Subscribe to our free daily newsletters
  Space Travel News  




Subscribe to our free daily newsletters



TIME AND SPACE
AAVSO observers contribute to understanding the black hole binary V404 Cygni
by Staff Writers
Boston MA (SPX) Jan 08, 2016


Artist's impression of a black hole binary system. Image courtesy ESA/ATG medialab.

V404 Cygni has been known as a variable star residing in the constellation Cygnus since the 18th century. It was believed to be a nova, a compact binary system containing a white dwarf primary and a sun-like secondary star, that undergoes unpredictable episodes of dramatic brightening - or 'outbursts' - before settling back down to quiescence for decades, until the next outburst.

The last outburst occurred in 1989. At that time, V404 Cyg released enormous amounts of energy in the x-ray, optical and radio wavelengths for several months before quieting back down again.

The 1989 outburst offered the first chance for astronomers of the space age to observe V404 Cyg with satellites and ground based telescopes. From what they learned, V404 Cygni was reclassified as one of a new class of X-ray transient sources called low mass X-ray binaries (LMXBs), x-ray emitting binary systems where one of the components is either a black hole or neutron star.

On June 15th, 2015- after a 26 year wait- V404 Cygni woke up again. The first signs of renewed activity were spotted by the Burst Alert Telescope on NASA's Swift satellite, when it detected a sudden burst of gamma rays. This then triggered observations with its own X-ray telescope. Soon after, MAXI (Monitor of All-sky X-ray Image), part of the Japanese Experiment Module on the International Space Station, observed an X-ray flare from the same patch of the sky.

These observations triggered alerts throughout networks of professional and amateur astronomers around the world, causing hundreds of instruments to point towards the latest outburst. Analysis of this unprecedented amount of data has begun to bear fruit.

One international research team found that observations of black hole binary outbursts in visible light could reveal important phenomena, such as the flickering light emerging from gases surrounding the black hole. The team's results, published in Nature, indicate that optical rays and not just X-rays provide reliable observational data for black hole activity.

"We now know that we can make observations based on optical rays - visible light, in other words - and that black holes can be observed without high-spec X-ray or gamma-ray telescopes," explains lead author Mariko Kimura, a master's student at Kyoto University.

Based on analyses of optical and X-ray data, Kyoto astronomers and their collaborators showed that the light originates from X-rays emerging from the innermost region of the accretion disk around a black hole. These X-rays irradiate and heat the outer region of the disk, making it emit optical rays and thus becoming visible to the human eye.

These important outburst observations were the fruit of international collaboration across countries in different time zones.

"Stars can only be observed after dark, and there are only so many hours each night, but by making observations from different locations around the globe we're able to take more comprehensive data," says co-author Daisaku Nogami. "We're very pleased that our international observation network was able to come together to document this rare event."

The team obtained unprecedented amounts of data from V404 Cygni, detecting repetitive patterns having timescales of several minutes to a few hours. The optical fluctuation patterns were correlated with those of X-rays.

The study also revealed that these repetitive variations occur at mass accretion rates lower than one tenth of that previously thought, indicating that the mass accretion rate isn't the main factor triggering repetitive activity around black holes, but rather the orbital periods.

Four members of the American Association of Variable Star Observers (AAVSO) are listed as co-authors on the paper in recognition of the high quality optical data they supplied to the research team - Lewis M. Cook, William (Bill) Goff, Michael Richmond and William (Bill) Stein.

"It is not a star I normally observe", explained Bill Goff, "but when I saw AAVSO Alert Notice 520 requesting observations I decided to get on it."

Bill continued, "The observations made on this target were immediately exciting. Seeing changes greater than one magnitude in less than an hour, and some high frequency changes occurring in the minutes range, was a wonder to see. I kept imagining how this target must be going through unbelievable eruptive changes."


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
AAVSO
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

Previous Report
TIME AND SPACE
NASA's Chandra Finds Supermassive Black Hole Burping Nearby
Boston MA (SPX) Jan 06, 2016
Evidence for powerful blasts produced by a giant black hole has been discovered using NASA's Chandra X-ray Observatory. This is one of the nearest supermassive black holes to Earth that is currently undergoing such violent outbursts. Astronomers found this outburst in the supermassive black hole centered in the small galaxy NGC 5195. This companion galaxy is merging with a large spiral gal ... read more


TIME AND SPACE
Arianespace starts year with record order backlog

Maintaining Arianespace's launch services leadership in 2016

Russian Space Forces launched 21 spacecraft in 2015

Russian Proton-M Carrier Rocket With Express-AMU1 Satellite Launched

TIME AND SPACE
Rover Rounds Martian Dune to Get to the Other Side

Boulders on a Martian Landslide

NASA suspends March launch of InSight mission to Mars

University researchers test prototype spacesuits at Kennedy

TIME AND SPACE
Chang'e-3 landing site named "Guang Han Gong"

South Korea to launch lunar exploration in 2016, land by 2020

Death rumors of Russian lunar program 'greatly exaggerated' - Deputy PM

Russia Postpones Plans on Extensive Moon Exploration Until 2025

TIME AND SPACE
Looking Back at the 'Year of Pluto'

Pluto through a Stained Glass Window

Postal Service honors NASA's Pluto discoveries

New Horizons team releases detailed slice of Pluto

TIME AND SPACE
Lab discovery gives glimpse of conditions found on other planets

Nearby star hosts closest alien planet in the 'habitable zone'

ALMA reveals planetary construction sites

Monster planet is 'dancing with the stars'

TIME AND SPACE
Falcon 9 Succeeds in Historical First-Stage Landing - But?

Russia concludes upgraded Soyuz-2 flight tests

Russia to Deliver 20 RD-180 Engines to US for Atlas 5 Carrier Rockets

SpaceX landing is a 'feat', but not a game-changer

TIME AND SPACE
Robotic telescope built by China and Thailand put into operation

China's Belt and Road Initiative catches world's imagination: Inmarsat CEO

China launches HD earth observation satellite

Chinese rover analyzes moon rocks: First new 'ground truth' in 40 years

TIME AND SPACE
How to Catch a Glimpse of a New Year's Comet

Asteroid 2003 SD220 Sleighs by Earth on Christmas Eve

Giant comets may threaten Earth: astronomers

Dwarf planet Ceres: water vapor in Occator crater




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






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - 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. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. 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