Radio astronomy of black hole

In summary, we discussed the feasibility of performing space VLBI at 230 GHz and how to detect radio jets at this frequency. We also looked at the Event Horizon Telescope and its capabilities for mm-VLBI. The carbon monoxide molecule has a strong transition line at 230 GHz, making it easily accessible for observations. We also discussed the potential for millimeter VLBI to detect signatures of hot spot and jet models and strong general relativistic effects. Additionally, we explored how to calculate the gain of a radio antenna at 230 GHz and the difficulties in calculating brightness temperature without knowing the value of blackbody temperature.
  • #1
isha89
5
0
Is it feasible to perform space VLBI at 230 GHz? Also how does one detect the radio jets at 230 GHz?
 
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  • #2
I don't know if it has been done before, but take a look at the event horizon telescope. It is designed to be a mm-VLBI instrument.

Why are you interested in 230 GHz? It happens to be among the strongest transition lines for the carbon monoxide molecule (2nd most abundant molecule after H[itex]_2[/itex]). Either way, 230 Ghz corresponds to a wavelength of 1.3mm, which means it is easily accessible to the CARMA, which is an array of millimeter to centimeter telescopes. It uses up to 23 dishes which can be moved around depending on the observations.

At this frequency, we are stepping out of the radio regime. Black hole jets emit most of the synchrotron radiation at much lower wavelengths. In general, though, we can map out a jet by taking measurements of the intensity of the light at different locations on the sky. One can also take measurements of different frequencies at a point on the sky. Most radio/mm observations do both.
 
  • #3
Well, the resolution of millimeter and submillimeter wavelength VLBI is well matched to the scale of inner disk physics. Base- lines from Hawaii or Western Europe to Chile provide fringe spacings as small as 30 μas (3 RS) at 230 GHz and 20 μas at 345 GHz. Millimeter VLBI thus has the potential to de- tect signatures of hot spot and jet models proposed to explain the rapid variability of Sgr A* as well as strong general relativistic effects, such as the black hole silhouette or shadow. Also the man made noise will also be eliminated if we use a space based technique.

What I'm confused about now is how to calculate the gain of the radio antenna at 230GHz. Because the gain requires the power radiated by the source. I only managed to obtain a value for bolometric luminosity which is 10^36 erg/s. But can this be used to calculate gain?
How do I calculate brightness temperature ?? I do not know the value of blackbody temperature T.
T = Bn(T)c2/2kn2
 

1. What is radio astronomy?

Radio astronomy is a branch of astronomy that uses radio waves to study celestial objects in space. It allows us to observe objects that may not be visible in other wavelengths of light, and provides valuable insights into the structure and behavior of these objects.

2. How do we detect black holes using radio astronomy?

Black holes emit strong radio signals due to the intense gravitational forces at their event horizons. These signals can be detected using radio telescopes, which can pick up the faint radio waves emitted by the matter falling into the black hole.

3. What are some key features of black holes that can be observed through radio astronomy?

Radio astronomy can provide valuable information about the size, mass, and spin of black holes. It can also reveal the surrounding environment, such as the presence of an accretion disk or jets of particles being ejected from the black hole.

4. How does studying black holes through radio astronomy contribute to our understanding of the universe?

By studying black holes through radio astronomy, we can gain insights into the processes that govern the behavior of these massive objects. This, in turn, can help us understand the evolution of galaxies, the formation of structures in the universe, and the fundamental laws of physics.

5. What are some current and future projects in radio astronomy that focus on black holes?

Some current projects include the Event Horizon Telescope, which aims to capture images of the supermassive black hole at the center of our galaxy, and the Square Kilometre Array, a radio telescope under construction that will have the sensitivity to detect black holes in the early universe. Future projects include the Next Generation Very Large Array, which will have even greater capabilities for studying black holes and other astronomical objects through radio waves.

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