Intergalactic magnetic field and the distance of quasars from Faraday rotation

In 1968 Sofue, Fujimoto and Kawabata and, later, Reinhardt and Thiel, showed that the amount of Faraday rotation measured for quasars is related to their distance from the observer. Such measures then become the only existing method to directly measure distances of quasars. It is shown here that the observed Faraday rotation as a function of redshift excludes the possibility that quasars are at distances proportional to their redshifts. Systematically larger Faraday rotations are observed for quasars with redshifts z ∼ 1. The strongest concentration of z ∼ 1 quasars is in an area of the sky ∼40° in diameter centered on the Virgo Cluster. The fact that these Faraday rotations are of the same sign demonstrates the existence of an ordered magnetic field throughout a large volume of intergalactic space in the direction toward the Local Supercluster. Quasars with z ∼ 2.0 and z ∼ 0.5 do not show such Faraday rotations and are confirmed to be at a closer distance. The organized magnetic field discovered in the space around the Virgo Cluster is 3 orders of magnitude larger than any previously known.     

Large-beam radio and infra-red observations toward the Virgo Cluster

Summary We show how combined large-beam infra-red and radio observations toward the Virgo Cluster may be explained by assuming the existence of a large tepid halo surrounding the giant galaxy M87. Such a halo would be able to close the cluster gravitationally. If interpreted as being due to bremmstrahlung radiation by a tepid extended halo, it also explains the infra-red observations, and it has important implications for the physics of M87. Paper presented at the Congress ?Galactic and Extragalactic Dark Matter?, Roma, 28 to 30 June 1983.     

The possible electromagnetic counterparts of the first high-probability NSBH merger LIGO/Virgo S190814bv

LIGO/Virgo S190814 bv is the first high-probability neutron star–black hole(NSBH) merger candidate, whose gravitational waves(GWs) triggered LIGO/Virgo detectors at21:10:39.012957 UT, 14 August 2019. It has a probability 99% of being an NSBH merger,with a low false alarm rate(FAR) of one per 1.559 e+25 years. For an NSBH merger,electromagnetic counterparts(especially short gamma-ray bursts(GRBs)) are generally expected. However, no electromagnetic counterpart has been found in the extensive follow-up observing campaign. In the present work, we propose a novel explanation for this null result. In our scenario, LIGO/Virgo S190814 bv is just a GW mirror image of the real NSBH merger which should have been detected before 14 September 2015, but at that time we had no ability to detect its GW signals. The electromagnetic counterparts associated with the real NSBH merger should be found in the archive data before 14 September 2015. In this work, we indeed find nine short GRBs that are possibly electromagnetic counterparts.     

SU(2) Lattice gauge theory in (2+1)D

Cluster expansion methods are applied to theSU(2) lattice gauge model in (2+1) dimensions. Strong-coupling series are calculated for the vacuum energy per site, the axial string tension, and the scalar mass gap; while ELCE approximants are used to estimate the string tension beyond its roughening transition. The simple scaling behaviour expected of this super-renormalizable theory is clearly seen, and we estimate that in the continuum limit the string tension σ～(0.14±0.01)g ⁴, while the mass gapM _s ～(2.2±0.25)g ². More accurate Monte Carlo simulations are needed to check the universality between the Hamiltonian and Euclidean versions of this model.     

A 1.82 m<Superscript>2</Superscript> ring laser gyroscope for nano-rotational motion sensing

We present a fully active-controlled He–Ne ring laser gyroscope operating in square cavity having a side length of 1.35 m. The apparatus is designed to provide a very low mechanical and thermal drift of the ring cavity geometry and is conceived to be operative in two different orientations of the laser plane, in order to detect rotations around the vertical or the horizontal direction. Since June 2010, the system is active inside the Virgo interferometer central area with the aim of performing high-sensitivity measurements of environmental rotational noise. So far, continuous unattended operation of the gyroscope has been longer than 30 days. The main characteristics of the laser, the active remote-controlled stabilization systems and the data acquisition techniques are presented. An offline data processing, supported by a simple model of the sensor, is shown to improve the effective long-term stability. A rotational sensitivity at the level of \(10^{-8}~\mathrm{rad}/\sqrt{\mathrm{Hz}}\) below 1 Hz, very close to the required specification for the improvement of the Virgo suspension control system, is demonstrated for the configuration where the laser plane is horizontal.     

Plane parallel mirrors Fabry-Perot cavity to improve Virgo superattenuators

The measurement of the finesse and the longitudinal locking of a 100 μm long plane mirrors Fabry-Perot cavity is described. a finesse of up to 5400 has been found. If attached to the Virgo antenna suspension (SA), a similar device is sensitive enough to detect the thermal displacement noise of the SA test mass, which is expected to limit the Virgo antenna sensitivity between 10 and 600 Hz. Reducing the Virgo noise floor is a challenge for future antenna development, as this region is the most promising one for coalescing binary stars and pulsar signals.     

Diffraction slope and inclusive reactions

The slope of the inelastic overlap function in the 30–1500 GeV p-p scattering is evaluated in a multi-Regge model for inclusive reactions of pp→π^±X and pX. The slope is found larger than the experimental, particularly at high energies. Cluster production and an increase with energy of the averaged pion multiplicity per cluster are inferred.     

Gamma radiation in the decay of249Cf

Gamma radiation following alpha decay of²⁴⁹Cf was investigated with high resolution Ge(Li) detectors in singles and coincidence arrangements. Nine new γ-rays were identified and placed in the previously-known decay scheme. Their energies in keV and intensities relative to the 388 keV (100) γ-ray are: 37.5±0.1 (0.026), 65.87±0.1 (0.017), 121.5±0.4 (0.070), 229.2±0.2 (0.072), 255.7±0.2 (0.065), 390.5±0.2 (0.025), 405.9±0.1 (0.014), 588.8±0.1 (0.003), and 643.5±0.1 (0.007). Coincidence measurements revealed that the intensity of the 54.7 keV γ-ray is shared by three intraband transitions and that the 121.5 keV crossover transition is present in the ground-state band.     

Note of correction: Broadening of NO γ-band lines

Errors in Ref. 1 are corrected. Using the new data, the collisional broadening coefficient of NO γ-band lines by N₂ is 2390 (±220) atm^-1-K (old value = 1270±200) and the optical collision diameter is 13.3±0.6 Å (instead of 3.5±0.3 Å). Values for argon (2150±200 atm^-1-K) and CO₂ (2040±200 atm^-1-K) yield the optical collision diameters of 13.2 and 13.1 Å, respectively.     

Half-lives and delayed neutron emission probabilities of short-lived Rb and Cs precursors

Half-lives and delayed-neutron emission probabilities (P _n ) of short-lived Rb and Cs precursors in the mass chains 94–98 and 143–147 were measured. Sources of isotope separated nuclides were obtained from the on-line mass-separator OSTIS installed at the Grenoble high-flux reactor. A newP _n -value of (25.4±3.2)% is given for the (214±30) ms¹⁴⁷Cs; theP _n -values of nine alkali precursor nuclides were redetermined: (2,730±20) ms⁹⁴Rb with (9.7±0.5)%, (377 ±6)ms⁹⁵Rb with (8.6±0.5)%, (197±5)ms⁹⁶Rb with (12.5±0.9)%, (171±4) ms⁹⁷Rb with (25.2±1.8)%, (114±13)ms⁹⁸Rb with (18.4±2.9)%, (1,765±30)ms¹⁴³Cs with (1.74 ±0.12)%, (1,000±10)ms¹⁴⁴Cs with (2.95±0.25)%, (616±20) ms¹⁴⁵Cs with (12.2±0.9)%, (325±10)ms¹⁴⁶Cs with (13.2±0.8)%. The results are compared with the existing data, and theP _n -values are discussed within some simple model predictions.     

Characteristics of the Raman spectra of archaeological Malachites

Archaeological malachites, represented by the malachites found on the ancient Chinese and Vietnamese copper/bronze coins, may also incorporate those on other archaeological objects. The Raman spectra with Ar laser of these malachites differ slightly from those of the natural malachites found in mines. In this study, 120 measurements of the malachites on 40 coins identified 26 bands, while only around 18 of them are frequently observed. The wavenumbers (cm⁻¹), shifts (±)and relative intensities (in parentheses) of the 18 common bands read, respectively: 153±4 (0‐vs), 179±7 (m‐vs), 217±8 (m‐vs), 274±7 (0‐vs), 355±5 (0‐m), 431±4 (0‐vs), 514±3 (0‐m), 533±5 (0‐s), 566±3 (0‐m), 599±2 (0‐m), 718±6 (0‐m), 754±2 (0‐m), 1061±7 (0‐m), 1093±10 (0‐m), 1365±9 (0‐m), 1491±7 (0‐vs), 3321±11 (0‐vs) and 3380±7 (0‐vs). In comparison with those of the 105 measurements on the natural malachites in five mines, the Raman spectra of the archaeological malachites tend to show less bands, higher backgrounds and greater shifts in the wavenumber position. The weakening or loss of bands is in the order of the OH stretch (3300 cm⁻¹) (most severe), CO₃ (600–1500 cm⁻¹) and CuO (<600 cm⁻¹) (less severe) groups, indicating successive stages of corrosion. The malachites on the coins from three climate zones show their own characteristics. Several coins may have experienced two or more climatic or geologic episodes and show complex Raman spectra different from those of the natural malachites. Copyright © 2012 John Wiley & Sons, Ltd.     

Neutron total,scattering and inelastic Gamma-ray cross sections of yttrium at few MeV energies

Neutron total, scattering and (n; n′,γ) cross sections of elemental yttrium (⁸⁹Y) were measured in the few-MeV region. The neutron total-cross-section measurements were made with broad resolutions from ≈0.5 to 4.2MeV in steps of ?0.1 MeV. Neutron elastic- and inelastic-scattering cross sections were measured from ≈1.5 to 4.0 MeV, at incident-neutron energy intervals of ≈50keV and at ten or more scattering angles distributed between 20 and 160 degrees using neutron detection. Inelastic-scattering cross sections were also determined using the (n; n′,γ) reaction at incident energies from 1.6 to 3.8 MeV at intervals of 0.1 MeV. Gamma-rays and/or inelastically-scattered neutrons were observed corresponding to the excitation of levels at: 909.0±0.5, 1,507.4 ±0.3, 1,744.5±0.3, 2,222.6±0.5, 2,530±0.8, 2,566.4±1.0, 2,622.5±1.0, 2,871.9 ±1.5, 2,880.6±2.0, 3,067.0±2.0, 3,107.0±2.0, 3,140.0±2.0, 3,410.0±2.0, 3,450.0±2.0, 3,504.0 ±1.5, 3,514.0±2.0, 3,556.0±2.0, 3,619.0±3.0, 3,629.0±3.0 and 3,715.0±3.0 keV. The experimental results are discussed in terms of the spherical-optical-statistical, coupledchannels, and core-coupling models, and in the context of previously reported excitedlevel structure.     

T2 Relaxation of peripheral nerve measured in vivo

It is demonstrated that multi-exponential transverse (T₂) relaxation components can be estimated from multi-echo images of peripheral nerve. Three T₂-relaxation components with T₂ values ± standard deviations (populations ± standard deviations) of 19 ± 7 ms (26 ± 9%), 63 ± 31 ms (29 ± 11%) and 241 ± 24 ms (45 ± 7%) have been identified in vivo in the sciatic nerve of the amphibian Xenopus laevis. The longer-lived component, not identified previously in vivo, provides a significant contrast-to-noise ratio (CNR) between nerve and muscle in the latter-echo images. It is shown that the CNR can be further improved by the averaging of selected images from the multi-echo set.     

Interaction of slow neutrons with the isotopes of molybdenum

Coherent neutron scattering lengths and total cross sections were measured on samples of ordinary Mo and isotopically enriched samples. From the experiments with neutrons of 0.57 meV and 1.26 eV the following values have been obtained:

1. the coherent scattering lengths (in fm) of the bound atoms of Mo (6.715±0.020) and for the isotopes with the mass numbers 92 (6.93±0.08), 94 (6.82±0.07), 95 (6.93±0.06), 96 (6.22±0.06), 97 (7.26±0.08), 98 (6.60±0.07) and 100 (6.75±0.07);
2. the incoherent scattering cross section at zero-energy for ordinary Mo: σ_i=0.02 ± 0.02 barn;
3. the absorption cross sections (in barn) for Mo (2.48 ± 0.04) and for the isotopes with the mass numbers 95(13.4 ± 0.3), 97(2.5 ± 0.2) and 100(0.4 ± 0.2). The relation of the present results to the resonance parameters of the neutron — Mo interaction has been discussed.

     

Messungen des freien und inkohärenten Neutronenwirkungsquerschnitts an Silizium und Blei

The free neutron cross section of Silicone and Lead has been determined to (2.022 ± 0.003) barns and (10.58 ± 0.03) barns respectively and the incoherent cross section of the same elements to (15 ± 1.3) · 10^?3 barns and (15 ± 15) · 10^?3 barns respectively. From these results the coherent cross sections have been calculated under consideration of various correction terms to (2.153 ± 0.005) barns and (10.65 ± 0.05) barns.     

Half-lives andP n values of delayed-neutron precursors in the mass chains 85–87, 92, 135, 136 and 145

Further results are presented on half-lives and neutron emission probabilities (P _n ) of short-lived delayed-neutron precursors in the mass chains 85–87, 92, 135, 136 and 145 obtained with the recoil focussing parabola-type mass separator for unslowed fission products LOHENGRIN installed at the Grenoble high-flux reactor. A newP _n -value of (44±14)% is given for the (0.73±0.06)s⁸⁷As; theP _n -values of seven precursor nuclides have been redetermined: (1.9±0.1)s⁸⁵As with (22±8)%, 0.9s⁸⁶As with (10.5±2.2)%, (0.35±0.04)s⁹²Br with (21±8)%, (1.6±0.15)s¹³⁵Sb with (14±1)%, (0.9±0.1)s¹³⁶Sb with (19±9)%, (17.5±0.2)s¹³⁶Te with (2.0±1.0)% and 0.6s¹⁴⁵Cs with (12.5±3.0)%. The results are compared with the existing data, and the neutron emission probabilities are discussed within a simple semi-empirical picture.     

Analysis of excited quark propagator effects on neutron charge form factor

The European Physical Journal A - The first neutron star (NS) merger observed by advanced LIGO and Virgo, GW170817, and its fireworks of electromagnetic counterparts across the entire...     

Interactions of slow neutrons with nuclides of antimony,tellurium and iodine

Coherent neutron scattering lengths and total cross sections have been measured on samples of ordinary Sb, Te, I and on isotopically enriched compounds. From the experimental data for neutron energies of 0.57 meV, 1.26 eV and 5.2 eV the following data were obtained: the coherent scattering lengths (in fm) of the bound atoms Sb (5.57±0.03);¹²¹Sb(5.71±0.06),¹²³Sb(5.38±0.07); Te(5.80±0.03) and for its isotopes of the mass number 122(3.8±0.2); 123(?0.05±0.25?i·0.100); 124(7.95±0.10); 125(5.01±0.08); 126(5.55±0.07); 128 (5.88±0.07); 130(6.01±0.07). the thermal absorption cross sections (in barn) for Sb(4.91±0.05);¹²¹Sb(5.77±0.12);¹²³Sb(3.8±0.2); Te(4.05±0.05) and I(6.15±0.06). The combination of the measured values of scattering lengths and -cross sections resulted in data for coherent and incoherent cross sections. Taking account of resonance data a complete set of spin state- and reconance scattering lengths has been obtained and discussed.     

The structure of the c(2 × 2) oxygen overlayer on the unreconstructed (110) surface of iridium

An Ir(110)-c(2 × 2)O structure has been prepared by adsorbing a half-monolayer of oxygen at room temperature on an unreconstructed (1 × 1)Ir surface stabilized by a quarter-monolayer of randomly adsorbed oxygen. Results of the low energy electron diffraction structural analysis indicate that the ordered oxygen atoms are residing on the short-bridged sites on the (110) surface. The Ir-O interlayer spacing is 1.37 ± 0.05 Å, and the bond length is 1.93 ± 0.07 Å. The topmost substrate interlayer spacing is found to be 1.33 ± 0.07 Å rather than 1.26 ± 0.07 Å which is the topmost interlayer spacing of the unreconstructed (1× 1)Ir surface.     

激光束的锥台光纤传输

 分析了锥台光纤的传输特性,建立了高斯近似模型,采用模场耦合理论,计算了锥台光纤的功率转换效率。并在激光器的输出光波长为532 nm,多模光纤的数值孔径为0.11,纤芯半径为12.5 μm条件下对细端半径分别为（4±1）,（5±1）,（6±1）,（7±1）和（8±1） μm的锥台光纤的转换效率进行了实验测定。提出利用锥台光纤的圆柱形多模光纤部分传输光功率,锥台部分保证光束质量的传输方案,在保证光束质量的同时能传输较高的光功率。