We consider the phenomenology of the 511 keV emission in the Galactic bulge, as recently observed by INTEGRAL, and propose a model is which the positrons are produced by gamma-ray bursts (GRB) associated with mini starbursts in the central molecular zone (CMZ). We show that the positrons can easily diffuse across the bulge on timescales of ∼ 10 7 yr, and that their injection rate by GRBs is com...

CO emission from the Sb(rs)I-II galaxy NGC 7331 has been mapped in the J=2–1 transition with a 21′′ beam over an area 3.5′ by 1.3′. A relatively low contrast enhancement of molecular line emission occurs in a ringlike zone at a distance of approximately 3.5 kpc from the center; there is no evidence for a pronounced central hole. The ring is located at the edge of the region of rigid rotation an...

Hydroforming process is largely used for the production of tubular parts in various industries, and has advantages such as less weight, higher quality, more strength and fewer production cost compared to the conventional methods of production. The aim of this study is forming a tube-shaped part with a special geometry that has both bulge- and T-zones with tube hydroforming process. The forming ...

Context. The central molecular zone at the Galactic center is currently being studied intensively to understand how star formation proceeds under extreme conditions of a galactic nucleus. Knowing position clouds along line sight toward has had important implications in our understanding physics gas and zone.It was recently claimed that dense cloud G0.253 + 0.016 (the Brick) distance $\sim$7.20 ...

Recently, we have developed and calibrated the Synthetic Field Method to derive total extinction through disk galaxies. The method is based on the number counts and colors of distant background field galaxies that can be seen through the foreground object. Here, we investigate how large (10-m) and very large (20 to 30-m), diffraction-limited, optical and infrared telescopes in space would impro...

We show that Earth mass planets orbiting stars in the Galactic disk and bulge can be detected by monitoring microlensed stars in the Galactic bulge. The star and its planet act as a binary lens which generates a lightcurve which can differ substantially from the lightcurve due only to the star itself. We show that the planetary signal remains detectable for planetary masses as small as an Earth...