View Full Version : Discussion: Astronomers Watch a Black Hole ...

2004-Sep-10, 05:06 PM
SUMMARY: Astronomers from the Institute of Astronomy (IoA) in Cambridge, England have watched a bundle of matter at the heart of a galaxy 100 million light-years away as it orbited a supermassive black hole four times on its way to being destroyed. The material was approximately the same distance as our Earth is from the Sun, but instead of taking a year, it only took a quarter of a day, because of the massive gravity of the black hole. By tracking the matter's doomed orbit, astronomers were then able to calculate the mass of the black hole: between 10 and 50 million solar masses.

What do you think about this story? Post your comments below.

2004-Sep-10, 05:23 PM
Thanks, Fraser, for an interesting story.

I looked in vain for the mass of the material falling into the "black hole".

The report states that "the scientists could pin down a mass measurement -- between 10 million and 50 million solar masses" for the black hole.

Anyone know the mass of the material falling onto this massive object?

With kind regards,


2004-Sep-10, 06:00 PM
Originally posted by om@umr.edu@Sep 10 2004, 05:23 PM
Anyone know the mass of the material falling onto this massive object?
I'll keep an eye open for the paper in arXiv. Hopefully it'll be out in the next day or two. I expect that the mass might be inferred from the intensity of the xrays, and some assumptions about what that implies about the material emitting it. The answer will astronomical error bars.

John L
2004-Sep-10, 07:40 PM
Antoniseb, I believe that is what they did. It was the wavelength/energy of the light emitted by the matter that gave them the necessary data to make this determination.

Is a range of 40 million solar masses very accurate, though? 10 - 50 million seems a pretty wide margin of error IMO.

2004-Sep-10, 08:00 PM
Originally posted by John L@Sep 10 2004, 07:40 PM
I believe that is what they did.
Thanks John L, but unless I misread Dr. manuel's query, he was asking about the matter that was emiting xrays as it was "falling in" actually, just orbiting very closely in a slow spiral. The mass of the actual SMBH seems relatively accurately known. The mass of the luminous material was not reported in the for-the-layman news releases.