zxcgzxcg

dfghcfxgh

xchch

Using a new technique, two NASA scientists have identified the lightest known black hole. With a mass only about 3.8 times greater than our Sun and a diameter of only 15 miles, the black hole lies very close to the minimum size predicted for black holes that originate from dying stars.
The tiny black hole resides in a Milky Way Galaxy binary system known as XTE J1650-500, named for its sky coordinates in the southern constellation Ara.

* NASA’s Rossi X-ray Timing Explorer (RXTE) satellite discovered the system in 2001*.

*Astronomers realized soon after J1650’s discovery that it harbors a normal star and a relatively lightweight black hole.* *But the black hole’s mass had never been measured to high precision. *

The method used by scientists has been described in several papers in the Astrophysical Journal.
* It uses a relationship between black holes and the inner part of their surrounding disks, where gas spirals inward before making the fatal plunge.*
When the feeding frenzy reaches a moderate rate, hot gas piles up near the black hole and radiates a torrent of X-rays.
The X-ray intensity varies in a pattern that repeats itself over a nearly regular interval. *This signal is called a quasi-periodic oscillation, or QPO.*

Astronomers have long suspected that a QPO’s frequency depends on the black hole’s mass.
In 1998, they realized that the congestion zone lies close in for small black holes, so the QPO clock ticks quickly.
*As black holes increase in mass, the congestion zone is pushed farther out, so the QPO clock ticks slower and slower.*

* To measure the black hole masses, astronomers use archival data from RXTE,* which has made exquisitely precise measurements of QPO frequencies in at least 15 black holes.
----------------------------------

Juodu skyliu parametrai yra randami naudojant didelius optinius teleskopus, orbitini NASA Rentgeno spinduliu palydova RXTE ir matuojant is taikinio primamamu rentgeno spinduliu intensyvumo kvazi periodini generacija

The Rossi X-ray Timing Explorer (RXTE) is a satellite that observes the time structure of astronomical x-ray sources.

The RXTE has three instruments :
-the Proportional Counter Array,
-the High-Energy X-ray Timing Experiment(HEXTE),
-and one instrument called the All Sky Monitor.

The RXTE observes x-rays from black holes, neutron stars, X-ray pulsars and x-ray bursts.

RXTE was launched from Cape Canaveral on 30 December 1995 on a Delta rocket, has an International Designator of 1995-074A and a mass of 3200 kg.

Observations from the Rossi X-ray Timing Explorer have been used as evidence for the existence of the frame-dragging effect predicted by the theory of general relativity.

RXTE results have, as of late 2007, been used in more than 1400 scientific papers.

In January 2006 it was announced that Rossi had been used to locate a candidate intermediate-mass black hole named M82 X-1.[1].

In February 2006 data from RXTE was used to prove that the diffuse background x-ray glow in our galaxy comes from innumerable, previously undetected white dwarfs and from other stars' coronae. [1]

In April 2008 RXTE data was used to infer the size of the smallest known black hole.[2]

Gal kas paaiškins, kokiu būdu nustatomas tos skylės dydis ? Ir per tokius atstumus ?