امتیاز موضوع:
  • 23 رأی - میانگین امتیازات: 2.57
  • 1
  • 2
  • 3
  • 4
  • 5
A Surprisingly Bright Superbubble (لذت ببرید ! )
#1
[تصویر:  13464506661.jpg].




This composite image shows a superbubble in the Large Magellanic Cloud
(LMC), a small satellite galaxy of the Milky Way located about 160,000
light years from Earth. Many new stars, some of them very massive, are
forming in the star cluster NGC 1929, which is embedded in the nebula
N44, so named because it is the 44th nebula in a catalog of such objects
in the Magellanic Clouds. The massive stars produce intense radiation,
expel matter at high speeds, and race through their evolution to explode
as supernovas. The winds and supernova shock waves carve out huge
cavities called superbubbles in the surrounding gas. X-rays from NASA's
Chandra X-ray Observatory (blue) show hot regions created by these winds
and shocks, while infrared data from NASA's Spitzer Space Telescope
(red) outline where the dust and cooler gas are found. The optical light
from the 2.2-m Max-Planck-ESO telescope (yellow) in Chile shows where
ultraviolet radiation from hot, young stars is causing gas in the nebula
to glow.

A long-running problem in high-energy astrophysics
has been that some superbubbles in the LMC, including N44, give off a
lot more X-rays than expected from models of their structure. These
models assume that hot, X-ray emitting gas has been produced by winds
from massive stars and the remains of several supernovas. A Chandra
study published in 2011 showed that there are two extra sources of N44’s
X-ray emission not included in these models: supernova shock waves
striking the walls of the cavities, and hot material evaporating from
the cavity walls. The Chandra observations also show no evidence for an
enhancement of elements heavier than hydrogen and helium in the
cavities, thus ruling out this possibility as a third explanation for
the bright X-ray emission. Only with long observations making full use
of the capabilities of Chandra has it now become possible to distinguish
between different sources of the X-rays produced by superbubbles.

Image credit: X-ray: NASA/CXC/U.Mich./S.Oey, IR: NASA/JPL, Optical: ESO/WFI/2.2-m
در مورد اظهار نظر آقایون در تاپیک دلخوری باید بگم:
آقایون: کم گوی و گزیده گوی چون در// تا ز اندک تو جهان شود پر!!!
هرچند ک کلام گوهر بار از زبان شما جاری نشده، نمیشود و نخواهد شد!!!
پاسخ
 سپاس شده توسط crux
#2
ممنون بابت این مطلبت!
فقط در خصوص تاپیک "دلخوری" میگم که بیایید بند دهان را ببندیم و بال اندیشه را بگشاییم!

یه کمی کاشکی فکر می کردین،
توی این چند قت اخیر،تاپیک های علمی آقا سعید(مدیر عامل راهکار گستر قرن) واقعا بار علمی سایت رو بالا بردن،
مثلا، "دوست داشتی امضای نفر قبلیت مال تو بود" و امثالهم!


مارا به خیر شما امید نیست، شر رو کم می کنیم!





پاسخ
 سپاس شده توسط amir astronomer


موضوعات مرتبط با این موضوع...
موضوع نویسنده پاسخ بازدید آخرین ارسال
  Superbubble DEM L50 amir astronomer 0 198 29-01-2013، 08:46 PM
آخرین ارسال: amir astronomer

پرش به انجمن:


کاربرانِ درحال بازدید از این موضوع: 1 مهمان