Subscribe free to our newsletters via your
. Space Travel News .




TIME AND SPACE
A black hole under the gravitational lens
by Staff Writers
Munich, Germany (SPX) Jul 10, 2015


Looking at a distant galaxy: the radio chart (left) shows the image of the blazar PKS 1830-211 distorted by the gravitational lens effect. The detail on the right is a simulation of the micro-gravitational lens effect in the gamma ray region; direct observation of the orange ring - it also represents images of the blazar - is not possible due to its small size. Image courtesy Patnaik et al. 1994, Liege Conference on Gravitational Lenses and the Universe and Vovk. For a larger version of this image please go here.

Turbulent processes take place close to supermassive black holes, which lurk in the centres of nearly all galaxies. They swallow up matter flowing in from the outside while at the same time producing so-called gas jets which shoot out into space in two opposite directions.

Researchers at the Max Planck Institute for Physics in Munich and the University of Geneva have now succeeded in localizing the origin of the high-energy gamma radiation in such a jet: it apparently originates very close to the black hole. This discovery was made possible by a micro-gravitational lens effect that occurs by chance and selectively amplifies the light from different regions close to the black hole like a magnifying glass.

Astronomers are aware of many active galaxies which emanate such jets from their centre. These gas jets can be seen in the radio region, and occasionally in visible light and in the X-ray and gamma radiation regions as well.

There is still a great deal of uncertainty about the mechanism of their formation. What is clear is that hot gas in the form of a disk orbits the central black hole. It is probable that strong magnetic fields, which accelerate the particles at right angles to the disk and into the jets, occur here as well.

This central machinery cannot, however, be observed directly from Earth due to the large distances involved. A stroke of luck helped Ievgen Vovk from the Max Planck Institute of Physics and his colleagues in Geneva here. The researchers looked at an active galaxy known as PKS 1830-211. This is a blazar - a rare case in which one of the two jets happens to be directed towards Earth so that the astronomers look directly into the jet along the longitudinal axis.

It so happens that there is a galaxy roughly half way between Earth and the blazar, which is billions of light years away. Its strong gravitation causes the space around it to curve. The light of the blazar behind it passes through this space well and takes a detour - as if it were passing through a lens. PKS 1830-211 thus appears in the sky as two images; and these images are brighter than the blazar would be without this lens effect.

Astronomers had already recorded intensity flare ups in the radio region which originated from events in the blazar. Since the light propagation paths of the two images are different in length, they do not light up simultaneously after a flare up, but around 26 days apart. Vovk and his colleagues have now scoured the data from the Large Area Telescope on board the Fermi space telescope looking for such flare ups in the gamma ray region.

The resolution of the telescope here is not sufficient to be able to image the two pictures separately, but the astronomers also found flare ups which occurred periodically with an almost constant delay. "The period was approximately as long as that in the radio region, but the amplification factors of the intensity were much larger and more variable," says Ievgen Vovk.

This behaviour and further findings from observations can be best explained with an interesting assumption: Although the brightness variations in the gamma ray region also originate from the flare ups in the blazar, they are amplified to different degrees by the gravitational lens effect of individual stars in the foreground galaxy. This always occurs when a star happens to pass in front of the gamma ray emitting part of the blazar as seen from Earth.

The splitting of the images produced here is so small as to be unobservable. "It would correspond to the size of an ant on the Moon," says Vovk. Astrophysicists call this a micro-gravitational lens effect. However, the intensity amplification of the images by factors of two to seven is much greater than in the radio region. The stars thus briefly highlight the gamma ray region, as it were, as if through a magnifying glass.

All findings can be best explained in the context of the micro-gravitational lens effect with a very compact gamma ray region which extends over several ten billion kilometres. This corresponds roughly to the diameter of our solar system or to that of a black hole with a mass of one billion solar masses.

"According to our findings, the gamma ray region is only slightly larger than the black hole itself," says Andrii Neronov from the University of Geneva. Since the jet originating from the centre widens with increasing distance, the gamma radiation is probably being generated very close to the black hole, i.e. quasi at the foot of the jet.

How this radiation is generated is still not known. According to the most prevalent theory, the black hole and the gas disk are surrounded by a strong magnetic field in which particles such as electrons are accelerated to almost the speed of light. These can collide with light particles (photons), transferring so much energy to the particles in the process that they become gamma or X-ray photons.

Original publication: A. Neronov, I. Vovk, D. Malyshev - Central engine of a gamma-ray blazar resolved through the "magnifying glass" of gravitational microlensing - Nature Physics, online 6 July 2015


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

.


Related Links
Max-Planck-Gesellschaft
Understanding Time and Space






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





TIME AND SPACE
NASA missions monitor a waking black hole
Greenbelt MD (SPX) Jul 01, 2015
NASA's Swift satellite detected a rising tide of high-energy X-rays from the constellation Cygnus on June 15, just before 2:32 p.m. EDT. About 10 minutes later, the Japanese experiment on the International Space Station called the Monitor of All-sky X-ray Image (MAXI) also picked up the flare. The outburst came from V404 Cygni, a binary system located about 8,000 light-years away that cont ... read more


TIME AND SPACE
India to launch its heaviest commercial mission to date

Final payload integration begins for next Ariane 5 launch

Licensed commercial spaceport to be built in Houston, Texas

More Fidelity for SpaceX In-Flight Abort Reduces Risk

TIME AND SPACE
Opportunity Gets Back to Work

NASA wants to send microbes to Mars to prepare for human habitation

Opportunity Rover's 7th Mars Winter to Include New Study Area

Could This Become the First Mars Airplane

TIME AND SPACE
Russia to Land Space Vessel on Moon's Polar Region in 2019

Moon engulfed in permanent, lopsided dust cloud

Crashing comets may explain mysterious lunar swirls

Google Lunar X-Prize meets Yoda

TIME AND SPACE
New Map of Pluto

Neptune's badly behaved magnetic field

Pluto Flyby Begins

In the Right Place at the Right Time for Pluto Observations

TIME AND SPACE
Bricks to build an Earth found in every planetary system

Observing the birth of a planet

Precise ages of largest number of stars hosting planets ever measured

Can Planets Be Rejuvenated Around Dead Stars?

TIME AND SPACE
Engineers help NASA fine-tune new Space Launch System

String of cargo disasters puts pressure on space industry

US Space Command warns on overly fast Russian rocket engine phase out

Longest SLS Engine Test Yet Heats Up Summer Sky

TIME AND SPACE
Chinese earth station is for exclusively scientific and civilian purposes

Cooperation in satellite technology put Belgium, China to forefront

China set to bolster space, polar security

China's super "eye" to speed up space rendezvous

TIME AND SPACE
Rosetta spacecraft sees sinkholes on comet

Million-mile journey to an asteroid begins for ASU-built instrument

NASA Wants to Nuke Asteroids That Threaten to Destroy Earth

Telescopes focus on target of ESA's asteroid mission




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.