NuSTAR discovery of a 3.76-second transient magnetar near Sagittarius A*

Understand

We report the discovery of 3.76-s pulsations from a new burst source near Sgr A* observed by the NuSTAR Observatory.

• The strong signal from SGR J1745-29 presents a complex pulse profile modulated with pulsed fraction 27+/-3 % in the 3-10 keV band.
• Two observations spaced 9 days apart yield a spin-down rate of Pdot = (6.5+/-1.4)x10^{-12}.
• This implies a magnetic field B = 1.6x10^14 G, spin-down power Edot = 5x10^33 erg/s, and characteristic age P/2Pdot = 9x10^3 yr, for the rotating dipole model.