69 research outputs found
Anisotropy of the space orientation of radio sources. I: The catalog
A catalog of the extended extragalactic radio sources consisting of 10461
objects is compiled based on the list of radio sources of the FIRST survey. A
total of 1801 objects are identified with galaxies and quasars of the SDSS
survey and the Veron-Veron catalog. The distribution of the position angles of
the axes of radio sources from the catalog is determined, and the probability
that this distribution is equiprobable is shown to be less then 10^(-7). This
result implies that at Z equal to or smaller then 0.5, spatial orientation of
the axes of radio sources is anisotropic at a statistically significant level.Comment: 8 pages, 7 figure
Optical Spectra of Four Objects Identified with Variable Radio Sources
We obtained optical spectra of four objects identified with variable radio
sources. Three objects (0029+0554, 0400+0550, 2245+0500) were found to be
quasars with redshifts of 1.314, 0.761, and 1.091. One object (2349+0534) has a
continuum spectrum characteristic of BL Lac objects. We analyze spectra of the
radio sources in the range 0.97-21.7 GHz for the epoch 1997 and in the range
3.9-11.1 GHz for the epoch 1990, as well as the pattern of variability of their
flux densities on time scales of 1.5 and 7 years.Comment: 4 pages, PD
Optical transition radiation in fused quartz under external acoustic field
In the present paper we have investigated the optical transition radiation in a plate excited by a longitudinal acoustic wave. The spectral-angular density of the radiated energy is calculated. The numerical examples are given for
a plate of fused quartz. These results show that the acoustic waves allow to control the parameters of the radiation. In particular, new resonance peaks appear in the
spectral distribution of the radiation intensity. The height of the peaks can be tuned by choosing the parameters of the acoustic wave
Experimental investigation of optical transition radiation in amorphous quartz
Optical transition radiation (OTR) in amorphous quartz is investigated experimentally for electrons with energies 7.5MeV. It is shown that the Cherenkov radiation and OTR can be separated at specific conditions. The linear
polarization of OTR is investigated and it is shown that the polarization is radial. The results of measurements for the spectral distribution of OTR have shown the maximum intensity of radiation at the wavelengths in the range 320–500 nm
Radio Frequency Spectra of 388 Bright 74 MHz Sources
As a service to the community, we have compiled radio frequency spectra from
the literature for all sources within the VLA Low Frequency Sky Survey (VLSS)
that are brighter than 15 Jy at 74 MHz. Over 160 references were used to
maximize the amount of spectral data used in the compilation of the spectra,
while also taking care to determine the corrections needed to put the flux
densities from all reference on the same absolute flux density scale. With the
new VLSS data, we are able to vastly improve upon previous efforts to compile
spectra of bright radio sources to frequencies below 100 MHz because (1) the
VLSS flux densities are more reliable than those from some previous low
frequency surveys and (2) the VLSS covers a much larger area of the sky
(declination >-30 deg.) than many other low frequency surveys (e.g., the 8C
survey). In this paper, we discuss how the spectra were constructed and how
parameters quantifying the shapes of the spectra were derived. Both the spectra
and the shape parameters are made available here to assist in the calibration
of observations made with current and future low frequency radio facilities.Comment: Accepted to ApJ
Parental health limitations, caregiving and loneliness among women with widowed parents: longitudinal eveidence from France
We investigate how daughters’ feelings of loneliness are impacted when widowed parents develop health limitations, and when daughters take on personal care tasks in response. Using longitudinal data from daughters of widowed parents drawn from the French Family and Intergenerational Relationships Study (ERFI, 1485 observations nested in 557 daughters), we assess (a) whether health limitations of widowed parents are associated with daughters’ feelings of loneliness regardless of whether or not daughters provide personal care and (b) whether there is an effect of care provision on loneliness that cannot be explained by parental health limitations. Fixed effect regression analyses show that widowed parents’ health limitations were associated with raised feelings of loneliness among their daughters. No significant additional effect of providing personal care to a widowed parent was found. Prior research on the impact of health limitations of older parents on the lives of their adult–children has focused mostly on issues related to informal caregiving. Our findings suggest that more attention to the psychosocial impact of parental health limitations—net of actual caregiving—on adult children’s lives is warranted
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