Featured Research

from universities, journals, and other organizations

NASA Observatory Confirms Black Hole Limits

Date:
February 26, 2005
Source:
Chandra X-Ray Center
Summary:
The very largest black holes reach a certain point and then grow no more. That's according to the best survey to date of black holes made with NASA's Chandra X-ray Observatory. Scientists also discovered previously hidden black holes well below their weight limit.

The Chandra mosaic of a region of the sky known as the Lockman Hole (named after astronomer Felix Lockman, who discovered that this region of the Galaxy is almost free of absorption by neutral hydrogen gas) shows hundreds of X-ray sources. The high spatial resolution of Chandra allowed for the identification of many supermassive black holes in this image. X-ray: NASA/CXC/U. Wisconsin/A.Barger et al.; Illustrations: NASA/CXC/M.Weiss

The very largest black holes reach a certain point and then grow no more. That's according to the best survey to date of black holes made with NASA's Chandra X-ray Observatory. Scientists also discovered previously hidden black holes well below their weight limit.

These new results corroborate recent theoretical work about how black holes and galaxies grow. The biggest black holes, those with at least 100 million times the mass of the sun, ate voraciously during the early universe. Nearly all of them ran out of "food" billions of years ago and went onto a forced starvation diet.

On the other hand, black holes approximately 10 to 100 million solar masses followed a more controlled eating plan. Because they took smaller portions of their meals of gas and dust, they continue growing.

"Our data show some super massive black holes seem to binge, while others prefer to graze," said Amy Barger of the University of Wisconsin and University of Hawaii. Barger is lead author of the paper describing the results in the latest issue of The Astronomical Journal. "We understand better than ever how super massive black holes grow."

One revelation is there is a strong connection between the growth of black holes and the birth of stars. Previously, astronomers had done careful studies of the birthrate of stars in galaxies but didn't know as much about the black holes at their centers.

"These galaxies lose material into their central black holes at the same time they make their stars," Barger said. "So whatever mechanism governs star formation in galaxies also governs black hole growth."

Astronomers made an accurate census of both the biggest, active black holes in the distance, and the relatively smaller, calmer ones closer to Earth. Now, for the first time, the ones in between have been properly counted.

"We need to have an accurate head count over time of all growing black holes if we ever hope to understand their habits, so to speak," said co-author Richard Mushotzky of NASA's Goddard Space Flight Center, Greenbelt, Md.

This study relied on the deepest X-ray images ever obtained, the Chandra Deep Fields North and South, plus a key wider-area survey of an area called the "Lockman Hole." The distances to the X-ray sources were determined by optical spectroscopic follow-up at the Keck 10-meter telescope on Mauna Kea in Hawaii, and show the black holes range from less than a billion to 12 billion light-years away. X-rays can penetrate the gas and dust that block optical and ultraviolet emissions. The very long-exposure images are crucial to find black holes that otherwise would go unnoticed.

Chandra found many of the black holes smaller than about 100 million suns are buried under large amounts of dust and gas. This prevents detection of the optical light from the heated material near the black hole. The X-rays are more energetic and able to burrow through this dust and gas. However, the largest of the black holes show little sign of being obscured by dust or gas. In a form of weight self-control, powerful winds generated by the black hole's feeding frenzy may have cleared out the remaining dust and gas.

NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the Space Mission Directorate, Washington. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass.


Story Source:

The above story is based on materials provided by Chandra X-Ray Center. Note: Materials may be edited for content and length.


Cite This Page:

Chandra X-Ray Center. "NASA Observatory Confirms Black Hole Limits." ScienceDaily. ScienceDaily, 26 February 2005. <www.sciencedaily.com/releases/2005/02/050222195058.htm>.
Chandra X-Ray Center. (2005, February 26). NASA Observatory Confirms Black Hole Limits. ScienceDaily. Retrieved April 24, 2014 from www.sciencedaily.com/releases/2005/02/050222195058.htm
Chandra X-Ray Center. "NASA Observatory Confirms Black Hole Limits." ScienceDaily. www.sciencedaily.com/releases/2005/02/050222195058.htm (accessed April 24, 2014).

Share This



More Space & Time News

Thursday, April 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Nuclear-Level Asteroids Might Be More Common Than We Realize

Nuclear-Level Asteroids Might Be More Common Than We Realize

Newsy (Apr. 23, 2014) The B612 Foundation says asteroids strike Earth much more often than previously thought, and are hoping to build an early warning system. Video provided by Newsy
Powered by NewsLook.com
NASA Chief Outlines Plan for Human Mission to Mars

NASA Chief Outlines Plan for Human Mission to Mars

AFP (Apr. 22, 2014) NASA administrator Charles Bolden, speaking at the 'Human to Mars Summit' in Washington, says that learning more about the Red Planet can help answer the 'fundamental question' of 'life beyond Earth'. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com
Nasa Gives You An Excuse to Post a Selfie on Earth Day

Nasa Gives You An Excuse to Post a Selfie on Earth Day

TheStreet (Apr. 22, 2014) NASA is inviting all social media users to take a selfie of themselves alongside nature and to post it to Twitter, Facebook, Flickr, Instagram, or Google Plus with the hashtag #globalselfie. NASA's goal is to crowd-source a collection of snapshots of the earth, ground-up, that will be used to create one "unique mosaic of the Blue Marble." This image will be available to all in May. Since this is probably one of the few times posting a selfie to Twitter won't be embarrassing, we suggest you give it a go for a good cause. Video provided by TheStreet
Powered by NewsLook.com
SpaceX's Dragon Spacecraft Captured by International Space Station

SpaceX's Dragon Spacecraft Captured by International Space Station

Reuters - US Online Video (Apr. 20, 2014) SpaceX's unmanned Dragon spacecraft makes a scheduled Easter Sunday rendezvous with the International Space Station. Rough Cut (no reporter narration). Video provided by Reuters
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