The Astronomical Picture Of the Day for 2012 November 2 [ http://apod.nasa.gov/a
ID: 233796 • Letter: T
Question
The Astronomical Picture Of the Day for 2012 November 2 [ http://apod.nasa.gov/apod/ap121102.html ] shows several X-ray images of an outburst in the center of the Milky Way made with the Nuclear Spectroscopic Telescope Array (NuSTAR). As I understand it, the X-ray flare depicted on the right probably results when a small amount of material falls onto the accretion disk around the supermassive black hole. The scale of the X-ray image spans 100 light years; that's a lot bigger than the size of the supermassive black hole, right? So what other observations allow us to precisely locate the position of the supermassive black hole?
Explanation / Answer
As I understand that your problem is to observe more information to locate the position of the supermassive black hole.1)Observer broad emission lines show gas whizzling around the central black hole.
The most direct way to demonstrate that a supermassive blackhole exists at the centre of a galaxy is to look for its signature from the motions of stars or gases at the galactic nucleus.
2)The laws of gravity can translate the average velocities of stars around the black hole into a mass.
3)Process to find the position of the nucleus through X-rays.
First X-ray emission on galaxy nucleus,high energy interactions between photons and electrons form an X-ray corona above the Accretion disk.
Corona region is very compact that light signals propagate from one side of the corona to the other rapidly,enabling variability on short timescales.X-rays from the accreting blackhole are much more luminous than those from other processes in the galaxy.Accretions radiate most of their energy in ultraviolet.
Observations facts: Supermassive blackholes attracts the surrounding gas,dust allowing them to grow to enomous sizes.Supermassive blackholes may be result thousands of tiny blackholes that merge together.
Large gas clouds are also responsible to form supermassive blackholes and hence can be used to find the positions of blackhole.As we zoom our field of view shrinks to a mere 5 acrseconds (one thousandth of a degree ).At radiowavelength the brightest feature of this region is point lie radiosource called "Sigittarius A star" .This source is compact object equal to 1AU.
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