Featured Research

from universities, journals, and other organizations

Belching black hole proves a biggie: First known 'middleweight' black hole

Date:
July 9, 2012
Source:
CSIRO Australia
Summary:
Astronomers have found the first known "middleweight" black hole. Before it was found, astronomers had good evidence for only supermassive black holes -- ones a million to a billion times the mass of the Sun -- and "stellar mass" ones, three to thirty times the mass of the Sun.

Galaxy ESO 243-49, about 300 million light-years away, is home to the newly found black hole. An arrow shows the location of the black hole HLX-1 in the galaxy ESO 243-49.
Credit: NASA, ESA and S. Farrell (U. Sydney)

Observations with CSIRO's Australia Telescope Compact Array have confirmed that astronomers have found the first known "middleweight" black hole.

Outbursts of super-hot gas observed with a CSIRO radio telescope have clinched the identity of the first known "middleweight" black hole, Science Express reports.

Called HLX-1 ("hyper-luminous X-ray source 1"), the black hole lies in a galaxy called ESO 243-49, about 300 million light-years away.

Before it was found, astronomers had good evidence for only supermassive black holes -- ones a million to a billion times the mass of the Sun -- and "stellar mass" ones, three to thirty times the mass of the Sun.

"This is the first object that we're really sure is an intermediate-mass black hole," said Dr Sean Farrell, an ARC Postdoctoral Fellow at the University of Sydney and a member of the research team, which included astronomers from France, Australia, the UK and the USA.

Since 2010 the researchers have been studying the black hole with CSIRO's Compact Array radio telescope near Narrabri, NSW.

CSIRO's Dr Ron Ekers, who studies supermassive black holes in the centres of galaxies, said "We don't know for sure how supermassive black holes form, but they might come from medium-size ones merging. So finding evidence of these intermediate-mass black holes is exciting."

HLX-1 was discovered by chance in 2009, because it stood out as a very bright X-ray source.

As gas from a star or gas cloud is being sucked into a black hole, it is heated to extreme temperatures and shines in X-rays.

"A number of other bright X-ray sources have been put forward as possibly being middleweight black holes. But all of those sources could be explained as resulting from lower mass black holes," Dr Farrell said. "Only this one can't. It is ten times brighter than any of those other candidates. We are sure this is an intermediate-mass black hole -- the very first."

Since 2010 the researchers have been studying the black hole with CSIRO's Compact Array radio telescope near Narrabri, NSW.

"From studying other black holes we know that sucking in the gas creates X-rays, but there's then a sort of reflux, with the region around the black hole shooting out jets of high-energy particles that hit gas around the black hole and generate radio waves," said Dr Farrell.

"So what we tend to see is the X-ray emission and then, a day or two or even a few days later, the source flaring up in radio waves."

By looking at the source's X-ray output, the researchers predicted two occasions when it should also be brightening in radio waves -- and they were right both times.

Dr Farrell speculates that a companion star traverses a very eccentric orbit around the black hole. When the companion comes close, the black hole strips gas from its partner, and it is this that gives rise to the X-ray flaring.

The brightness of the X-ray and radio flares have allowed the team to put an upper limit on the mass of the black hole of 90,000 times the mass of the Sun. However, Dr Farrell says that this is a conservative estimate, and for a variety of reasons a lower figure of around 20,000 solar masses is more likely.

Why have we found only this one confirmed intermediate-mass black hole? "There maybe lots of others out there that are not currently feeding, and so are not detectable, or are feeding at a very low rate, so they don't stand out as intermediate-mass black holes," Dr Ekers said.

HLX-1 may have been the central black hole of a low-mass "dwarf" galaxy, Dr Farrell speculates; a dwarf galaxy that was swallowed by the larger galaxy ESO 243-49, just as our own Milky Way Galaxy has swallowed dwarf galaxies. There is evidence of star-formation about HLX-1, which would be consistent with a "plunging dwarf." The research team is now looking for other signs of disturbance around the site of the black hole, such as gas streams, which would also support this idea.


Story Source:

The above story is based on materials provided by CSIRO Australia. Note: Materials may be edited for content and length.


Journal Reference:

  1. N. Webb, D. Cseh, E. Lenc, O. Godet, D. Barret, S. Corbel, S. Farrell, R. Fender, N. Gehrels, I. Heywood. Radio Detections During Two State Transitions of the Intermediate-Mass Black Hole HLX-1. Science, 2012; DOI: 10.1126/science.1222779

Cite This Page:

CSIRO Australia. "Belching black hole proves a biggie: First known 'middleweight' black hole." ScienceDaily. ScienceDaily, 9 July 2012. <www.sciencedaily.com/releases/2012/07/120709102720.htm>.
CSIRO Australia. (2012, July 9). Belching black hole proves a biggie: First known 'middleweight' black hole. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2012/07/120709102720.htm
CSIRO Australia. "Belching black hole proves a biggie: First known 'middleweight' black hole." ScienceDaily. www.sciencedaily.com/releases/2012/07/120709102720.htm (accessed July 31, 2014).

Share This




More Space & Time News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Supply Ship Takes Off for International Space Station

Supply Ship Takes Off for International Space Station

AFP (July 30, 2014) — The European Space Agency's fifth Automated Transfer Vehicle (ATV-5) is takes off to the International Space Station on an Ariane 5 rocket from French Guiana. Duration: 00:34 Video provided by AFP
Powered by NewsLook.com
Raw: Rocket Launches Into Space With Cargo Ship

Raw: Rocket Launches Into Space With Cargo Ship

AP (July 30, 2014) — Arianespace launched a rocket Tuesday from French Guiana carrying a robotic cargo ship to deliver provisions to the International Space Station. (July 30) Video provided by AP
Powered by NewsLook.com
In Virginia, the Rise of a New Space Coast

In Virginia, the Rise of a New Space Coast

AP (July 30, 2014) — Every summer, tourists make the pilgrimage to Chincoteague Island, Va. to see wild ponies cross the Assateague Channel. But, it's the rockets sending to supplies to the International Space Station that are making this a year-round destination. (July 30) Video provided by AP
Powered by NewsLook.com
Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Newsy (July 27, 2014) — The satellite is back under ground control after a tense few days, but with a gecko sex experiment on board, the media just couldn't help themselves. Video provided by Newsy
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:
from the past week

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