In my previous blog post, I introduced the General-relativistic Radiative Transfer Code, which is an important tool for computing the radiative properties from simulated results (see “a bridge between observation and numerical simulation”). Today, I would like to provide some examples of how the image of black hole shadow, photon ring and the spectrum would […]
Exploring the appearance of black hole by Ray-tracing Read More »
On December 25th 2021, while many people were opening their Christmas presents, astronomers around the world were getting excited about another kind of present: the James Webb Space Telescope (JWST). Launched at 13:20 on Christmas day, this new telescope built by ESA, NASA, and the Canadian Space Agency, finally made it to space after years
For over a century, scientists have been detecting elementary particles of extraterrestrial origin, known as cosmic rays. These particles carry energy that sometimes exceeds their rest mass by a million times. The mechanism behind this energization and the environmental properties capable of such a process remains unclear. Among these cosmic rays, the dominant population is
Stellar-mass black holes as particle accelerators Read More »
When you stand on the top of a hill, and shout your name, after a short delay, you will recursively hear your bellow, although your voice is successively fainted. The returned sound is an echo. You might be curious, why cannot we hear an echo in a room? This is because the human ear cannot
Sound Echoes and Echoes in the Universe Read More »
Black holes are highly destructive objects in the universe, e. g., a star can be destroyed if it gets too close to the extreme gravity of a black hole (figure 1). On the other hand, there is nothing we could throw at a black hole that would damage it, not even another black hole would
How to Destroy a Black Hole Read More »
When reading our blog posts, you might find yourself asking what the scale of the black holes, jets, or accretion disks we speak of are. If that is the case, then this post is for you! Given that Halloween just happened, let us choose our base unit as one Jack-o’-lantern pumpkin (JOLP) that is 20
Scales, scales, scales?! (Part I) Read More »
This is the second and final part on the series of blogposts titled “The Science Behind the Solar Eclipse”. In this post, I will build upon the ideas and concepts discussed in Part I of the post to describe how solar eclipses occur. So I strongly recommend reading through it here. Solar eclipses occur because
The Science Behind the Solar Eclipse (Part II) Read More »
It is widely believed that the luminosities of M87 and Sagittarius A*, which are the major targets of the Event Horizon Telescope collaboration, are significantly lower than their Eddington luminosities. It means that the mass accretion rates of these objects are so low that the material accreting onto the central supermassive black hole can be
Electron Microphysics in the global GRMHD simulation Read More »
No, not the West Side Story musical kind… (although they are awesome) The Jets gang from West Side Story. So our research group is called Jetset. We work on trying to figure out the physical processes that launch jets of matter and light from (very close to) black holes. So what are these jets actually?
When you’re a JET… Read More »
Energy source is an eternal topic of human development, as any activity in nature requires a supply of energy. In ancient times, nearly all production work relied on human or animal power, resulting in very low productivity for thousands of years. The Industrial Revolution in the 18th century changed this situation completely, replacing human labour
Black Holes, the most Powerful Engines in Nature Read More »
