Featured Research

from universities, journals, and other organizations

Astrophysicists detect destruction of three stars by supermassive black holes

Date:
August 11, 2014
Source:
Moscow Institute of Physics and Technology
Summary:
Researchers have reported registering three possible occasions of the total destruction of stars by supermassive black holes at the centers of galaxies.

Researchers from MIPT and the Space Research Institute of the Russian Academy of Sciences have reported registering three possible occasions of thetidal destruction of stars by supermassive black holes at the centers of galaxies. Details are given in an article by IldarKhabibullin and Sergei Sazonov, accepted for publication by the Monthly Notices of the Royal Astronomical Society.

The astrophysicists used data obtained by X-ray orbiting observatories ROSAT and XMM-Newton. The former was put into orbit in 1990 and served until 1999, when XMM-Newton took over. The two satellites gathered enough information to detect very rare events, the destruction of stars by supermassive black holes.

A star in a galaxy passes by a black hole closely enough to be destroyed once every 10,000 years. It is possible to detect the death of a star in a fairly distant galaxyas the destruction of a star generates a bright X-ray flare; it is only necessary to distinguish such a flare from other types of X-ray radiation. Because flares occur in a variety of astrophysical processes, the task of finding stars destroyed by black holes is quite complicated.

The researchers developed a number of methods to distinguish the destruction of a star by a black hole from other occurrences. The easiest way to filter out extraneous signals is to eliminate from consideration flares in our galaxy; there is only one supermassive black hole at the center of the Milky Way, so there clearly could not have been stars that have become victims of gravity on the periphery of our galaxy. The researchers also excludedsourcesof radiation that were too large (in angular measurements)and additionally analyzed the range of objects along with the dependence of brightness on time.

Since a supermassive black hole takes just a few years to fully absorb the captured matter of a destroyed star (typically, this makes up about a quarter of its original mass), observations repeateda decade later should detect significant dimming of an X-ray source. The researchers obtained sky surveydata in the 1990s and in the 2000s, so they were able to detect objects whose brightness reduced by at least tenfold.

The data led to the identification of three X-ray sources labeled1RXS J114727.1 + 494302, 1RXS J130547.2 + 641252 and 1RXS J235424.5-102053. [1RXS means that the object was first noticed during the first survey of the sky by the ROSATtelescope, and the two six-digit numbers after the letter J are angular coordinates.]

There is another object that may be a starthat has been rippedapart, but theavailable data does not allow for distinguishing it from the active nucleus of a distant galaxy. New data suggests that the destruction of stars near black holes occur once every30,000 years within the same galaxy, which agrees quite well with estimates derived from observations in the visible and ultraviolet spectral range.

The uncertainty of these estimates is quite significant since they are based on a very small number of occurrences -- the full sample contains no more than two dozen "credible"X-ray sourcesregistered by various methods in different spectral bands. Progress in this area is expected to be made with the launch of the space observatory Spectrum-X-Gamma in 2016, which will be equipped with two X-ray telescopes in the soft X-ray wavelength (the Russian-German unit eROSITA) and in the hard wavelength (Russia's ART-XC). They will be used to carry out eight new legs of X-ray sky surveys within four years. The sensitivity of each shot will be several times greater than that of ROSAT.

Researchers estimate that several hundred such occurrences will be registered annually with the help of Spectrum-X-Gamma. This will not only allow them to more accurately measure the average frequency of such occurrences in the universe, but also to examine in greater detail the interaction of supermassive black holeswith surrounding objects.


Story Source:

The above story is based on materials provided by Moscow Institute of Physics and Technology. Note: Materials may be edited for content and length.


Cite This Page:

Moscow Institute of Physics and Technology. "Astrophysicists detect destruction of three stars by supermassive black holes." ScienceDaily. ScienceDaily, 11 August 2014. <www.sciencedaily.com/releases/2014/08/140811125151.htm>.
Moscow Institute of Physics and Technology. (2014, August 11). Astrophysicists detect destruction of three stars by supermassive black holes. ScienceDaily. Retrieved October 22, 2014 from www.sciencedaily.com/releases/2014/08/140811125151.htm
Moscow Institute of Physics and Technology. "Astrophysicists detect destruction of three stars by supermassive black holes." ScienceDaily. www.sciencedaily.com/releases/2014/08/140811125151.htm (accessed October 22, 2014).

Share This



More Space & Time News

Wednesday, October 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Russian Cosmonauts Kick Off Final Spacewalk of 2014

Russian Cosmonauts Kick Off Final Spacewalk of 2014

Reuters - US Online Video (Oct. 22, 2014) — Russian cosmonauts Maxim Suraev and Alexander Samokutyaev step outside the International Space Station to perform work on the exterior of the station's Russian module. Rough Cut (no reporter narration) Video provided by Reuters
Powered by NewsLook.com
Comet Siding Spring Grazes Mars' Atmosphere

Comet Siding Spring Grazes Mars' Atmosphere

Newsy (Oct. 19, 2014) — A comet from the farthest reaches of the solar system passed extremely close to Mars this weekend, giving astronomers a rare opportunity to study it. Video provided by Newsy
Powered by NewsLook.com
Latin America Launches Communications Satellite

Latin America Launches Communications Satellite

AFP (Oct. 17, 2014) — Argentina launches a home-built satellite, a first for Latin America. It will ride a French-made Ariane 5 rocket into orbit, and will provide cell phone, digital TV, Internet and data services to the lower half of South America. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
This Week @ NASA, October 17, 2014

This Week @ NASA, October 17, 2014

NASA (Oct. 17, 2014) — Power spacewalk, MAVEN’s “First Light”, Hubble finds extremely distant galaxy and more... Video provided by NASA
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins