The Maximum Accreted Mass of Recycled Pulsars

The maximum mass of neutron stars (NSs) is of great importance for constraining equations of state of NSs and understanding the mass gap between NSs and stellar-mass black holes. NSs in X-ray binaries increase in mass by accreting material from their companions (known as the recycling process), and the uncertainties in the accretion process make studying the NS mass at birth a challenge. In this work, we investigate the NS accreted mass while considering the effect of NS spin evolution and provide the maximum accreted mass for NSs in the recycling process. By exploring a series of binary evolution calculations, we obtain the final NS mass and the maximum accreted mass for a given birth mass of an NS and a mass transfer efficiency. Our results show that NSs can accrete relatively more material for binary systems with donor masses in the range of 1.8 ∼ 2.4 M ⊙, NSs accrete relatively more mass when the remnant WD mass is in the range of ∼ 0.25–0.30 M ⊙, and the maximum accreted mass is positively correlated with the initial NS mass. For a 1.4 M ⊙ NS at birth with a moderate mass transfer efficiency of 0.3, the maximum accreted mass could be 0.27 M ⊙. The results can be used to estimate the minimum birth mass for systems with massive NSs in observations.

TRADITIONAL ECONOMIES AND SOCIAL PROTEST IN WEST GERMANY AND ITALY IN 1966-1974

Every crisis of the world capitalist economy prompts a new wave of interest in long economic cycles. In the second half of the 20 century, the emergence of new social movements and activity of «traditional» working class can be analyzed as important barometers of socio-economic development in transitional economies of European countries towards postindustrial society. In this article the author employs a theory of the dynamics of protest waves developed by Ruud Koopmans to analyse social processes in West Germany and Italy between 1966 and 1974. Special attention is given to study of different types of social protest movements: spontaneous, semi-military groups and those affiliated with political parties. A special emphasis is put on showing how the protest wave started with confrontational actions, subsequently entered a phase of moderate mass mobilization, and ended up with a twin process of institutionalization and radicalization.

Supermassive Black Holes and Dark Halo from the Bose-Condensed Dark Matter

Most of the galaxies harbor supermassive Black Holes (SMBH) in their center. Some of them are observed in very high redshifts. We explore the possibility that SMBH form from the coherent waves of Bose-Einstein condensate (BEC) which are supposed to form the dark matter. We first study the isotropic and anisotropic collapses of BEC. We find the BEC wave can easily collapse to form SMBH but the realistic amount of angular momentum completely prevents the collapse. We further explore the Axion case with attractive interaction and find the moderate mass ratio between the SMBH and the dark halo around it. We also obtain the mass distribution function of BH within a single galaxy.

A reference sample of face-on bulgeless galaxies

We present a list of 220 face-on, almost bulgeless galaxies assumed to be counterparts to the objects from the Reference Flat Galaxy Catalogue (RFGC). We selected the Sc-, Scd-, and Sd-type galaxies according to their apparent axial ratio log(r25) < 0.05 and major standard angular diameter log(d25) > 0.90 as defined in HyperLEDA. The sample objects are restricted by the radial velocity $V_{\mathrm{ LG}} \lt 10\, 000$ km s−1 and a declination of above –30 deg. The morphological composition of our sample is quite similar to that of RFGC. We notice the following common properties of face-on bulgeless galaxies. About half of them have bar-like structures occurring in the whole range of the absolute magnitudes of galaxies: from −17 to −22 mag. An essential part of our sample (27–50 per cent) exhibit distorted spiral patterns. The galaxies do not show significant asymmetry in numbers of the ‘S’- and ‘Z’-like spin orientation. The mean (pseudo-)bulge-to-total mass ratio for the sample is estimated as 0.11. Due to a negligible internal extinction, low-light background, and small projection effect, the face-on Sc–Sd discs are suitable objects to recognize their central nuclei as moderate-mass BH candidates. About 40–60 per cent of the galaxies have distinct unresolved nuclei, and their presence steeply depends on the luminosity of the host galaxy.

Moderate mass loss of Kanchenjunga Glacier in the eastern Nepal Himalaya since 1975 revealed by Hexagon KH-9 and ALOS satellite Imageries

This study presents the geodetic mass balance of Kanchenjunga Glacier, a heavily debris-covered glacier, in the easternmost Nepal Himalaya between 1975 and 2010 using high-resolution (5-m) digital elevation models (DEMs) generated from Hexagon KH-9 and ALOS PRISM stereo-images. Glacier velocities are also calculated using a feature tracking method with two ALOS ortho-images taken in 2010. The difference between the two DEMs shows the rate of elevation change of the glacier, considerable surface lowering across the debris-covered area, and slight thickening in the accumulation area between 1975 and 2010. The velocity throughout the debris-covered area is slow, which stands in contrast with the faster velocity in the lower accumulation area. The rates of elevation change positively correlate with the elevation along the debris-free part, while they negatively correlate with elevation over the debris-covered part, which may result from the distribution of debris thickness. The rate of elevation change also positively correlates with the glacier velocity, whereas no correlation is found with slope and gradient of flow speed. Significant surface lowering is observed at supraglacial ponds, though the ponds should have short life spans. The geodetic mass balance of Kanchenjunga Glacier for the period of 1975–2010 (–0.14 ± 0.12 m w.e. a–1) is considerably less negative than those estimated for Khumbu Glacier (–0.27 m w.e. a–1) in the neighbouring Khumbu region. Disparities in the density of supraglacial ponds and the area contributions of accumulation and debris-covered areas may be principal causes of the difference in geodetic mass balance between the two glaciers.