The possible impact of Intermediate Mass Black Holes on our Galaxy

Orbit integration for three different assumed Intermediate-mass Black Hole (IMBH, defined as black holes with mass MBH in the range 100Mo 5 x 104Mo can create IMBHs, while model B assumes cluster have only to obey Mcluster > 2.5 x 103Mo to do so. In turn, given the different mass distributions within the IMBH population assuming model A or B, not more than about 15000 (A) or 16000 (B) IMBHs can be present today within the galactic disc. From the total number of IMBHs formed within star cluster in the disc, 49 % (A) or 54 % (B) have already lost their host cluster due to disruption in molecular cloud encounters. With the exception of NGC 6838, no globular cluster is expected to be destroyed via molecular cloud collisions within 10 Gyr

2 kirja Karl Morgensternile, Liebau

http://tartu.ester.ee/record=b1776700~S1*es

Kiri Karl Morgensternile, Bauske

http://tartu.ester.ee/record=b1813255~S1*es

Letzte Worte am Grabe Carl Ernst Pusins Consistorialraths, Propster zu Candau, Pastors Tuckum

https://www.ester.ee/record=b4005039*es

Triple-q order in Na2_2Co2_2TeO6_6 from proximity to hidden-SU(2)-symmetric point

In extended Heisenberg-Kitaev-Gamma-type spin models, hidden-SU(2)-symmetric points are isolated points in parameter space that can be mapped to pure Heisenberg models via nontrivial duality transformations. Such points generically feature quantum degeneracy between conventional single-q and exotic multi-q states. We argue that recent single-crystal inelastic neutron scattering data place the honeycomb magnet Na$_2$Co$_2$TeO$_6$ in proximity to such a hidden-SU(2)-symmetric point. The low-temperature order is identified as a triple-q state arising from the N\'eel antiferromagnet with staggered magnetization in the out-of-plane direction via a 4-sublattice duality transformation. This state naturally explains various distinctive features of the magnetic excitation spectrum, including its surprisingly high symmetry and the dispersive low-energy and flat high-energy bands. Our result demonstrates the importance of bond-dependent exchange interactions in cobaltates, and illustrates the intriguing magnetic behavior resulting from them.Comment: 7+14 pages, 3+10 figures; v2: exact diagonalization calculations added, elucidating proximity of Na$_2$Co$_2$TeO$_6$ to Kitaev quantum spin liqui

Radar-absorbent properties of a foam glass with gallium arsenide addition

The principal possibility of using wastes of semiconductor devices production containing gallium arsenide as a component of radio-absorbing material was established. The composition formulation including perlite, liquid glass, complex blowing agent and waste is developed. It is shown that with increase the waste amount in the composition from 10 to 30 wt. % the absorption coefficient increases from 80 to 98%, the transmission coefficient decreases to zero. The obtained results indicate a high absorbing capacity of composite in the frequency range of 120 - 260 GHz that refers to ultrasonic waves