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 »
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 »
As introduced in the previous posts, nowadays it is well known that spacetime is not always ‘flat’ but can be distorted by the presence of massive (dense) objects, according to Albert Einstein’s general theory of relativity. The amount of distortion in spacetime depends on the mass of the object and on how compact it is.
A couple of weeks ago, the Event Horizon Telescope (EHT) collaboration has revealed, for the first time, the black hole image of the M87 in polarized light. This is the next big step closer to better understanding how accreting materials evolve and how M87 launches the energetic jets, which extend at least 5000 light-years. Light
Unveiled shape of magnetic field around black hole from polarized light Read More »
Infalling on to the black hole may drive materials crazy. How on earth can they keep their sanity while all bodies undergo extreme gravity? These days, most researchers who are simulating an accreting flow around a black hole choose the condition of the accretion disc between the “SANE” and “MAD”. Now you may think that
To be MAD or not to be MAD Read More »
Making an assumption is inevitable and reasonable in many research projects since it is practically impossible to handle all physics we know in a single study; even if it is feasible, it would rather squander resources, which are given to us. However, it is always required to evaluate carefully whether the assumptions are applicable for
What cooling can do for Sagittarius A* Read More »
In today’s post, I will talk about a subset of compact objects (neutron stars or stellar mass black holes), which run with very high spatial velocity through the interstellar medium. Those runners, in general, imprint characteristic signatures on their way: trails and bubbles. For the case of static objects (i.e., no proper motion), which the
Relativistic jets are ubiquitous and we can observe them in a wide range of scales: from stellar-mass objects (e.g., stellar-mass black holes, neutron stars or pulsars) to massive objects (e.g., active galactic nuclei, radio galaxies). In fact, those jets are key players in shaping our universe into what it is now. For example, jets from
Fate of Jets in X-ray binaries: jet-wind interaction Read More »
In today’s post, I would like to briefly talk about the features shown in the recent black hole image, and the efforts many people have paid for interpreting them. Someone would say that a black hole must be in the form of singularity, which makes it extremely difficult to prove its existence. However, over the
The journey of lights to a black hole Read More »
An international team of the Event Horizon Telescope (EHT) project, including members from API, has announced the first results at the press conference on last Wednesday (Streaming link). The team has revealed the first ever image of the supermassive black at the heart of M87, a galaxy within the Virgo galaxy cluster, 55 million light
Black Holes’ Dining Table: thin or thick Read More »
