all Lincoln Greenhill stories

CfA researchers discover black holes aren't so black

50443248 — Fri, 20 Jul 2007 12:47:25 -0400

Common wisdom holds that we can never see a black hole because nothing can escape it - not even light. Fortunately, black holes aren't completely black. As gas is pulled into a black hole by its strong gravitational force, the gas heats up and radiates. That radiation can be used to illuminate the black hole and paint its profile.

New maser measurements trace detail in active galactic core

70652986 — Mon, 26 Mar 2007 06:23:54 -0400

The roiling cores of many active galaxies are difficult to see in detail because of surrounding gas and interstellar dust. Smithsonian astronomers announced Jan. 12, 2006, however, a first-time measurement that may help to better trace the structure of these unusual regions.

Elizabeth M. L. Humphreys and other Harvard-Smithsonian Center for Astrophysics (CfA) research team members presented the first detection at millimeter and submillimeter wavelengths of extragalactic water maser emission in the core of active galaxy NGC 3079 in their paper at the 207th meeting of the American Astronomical Society in Washington, D. C.

A pancake, not a doughnut, shapes distant galactic center

70652986 — Mon, 26 Mar 2007 05:31:13 -0400

Astronomer Lincoln Greenhill (Harvard-Smithsonian Center for Astrophysics) and colleagues have found direct evidence for a "pancake" of gas and dust at the center of Circinus -- a thin, warped disk surrounding the galaxy's central, supermassive black hole. That disk shapes the galaxy's nucleus. It shadows different regions from the "glare" of the black hole, a glare created by the glow of accreting gas. And when some of this material is blown away from the black hole, as by radiation, the disk channels it, leaving shadowed regions in relative peace.