NGC 1132X射线图
来源:http://www.nasa.gov/multimedia/imagegallery/iotd.html
Mysterious Galaxy
This image of the elliptical galaxy NGC 1132 and its surrounding region combines data from NASA's Chandra X-ray Observatory and the Hubble Space Telescope. The blue/purple in the image is the x-ray glow from hot, diffuse gas detected by Chandra. Hubble's data reveal a giant foreground elliptical galaxy, plus numerous dwarf galaxies in its neighborhood, and many much more distant galaxies in the background.
Astronomers have dubbed NGC 1132 a "fossil group" because it contains an enormous amount of dark matter, comparable to the dark matter found in an entire group of galaxies. Also, the large amount of hot gas detected by Chandra is usually found for groups of galaxies, rather than a single galaxy.
The origin of such fossil-group systems remains a puzzle. They may be the end products of the complete merging of groups of galaxies. Or, they may be very rare objects that formed in a region or period of time where the growth of moderate-sized galaxies was somehow suppressed, and only one large galaxy formed.
Elliptical galaxies are smooth and featureless. Containing hundreds of millions to trillions of stars, they range from nearly spherical to very elongated shapes. Their overall yellowish color comes from the aging stars. Because elliptical galaxies do not contain much cool gas, they can no longer make large numbers of new stars.
Image Credit: Optical: NASA/ESA/STScI/M. West X-ray: NASA/CXC/Penn State/G. Garmire
每日一天文图(台湾成大镜像)http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod/apod.html
椭圆星系NGC 1132
影像版权: NASA, ESA, M. West (ESO, Chile), and CXC / Penn. State / G. Garmire, et al.
说明: NGC 1132是一个平滑的星系，但它是如何形成的？ NGC 1132是一个椭圆星系，因此少有尘埃和气体，最近也很少有新恒星形成。虽然有许多椭圆星系是存在于星系团之中，但位于波江座的NGC 1132似乎是一个巨大的孤立星系。为了研究这个拥有数百万兆颗恒星的星系的过去，天文学家们利用可见光波段的哈伯太空望远镜以及X光波段的钱卓拉太空望远镜对NGC 1132进行观测。在这张合成的假色影像中，可见光是以白色表示，而X光则是以蓝色表示，而它所代表的意义便是异常高温的气体。 X光波段也能描绘出暗物质的位置。有一个假设认为NGC 1132是由一个小星系群进行一系列星系融合之后的产物。 NGC 1132的距离大约是三亿光年远，因此我们现在看到的光是在恐龙时代之前就发出来的。在更遥远的地方，可以看到许多迷人的背景星系。
[ 本帖最后由 寻找拉玛 于 2008-2-13 14:18 编辑 ] |
|
![210359main_ngc1132[1]_full.jpg](http://image.imufu.cn/forum/month_0802/20080207_92c8c3c76e9d7f414da5BiN80cBzxfz0.jpg "210359main_ngc1132[1]_full.jpg")
置顶卡
变色卡
千斤顶
显身卡
