Редовната сбирка на семинара на Института по Астрономия ще се проведе на 29 юни от 13:30 часа в зала 301 на Института по Електроника на БАН, Цариградско Шосе 72, София.
Тема: “Ultraluminous X-ray sources”
Докладва: prof. DSc Sergei Fabrika, Head of the Laboratory of Stellar Physics at the
Special Astrophysical Observatory of the Russian Academy of Sciences
Поканени са всички интересуващи се.
От ръководството на семинара
The origin of Ultraluminous X-ray sources (ULXs) in external
galaxies whose X-ray luminosities exceed those of the brightest black
holes in our Galaxy by hundreds and thousands of times is mysterious. The
most popular models for the ULXs involve either intermediate mass black
holes (IMBH, ~1000 solar masses) with standard accretion disks or
stellar-mass black holes (10 solar masses) accreting at super-Eddington
rates. We find that all ever spectrally observed ULX counterparts have the
same optical spectra and they are very similar to that of SS 433, the only
known supercritical accretor in Milky Way. We study ULXs in two classical
galactic mergings Antennae and NGC3256. All the ULXs are located nearby
(in 200 pc) or inside extremely young (< 5 Myrs) massive stellar clusters,
and this association is not occasional. The ULX progenitor mass is bigger
than 40-50 solar masses. Probably, these close binary systems were ejected
from the interior of massive-star clusters during the cluster formation.