U.S. researchers published new images of the novel coronavirus that has infected tens of thousands of people in China, Bloomberg reported.

The images were released on Thursday, February 13, by the U.S. National Institute of Allergy and Infectious Diseases. They were made with scanning and transmission electron microscopes. Electron microscopes use a beam of energy to take detailed pictures of objects that can be too small to see with normal microscope.

Images of the virus, known as 2019-nCoV, have been colorized to make them easier to view. Researchers have been growing samples of the virus in labs in order to study it, and to begin testing experimental and existing drugs against the disease. Coronaviruses are named for the crown-like shapes on their surface.

More than 63,000 people in China have been infected by the virus, and more than 1,300 have died. There is no known vaccine or drug that’s been proven effective.