Starting in 2013 February , Swift has been performing short daily monitoring observations of the G2 gas cloud near Sgr A* with the X-Ray Telescope to determine whether the cloud interaction leads to an increase in the flux from the Galactic center .
On 2013 April 24 Swift detected an order of magnitude rise in the X-ray flux from the region near Sgr A* .
Initially thought to be a flare from Sgr A* , detection of a short hard X-ray burst from the same region by the Burst Alert Telescope suggested that the flare was from an unresolved new Soft Gamma Repeater , SGR J1745 - 29 .
Here we present the discovery of SGR J1745 - 29 by Swift , including analysis of data before , during , and after the burst .
We find that the spectrum in the 0.3–10 keV range is well fit by an absorbed blackbody model with kT _ { \mathrm { BB } } \simeq 1 keV and absorption consistent with previously measured values from the quiescent emission from Sgr A* , strongly suggesting that this source is at a similar distance .
Only one SGR burst has been detected so far from the new source , and the persistent light curve shows little evidence of decay in approximately 2 weeks of monitoring after outburst .
We discuss this light curve trend and compare it with those of other well covered SGR outbursts .
We suggest that SGR J1745 - 29 belongs to an emerging subclass of magnetars characterized by low burst rates and prolonged steady X-ray emission 1-2 weeks after outburst onset .