Moscow State University to Find the Mysterious Black Holes
Lomonosov Moscow State University | via EurekAlert | 2016 Jan 22
An international team of astronomers led by Ivan Zolotukhin is close to understanding the so-called intermediate-mass black holes (IMBH).
The term "black holes" was first used in the mid-20th century by theoretical physicist John Wheeler. This term denotes relativistic supermassive objects that are invisible in all electromagnetic waves, but a great number of astrophysical effects confirms their existence.
There are two basic types of black holes known to scientists according to observations: supermassive black holes and stellar-mass black holes. It is generally believed that stellar-mass black holes are formed in the end of the evolution of massive stars, when stellar energy sources are exhausted, and the star collapse due to its own gravity. Theoretical calculations impose restrictions on their mass to the extent of 5-50 solar masses.
It's less clear how supermassive black holes come to existence. Masses of these black holes sitting in the center of most galaxies range between millions and billions of solar masses. Quasars, the active galactic nuclei, are supermassive black holes observed by astronomers at high redshift. It means that these giants existed in the first few hundred million years after the Big Bang. Ivan Zolotukhin, who works at the Research Institute of Astrophysics and Planetology (Toulouse), said: "The astronomers look for black holes of intermediate mass, because no black hole that weighs a billion times more than the Sun could have been formed without them in just 700 million years."
It is believed that the first generation of stars did not contain metals and, therefore, their masses could have exceeded that of the Sun hundreds of times, and in the end of their evolution, they could become much more massive black holes than those observed today. These black holes merged into formation of thousands of solar masses, and further inclusion of galaxies and the accretion of matter led to the formation of supermassive black holes. Calculation models of hierarchical galaxy buildup have shown that there should have remained a small number of these intermediate mass black holes astronomers are looking for. ...
A Search for Hyperluminous X-ray Sources in the XMM-Newton Source Catalog - Ivan Zolotukhin et al
- Astrophysical Journal 817(2):88 (2016 Feb 01) DOI: 10.3847/0004-637X/817/2/88
arXiv.org > astro-ph > arXiv:1511.06765 > 20 Nov 2015