An overview of the Chandra mission and goals, Chandra's namesake, top 10 facts.
Classroom activities, printable materials, interactive games & more.
Overview of X-ray Astronomy and X-ray sources: black holes to galaxy clusters.
All Chandra images released to the public listed by date & by category
Current Chandra press releases, status reports, interviews & biographies.
A collection of multimedia, illustrations & animations, a glossary, FAQ & more.
A collection of illustrations, animations and video.
Chandra discoveries in an audio/video format.
Return to Main Site

Disclaimer: This material is being kept online for historical purposes. Though accurate at the time of publication, it is no longer being updated. The page may contain broken links or outdated information, and parts may not function in current web browsers. Visit chandra.si.edu for current information.

Chandra Implicates Type 2 Quasars in the X-ray Background Mystery!

Episode 4 of Beyond The Veil:
The Search for Hidden Black Holes, a.k.a. Type 2 Quasars

April 10, 2000 ::

Chandra Image of Deep Field in Canes Venatici Chandra Image of Deep Field in Canes Venatici
During the last few years deep sky surveys with Japan's Advanced Satellite for Cosmology and Astrophysics (ASCA) and the Italian-Dutch BeppoSAX X-ray satellite gave support to the idea that more than Type 1 quasars are needed to produce the X-ray background glow. This research showed that about 30% of the X-ray background could be resolved into distinct sources.

With Chandra's great sensitivity and focusing ability, a team led by Richard Mushotzky of the NASA Goddard Space Flight Center reported that they were able to resolve at least 75 percent of the X-ray background. Another team led by Gordon Garmire of Penn State University has reported similar results.

Missing Ducks 2/3 of the ducks on the cosmic pond were missed by previous surveys.
About a third of the sources detected by Mushotzky's team were Type 1 quasars, that is, they showed no evidence of a dense blanketing cloud of gas and dust. The remaining two-thirds of the sources appear to be veiled giant black holes.

Conclusion: The giant black hole population in the universe is 3 times as great as observations with optical telescopes indicate. It is as if previous bird counts had missed two-thirds of the ducks because they didn't sound like ducks!

ducks Episode 3
April 3, 2000 :: Many astronomers believe it is possible that type 2 quasars exist. Others maintain that they MUST exist in order to explain the mysterious X-ray background radiation. Episode 3


To be continued...

Next Week: Final Episode: Veiled Giant Black Holes and Implications for the universe's Energy Source.


Subscribe to the Chandra Chronicles
Receive updates by email GO
Info & Privacy Policy.
Chronicles Archives
Articles from:
['15 | '14 | '13 | '12 | '11 | '10 | '09 | '08 |
'07 | '06 | '05 | '04 | '03 | '02 | '01 | '00 |
'99]
Recent Articles
Where is Chandra Now? Globe
RSS Feed RSS Feed
Chandra Twitter Updates
    Follow Chandra on Twitter

    Disclaimer: This material is being kept online for historical purposes. Though accurate at the time of publication, it is no longer being updated. The page may contain broken links or outdated information, and parts may not function in current web browsers. Visit chandra.si.edu for current information.

    Return to Main Site

    Help | Site Map | Image Use Polcy | Privacy | Accessibility | Downloads & Plugins | Glossary | Q & A

    Contact us: cxcpub@cfa.harvard.edu
    Harvard-Smithsonian Center for Astrophysics
    60 Garden Street, Cambridge, MA 02138 USA
    Phone: 617.496.7941 Fax: 617.495.7356
    Chandra X-ray Center, Operated for NASA by
    the Smithsonian Astrophysical Observatory
    This site was developed with funding from NASA under contract NAS8-03060.
    NASASmithsonianChandra X-Ray Center
    Subscribe