Experimental study of emission Z-pinch spectra in the axial and radial directions at the Angara-5-1 facility

Data on the energy, power and spectra composition of the soft x-ray pulse of powerful Z-pinch plasmas in the axial and radial directions in the photon energy range of 0.02 - 2 keV are presented. The data are obtained from the analysis of experimental results on the implosion of cylindrical arrays with a diameter of 1.2 cm and a height of 1.6 cm of tungsten wires diameter of 6 μm, the linear mass of 220 μg/cm at a current in the range of 2.2 – 3.5 MA at the Angara-5-1 facility

Experimental study of emission Z-pinch spectra in the axial and radial directions at the Angara-5-1 facility

Data on the energy, power and spectra composition of the soft x-ray pulse of powerful Z-pinch plasmas in the axial and radial directions in the photon energy range of 0.02 - 2 keV are presented. The data are obtained from the analysis of experimental results on the implosion of cylindrical arrays with a diameter of 1.2 cm and a height of 1.6 cm of tungsten wires diameter of 6 μm, the linear mass of 220 μg/cm at a current in the range of 2.2 – 3.5 MA at the Angara-5-1 facility

Influence of a radial electrical field on implosion of wire array

The effect of polarity on implosion of wire liners on the Angara-5-1 facility has been investigated. The electrode configuration provided creation of a radial electric field of up to 5000 kV/cm and of different direction on various sections of initial wires. The plasma production process was found to proceed in a distinctive manner in the wire sections where the radial electric field has different direction. The polarity effect at implosion of the wire liners on the Angara-5-1 facility becomes notable at increasing the rate of rising the electric field strength

Experimental study of emission Z-pinch spectra in the axial and radial directions at the Angara-5-1 facility

Data on the energy, power and spectra composition of the soft x-ray pulse of powerful Z-pinch plasmas in the axial and radial directions in the photon energy range of 0.02 - 2 keV are presented. The data are obtained from the analysis of experimental results on the implosion of cylindrical arrays with a diameter of 1.2 cm and a height of 1.6 cm of tungsten wires diameter of 6 μm, the linear mass of 220 μg/cm at a current in the range of 2.2 – 3.5 MA at the Angara-5-1 facility

Swift-BAT GUANO follow-up of gravitational-wave triggers in the third LIGO-Virgo-KAGRA observing run

International audienceWe present results from a search for X-ray/gamma-ray counterparts of gravitational-wave (GW) candidates from the third observing run (O3) of the LIGO-Virgo-KAGRA (LVK) network using the Swift Burst Alert Telescope (Swift-BAT). The search includes 636 GW candidates received in low latency, 86 of which have been confirmed by the offline analysis and included in the third cumulative Gravitational-Wave Transient Catalogs (GWTC-3). Targeted searches were carried out on the entire GW sample using the maximum--likelihood NITRATES pipeline on the BAT data made available via the GUANO infrastructure. We do not detect any significant electromagnetic emission that is temporally and spatially coincident with any of the GW candidates. We report flux upper limits in the 15-350 keV band as a function of sky position for all the catalog candidates. For GW candidates where the Swift-BAT false alarm rate is less than 10$^{-3}$ Hz, we compute the GW--BAT joint false alarm rate. Finally, the derived Swift-BAT upper limits are used to infer constraints on the putative electromagnetic emission associated with binary black hole mergers

Ultralight vector dark matter search using data from the KAGRA O3GK run

International audienceAmong the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for $U(1)_{B-L}$ gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the $U(1)_{B-L}$ gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Ultralight vector dark matter search using data from the KAGRA O3GK run

International audienceAmong the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for $U(1)_{B-L}$ gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the $U(1)_{B-L}$ gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Observation of Gravitational Waves from the Coalescence of a 2.5−4.5 M⊙2.5-4.5~M_\odot Compact Object and a Neutron Star

International audienceWe report the observation of a coalescing compact binary with component masses $2.5-4.5~M_\odot$ and $1.2-2.0~M_\odot$ (all measurements quoted at the 90% credible level). The gravitational-wave signal GW230529_181500 was observed during the fourth observing run of the LIGO-Virgo-KAGRA detector network on 2023 May 29 by the LIGO Livingston Observatory. The primary component of the source has a mass less than $5~M_\odot$ at 99% credibility. We cannot definitively determine from gravitational-wave data alone whether either component of the source is a neutron star or a black hole. However, given existing estimates of the maximum neutron star mass, we find the most probable interpretation of the source to be the coalescence of a neutron star with a black hole that has a mass between the most massive neutron stars and the least massive black holes observed in the Galaxy. We estimate a merger rate density of $55^{+127}_{-47}~\text{Gpc}^{-3}\,\text{yr}^{-1}$ for compact binary coalescences with properties similar to the source of GW230529_181500; assuming that the source is a neutron star-black hole merger, GW230529_181500-like sources constitute about 60% of the total merger rate inferred for neutron star-black hole coalescences. The discovery of this system implies an increase in the expected rate of neutron star-black hole mergers with electromagnetic counterparts and provides further evidence for compact objects existing within the purported lower mass gap