“2019年IOAA理论第3题-银河系与M87中心的超大质量黑洞”的版本间的差异

来自astro-init
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c) What type of technology is needed for the development of such an instrument? Mark the letter  
 
c) What type of technology is needed for the development of such an instrument? Mark the letter  
 
of your answer with × on the answer sheet. (2 p)
 
of your answer with × on the answer sheet. (2 p)
 +
 
(A) Gravitational lensing by dark matter
 
(A) Gravitational lensing by dark matter
 +
 
(B) Interferometry with an array of radio telescopes
 
(B) Interferometry with an array of radio telescopes
 +
 
(C) Photon deceleration in a dense environment
 
(C) Photon deceleration in a dense environment
 +
 
(D) Reducing the effect of incoming wavefront distortions
 
(D) Reducing the effect of incoming wavefront distortions
 +
 
(E) Neutrino focusing with strong electromagnetic fields
 
(E) Neutrino focusing with strong electromagnetic fields
  
 
==中文题目==
 
==中文题目==

2019年9月4日 (三) 22:04的版本

英文题目

3. The supermassive black hole in the centre of Milky Way Galaxy and M87 (10 p)

The first image of a black hole was constructed recently by the international team of the Event Horizon Telescope (EHT). The imaged area surrounds the supermassive black hole in the centre of the galaxy M87. The observations resulting in the final image were carried out at a wavelength 𝜆 = 1.3 mm where the interstellar extinction is not prohibitively large.

a) How large an instrument would be needed to resolve the shadow (in effect the photon capture radius, which is three times the size of event horizon) of a supermassive black hole in the centre of a galaxy? Express the result as a function of the distance 𝑑 and the mass 𝑀 of the black hole. (6 p)

b) Give the size of the instrument in units of Earth radius for i. the supermassive black hole in the centre of M87, (1 p)

$$d_{BH-M87}=5.5*10^7ly$$ , $$M_{BH-M87}=6.5*10^9M_☉$$

ii. and Sgr A*, the supermassive black hole of our own galaxy, Milky Way. (1 p)

$$d_{SgrA^*}=8.5kpc$$ , $$M_{SgrA^*}=3.6*10^6M_☉$$

c) What type of technology is needed for the development of such an instrument? Mark the letter of your answer with × on the answer sheet. (2 p)

(A) Gravitational lensing by dark matter

(B) Interferometry with an array of radio telescopes

(C) Photon deceleration in a dense environment

(D) Reducing the effect of incoming wavefront distortions

(E) Neutrino focusing with strong electromagnetic fields

中文题目