امتیاز موضوع:
  • 24 رأی - میانگین امتیازات: 2.88
  • 1
  • 2
  • 3
  • 4
  • 5
سیاه چاله ای پرجرم در ngc4178
#1
[تصویر:  13511953821.jpg]




One of the lowest mass supermassive black holes ever observed in the
middle of a galaxy has been identified, thanks to NASA's Chandra X-ray
Observatory and several other observatories. The host galaxy is of a
type not expected to harbor supermassive black holes, suggesting that
this black hole, while related to its supermassive cousins, may have a
different origin.




The black hole is located in the middle of the spiral galaxy NGC 4178,
shown in this image from the Sloan Digital Sky Survey. The inset shows
an X-ray source at the position of the black hole, in the center of a
Chandra image. An analysis of the Chandra data, along with infrared data
from NASA's Spitzer Space Telescope and radio data from the NSF's Very
Large Array suggests that the black hole is near the extreme low-mass
end of the supermassive black hole range.




These results were published in the July 1, 2012 issue of The Astrophysical Journal by Nathan Secrest, from George Mason University in Fairfax, Virginia, and collaborators.




The properties of the X-ray source, including its brightness and
spectrum - the amount of X-rays at different wavelengths - and its
brightness at infrared wavelengths, suggest that a black hole in the
center of NGC 4178 is rapidly pulling in material from its surroundings.
The same data also suggest that light generated by this infalling
material is heavily absorbed by gas and dust surrounding the black hole.





A known relationship between the mass of a black hole and the amount of
X-rays and radio waves it generates was used to estimate the mass of the
black hole. This method gives a black hole mass estimate of less than
about 200,000 times that of the sun. This agrees with mass estimates
from several other methods employed by the authors, and is lower than
the typical values for supermassive black holes of millions to billions
of times the mass of the sun.




NGC 4178 is a spiral galaxy located about 55 million light years from
Earth. It does not contain a bright central concentration, or bulge, of
stars in its center. Besides NGC 4178, four other galaxies without
bulges are currently thought to contain supermassive black holes. Of
these four black holes, two have masses that may be close to that of the
black hole in NGC 4178. XMM-Newton observations of an X-ray source
discovered by Chandra in the center of the galaxy NGC 4561 indicate that
the mass of this black hole is greater than 20,000 times the mass of
the sun, but the mass could be substantially higher if the black hole is
pulling in material slowly, causing it to generate less X-ray emission.
A paper describing these results was published in the October 1st, 2012
issue of The Astrophysical Journal by Araya Salvo and collaborators.




The mass of the black hole in the galaxy NGC 4395 is estimated to be
about 360,000 times the mass of the sun, as published by Peterson and
collaborators in the October 20, 2005 issue of the Astrophysical
Journal.




Credits: X-ray: NASA/CXC/George Mason Univ/N.Secrest et al; Optical: SDSS




› Read more/access all images


› Chandra's Flickr photoset




J.D. Harrington, 202-358-0321
Headquarters, Washington
j.d.harrington@nasa.gov

Janet Anderson, 256-544-0034
Marshall Space Flight Center, Huntsville, Ala.
janet.l.anderson@nasa.gov

Peter Edmonds, 617-571-7279
Chandra X-ray Center, Cambridge, Mass.
pedmonds@cfa.harvard.edu
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 Hamid Jafary Pooya


موضوعات مرتبط با این موضوع...
موضوع نویسنده پاسخ بازدید آخرین ارسال
  به دنبال فرمولی برای سیاه چاله ها در NGC 922 amir astronomer 0 215 07-12-2012، 02:52 PM
آخرین ارسال: amir astronomer
  کهکشان یا سیاه چاله؛ کدام یک اول بوجود آمد؟ M@h$A 0 347 11-01-2012، 06:52 PM
آخرین ارسال: M@h$A

پرش به انجمن:


کاربرانِ درحال بازدید از این موضوع: 1 مهمان