SGR J1745−2900, or PSR J1745−2900, is the first-discovered magnetar orbiting the

black hole A black hole is a region of spacetime where gravitation, gravity is so strong that nothing, including light or other Electromagnetic radiation, electromagnetic waves, has enough energy to escape it. The theory of general relativity predicts t ...

Sagittarius A*, in the center of the Milky Way. The magnetar was discovered in 2013 using the

Effelsberg 100-m Radio Telescope The Effelsberg 100-m Radio Telescope is a radio telescope in the Ahr Hills (part of the Eifel) in Bad Münstereifel, Germany. For 29 years the Effelsberg Radio Telescope was the largest fully steerable radio telescope on Earth, surpassing the Lo ...

, the Nancay Decimetric Radio Telescope, and the Jodrell Bank Lovell Telescope. The magnetar has a period of 3.76 s and a magnetic flux density of ~ 10¹⁰ T (10¹⁴ G). The magnetar is 0.33 ly from the central black hole. The object offers an unparalleled tool for probing the ionized

interstellar medium In astronomy, the interstellar medium is the matter and radiation that exist in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, as well as dust and cosmic rays. It fills interstella ...

(ISM) toward the Galactic Center (GC), and a possible way to test quantum gravity effects.

References

Soft gamma repeaters Sagittarius (constellation) ? Magnetars {{var-star-stub