520 research outputs found
Extragalactic Millimeter-wave Point-source Catalog, Number Counts and Statistics from 771 deg^2 of the SPT-SZ Survey
We present a point-source catalog from 771 deg^2 of the South Pole Telescope Sunyaev-Zel'dovich survey at 95, 150, and 220 GHz. We detect 1545 sources above 4.5Ï significance in at least one band. Based on their relative brightness between survey bands, we classify the sources into two populations, one dominated by synchrotron emission from active galactic nuclei, and one dominated by thermal emission from dust-enshrouded star-forming galaxies. We find 1238 synchrotron and 307 dusty sources. We cross-match all sources against external catalogs and find 189 unidentified synchrotron sources and 189 unidentified dusty sources. The dusty sources without counterparts are good candidates for high-redshift, strongly lensed submillimeter galaxies. We derive number counts for each population from 1 Jy down to roughly 11, 4, and 11 mJy at 95, 150, and 220 GHz. We compare these counts with galaxy population models and find that none of the models we consider for either population provide a good fit to the measured counts in all three bands. The disparities imply that these measurements will be an important input to the next generation of millimeter-wave extragalactic source population models
Synthesis and electronic properties of polycyclic aromatic hydrocarbons doped with phosphorus and sulfur
International audienc
Thomas rotation and Thomas precession
Exact and simple calculation of Thomas rotation and Thomas precessions along
a circular world line is presented in an absolute (coordinate-free) formulation
of special relativity. Besides the simplicity of calculations the absolute
treatment of spacetime allows us to gain a deeper insight into the phenomena of
Thomas rotation and Thomas precession.Comment: 20 pages, to appear in Int. J. Theo. Phy
A Monte Carlo comparison between template-based and Wiener-filter CMB dipole estimators
We review and compare two different CMB dipole estimators discussed in the
literature, and assess their performances through Monte Carlo simulations. The
first method amounts to simple template regression with partial sky data, while
the second method is an optimal Wiener filter (or Gibbs sampling)
implementation. The main difference between the two methods is that the latter
approach takes into account correlations with higher-order CMB temperature
fluctuations that arise from non-orthogonal spherical harmonics on an
incomplete sky, which for recent CMB data sets (such as Planck) is the dominant
source of uncertainty. For an accepted sky fraction of 81% and an angular CMB
power spectrum corresponding to the best-fit Planck 2018 CDM model, we
find that the uncertainty on the recovered dipole amplitude is about six times
smaller for the Wiener filter approach than for the template approach,
corresponding to 0.5 and 3K, respectively. Similar relative differences
are found for the corresponding directional parameters and other sky fractions.
We note that the Wiener filter algorithm is generally applicable to any dipole
estimation problem on an incomplete sky, as long as a statistical and
computationally tractable model is available for the unmasked higher-order
fluctuations. The methodology described in this paper forms the numerical basis
for the most recent determination of the CMB solar dipole from Planck, as
summarized by arXiv:2007.04997.Comment: 8 pages, 10 figures, submitted to A&
CERTAIN ENVIRONMENT, ECONOMIC AND SOCIAL ASPECTS OF THE HIGH NATURAL VALUE (HNV) FARMING: ROMANIANâS STATE OF THE ART
HNV farming is a new concept that describes those farming systems in Europe that have the widest biodiversity. It brings an alternative and complementary approach to the typology that has become conventional by nature conservation. The paper presents the role of the HNV farming system for the conservation of rare and threatened species and habitats in protected areas as well as preservation of biodiversity inEurope, which largely depends on the continuation of traditional agricultural practices in much wider areas of European rural space. Thus, one of the major problems in the implementation of agricultural policies in many European countries has been made aware: support for ,,natureâ focuses on ,,designated areasâ while support for ,,agricultureâ flows abundantly towards large, intensive producers. This situation needs to be reconsidered because in the distribution of European funds there has been a recommendation on the major change towards environmentally beneficial land use
Rms-flux relation in the optical fast variability data of BL Lacertae object S5 0716+714
The possibility that BL Lac S5 0716+714 exhibits a linear root mean square
(rms)-flux relation in its IntraDay Variability (IDV) is analysed. The results
may be used as an argument in the existing debate regarding the source of
optical IDV in Active Galactic Nuclei. 63 time series in different optical
bands were used. A linear rms-flux relation at a confidence level higher than
65% was recovered for less than 8% of the cases. We were able to check if the
magnitude is log-normally distributed for eight timeseries and found, with a
confidence > 95%, that this is not the case.Comment: Accepted by Astrophysics and Space Scienc
Consistency of cosmic microwave background temperature measurements in three frequency bands in the 2500-square-degree SPT-SZ survey
We present an internal consistency test of South Pole Telescope (SPT)
measurements of the cosmic microwave background (CMB) temperature anisotropy
using three-band data from the SPT-SZ survey. These measurements are made from
observations of ~2500 deg^2 of sky in three frequency bands centered at 95,
150, and 220 GHz. We combine the information from these three bands into six
semi-independent estimates of the CMB power spectrum (three single-frequency
power spectra and three cross-frequency spectra) over the multipole range 650 <
l < 3000. We subtract an estimate of foreground power from each power spectrum
and evaluate the consistency among the resulting CMB-only spectra. We determine
that the six foreground-cleaned power spectra are consistent with the null
hypothesis, in which the six cleaned spectra contain only CMB power and noise.
A fit of the data to this model results in a chi-squared value of 236.3 for 235
degrees of freedom, and the probability to exceed this chi-squared value is
46%.Comment: 21 pages, 4 figures, current version matches version published in
JCA
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