David Kirkpatrick

September 2, 2010

Cool space image — galaxy NGC 4666

Filed under: et.al., Science — Tags: , , , , , — David Kirkpatrick @ 1:05 am

Enjoy

This visible light image, made with the Wide Field Imager on the MPG/ESO 2.2-meter telescope at the La Silla Observatory in Chile, shows the galaxy NGC 4666 in the center. It is a starburst galaxy, about 80 million light-years from Earth, in which particularly intense star formation is taking place. The starburst is thought to be caused by gravitational interactions with neighboring galaxies, including NGC 4668, visible to the lower left. A combination of supernova explosions and strong winds from massive stars in the starburst region drives a vast outflow of gas from the galaxy into space — a so-called “superwind”. NGC 4666 had previously been observed in X-rays by the ESA XMM-Newton space telescope, and these visible light observations were made to target background objects detected in the earlier X-ray images. This picture, which covers a field of 16 by 12 arcminutes, is a combination of twelve CCD frames, 67 megapixels each, taken through blue, green and red filters. Credit: ESO/J. Dietrich

Hit the link up there for more about NGC 4666, and a (sorta cheesy) video of its location in space. And for even more info, here’s the release.

October 16, 2008

Black holes are violent

The more we learn about black holes, the more intense they sound. Here’s a report on the turbulent light — visual and X-ray — surrounding these phenomenae.

From the link:

The observations tracked the shimmering of the black holes simultaneously using two different instruments, one on the ground and one in space. The X-ray data were taken using NASA’s Rossi X-ray Timing Explorer satellite. The visible light was collected with the high speed camera ULTRACAM, a visiting instrument at ESO’s Very Large Telescope (VLT), recording up to 20 images a second. ULTRACAM was developed by team members Vik Dhillon and Tom Marsh. “These are among the fastest observations of a black hole ever obtained with a large optical telescope,” says Dhillon.

To their surprise, astronomers discovered that the brightness fluctuations in the visible light were even more rapid than those seen in X-rays. In addition, the visible-light and X-ray variations were found not to be simultaneous, but to follow a repeated and remarkable pattern: just before an X-ray flare the visible light dims, and then surges to a bright flash for a tiny fraction of a second before rapidly decreasing again.