The black hole shadow is the optical silhouette of the black hole seen by the observer on Earth when there is a distant bright source behind it. Observing the black hole shadow is an important method to directly detect the black hole.

In a recent study published in the Journal of Cosmology and Astroparticle Physics , a research group led by Dr. HOU Xian from the High-Energy Astrophysics Research Group at Yunnan Observatories of Chinese Academy of Sciences, for the first time, obtained the shadow of the black hole Sgr A* at the center of the Milky Way in dark matter halos.

Dark matter constitutes around 27% of the components of the Universe, and high-energy astronomical observations have shown that its strongest source is believed to be the center of the Milky Way.

The shadow of the black hole Sgr A* in the framework of the current two popular dark matter models (cold dark matter model and scalar field dark matter model) was analyzed in this study.

Scientists found that dark matter halo has little effect on the black hole shadow, and the angular resolution required to detect the influence of the dark matter halo on the black hole shadow exceeds the level that the current "Event Horizon Telescope" can achieve.

Also, they found that the angular resolution required by these two dark matter halos differs by two orders of magnitude.

This study indicated that observing the shadow of Sgr A* may serve as a tool of distinguishing the two kinds of dark matter models from each other, and shed light on the nature of Sgr A* and dark matter.

In the future, to observe the effect of dark matter halos on the black hole shadow of Sgr A*, astronomical instruments with higher angular resolution would be necessary.

Contact:

HOU Xian，XU Zhaoyi

High-Energy Astrophysics Research Group, YNAO

Email: xhou@ynao.ac.cn，zyxu88@ynao.ac.cn