Featured Research

from universities, journals, and other organizations

Which Came First: Black Hole Or Galaxy?

Date:
January 14, 2000
Source:
University Of Michigan
Summary:
U-M astronomer says black holes formed early and influenced galactic evolution.

U-M astronomer says black holes formed early and influenced galactic evolution.

Related Articles


ATLANTA --- A team of astronomers conducting a systematic search for supermassive black holes has discovered three more of the mysterious objects lurking in the centers of nearby elliptical galaxies. This brings the total number of supermassive black holes definitively identified so far to 20. The discovery was announced at a news conference held here Jan. 13 during the American Astronomical Society Meeting.

"The formation and evolution of galaxies are intimately connected to the presence of a central massive black hole," said Douglas Richstone, leader of the research team and a University of Michigan professor of astronomy. "Radiation and high-energy particles released by the formation and growth of black holes are the dominant sources of heat and kinetic energy for star-forming gas in protogalaxies."

Richstone says the team's conclusions are inferred from two pieces of evidence. First, all or nearly all galaxies with spheroidal distributions of stars (bulges in spirals) seem to have massive black holes. The mass of these objects seems to correlate with the mass of the central part of the host galaxy. "The ubiquity of this association, as well as the correlation, points to a connection between the massive black hole and the galaxy, and poses a 'chicken and egg' dilemma of which came first," Richstone said.

Second, comparisons of the history of star formation in the universe with the history of quasars, conducted by other scientists, reveal that quasars developed well before most star formation in galaxies. Quasars are extremely powerful bright objects capable of generating the luminosity of one trillion suns within a region the size of Mars' orbit.

"The massive black holes now seen in centers of galaxies are relics of these quasars," Richstone explained. "So these black holes must have been present at the height of the quasar epoch when the universe was about one billion years old."

To detect the existence of new black holes, Richstone and his colleagues use a computer model to detect abrupt changes in star velocity patterns as stars spiral closer to the galactic center. Input for the computer model comes from Hubble Space Telescope observations and ground-based spectroscopic data obtained at MDM Observatory, which is operated by the University of Michigan, Dartmouth College, Columbia University and Ohio State University. The technique was developed by Karl Gebhardt, a former U-M postdoctoral fellow, who is now affiliated with Lick Observatory at the University of California-Santa Cruz.

"Based on the size of the galaxy and the velocity pattern of stars at the core of the galaxy, we not only can detect the signal from a black hole, we also can estimate its mass," Gebhardt said. "Masses of the three new black holes detected with the model range from 50 million to 100 million suns, which continues our previously reported correlation of black hole mass with galaxy mass."

The team's newest black holes were identified in galaxies NGC 4473 and NGC 4697, located in the constellation Virgo, and NGC 821 in Aries. "Stellar orbital distributions in these three galaxies are characteristic of others studied with our model, suggesting a common history among all galaxies," Gebhardt said.

Other astronomers on the black-hole-census research team include Jason Pinkney, a U-M postdoctoral fellow; John Magorrian, Cambridge University; John Kormendy, University of Hawaii; Tod Lauer, Gary Bower and Richard Green, National Optical Astronomy Observatory (NOAO); Alan Dressler and Luis Ho, Carnegie Observatories; Sandra Faber and Alex Filippenko, University of California; Ralf Bender, Ludwig Maximilian University in Munich; and Scott Tremaine, Princeton University.

Research funding was provided by NASA and the Space Telescope Science Institute.


Story Source:

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


Cite This Page:

University Of Michigan. "Which Came First: Black Hole Or Galaxy?." ScienceDaily. ScienceDaily, 14 January 2000. <www.sciencedaily.com/releases/2000/01/000113103114.htm>.
University Of Michigan. (2000, January 14). Which Came First: Black Hole Or Galaxy?. ScienceDaily. Retrieved January 30, 2015 from www.sciencedaily.com/releases/2000/01/000113103114.htm
University Of Michigan. "Which Came First: Black Hole Or Galaxy?." ScienceDaily. www.sciencedaily.com/releases/2000/01/000113103114.htm (accessed January 30, 2015).

Share This


More From ScienceDaily



More Space & Time News

Friday, January 30, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

NASA Holds Memorial to Remember Astronauts

NASA Holds Memorial to Remember Astronauts

AP (Jan. 29, 2015) NASA is remembering 17 astronauts who were killed in the line of duty and dozens more who have died since the agency&apos;s beginning. A remembrance ceremony was held Thursday at NASA&apos;s Marshall Space Flight Center in Alabama. (Jan. 29) Video provided by AP
Powered by NewsLook.com
Asteroid's Moon Spotted During Earth Flyby

Asteroid's Moon Spotted During Earth Flyby

Rumble (Jan. 27, 2015) Scientists working with NASA&apos;s Deep Space Network antenna at Goldstone, California discovered an unexpected moon while observing asteroid 2004 BL86 during its recent flyby past Earth. Credit to &apos;NASA JPL&apos;. Video provided by Rumble
Powered by NewsLook.com
Water Fleas Prepare for Space Voyage

Water Fleas Prepare for Space Voyage

Reuters - Innovations Video Online (Jan. 26, 2015) Scientists are preparing a group of water fleas for a unique voyage into space. The aquatic crustaceans, known as Daphnia, can be used as a miniature model for biomedical research, and their reproductive and swimming behaviour will be tested for signs of stress while on board the International Space Station. Jim Drury went to meet the team. Video provided by Reuters
Powered by NewsLook.com
Mars Rover Opportunity Celebrates 11-Year Anniversary

Mars Rover Opportunity Celebrates 11-Year Anniversary

Rumble (Jan. 26, 2015) Eleven years ago NASA&apos;s Opportunity rover touched down on Mars for what was only supposed to be a 90-day mission. Since then it has traveled 25.9 miles (41.7 kilometers), further than any other off-Earth surface vehicle has ever driven. Credit to &apos;NASA&apos;. Video provided by Rumble
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