scholarly journals 10 to 60 Arcmin Fluctuations in the Cosmic Microwave Background

1983 ◽  
Vol 104 ◽  
pp. 127-129
Author(s):  
A. N. Lasenby ◽  
R. D. Davies
Keyword(s):  
High Sensitivity ◽  
Discrete Source ◽  
Central Field ◽  
Microwave Background ◽  
Long Wavelength ◽  
The North ◽  
Celestial Pole ◽  
Systematic Effects ◽  
Series Of Experiments ◽  
Made In

Considerable astronomical interest attaches to sensitive measurements of temperature fluctuations of the microwave background on scales of a few arcmins to a few degrees. We describe here the first in a series of experiments being carried out at Jodrell Bank which are aimed at providing reliable and repeatable information on these angular scales. The first experiment used the MK II 25m dish at λ6 cm and covered scales from 10 arcmin (the beamwidth) to 60 arcmin (twice the beamthrow). At this relatively long wavelength, the atmosphere has negligible effect on the observations and day to day repeatability consistent with receiver noise alone was obtained. The observations were made in wagging mode near the North Celestial Pole (NCP) so that the two beams alternately traced out a reference circle on the sky, radius 30 arcmin, over the course of 24 hours. The NCP field was chosen since a high sensitivity discrete source survey (Pauliny-Toth et al. 1978) was already available covering the area. This meant that antenna temperatures around the reference circle could be corrected for any source induced effects ≳0.4 mK. In addition control observations were made at positions 30 arcmin East and West of the central field, so that systematic effects due to interaction of telescope sidelobes with objects in the immediate telescope environment, could be monitored and removed.

scholarly journals Planck2018 results

2020 ◽  
Vol 641 ◽  
pp. A7 ◽  
Author(s):  
◽  
Y. Akrami ◽  
M. Ashdown ◽  
J. Aumont ◽  
C. Baccigalupi ◽  
...  
Keyword(s):  
Cosmological Model ◽  
Excellent Agreement ◽  
Stokes Parameters ◽  
Microwave Background ◽  
Data Set ◽  
Systematic Effects ◽  
Cold Spots ◽  
Remarkable Progress ◽  
Cmb Temperature ◽  
Made In

Analysis of thePlanck2018 data set indicates that the statistical properties of the cosmic microwave background (CMB) temperature anisotropies are in excellent agreement with previous studies using the 2013 and 2015 data releases. In particular, they are consistent with the Gaussian predictions of the ΛCDM cosmological model, yet also confirm the presence of several so-called “anomalies” on large angular scales. The novelty of the current study, however, lies in being a first attempt at a comprehensive analysis of the statistics of the polarization signal over all angular scales, using either maps of the Stokes parameters,QandU, or theE-mode signal derived from these using a new methodology (which we describe in an appendix). Although remarkable progress has been made in reducing the systematic effects that contaminated the 2015 polarization maps on large angular scales, it is still the case that residual systematics (and our ability to simulate them) can limit some tests of non-Gaussianity and isotropy. However, a detailed set of null tests applied to the maps indicates that these issues do not dominate the analysis on intermediate and large angular scales (i.e.,ℓ ≲ 400). In this regime, no unambiguous detections of cosmological non-Gaussianity, or of anomalies corresponding to those seen in temperature, are claimed. Notably, the stacking of CMB polarization signals centred on the positions of temperature hot and cold spots exhibits excellent agreement with the ΛCDM cosmological model, and also gives a clear indication of howPlanckprovides state-of-the-art measurements of CMB temperature and polarization on degree scales.

scholarly journals The C-Band All-Sky Survey (C-BASS): constraining diffuse Galactic radio emission in the North Celestial Pole region

2019 ◽  
Vol 485 (2) ◽  
pp. 2844-2860 ◽  
Author(s):  
C Dickinson ◽  
A Barr ◽  
H C Chiang ◽  
C Copley ◽  
R D P Grumitt ◽  
...  
Keyword(s):  
Dust Emission ◽  
High Sensitivity ◽  
Far Infrared ◽  
Microwave Emission ◽  
Correlation Technique ◽  
The North ◽  
Sky Survey ◽  
Celestial Pole ◽  
Source Confusion ◽  
5 Ghz

ABSTRACT The C-Band All-Sky Survey (C-BASS) is a high sensitivity all-sky radio survey at an angular resolution of 45 arcmin and a frequency of 4.7 GHz. We present a total intensity map of the North Celestial Pole (NCP) region of sky, above declination >+80°, which is limited by source confusion at a level of ≈0.6 mK rms. We apply the template-fitting (cross-correlation) technique to WMAP and Planck data, using the C-BASS map as the synchrotron template, to investigate the contribution of diffuse foreground emission at frequencies ∼20–40 GHz. We quantify the anomalous microwave emission (AME) that is correlated with far-infrared dust emission. The AME amplitude does not change significantly (${\lt }10\, {{\ \rm per\ cent}}$) when using the higher frequency C-BASS 4.7 GHz template instead of the traditional Haslam 408 MHz map as a tracer of synchrotron radiation. We measure template coefficients of 9.93 ± 0.35 and $9.52\pm 0.34\,$ K per unit τ353 when using the Haslam and C-BASS synchrotron templates, respectively. The AME contributes $55\pm 2\, \mu$K rms at 22.8 GHz and accounts for ${\approx } 60{{\ \rm per\ cent}}$ of the total foreground emission. Our results show that a harder (flatter spectrum) component of synchrotron emission is not dominant at frequencies ≳5 GHz; the best-fitting synchrotron temperature spectral index is β = −2.91 ± 0.04 from 4.7 to 22.8 GHz and β = −2.85 ± 0.14 from 22.8 to 44.1 GHz. Free–free emission is weak, contributing ${\approx } 7\, \mu$K rms (${\approx } 7{{\ \rm per\ cent}}$) at 22.8 GHz. The best explanation for the AME is still electric dipole emission from small spinning dust grains.

scholarly journals A High-Resolution Map of the Cosmic Microwave Background around the North Celestial Pole

1997 ◽  
Vol 474 (2) ◽  
pp. L77-L80 ◽  
Author(s):  
Max Tegmark ◽  
Angélica de Oliveira-Costa ◽  
Marc J. Devlin ◽  
C. Barth Netterfield ◽  
Lyman Page ◽  
...  
Keyword(s):  
High Resolution ◽  
Cosmic Microwave Background ◽  
Microwave Background ◽  
The North ◽  
Celestial Pole ◽  
High Resolution Map ◽  
Resolution Map

scholarly journals Zadarski gotički vezeni antependij u Budimpešti

Ars Adriatica ◽  
2014 ◽  
pp. 75 ◽  
Author(s):  
Silvija Banić
Keyword(s):  
Eighteenth Century ◽  
Central Field ◽  
Original Surface ◽  
The North ◽  
Short Period ◽  
The Right ◽  
Female Saints ◽  
The Church ◽  
Made In ◽  
Applied Arts

The Museum of Applied Arts (Iparművészeti Múzeum) at Budapest houses an embroidered Gothic antependium which belonged to the church of St Chrysogonus, which was the seat of the Benedictine Abbey at Zadar. At an unspecified time, the antependium became part of the collection of Zsigmund Bubics, an art historian, collector and the bishop of Košice in present-day Slovakia from 1887 to 1906, and was donated to the Museum of Applied Arts in 1909. It measures 94 by 190 cm. The majority of the antependium’s surface is filled with the figures of saints set beneath three pointed, Gothic arches. The central field is occupied by the enthroned Virgin with the Christ Child, in the left field is St Chrysogonus and in the right St Benedict. In the upper section of the antependium one can see the busts of two saints who might be identified as St Gregory the Pope and St Donatus. Along the lateral edges of this triptych-like antependium are vertical borders, at the centres of which are niches with two small standing female saints who wear crowns (St Scholastica and St Anastasia). To the left of the Virgin’s throne is the figure of a donor depicted kneeling with his hands clasped in prayer, which has unfortunately not been provided with an inscription. It is clear, however, that he is wearing the Benedictine habit with a somewhat over-emphasized hood falling down his back. The Benedictine donor might be identified as one of the abbots of the monastery of St Chrysogonus. It is suggested in the article that this may have been John de Ontiaco (Joannes de Onciache) from the bishopric of Lyon, who was the abbot of the monastery of St Chrysogonus from 1345 to 1377. The author argues that the antependium was produced in a weaving workshop in Venice during the late 1360s or early 1370s, on the basis of comparisons with similar contemporary painted and embroidered artworks. Based on the iconographic programme which was depicted on the antependium, but also on the information found in archival records, the author proposes that the antependium was made for the altar of St Chrysogonus which stood in the north apse of the abbey church. Although it has not been established when the antependium left Zadar, based on the similarities between the crimson satin fabric, which replaced the original surface on which the embroidery was applied, on the antependium from the Church of St Mary at Zadar, and the antependium from the Church of St Chrysogonus, it is stated that both interventions were made in the Benedictine Convent of St Mary at Zadar during a short period of time in the last quarter of the eighteenth century. This is also understood as evidence that at that time the antependium from the Church of St Chrysogonus was still being carefully kept at Zadar.

scholarly journals Average fractional polarization of extragalactic sources at Planck frequencies

2018 ◽  
Vol 618 ◽  
pp. A29 ◽  
Author(s):  
T. Trombetti ◽  
C. Burigana ◽  
G. De Zotti ◽  
V. Galluzzi ◽  
M. Massardi
Keyword(s):  
High Sensitivity ◽  
Point Sources ◽  
Distribution Analysis ◽  
Microwave Background ◽  
Residual Noise ◽  
Upper Limits ◽  
Dusty Galaxies ◽  
Using Data ◽  
Polarization Fraction

Recent detailed simulations have shown that an insufficiently accurate characterization of the contamination of unresolved polarized extragalactic sources can seriously bias measurements of the primordial cosmic microwave background (CMB) power spectrum if the tensor-to-scalar ratio r ∼ 0.001, as predicted by models currently of special interest (e.g., Starobinsky’s R2 and Higgs inflation). This has motivated a reanalysis of the median polarization fraction of extragalactic sources (radio-loud AGNs and dusty galaxies) using data from the Planck polarization maps. Our approach, exploiting the intensity distribution analysis, mitigates or overcomes the most delicate aspects of earlier analyses based on stacking techniques. By means of simulations, we have shown that the residual noise bias on the median polarization fraction, Πmedian, of extragalactic sources is generally ≲0.1%. For radio sources, we have found Πmedian ≃ 2.83%, with no significant dependence on either frequency or flux density, in good agreement with the earlier estimate and with high-sensitivity measurements in the frequency range 5–40 GHz. No polarization signal is detected in the case of dusty galaxies, implying 90% confidence upper limits of Πdusty ≲ 2.2% at 353 GHz and of ≲3.9% at 217 GHz. The contamination of CMB polarization maps by unresolved point sources is discussed.

scholarly journals GERBERT OF AURILLAC: ASTRONOMY AND GEOMETRY IN TENTH CENTURY EUROPE

2013 ◽  
Vol 23 ◽  
pp. 467-471 ◽  
Author(s):  
COSTANTINO SIGISMONDI
Keyword(s):  
Rational Approximation ◽  
Equilateral Triangle ◽  
Tenth Century ◽  
The Sun ◽  
Astronomical Observations ◽  
The North ◽  
Celestial Pole ◽  
Gerbert Of Aurillac

Gerbert of Aurillac was the most prominent personality of the tenth century: astronomer, organ builder and music theoretician, mathematician, philosopher, and finally pope with the name of Silvester II (999–1003). Gerbert introduced firstly the arabic numbers in Europe, invented an abacus for speeding the calculations and found a rational approximation for the equilateral triangle area, in the letter to Adelbold here discussed. Gerbert described a semi-sphere to Constantine of Fleury with built-in sighting tubes, used for astronomical observations. The procedure to identify the star nearest to the North celestial pole is very accurate and still in use in the XII century, when Computatrix was the name of Polaris. For didactical purposes the Polaris would have been precise enough and much less time consuming, but here Gerbert was clearly aligning a precise equatorial mount for a fixed instrument for accurate daytime observations. Through the sighting tubes it was possible to detect equinoxes and solstices by observing the Sun in the corresponding days. The horalogium of Magdeburg was probably a big and fixed-mount nocturlabe, always pointing the star near the celestial pole.

scholarly journals Experimental researches on the emission of oxygen by the pelvic filaments of the male lepidosiren with some experiments on symbranchus marmoratus

1932 ◽  
Vol 110 (766) ◽  
pp. 234-248 ◽  
Keyword(s):  
Dissolved Oxygen ◽  
North Coast ◽  
The Political ◽  
Medical College ◽  
The North ◽  
Gran Chaco ◽  
Glass Tubes ◽  
Political Conditions ◽  
Experimental Researches ◽  
Made In

The stage which the question of the function of the pelvic filaments of the male Lepidosiren had reached before the researches described in this paper can be seen by reference to the paper by Carter and Beadle (1930) and that by Cunningham in the previous year. The researches of Carter and Beadle as well as those previously carried out by Graham Kerr were made in the Gran Chaco of Paraguay, in the swamps of which region Lepidosiren is rather abundant. But when direct experiments on the function of the filaments were contemplated the political conditions made it inadvisable to attempt to visit this region, and it was suggested that Lepidosiren would be found in sufficient abundance on the island of Marajó at the mouth of the River Amazon. No evidence was obtained that the fish had recently been taken in that island, but three specimens, all from the same locality, namely a “papyrus meadow” near Fazenda Dunas on the north coast of the island, were recorded in 1896 and 1898 by Dr. Goeldi, Director and founder of the Muséu Goeldi at Belem. It was therefore decided to organise and carry out an expedition to Marajó. The equipment was prepared in the Physiological Department of the London Hospital Medical College and consisted of large glass tubes from 18 inches to 30 inches in length and 1½ inches to 3 inches in diameter; and weighed quantities in hermetically sealed tubes or bottles of the reagents required for the estimation of dissolved oxygen in water, together with the necessary accessories, and a special pump for obtaining water from below the surface of swamp pools.

The mineralogical composition of some Scottish soils

1925 ◽  
Vol 15 (3) ◽  
pp. 257-271 ◽  
Author(s):  
James Hendrick ◽  
George Newlands
Keyword(s):  
Mineralogical Composition ◽  
Fine Sand ◽  
Plant Food ◽  
Sand Fraction ◽  
Extensive Survey ◽  
North East ◽  
The North ◽  
Local Origin ◽  
East West ◽  
Made In

1. Previous investigations showed that certain Scottish soils were of glacial drift origin, that they were comparatively rich in unweathered silicates and therefore in reserves of plant-food, that they showed considerable variation in such silicates and were capable of classification accordingly. Some indication was also shown that the glacial drift, and hence the resulting soil, was sometimes of local origin, its character being determined by the underlying rock. In the present investigation a more extensive survey of Scottish soils has been made in order to discover to what extent these preliminary findings might be applicable generally.2. For this purpose soils have been collected from various localities in the north, north-east, west and south of Scotland, and have been analysed mechanically and the “fine sand” fraction examined mineralogically.

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