NGC 2808
We studied the color distribution of the main sequence of the Globular
Cluster NGC 2808, based on new deep HST-WFPC2 photometry of a field in the
uncrowded outskirts of the cluster. The color distribution of main sequence
stars is wider than expected for a single stellar population, given our
(carefully determined) measurement errors. About 20% of the sample stars are
much bluer than expected and are most plausibly explained as a population
having a much larger helium abundance than the bulk of the main sequence. We
estimate that the helium mass fraction of these stars is Y ~ 0.4. NGC 2808 may
have suffered self-enrichment, with different stellar populations born from the
ejecta of the intermediate mass asymptotic giant branch (AGB) stars of the
first generation. In addition to the Y=0.40 stars, roughly 30% of the stars
should have Y distributed between 0.26-0.29 while 50% have primordial Y, to
explain also the peculiar horizontal branch morphology. Three main stages of
star formation are identified, the first with primordial helium content Y ~
0.24, the second one born from the winds of the most massive AGBs of the first
stellar generation (6-7msun), having Y ~ 0.4, and a third one born from the
matter ejected from less massive AGBs (~ 3.5-4.5msun) with Y ~ 0.26-0.29. For a
long hiatus of time (several 10^7yr) between the second and third generation,
star formation might have been inhibited by the explosion of late Supernovae II
deriving from binary evolution.Comment: accepted for publication on "The Astrophysical Journal
UV/Optical Nuclear Activity in the gE Galaxy NGC 1399
Using HST/STIS, we have detected far-ultraviolet nuclear activity in the
giant elliptical galaxy NGC 1399, the central and brightest galaxy in the
Fornax I cluster. The source reached a maximum observed far-UV luminosity of
\~1.2 x 10e39 ergs/s in January 1999. It was detectable in earlier HST archival
images in 1996 (B band) but not in 1991 (V band) or 1993 (UV). It faded by a
factor of ~4x by mid-2000. The source is almost certainly associated with the
low luminosity AGN responsible for the radio emission in NGC 1399. The
properties of the outburst are remarkably similar to the UV-bright nuclear
transient discovered earlier in NGC 4552 by Renzini et al. (1995). The source
is much fainter than expected from its Bondi accretion rate (estimated from
Chandra high resolution X-ray images), even in the context of "radiatively
inefficient accretion flow" models, and its variability also appears
inconsistent with such models. High spatial resolution UV monitoring is a
valuable means to study activity in nearby LLAGNs.Comment: 18 pages, 2 figures, 1 table; accepted for publication in Ap
Horizontal Branch Stars: The Interplay between Observations and Theory, and Insights into the Formation of the Galaxy
We review HB stars in a broad astrophysical context, including both variable
and non-variable stars. A reassessment of the Oosterhoff dichotomy is
presented, which provides unprecedented detail regarding its origin and
systematics. We show that the Oosterhoff dichotomy and the distribution of
globular clusters (GCs) in the HB morphology-metallicity plane both exclude,
with high statistical significance, the possibility that the Galactic halo may
have formed from the accretion of dwarf galaxies resembling present-day Milky
Way satellites such as Fornax, Sagittarius, and the LMC. A rediscussion of the
second-parameter problem is presented. A technique is proposed to estimate the
HB types of extragalactic GCs on the basis of integrated far-UV photometry. The
relationship between the absolute V magnitude of the HB at the RR Lyrae level
and metallicity, as obtained on the basis of trigonometric parallax
measurements for the star RR Lyrae, is also revisited, giving a distance
modulus to the LMC of (m-M)_0 = 18.44+/-0.11. RR Lyrae period change rates are
studied. Finally, the conductive opacities used in evolutionary calculations of
low-mass stars are investigated. [ABRIDGED]Comment: 56 pages, 22 figures. Invited review, to appear in Astrophysics and
Space Scienc
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